Edgar Filing: MICROMET, INC.

Unassociated Document

Filed pursuant to Rule 424(b)(5)

Registration Statement No. 333-160130 and No. 333-160888

PROSPECTUS SUPPLEMENT

(To Prospectus dated July 2, 2009)

14,000,000 Shares

MICROMET, INC.

Common Stock

$5.00 per share

·	Micromet, Inc. is offering 14,000,000 shares of common stock.	·	Trading symbol: Nasdaq Global Market − MITI

·	The last reported sale price of our common stock on July 29, 2009 was $5.59 per share.

This investment involves risks. See “Risk Factors” beginning on page S-4.



	Per Share		Total
Public offering price	$	5.000	$	70,000,000
Underwriting discount	$	0.325	$	4,550,000
Proceeds, before expenses, to Micromet, Inc	$	4.675	$	65,450,000

The underwriters have a 30-day option to purchase up to 2,100,000 additional shares of common stock to cover over-allotments, if any. If the underwriters exercise this option in full, the total underwriting discount will be $5,232,500, and our total proceeds, before expenses, will be $75,267,500.

The underwriters expect to deliver the shares against payment on or about August 4, 2009.

Neither the Securities and Exchange Commission nor any state securities commission has approved of anyone’s investment in these securities or determined if this prospectus supplement and the accompanying prospectus are truthful or complete. Any representation to the contrary is a criminal offense.

Piper Jaffray

RBC Capital Markets

	Merriman Curhan Ford

The date of this prospectus supplement is July 30, 2009.

TABLE OF CONTENTS

	Page
Prospectus Supplement
Prospectus Supplement Summary	S-1
Risk Factors	S-4
Special Note Regarding Forward-Looking Statements	S-21
Use of Proceeds	S-22
Dilution	S-23
Underwriting	S-24
Legal Matters	S-26
Experts	S-26
Where You Can Find More Information	S-26
Important Information Incorporated by Reference	S-26

Prospectus
About this Prospectus	i
Summary	1
Risk Factors	5
Special Note Regarding Forward-Looking Statements	5
Financial Ratios	6
Use of Proceeds	6
Description of Capital Stock	6
Description of Debt Securities	12
Description of Warrants	19
Description of Units	21
Legal Ownership of Securities	22
Plan of Distribution	26
Legal Matters	27
Experts	27
Where You Can Find More Information	27
Incorporation by Reference	28
Disclosure of Commission Position on Indemnification for Securities Act Liability	29

We provide information to you about this offering of shares of our common stock in two separate documents that are bound together: (1) this prospectus supplement, which describes the specific details regarding this offering; and (2) the accompanying prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this “prospectus,” we are referring to both documents combined. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should rely on this prospectus supplement.

You should rely only on information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We have not, and the underwriters have not, authorized anyone to provide you with information that is different. We are offering to sell and seeking offers to buy shares of our common stock only in jurisdictions where offers and sales are permitted. The information contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein are accurate only as of their respective dates, regardless of the time of delivery of this prospectus supplement or of any sale of our common stock.

Unless otherwise stated in this prospectus supplement, we have assumed throughout this prospectus supplement that the over-allotment option granted to the underwriters will not be exercised.

In connection with this offering, we registered an additional $500,000 of securities pursuant to Rule 462(b) of the Securities Act on a registration statement on Form S-3.

PROSPECTUS SUPPLEMENT SUMMARY

The items in the following summary are described in more detail later in this prospectus supplement, in the accompanying prospectus and in the documents incorporated by reference herein and therein. This summary provides an overview of selected information and does not contain all the information you should consider before investing in our common stock. Therefore, you should read the more detailed information set out in this prospectus supplement, accompanying prospectus and the other information incorporated by reference herein and therein carefully.

Our Business

We are a biopharmaceutical company developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases. Our product development pipeline includes novel antibodies generated with our proprietary BiTE® antibody platform, as well as conventional monoclonal antibodies. BiTE antibodies represent a new class of antibodies that activate the T cells of a patient’s immune system to eliminate cancer cells. T cells are considered the most powerful “killer cells” of the human immune system. Five of our antibodies are currently in clinical trials, while the remainder of our product pipeline is in preclinical development. Our BiTE antibody blinatumomab, also known as MT103, is being evaluated in a phase 2 clinical trial for the treatment of patients with acute lymphoblastic leukemia, or ALL, and in a phase 1 clinical trial for the treatment of patients with non-Hodgkin’s lymphoma, or NHL. A second BiTE antibody, MT110, is being tested in a phase 1 clinical trial for the treatment of patients with solid tumors. MT110 binds to the epithelial cell adhesion molecule, or EpCAM, which is overexpressed in many solid tumors. Our human monoclonal antibody adecatumumab, also known as MT201, also binds to EpCAM and is being developed under a collaboration with Merck Serono. The current clinical development of this antibody includes a phase 2 clinical trial in colorectal carcinoma patients after complete resection of liver metastases, and a phase 1b clinical trial evaluating adecatumumab in combination with docetaxel for the treatment of patients with metastatic breast cancer. Our monoclonal antibody MT293, also known as TRC093, is licensed to TRACON Pharmaceuticals, Inc. and is being developed in a phase 1 clinical trial for the treatment of patients with cancer. MT203, a human antibody neutralizing the activity of granulocyte/macrophage colony stimulating factor, or GM-CSF, which has potential applications in the treatment of various inflammatory and autoimmune diseases, such as rheumatoid arthritis, psoriasis, or multiple sclerosis, is under development in a phase 1 clinical trial being conducted by our collaboration partner Nycomed. Our licensee Morphotek, a wholly-owned subsidiary of Eisai, is also expected to commence a phase 1 clinical trial in 2009 to evaluate our glycolipid-binding human antibody MT228 for the treatment of melanoma.

Our preclinical product pipeline includes several novel BiTE antibodies generated with our proprietary BiTE antibody platform technology. A BiTE antibody targeting carcinoembryonic antigen, or CEA, for the treatment of solid tumors is being developed in collaboration with MedImmune LLC, a wholly owned subsidiary of AstraZeneca plc. In addition, we have entered into an option, collaboration and license agreement with Bayer Schering Pharma AG under which Bayer Schering Pharma was granted an exclusive option until January 2010 to license a specified BiTE antibody against an undisclosed solid tumor target. Other BiTE antibodies targeting melanoma chondroitin sulfate proteoglycan, or MCSP, as well as the antigens CD33, HER2, EGFR and other targets are in various stages of preclinical development.

To date, we have incurred significant research and development expenses and have not achieved any revenues from sales of our product candidates. Each of our programs will require a number of years and significant costs to advance through development. Typically, it takes many years from the initial identification of a lead compound to the completion of preclinical and clinical trials, before applying for marketing approval from the United States Food and Drug Administration, or FDA, or European Medicines Agency, or EMEA, or equivalent regulatory agencies in other countries and regions. The risk that a program has to be terminated, in part or in full, for safety reasons or lack of adequate efficacy is very high. In particular, we cannot predict which, if any, product candidates can be successfully developed and for which marketing approval may be obtained, or the time and cost to complete development.

As we obtain results from preclinical studies or clinical trials, we may elect to discontinue the development of one or more product candidates for safety, efficacy or commercial reasons. We may also elect to discontinue or delay development of one or more product candidates in order to focus our resources on more promising product candidates. Our business strategy includes entering into collaborative agreements with third parties for the development and commercialization of our product candidates. Depending on the structure of such collaborative agreements, a third party may be granted control over the clinical trial process for one of our product candidates. In such a situation, the third party, rather than us, may in fact control development and commercialization decisions for the respective product candidate. Consistent with our business model, we may enter into additional collaboration agreements in the future. We cannot predict the terms of such agreements or their potential impact on our capital requirements. Our inability to complete our research and development projects in a timely manner, or our failure to enter into new collaborative agreements, when appropriate, could significantly increase our capital requirements and affect our liquidity.

S-1

Since our inception, we have financed our operations through private placements of preferred stock, government grants for research, research-contribution revenues from our collaborations with pharmaceutical companies, debt financing, licensing revenues and milestone achievements and, more recently, private placements of common stock and associated warrants. We intend to continue to seek funding through public or private financings in the future. If we are successful in raising additional funds through the issuance of equity securities, stockholders may experience substantial dilution, or the equity securities may have rights, preferences or privileges senior to existing stockholders. If we are successful in raising additional funds through debt financings, these financings may involve significant cash payment obligations and covenants that restrict our ability to operate our business. There can be no assurance that we will be successful in raising additional capital on acceptable terms, or at all.

Unless the context indicates otherwise, as used in this prospectus supplement, the terms “Micromet,” “the Company,” “we,” “us” and “our” refer to Micromet, Inc., a Delaware corporation, and its subsidiaries on a consolidated basis. We use Micromet®, BiTE®, and the Micromet logo as trademarks in the United States and other countries. All other trademarks or trade names referred to in this prospectus supplement and the accompanying prospectus are the property of their respective owners.

Description of Capital Stock

As of the date of this prospectus supplement, our certificate of incorporation authorizes us to issue 150,000,000 shares of common stock, par value $0.00004 per share, and 10,000,000 shares of preferred stock, par value $0.00004 per share. As of June 30, 2009, 52,578,875 shares of common stock were outstanding and no shares of preferred stock were outstanding. Our board of directors has designated 75,000 of the 10,000,000 authorized shares of preferred stock as Series A Junior Participating Preferred Stock.

Certain Balance Sheet Data

Our cash, cash equivalents and short-term investments available for sale was approximately $49.2 million as of June 30, 2009.

Corporate Information

We were incorporated in Delaware in 1998 under the name CancerVax Corporation. In May 2006, we changed our corporate name to Micromet, Inc. Our principal executive offices are located at 6707 Democracy Blvd., Suite 505, Bethesda, Maryland 20817, and our main telephone number is (240) 752-1420. Our website is located on the world wide web at http://www.micromet-inc.com. We do not incorporate by reference into this prospectus supplement or the accompanying prospectus the information on, or accessible through, our website, and you should not consider it as part of this prospectus supplement or the accompanying prospectus.

S-2

THE OFFERING

Common stock offered		14,000,000 shares

Common stock to be outstanding after this offering		66,578,875 shares

Use of proceeds		We intend to use the net proceeds from this offering for preclinical and clinical development of our drug candidates, for discovery research for new drug candidates and for general corporate purposes, including working capital. In addition, we may use a portion of the proceeds to acquire drugs or drug candidates, technologies, businesses or other assets.

Risk factors		You should read the “Risk Factors” section of this prospectus supplement and in the documents incorporated by reference in this prospectus supplement for a discussion of factors to consider before deciding to purchase shares of our common stock.

Nasdaq Global Market symbol		MITI

The number of shares of common stock to be outstanding after this offering as reflected in the table above is based on the actual number of shares outstanding as of June 30, 2009, which was 52,578,875, and does not include, as of that date:

9,295,559 shares of common stock issuable upon the exercise of outstanding options, with a weighted average exercise price of $3.60 per share;

8,222,416 shares of common stock issuable upon the exercise of outstanding warrants, with a weighted average exercise price of $3.92 per share; and

1,465,035 shares of common stock reserved for future issuance under our stock-based compensation plans, consisting of 1,016,602 shares of common stock reserved for issuance under our 2003 Amended and Restated Equity Incentive Plan, 243,614 shares of common stock reserved for issuance under our 2006 Equity Incentive Award Plan and 204,819 shares of common stock reserved for issuance under our Employee Stock Purchase Plan.

S-3

RISK FACTORS

Before you make a decision to invest in our common stock, you should consider carefully the risks described below, together with other information in this prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein. If any of the following events actually occur, our business, operating results, prospects or financial condition could be materially and adversely affected. This could cause the trading price of our common stock to decline and you may lose all or part of your investment. The risks described below are not the only ones that we face. Additional risks not presently known to us or that we currently deem immaterial may also significantly impair our business operations and could result in a complete loss of your investment.

Risks Relating to Our Financial Results, Financial Reporting and Need for Financing

We have a history of losses, we expect to incur substantial losses and negative operating cash flows for the foreseeable future and we may never achieve or maintain profitability.

We have incurred losses from our inception through June 30, 2009, and we expect to incur substantial losses for the foreseeable future. We have no current sources of material ongoing revenue, other than the reimbursement of development expenses and potential future milestone payments from our current collaborators or licensees, including Merck Serono, MedImmune, Nycomed and TRACON. We have not commercialized any products to date, either alone or with a third party collaborator. If we are not able to commercialize any products, whether alone or with a collaborator, we may not achieve profitability. Even if our collaboration agreements provide funding for a portion of our research and development expenses for some of our programs, we expect to spend significant capital to fund our internal research and development programs for the foreseeable future. As a result, we will need to generate significant revenues in order to achieve profitability. We cannot be certain whether or when this will occur because of the significant uncertainties that affect our business. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable may depress the market value of our common stock and could impair our ability to raise capital, expand our business, diversify our product offerings or continue our operations and, as a result, you could lose part or all of your investment.

We will require additional financing, which may be difficult to obtain and may dilute your ownership interest in us. If we fail to obtain the capital necessary to fund our operations, we will be unable to develop or commercialize our product candidates and our ability to operate as a going concern may be adversely affected.

We will require substantial funds to continue our research and development programs and our future capital requirements may vary from what we expect. There are factors, many of which are outside our control, that may affect our future capital requirements and accelerate our need for additional financing. Among the factors that may affect our future capital requirements and accelerate our need for additional financing are:

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continued progress in our research and development programs, as well as the scope of these programs;

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our ability to establish and maintain collaborative arrangements for the discovery, research or development of our product candidates;

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the timing, receipt and amount of research funding and milestone, license, royalty and other payments, if any, from collaborators;

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the timing, receipt and amount of sales revenues and associated royalties to us, if any, from our product candidates in the market;

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our ability to sell shares of our common stock under our December 2008 committed equity financing facility, or CEFF, with Kingsbridge Capital Limited, or Kingsbridge;

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the costs of preparing, filing, prosecuting, maintaining, defending and enforcing patent claims and other patent-related costs, including litigation costs and technology license fees;

S-4

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costs associated with litigation; and

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competing technological and market developments.

We expect to seek funding through public or private financings or from existing or new collaborators with whom we enter into research or development collaborations with respect to programs that are not currently licensed. However, the market for stock of companies in the biotechnology sector in general, and the market for our common stock in particular, is highly volatile. Due to market conditions and the status of our product development pipeline, additional funding may not be available to us on acceptable terms, or at all. Having insufficient funds may require us to delay, scale back or eliminate some or all of our research or development programs or to relinquish greater or all rights to product candidates at an earlier stage of development or on less favorable terms than we would otherwise choose. Failure to obtain adequate financing also may adversely affect our ability to operate as a going concern.

If we raise additional funds through the issuance of equity securities, our stockholders may experience substantial dilution, including as a result of the issuance of warrants in connection with the financing, or the equity securities may have rights, preferences or privileges senior to those of existing stockholders. If we raise additional funds through debt financings, these financings may involve significant cash payment obligations and covenants that restrict our ability to operate our business and make distributions to our stockholders. We also could elect to seek funds through arrangements with collaborators or others that may require us to relinquish rights to certain technologies, product candidates or products.

Our committed equity financing facility with Kingsbridge may not be available to us if we elect to make a draw down, may require us to make additional “blackout” or other payments to Kingsbridge and may result in dilution to our stockholders.

In December 2008, we entered into a CEFF with Kingsbridge, which entitles us to sell and obligates Kingsbridge to purchase, from time to time over a period of three years, up to 10,104,919 shares of our common stock for cash consideration of up to $75.0 million, subject to certain conditions and restrictions. To date, we have sold 1,420,568 shares of common stock for gross proceeds of $5.3 million under this agreement. Kingsbridge will not be obligated to purchase additional shares under the CEFF unless certain conditions are met, which include:

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a minimum price for our common stock that is not less than 85% of the closing price of the day immediately preceding the applicable eight-day pricing period, but in no event less than $2.00 per share;

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the accuracy of representations and warranties made to Kingsbridge;

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our compliance with all applicable laws which, if we failed to so comply, would have a Material Adverse Effect (as that term is defined in the purchase agreement with Kingsbridge); and

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the effectiveness of a registration statement registering for resale the shares of common stock to be issued in connection with the CEFF.

Kingsbridge is permitted to terminate the CEFF by providing written notice to us upon the occurrence of certain events. For example, we are only eligible to draw down funds under the CEFF at such times as our stock price is above $2.00 per share. Kingsbridge is also able to terminate the CEFF at any time that we have not drawn down at least $1.25 million in funds over a consecutive 12-month period. If we are unable to access funds through the CEFF, or if Kingsbridge terminates the CEFF or it otherwise expires, we may be unable to access capital from other sources on favorable terms, or at all.

We are entitled, in certain circumstances, to deliver a blackout notice to Kingsbridge to suspend the use of the resale registration statement and prohibit Kingsbridge from selling shares under the resale registration statement for a certain period of time. If we deliver a blackout notice during the fifteen trading days following our delivery of shares to Kingsbridge in connection with any draw down, then we may be required to make a payment to Kingsbridge, or issue to Kingsbridge additional shares in lieu of this payment, calculated on the basis of the number of shares purchased by Kingsbridge in the most recent draw down and held by Kingsbridge immediately prior to the blackout period and the decline in the market price, if any, of our common stock during the blackout period. If the trading price of our common stock declines during a blackout period, this blackout payment could be significant.

S-5

In addition, if we fail to maintain the effectiveness of the resale registration statement or related prospectus in circumstances not permitted by our agreement with Kingsbridge, we may be required to make a payment to Kingsbridge, calculated on the basis of the number of shares held by Kingsbridge during the period that the registration statement or prospectus is not effective, multiplied by the decline in market price, if any, of our common stock during the ineffective period. If the trading price of our common stock declines during a period in which the resale registration statement or related prospectus is not effective, this payment could be significant.

Should we sell shares to Kingsbridge under the CEFF or issue shares in lieu of a blackout payment, it will have a dilutive effect on the holdings of our current stockholders and may result in downward pressure on the price of our common stock. If we draw down under the CEFF, we will issue shares to Kingsbridge at a discount of 6% to 14% from the volume weighted average price of our common stock. If we draw down amounts under the CEFF when our share price is decreasing, we will need to issue more shares to raise the same amount than if our stock price was higher. Issuances in the face of a declining share price will have an even greater dilutive effect than if our share price were stable or increasing and may further decrease our share price. Moreover, the number of shares that we will be able to issue to Kingsbridge in a particular draw down may be materially reduced if our stock price declines significantly during the applicable eight-day pricing period.

Our quarterly operating results and stock price may fluctuate significantly.

We expect our results of operations to be subject to quarterly fluctuations. The level of our revenues, if any, and results of operations for any given period, will be based primarily on the following factors:

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the status of development of our product candidates;

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the time at which we enter into research and license agreements with strategic collaborators that provide for payments to us, the timing and accounting treatment of payments to us, if any, under those agreements, and the progress made by our strategic collaborators in moving forward the development of our product candidates;

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whether or not we achieve specified research, development or commercialization milestones under any agreement that we enter into with strategic collaborators and the timely payment by these collaborators of any amounts payable to us;

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the addition or termination of research programs or funding support under collaboration agreements;

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the timing of milestone payments under license agreements, repayments of outstanding amounts under loan agreements, and other payments that we may be required to make to others;

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variations in the level of research and development expenses related to our clinical or preclinical product candidates during any given period;

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the change in fair value of the common stock warrants issued to investors in connection with our 2007 private placement financing, remeasured at each balance sheet date using a Black-Scholes option-pricing model, with the change in value recorded as other income or expense; and

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general market conditions affecting companies with our risk profile and market capitalization.

These factors may cause the price of our stock to fluctuate substantially. We believe that quarterly comparisons of our financial results are not necessarily meaningful and should not be relied upon as an indication of our future performance.

S-6

If the estimates we make and the assumptions on which we rely in preparing our financial statements prove inaccurate, our actual results may vary significantly.

Our financial statements have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of our assets, liabilities, revenues and expenses, the amounts of charges taken by us and related disclosure. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. We cannot assure you that our estimates, or the assumptions underlying them, will be correct. Accordingly, our actual financial results may vary significantly from the estimates contained in our financial statements.

Changes in, or interpretations of, accounting rules and regulations could result in unfavorable accounting charges or require us to change our compensation policies.

Accounting methods and policies for biopharmaceutical companies, including policies governing revenue recognition, research and development and related expenses, accounting for stock options and in-process research and development costs are subject periodically to further review, interpretation and guidance from relevant accounting authorities, including the SEC. Changes to, or interpretations of, accounting methods or policies in the future may require us to reclassify, restate or otherwise change or revise our financial statements, including those contained in this filing.

Risks Relating to Our Common Stock

Substantial sales of shares may adversely impact the market price of our common stock and our ability to issue and sell shares in the future.

Substantially all of the outstanding shares of our common stock are eligible for resale in the public market. A significant portion of these shares is held by a small number of stockholders. We have also registered shares of our common stock that we may issue under our equity incentive compensation plans and our employee stock purchase plan. In addition, any shares issued under our CEFF with Kingsbridge will be eligible for resale in the public market. These shares generally can be freely sold in the public market upon issuance. If our stockholders sell substantial amounts of our common stock, the market price of our common stock may decline, which might make it more difficult for us to sell equity or equity-related securities in the future at a time and price that we deem appropriate. We are unable to predict the effect that sales of our common stock may have on the prevailing market price of our common stock.

Our stock price may be volatile, and you may lose all or a substantial part of your investment.

The market price for our common stock is volatile and may fluctuate significantly in response to a number of factors, many of which we cannot control. Among the factors that could cause material fluctuations in the market price for our common stock are:

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our ability to successfully raise capital to fund our continued operations;

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our ability to successfully develop our product candidates within acceptable timeframes;

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changes in the regulatory status of our product candidates;

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changes in significant contracts, strategic collaborations, new technologies, acquisitions, commercial relationships, joint ventures or capital commitments;

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the execution of new collaboration agreements or termination of existing collaborations related to our clinical or preclinical product candidates or our BiTE antibody technology platform;

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announcements of the invalidity of, or litigation relating to, our key intellectual property;

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announcements of the achievement of milestones in our agreements with collaborators or the receipt of payments under those agreements;

S-7

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announcements of the results of clinical trials by us or by companies with commercial products or product candidates in the same therapeutic category as our product candidates;

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events affecting our collaborators;

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fluctuations in stock market prices and trading volumes of similar companies;

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announcements of new products or technologies, clinical trial results, commercial relationships or other events by us, our collaborators or our competitors;

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our ability to successfully complete strategic collaboration arrangements with respect to our product candidates, BiTE antibodies or our BiTE antibody platform;

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variations in our quarterly operating results;

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changes in securities analysts’ estimates of our financial performance or product development timelines;

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changes in accounting principles;

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sales of large blocks of our common stock, including sales by our executive officers, directors and significant stockholders;

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additions or departures of key personnel; and

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discussions of Micromet or our stock price by the financial and scientific press and online investor communities such as chat rooms.

If our officers and directors choose to act together, they can significantly influence our management and operations in a manner that may be in their best interests and not in the best interests of other stockholders.

Our officers and directors, together with their affiliates, collectively own an aggregate of approximately 24% of our outstanding common stock. As a result, if they act together, they may significantly influence all matters requiring approval by our stockholders, including the election of directors and the approval of mergers or other business combination transactions. The interests of this group of stockholders may not always coincide with our interests or the interests of other stockholders, and this group may act in a manner that advances their best interests and not necessarily those of other stockholders.

Our stockholder rights plan, anti-takeover provisions in our organizational documents and Delaware law may discourage or prevent a change in control, even if an acquisition would be beneficial to our stockholders, which could affect our stock price adversely and prevent attempts by our stockholders to replace or remove our current management.

Our stockholder rights plan and provisions contained in our amended and restated certificate of incorporation and amended and restated bylaws may delay or prevent a change in control, discourage bids at a premium over the market price of our common stock and adversely affect the market price of our common stock and the voting and other rights of the holders of our common stock. The provisions in our amended and restated certificate of incorporation and amended and restated bylaws include:

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dividing our board of directors into three classes serving staggered three-year terms;

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prohibiting our stockholders from calling a special meeting of stockholders;

S-8

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permitting the issuance of additional shares of our common stock or preferred stock without stockholder approval;

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prohibiting our stockholders from making certain changes to our amended and restated certificate of incorporation or amended and restated bylaws except with 66 2/3% stockholder approval; and

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requiring advance notice for raising matters of business or making nominations at stockholders’ meetings.

We are also subject to provisions of the Delaware corporation law that, in general, prohibit any business combination with a beneficial owner of 15% or more of our common stock for five years unless the holder’s acquisition of our stock was approved in advance by our board of directors.

We may become involved in securities class action litigation that could divert management’s attention and harm our business and our insurance coverage may not be sufficient to cover all costs and damages.

The stock market has from time to time experienced significant price and volume fluctuations that have affected the market prices for the common stock of pharmaceutical and biotechnology companies. These broad market fluctuations may cause the market price of our common stock to decline. In the past, following periods of volatility in the market price of a particular company’s securities, securities class action litigation has often been brought against that company. We may become involved in this type of litigation in the future. Litigation often is expensive and diverts management’s attention and resources, which could adversely affect our business.

Risks Relating to Our Collaborations and Clinical Programs

We are dependent on collaborators for the development and commercialization of many of our product candidates. If we lose any of these collaborators, or if they fail or incur delays in the development or commercialization of our current and future product candidates, our operating results would suffer.

The success of our strategy for development and commercialization of our product candidates depends upon our ability to form and maintain productive strategic collaborations and license arrangements. We currently have strategic collaborations or license arrangements with Merck Serono, MedImmune, Nycomed and TRACON. In addition, we have an option, collaboration and license agreement with Bayer Schering Pharma, under which Bayer Schering may elect to commence a development collaboration for a BiTE antibody targeting a solid tumor until January 2010. We expect to enter into additional collaborations and license arrangements in the future. Our existing and any future collaborations and licensed programs may not be scientifically or commercially successful. The risks that we face in connection with these collaborations and licensed programs include the following:

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Each of our collaborators has significant discretion in determining the efforts and resources that it will apply to the collaboration. The timing and amount of any future royalty and milestone revenue that we may receive under collaborative and licensing arrangements will depend on, among other things, each collaborator’s efforts and allocation of resources.

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All of our strategic collaboration and license agreements are for fixed terms and are subject to termination under various circumstances, including, in some cases, on short notice without cause. If any of our collaborative partners were to terminate its agreement with us, we may attempt to identify and enter into an agreement with a new collaborator with respect to the product candidate covered by the terminated agreement. If we are not able to do so, we may not have the funds or capability to undertake the development, manufacturing and commercialization of that product candidate, which could result in a discontinuation or delay of the development of that product candidate.

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Our collaborators may develop and commercialize, either alone or with others, products and services that are similar to or competitive with the product candidates and services that are the subject of their collaborations with us or programs licensed from us.

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Our collaborators may discontinue the development of our product candidates in specific indications, for example as a result of their assessment of the results obtained in clinical trials, or fail to initiate the development in indications that have a significant commercial potential.

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Pharmaceutical and biotechnology companies from time to time re-evaluate their research and development priorities, including in connection with mergers and consolidations, which have been common in recent years. The ability of our product candidates involved in strategic collaborations to reach their potential could be limited if, as a result of changes in priorities, our collaborators decrease or fail to increase spending related to our product candidates, or decide to discontinue the development of our product candidates and terminate their collaboration or license agreement with us. In the event of such a termination, we may not be able to identify and enter into a collaboration agreement for our product candidates with another pharmaceutical or biotechnology company on terms favorable to us or at all, and we may not have sufficient financial resources to continue the development program for these product candidates on our own. As a result, we may incur delays in the development for these product candidates following any termination of the collaboration agreement, or we may need to reallocate financial resources that could cause delays in other development programs for our other product candidates.

As noted in our Annual Report on Form 10-K for the year ended December 31, 2008 and our Form 10-Q for the quarter ended March 31, 2009, which are incorporated herein by reference, pursuant to the terms of our collaboration and license agreement with MedImmune, MedImmune has notified us of its election to develop a new BiTE antibody and to discontinue the development of blinatumomab in North America. There can be no assurances that we will be able to successfully develop blinatumomab in North America, that such development will not be delayed as a result of contractual or financial constraints, that MedImmune will comply with its continuing obligations to develop the commercial scale manufacturing process for blinatumomab and to supply us with blinatumomab for clinical trials, on a timeline or in a manner that is consistent with our development plans for blinatumobab that we would be successful in enforcing MedImmune’s continuing obligations under the collaboration and license agreement, or that we will be able to enter into a new collaboration agreement with respect to blinatumomab with another industry partner if we desire to do so.

We may not be successful in establishing additional strategic collaborations, which could adversely affect our ability to develop and commercialize product candidates.

As an integral part of our ongoing research and development efforts, we periodically review opportunities to establish new collaborations for development and commercialization of new BiTE antibodies or existing product candidates in our development pipeline. We face significant competition in seeking appropriate collaborators and the negotiation process is time-consuming and complex. We may not be successful in our efforts to establish additional collaborations or other alternative arrangements. Even if we are successful in our efforts to establish a collaboration, the terms of the agreement may not be favorable to us. Finally, such collaborations or other arrangements may not result in successful products and associated revenue from milestone payments, royalties or profit share payments.

Our clinical stage product candidates adecatumumab, blinatumomab and MT110 have not yet been proven to be safe or to be effective at the currently tested dose levels. If we discontinue the development of any of our clinical stage product candidates due to adverse events or lack of efficacy, our business could suffer and the value of our company may be adversely affected.

We previously have reported that two phase 2 clinical trials of adecatumumab did not reach their respective primary endpoint in patients with metastatic breast cancer (clinical benefit rate at week 24) and in patients with prostate cancer (mean change in prostate specific antigen, compared to placebo control). We have also reported that the treatment with blinatumomab was discontinued permanently in some patients due to adverse events that included infections, central nervous system events, and liver enzyme increases. MT110 is in a phase 1 dose-escalation clinical trial, and we may reach the maximum tolerated dose without reaching a dose level at which MT110 shows a clinically meaningful anti-tumor effect. We are continuing the development of these product candidates in phase 1 and/or phase 2 clinical trials, but there can be no assurance that we will not encounter unacceptable adverse events or that any preliminary suggestion of anti-tumor activity of these product candidates will be confirmed during the ongoing or any future clinical trials.

Risks Relating to Our Operations, Business Strategy, and the Life Sciences Industry

We face substantial competition, which may result in our competitors discovering, developing or commercializing products before or more successfully than we do.

Our product candidates face competition with existing and new products being developed by biotechnology and pharmaceutical companies, as well as universities and other research institutions. For example, research in the fields of antibody-based therapeutics for the treatment of cancer, and autoimmune and inflammatory diseases, is highly competitive. A number of entities are seeking to identify and patent antibodies, potentially active proteins and other potentially active compounds without specific knowledge of their therapeutic functions. Our competitors may discover, characterize and develop important inducing molecules or genes in advance of us.

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Many of our competitors have substantially greater capital resources, research and development staffs and facilities than we have. Efforts by other biotechnology and pharmaceutical companies could render our programs or product candidates uneconomical or result in therapies that are superior to those that we are developing alone or with a collaborator. We and our collaborators face competition from companies that may be more experienced in product development and commercialization, obtaining regulatory approvals and product manufacturing. As a result, they may develop competing products more rapidly that are safer, more effective, or have fewer side effects, or are less expensive, or they may discover, develop and commercialize products, which render our product candidates non-competitive or obsolete. We expect competition to intensify in antibody research as technical advances in the field are made and become more widely known.

We may not be successful in our efforts to expand our portfolio of product candidates.

A key element of our strategy is to discover, develop and commercialize a portfolio of new antibody therapeutics. We are seeking to do so through our internal research programs and in-licensing activities, which could place a strain on our human and capital resources. A significant portion of the research that we are conducting involves new and unproven technologies. Research programs to identify new disease targets and product candidates require substantial technical, financial and human resources regardless of whether or not any suitable candidates are ultimately identified. Our research programs may initially show promise in identifying potential product candidates, yet fail to yield product candidates suitable for clinical development. If we are unable to discover suitable potential product candidates, develop additional delivery technologies through internal research programs or in-license suitable product candidates or delivery technologies on acceptable business terms, our business prospects will suffer.

The product candidates in our pipeline are in early stages of development and our efforts to develop and commercialize these product candidates are subject to a high risk of delay and failure. If we fail to successfully develop our product candidates, our ability to generate revenues will be substantially impaired.

All of our product candidates are in early stages of clinical and preclinical development, so we will require substantial additional financial resources, as well as research, product development and clinical development capabilities, to pursue the development of these product candidates, and we may never develop an approvable or commercially viable product. The process of successfully developing product candidates for the treatment of human diseases is very time-consuming, expensive and unpredictable and there is a high rate of failure for product candidates in preclinical development and in clinical trials. The preclinical studies and clinical trials may produce negative, inconsistent or inconclusive results, and the results from early clinical trials may not be statistically significant or predictive of results that will be obtained from expanded, advanced clinical trials. Further, we or our collaborators may decide, or the FDA, EMEA or other regulatory authorities may require us, to conduct preclinical studies or clinical trials or other development activities in addition to those performed or planned by us or our collaborators, which may be expensive or could delay the time to market for our product candidates. In addition, we do not know whether the clinical trials will result in marketable products.

We do not know whether our planned preclinical development or clinical trials for our product candidates will begin on time or be completed on schedule, if at all. The timing and completion of clinical trials of our product candidates depend on, among other factors, the number of patients that will be required to enroll in the clinical trials, the inclusion and exclusion criteria used for selecting patients for a particular clinical trial, and the rate at which those patients are enrolled. Any increase in the required number of patients, tightening of selection criteria, or decrease in recruitment rates or difficulties retaining study participants may result in increased costs, delays in the development of the product candidate, or both.

Our product candidates may not be effective in treating any of our targeted diseases or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may prevent or limit their commercial use. Institutional review boards or regulators, including the FDA and EMEA, may hold, suspend or terminate our clinical research or the clinical trials of our product candidates for various reasons, including non-compliance with regulatory requirements or if, in their opinion, the participating subjects are being exposed to unacceptable health risks, or if additional information may be required for the regulatory authority to assess the proposed development activities. Further, regulators may not approve study protocols at all or in a timeframe anticipated by us if they believe that the study design or the mechanism of action of our product candidates poses an unacceptable health risk to study participants.

We have limited financial and managerial resources. These limitations require us to focus on a select group of product candidates in specific therapeutic areas and to forego the exploration of other product opportunities. While our technologies may permit us to work in multiple areas, resource commitments may require trade-offs resulting in delays in the development of certain programs or research areas, which may place us at a competitive disadvantage. Our decisions as to resource allocation may not lead to the development of viable commercial products and may divert resources away from other market opportunities, which would otherwise have ultimately proved to be more profitable.

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In addition, our product candidates may have different efficacy profiles in certain clinical indications, sub-indications or patient profiles, and an election by us or our collaborators to focus on a particular indication, sub-indication or patient profile may result in a failure to capitalize on other potentially profitable applications of our product candidates.

We rely heavily on third parties for the conduct of preclinical studies and clinical trials of our product candidates, and we may not be able to control the proper performance of the studies or trials.

In order to obtain regulatory approval for the commercial sale of our product candidates, we and our collaborators are required to complete extensive preclinical studies as well as clinical trials in humans to demonstrate to the FDA, EMEA and other regulatory authorities that our product candidates are safe and effective. We have limited experience and internal resources for conducting certain preclinical studies and clinical trials and rely primarily on collaborators and contract research organizations for the performance and management of preclinical studies and clinical trials of our product candidates.

We are responsible for confirming that our preclinical studies are conducted in accordance with applicable regulations and that each of our clinical trials is conducted in accordance with its general investigational plan and protocol. Our reliance on third parties does not relieve us of responsibility for ensuring compliance with appropriate regulations and standards for conducting, monitoring, recording and reporting of preclinical and clinical trials. If our collaborators or contractors fail to properly perform their contractual or regulatory obligations with respect to conducting or overseeing the performance of our preclinical studies or clinical trials, do not meet expected deadlines, fail to comply with the good laboratory practice guidelines or good clinical practice regulations, do not adhere to our preclinical and clinical trial protocols, suffer an unforeseen business interruption unrelated to our agreement with them that delays the clinical trial, or otherwise fail to generate reliable clinical data, then the completion of these studies or trials may be delayed, the results may not be useable and the studies or trials may have to be repeated, and we may need to enter into new arrangements with alternative third parties. Any of these events could cause our clinical trials to be extended, delayed, or terminated or create the need for them to be repeated, or otherwise create additional costs in the development of our product candidates and could adversely affect our and our collaborators’ ability to market a product after marketing approvals have been obtained.

Even if we complete the lengthy, complex and expensive development process, there is no assurance that we or our collaborators will obtain the regulatory approvals necessary for the launch and commercialization of our product candidates.

To the extent that we or our collaborators are able to successfully complete the clinical development of a product candidate, we or our collaborators will be required to obtain approval by the FDA, EMEA or other regulatory authorities prior to marketing and selling such product candidate in the United States, the European Union or other countries. The process of preparing and filing applications for regulatory approvals with the FDA, EMEA and other regulatory authorities, and of obtaining the required regulatory approvals from these regulatory authorities, is lengthy and expensive, and may require two years or more. This process is further complicated because some of our product candidates use non-traditional or novel materials in non-traditional or novel ways, and the regulatory officials have little precedent to follow.

Any marketing approval by the FDA, EMEA or other regulatory authorities may be subject to limitations on the indicated uses for which we or our collaborators may market the product candidate. These limitations could restrict the size of the market for the product and affect reimbursement levels by third-party payers.

As a result of these factors, we or our collaborators may not successfully begin or complete clinical trials and launch and commercialize any product candidates in the time periods estimated, if at all. Moreover, if we or our collaborators incur costs and delays in development programs or fail to successfully develop and commercialize products based upon our technologies, we may not become profitable and our stock price could decline.

We and our collaborators are subject to governmental regulations in addition to those imposed by the FDA and EMEA, and we or our collaborators may not be able to comply with these regulations. Any non-compliance could subject us or our collaborators to penalties and otherwise result in the limitation of our operations.

In addition to regulations imposed by the FDA, EMEA and other health regulatory authorities, we and our collaborators are subject to regulation under the Occupational Safety and Health Act, the Environmental Protection Act, the Toxic Substances Control Act, the Research Conservation and Recovery Act, as well as regulations administered by the Nuclear Regulatory Commission, national restrictions on technology transfer, import, export and customs regulations and certain other local, state or federal regulations, or their counterparts in Europe and other countries. From time to time, other governmental agencies and legislative or international governmental bodies have indicated an interest in implementing further regulation of biotechnology applications. We are not able to predict whether any such regulations will be adopted or whether, if adopted, such regulations will apply to our or our collaborators’ business, or whether we or our collaborators would be able to comply, without incurring unreasonable expense, or at all, with any applicable regulations.

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Our growth could be limited if we are unable to attract and retain key personnel and consultants.

We have limited experience in filing and prosecuting regulatory applications to obtain marketing approval from the FDA, EMEA or other regulatory authorities. Our success depends on the ability to attract, train and retain qualified scientific and technical personnel, including consultants, to further our research and development efforts. The loss of services of one or more of our key employees or consultants could have a negative impact on our business and operating results. Competition for skilled personnel is intense and the turnover rate can be high. Competition for experienced management and clinical, scientific and engineering personnel from numerous companies and academic and other research institutions may limit our ability to attract and retain qualified personnel on acceptable terms. As a result, locating candidates with the appropriate qualifications can be difficult, and we may not be able to attract and retain sufficient numbers of highly skilled employees.

Any growth and expansion into areas and activities that may require additional personnel or expertise, such as in regulatory affairs, quality assurance, and control and compliance, would require us to either hire new key personnel or obtain such services from a third party. The pool of personnel with the skills that we require is limited, and we may not be able to hire or contract such additional personnel. Failure to attract and retain personnel would prevent us from developing and commercializing our product candidates.

If our third-party manufacturers do not follow current good manufacturing practices or do not maintain their facilities in accordance with these practices, our product development and commercialization efforts may be harmed.

We have no manufacturing experience or manufacturing capabilities for the production of our product candidates for clinical trials or commercial sale. Product candidates used in clinical trials or sold after marketing approval has been obtained must be manufactured in accordance with current good manufacturing practices regulations. There are a limited number of manufacturers that operate under these regulations, including the FDA’s and EMEA’s good manufacturing practices regulations, and that are capable of manufacturing our product candidates. Third-party manufacturers may encounter difficulties in achieving quality control and quality assurance and may experience shortages of qualified personnel. Also, manufacturing facilities are subject to ongoing periodic, unannounced inspection by the FDA, the EMEA, and other regulatory agencies or authorities, to ensure strict compliance with current good manufacturing practices and other governmental regulations and standards. A failure of third-party manufacturers to follow current good manufacturing practices or other regulatory requirements or to document their adherence to such practices may lead to significant delays in the availability of product candidates for use in a clinical trial or for commercial sale, the termination of, or hold on a clinical trial, or may delay or prevent filing or approval of marketing applications for our product candidates. In addition, as a result of such a failure, we could be subject to sanctions, including fines, injunctions and civil penalties, refusal or delays by regulatory authorities to grant marketing approval of our product candidates, suspension or withdrawal of marketing approvals, seizures or recalls of product candidates, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect our business. If we were required to change manufacturers, it may require additional clinical trials and the revalidation of the manufacturing process and procedures in accordance with applicable current good manufacturing practices and may require FDA or EMEA approval. This revalidation may be costly and time-consuming. If we are unable to arrange for third-party manufacturing of our product candidates, or to do so on commercially reasonable terms, we may not be able to complete development or marketing of our product candidates.

Even if regulatory authorities approve our product candidates, we may fail to comply with ongoing regulatory requirements or experience unanticipated problems with our product candidates, and these product candidates could be subject to restrictions or withdrawal from the market following approval.

Any product candidates for which we obtain marketing approval, along with the manufacturing processes, post-approval clinical trials and promotional activities for such product candidates, will be subject to continual review and periodic inspections by the FDA, EMEA and other regulatory authorities. Even if regulatory approval of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the product may be marketed or contain requirements for costly post-marketing testing and surveillance to monitor the safety or efficacy of the product. Post-approval discovery of previously unknown problems with any approved products, including unanticipated adverse events or adverse events of unanticipated severity or frequency, difficulties with a manufacturer or manufacturing processes, or failure to comply with regulatory requirements, may result in restrictions on such approved products or manufacturing processes, limitations in the scope of our approved labeling, withdrawal of the approved products from the market, voluntary or mandatory recall and associated publicity requirements, fines, suspension or withdrawal of regulatory approvals, product seizures, injunctions or the imposition of civil or criminal penalties.

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The procedures and requirements for granting marketing approvals vary among countries, which may cause us to incur additional costs or delays or may prevent us from obtaining marketing approvals in different countries and regulatory jurisdictions.

We intend to market our product candidates in many countries and regulatory jurisdictions. In order to market our product candidates in the United States, the European Union and many other jurisdictions, we must obtain separate regulatory approvals in each of these countries and territories. The procedures and requirements for obtaining marketing approval vary among countries and regulatory jurisdictions, and can involve additional clinical trials or other tests. Also, the time required to obtain approval may differ from that required to obtain FDA and EMEA approval. The various regulatory approval processes may include all of the risks associated with obtaining FDA and EMEA approval. We may not obtain all of the desirable or necessary regulatory approvals on a timely basis, if at all. Approval by a regulatory authority in a particular country or regulatory jurisdiction, such as the FDA in the United States and the EMEA in the European Union, generally does not ensure approval by a regulatory authority in another country. We may not be able to file for regulatory approvals and may not receive necessary approvals to commercialize our product candidates in any or all of the countries or regulatory jurisdictions in which we desire to market our product candidates.

If we fail to obtain an adequate level of reimbursement for any approved products by third-party payers, there may be no commercially viable markets for these products or the markets may be much smaller than expected. The continuing efforts of the government, insurance companies, managed care organizations and other payers of health care costs to contain or reduce costs of healthcare may adversely affect our ability to generate revenues and achieve profitability, the future revenues and profitability of our potential customers, suppliers and collaborators, and the availability of capital.

Our ability to commercialize our product candidates successfully will depend in part on the extent to which governmental authorities, private health insurers and other organizations establish appropriate reimbursement levels for the price charged for our product candidates and related treatments. The efficacy, safety and cost-effectiveness of our product candidates as well as the efficacy, safety and cost-effectiveness of any competing products will determine in part the availability and level of reimbursement. These third-party payers continually attempt to contain or reduce the costs of healthcare by challenging the prices charged for healthcare products and services. Given recent federal and state government initiatives directed at lowering the total cost of healthcare in the United States, the U.S. Congress and state legislatures will likely continue to focus on healthcare reform, the cost of prescription pharmaceuticals and on the reform of the Medicare and Medicaid systems. In certain countries, particularly the countries of the European Union, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take six to twelve months or longer after the receipt of regulatory marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct clinical trials that compare the cost-effectiveness of our product candidates to other available therapies. If reimbursement for our product candidates were unavailable or limited in scope or amount or if reimbursement levels or prices are set at unsatisfactory levels, our projected and actual revenues and our prospects for profitability would be negatively affected.

Another development that may affect the pricing of drugs in the United States is regulatory action regarding drug reimportation into the United States. The Medicare Prescription Drug, Improvement and Modernization Act requires the Secretary of the U.S. Department of Health and Human Services to promulgate regulations allowing drug reimportation from Canada into the United States under certain circumstances. These provisions will become effective only if the Secretary certifies that such imports will pose no additional risk to the public’s health and safety and result in significant cost savings to consumers. Proponents of drug reimportation may also attempt to pass legislation that would remove the requirement for the Secretary’s certification or allow reimportation under circumstances beyond those anticipated under current law. If legislation is enacted, or regulations issued, allowing the reimportation of drugs, it could decrease the reimbursement we would receive for any product candidates that we may commercialize, or require us to lower the price of our product candidates then on the market that face competition from lower-priced supplies of that product from other countries. These factors would negatively affect our projected and actual revenues and our prospects for profitability.

We are unable to predict what additional legislation or regulation, if any, relating to the healthcare industry or third-party coverage and reimbursement may be enacted in the future or what effect such legislation or regulation would have on our business. Any cost containment measures or other healthcare system reforms that are adopted could have a material adverse effect on our ability to commercialize successfully any future products or could limit or eliminate our spending on development projects and affect our ultimate profitability.

If physicians and patients do not accept the product candidates that we may develop, our ability to generate product revenue in the future will be adversely affected.

Our product candidates, if successfully developed and approved by the regulatory authorities, may not gain market acceptance among physicians, healthcare payers, patients and the medical community. Market acceptance of and demand for any product candidate that we may develop will depend on many factors, including:

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our ability to provide acceptable evidence of safety and efficacy;

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convenience and ease of administration;

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prevalence and severity of adverse side effects;

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the timing of market entry relative to competitive treatments;

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cost effectiveness;

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effectiveness of our marketing and pricing strategy for any product candidates that we may develop;

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publicity concerning our product candidates or competitive products;

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the strength of marketing and sales support; and

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our ability to obtain third-party coverage or reimbursement.

If any product candidates for which we may receive marketing approval fail to gain market acceptance, our ability to generate product revenue in the future will be adversely affected.

We face the risk of product liability claims and may not be able to obtain insurance.

Our business exposes us to the risk of product liability claims that is inherent in the testing, manufacturing, and marketing of drugs and related devices. Although we have product liability and clinical trial liability insurance that we believe is appropriate, this insurance is subject to deductibles and coverage limitations. We may not be able to obtain or maintain adequate protection against potential liabilities. If any of our product candidates is approved for marketing, we may seek additional insurance coverage. If we are unable to obtain insurance at acceptable cost or on acceptable terms with adequate coverage or otherwise protect ourselves against potential product liability claims, we will be exposed to significant liabilities, which may cause a loss of revenue or otherwise harm our business. These liabilities could prevent or interfere with our product commercialization efforts. Defending a suit, regardless of merit, could be costly, could divert management attention and might result in adverse publicity, injury to our reputation, or reduced acceptance of our product candidates in the market. If we are sued for any injury caused by any future products, our liability could exceed our total assets.

Our operations involve hazardous materials and we must comply with environmental laws and regulations, which can be expensive.

Our research and development activities involve the controlled use of hazardous materials, including chemicals and radioactive and biological materials. Our operations also produce hazardous waste products. We are subject in the United States to a variety of federal, state and local regulations, and in Europe to European, national, state and local regulations, relating to the use, handling, storage and disposal of these materials. We generally contract with third parties for the disposal of such substances and store certain low-level radioactive waste at our facility until the materials are no longer considered radioactive. We cannot eliminate the risk of accidental contamination or injury from these materials. We may be required to incur substantial costs to comply with current or future environmental and safety regulations which could impose greater compliance costs and increased risks and penalties associated with violations. If an accident or contamination occurred, we would likely incur significant costs associated with civil penalties or criminal fines, substantial investigation and remediation costs, and costs associated with complying with environmental laws and regulations. There can be no assurance that violations of environmental laws or regulations will not occur in the future as a result of the inability to obtain permits, human error, accident, equipment failure or other causes. We do not have any insurance for liabilities arising from hazardous materials. Compliance with environmental and safety laws and regulations is expensive, and current or future environmental regulation may impair our research, development or production efforts.

Risks Relating to Our Intellectual Property and Litigation

We may not be able to obtain or maintain adequate patents and other intellectual property rights to protect our business and product candidates against competitors.

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Our value will be significantly enhanced if we are able to obtain adequate patents and other intellectual property rights to protect our business and product candidates against competitors. For that reason, we allocate significant financial and personnel resources to the filing, prosecution, maintenance and defense of patent applications, patents and trademarks claiming or covering our product candidates and key technology relating to these product candidates.

To date, we have sought to protect our proprietary positions related to our important technology, inventions and improvements by filing patent applications in the U.S., Europe and other jurisdictions. Because the patent position of pharmaceutical and biopharmaceutical companies involves complex legal and factual questions, the issuance, scope and enforceability of patents cannot be predicted with certainty, and we cannot be certain that patents will be issued on pending or future patent applications that cover our product candidates and technologies. Claims could be restricted in prosecution that might lead to a scope of protection which is of minor value for a particular product candidate. Patents, if issued, may be challenged and sought to be invalidated by third parties in litigation. In addition, U.S. patents and patent applications may also be subject to interference proceedings, and U.S. patents may be subject to reexamination proceedings in the U.S. Patent and Trademark Office. European patents may be subject to opposition proceedings in the European Patent Office. Patents might be invalidated in national jurisdictions. Similar proceedings may be available in countries outside of Europe or the U.S. These proceedings could result in either a loss of the patent or a denial of the patent application or loss or reduction in the scope of one or more of the claims of the patent or patent application. Thus, any patents that we own or license from others may not provide any protection against competitors. Furthermore, an adverse decision in an interference proceeding could result in a third party receiving the patent rights sought by us, which in turn could affect our ability to market a potential product or product candidate to which that patent filing was directed. Our pending patent applications, those that we may file in the future, or those that we may license from third parties may not result in patents being issued. If issued, they may not provide us with proprietary protection or competitive advantages against competitors with similar technology. Furthermore, others may independently develop similar technologies or duplicate any technology that we have developed, which fall outside the scope of our patents. Products or technology could also be copied by competitors after expiration of the patent life. Furthermore, claims of employees or former employees of Micromet related to their inventorship or compensation pursuant to the German Act on Employees’ Inventions may lead to legal disputes.

We rely on third-party payment services and external law firms for the payment of foreign patent annuities and other fees. Non-payment or delay in payment of such fees, whether intentional or unintentional, may result in loss of patents or patent rights important to our business.

We may incur substantial costs enforcing our patents against third parties. If we are unable to protect our intellectual property rights, our competitors may develop and market products with similar features that may reduce demand for our potential products.

We own or control a substantial portfolio of issued patents. From time to time, we may become aware of third parties that undertake activities that infringe on our patents. We may decide to grant those third parties a license under our patents, or to enforce the patents against those third parties by pursuing an infringement claim in litigation. If we initiate patent infringement litigation, it could consume significant financial and management resources, regardless of the merit of the claims or the outcome of the litigation. The outcome of patent litigation is subject to uncertainties that cannot be adequately quantified in advance, including the demeanor and credibility of witnesses and the identity of the adverse party, especially in biotechnology-related patent cases that may turn on the testimony of experts as to technical facts upon which experts may reasonably disagree. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could harm our ability to compete in the marketplace.

Our ability to enforce our patents may be restricted under applicable law. Many countries, including certain countries in Europe, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. For example, compulsory licenses may be required in cases where the patent owner has failed to “work” the invention in that country, or the third-party has patented improvements. In addition, many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of the patent. Moreover, the legal systems of certain countries, particularly certain developing countries, do not favor the aggressive enforcement of patent and other intellectual property rights, which makes it difficult to stop infringement. In addition, our ability to enforce our patent rights depends on our ability to detect infringement. It is difficult to detect infringers who do not advertise the compounds that are used in their products or the methods they use in the research and development of their products. If we are unable to enforce our patents against infringers, it could have a material adverse effect on our competitive position, results of operations and financial condition.

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If we are not able to protect and control our unpatented trade secrets, know-how and other technological innovation, we may suffer competitive harm.

We rely on proprietary trade secrets and unpatented know-how to protect our research, development and manufacturing activities and maintain our competitive position, particularly when we do not believe that patent protection is appropriate or available. However, trade secrets are difficult to protect. We attempt to protect our trade secrets and unpatented know-how by requiring our employees, consultants and advisors to execute confidentiality and non-use agreements. We cannot guarantee that these agreements will provide meaningful protection, that these agreements will not be breached, that we will have an adequate remedy for any such breach, or that our trade secrets or proprietary know-how will not otherwise become known or independently developed by a third party. Our trade secrets, and those of our present or future collaborators that we utilize by agreement, may become known or may be independently discovered by others, which could adversely affect the competitive position of our product candidates. If any trade secret, know-how or other technology not protected by a patent or intellectual property right were disclosed to, or independently developed by a competitor, our business, financial condition and results of operations could be materially adversely affected.

If third parties claim that our product candidates or technologies infringe their intellectual property rights, we may become involved in expensive patent litigation, which could result in liability for damages or require us to stop our development and commercialization of our product candidates after they have been approved and launched in the market, or we could be forced to obtain a license and pay royalties under unfavorable terms.

Our commercial success will depend in part on not infringing the patents or violating the proprietary rights of third parties. Competitors or third parties may obtain patents that may claim the composition, manufacture or use of our product candidates, or the technology required to perform research and development activities relating to our product candidates.

From time to time we receive correspondence inviting us to license patents from third parties. While we believe that our pre-commercialization activities fall within the scope of an available exemption against patent infringement provided in the United States by 35 U.S.C. § 271(e) and by similar research exemptions in Europe, claims may be brought against us in the future based on patents held by others. Also, we are aware of patents and other intellectual property rights of third parties relating to our areas of practice, and we know that others have filed patent applications in various countries that relate to several areas in which we are developing product candidates. Some of these patent applications have already resulted in patents and some are still pending. The pending patent applications may also result in patents being issued. In addition, the publication of patent applications occurs with a certain delay after the date of filing, so we may not be aware of all relevant patent applications of third parties at a given point in time. Further, publication of discoveries in the scientific or patent literature often lags behind actual discoveries, so we may not be able to determine whether inventions claimed in patent applications of third parties have been made before or after the date on which inventions claimed in our patent applications and patents have been made. All issued patents are entitled to a presumption of validity in many countries, including the United States and many European countries. Issued patents held by others may therefore limit our freedom to operate unless and until these patents expire or are declared invalid or unenforceable in a court of applicable jurisdiction. For example, we are aware that GlaxoSmithKline holds a European patent covering the administration of adecatumumab in combination with docetaxel, which is the combination that we are currently testing in a phase 1b clinical trial. We have filed an opposition proceeding against this patent with the European Patent Office seeking to have the patent invalidated. We may not be successful in this proceeding, and if it is not resolved in our favor, we could be required to obtain a license under this patent from GlaxoSmithKline, which we may not be able to obtain on commercially reasonable terms, if at all.

We and our collaborators may not have rights under some patents that may cover the composition of matter, manufacture or use of product candidates that we seek to develop and commercialize, drug targets to which our product candidates bind, or technologies that we use in our research and development activities. As a result, our ability to develop and commercialize our product candidates may depend on our ability to obtain licenses or other rights under these patents. The third parties who own or control such patents may be unwilling to grant those licenses or other rights to us or our collaborators under terms that are commercially viable or at all. Third parties who own or control these patents could bring claims based on patent infringement against us or our collaborators and seek monetary damages and to enjoin further clinical testing, manufacturing and marketing of the affected product candidates or products. There has been, and we believe that there will continue to be, significant litigation in the pharmaceutical industry regarding patent and other intellectual property rights. If a third party sues us for patent infringement, it could consume significant financial and management resources, regardless of the merit of the claims or the outcome of the litigation.

If a third party brings a patent infringement suit against us and we do not settle the patent infringement suit and are not successful in defending against the patent infringement claims, we could be required to pay substantial damages or we or our collaborators could be forced to stop or delay research, development, manufacturing or sales of the product or product candidate that is claimed by the third party’s patent. We or our collaborators may choose to seek, or be required to seek, a license from the third party and would most likely be required to pay license fees or royalties or both. However, there can be no assurance that any such license would be available on acceptable terms or at all. Even if we or our collaborators were able to obtain a license, the rights may be nonexclusive, which would give our competitors access to the same intellectual property. Ultimately, we could be prevented from commercializing a product candidate, or forced to cease some aspect of our business operations as a result of patent infringement claims, which could harm our business.

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Our success depends on our ability to maintain and enforce our licensing arrangements with various third party licensors.

We are party to intellectual property licenses and agreements that are important to our business, and we expect to enter into similar licenses and agreements in the future. These licenses and agreements impose various research, development, commercialization, sublicensing, milestone payments, indemnification, insurance and other obligations on us. Moreover, certain of our license agreements contain an obligation for us to make payments to our licensors based upon revenues received in connection with such licenses. If we or our collaborators fail to perform under these agreements or otherwise breach obligations thereunder, our licensors may terminate these agreements, we could lose licenses to intellectual property rights that are important to our business and we could be required to pay damages to our licensors. Any such termination could materially harm our ability to develop and commercialize the product candidate that is the subject of the agreement, which could have a material adverse impact on our results of operations.

If licensees or assignees of our intellectual property rights breach any of the agreements under which we have licensed or assigned our intellectual property to them, we could be deprived of important intellectual property rights and future revenue.

We are a party to intellectual property out-licenses, collaborations and agreements that are important to our business, and we expect to enter into similar agreements with third parties in the future. Under these agreements, we license or transfer intellectual property to third parties and impose various research, development, commercialization, sublicensing, royalty, indemnification, insurance, and other obligations on them. If a third party fails to comply with these requirements, we generally retain the right to terminate the agreement and to bring a legal action in court or in arbitration. In the event of breach, we may need to enforce our rights under these agreements by resorting to arbitration or litigation. During the period of arbitration or litigation, we may be unable to effectively use, assign or license the relevant intellectual property rights and may be deprived of current or future revenues that are associated with such intellectual property, which could have a material adverse effect on our results of operations and financial condition.

We may be subject to damages resulting from claims that we or our employees have wrongfully used or disclosed alleged trade secrets of their former employers.

Many of our employees were previously employed at other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although no claims against us are currently pending, we may be subject to claims that these employees or we have inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers. Litigation may be necessary to defend against these claims. Even if we are successful in defending against these claims, litigation could result in substantial costs and be a distraction to management. If we fail in defending such claims, in addition to paying money claims, we may lose valuable intellectual property rights or personnel. A loss of key personnel or their work product could hamper or prevent our ability to commercialize certain product candidates.

Risks Relating to Manufacturing and Sales of Products

We depend on our collaborators and third-party manufacturers to produce most, if not all, of our product candidates and if these third parties do not successfully manufacture these product candidates, or do not follow current good manufacturing practices or do not maintain their facilities in accordance with these practices, our product development and commercialization efforts may be harmed.

We have no manufacturing experience or manufacturing capabilities for the production of our product candidates for clinical trials or commercial sale. In order to continue to develop product candidates, apply for regulatory approvals, and commercialize our product candidates following approval, we or our collaborators must be able to manufacture or contract with third parties to manufacture our product candidates in clinical and commercial quantities, in compliance with regulatory requirements, at acceptable costs and in a timely manner. The manufacture of our product candidates may be complex, difficult to accomplish and difficult to scale-up when large-scale production is required. Manufacture may be subject to delays, inefficiencies and poor or low yields of quality products. The cost of manufacturing our product candidates may make them prohibitively expensive. If supplies of any of our product candidates or related materials become unavailable on a timely basis or at all or are contaminated or otherwise lost, clinical trials by us and our collaborators could be seriously delayed. This is due to the fact that such materials are time-consuming to manufacture and cannot be readily obtained from third-party sources.

Product candidates used in clinical trials or sold after marketing approval has been obtained must be manufactured in accordance with current good manufacturing practices regulations. There are a limited number of manufacturers that operate under these regulations, including the FDA’s and EMEA’s good manufacturing practices regulations, and that are capable of manufacturing our product candidates. Third-party manufacturers may encounter difficulties in achieving quality control and quality assurance and may experience shortages of qualified personnel. Also, manufacturing facilities are subject to ongoing periodic, unannounced inspection by the FDA, the EMEA, and other regulatory agencies or authorities, to ensure strict compliance with current good manufacturing practices and other governmental regulations and standards. A failure of third-party manufacturers to follow current good manufacturing practices or other regulatory requirements and to document their adherence to such practices may lead to significant delays in the availability of product candidates for use in a clinical trial or for commercial sale, the termination of, or hold on, a clinical trial, or may delay or prevent filing or approval of marketing applications for our product candidates. In addition, as a result of such a failure, we could be subject to sanctions, including fines, injunctions and civil penalties, refusal or delays by regulatory authorities to grant marketing approval of our product candidates, suspension or withdrawal of marketing approvals, seizures or recalls of product candidates, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect our business.

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To the extent that we or our collaborators seek to enter into manufacturing arrangements with third parties, we and such collaborators will depend upon these third parties to perform their obligations in a timely and effective manner and in accordance with government regulations. Contract manufacturers may breach their manufacturing agreements because of factors beyond our control or may terminate or fail to renew a manufacturing agreement based on their own business priorities at a time that is costly or inconvenient for us. If third-party manufacturers fail to perform their obligations, our competitive position and ability to generate revenue may be adversely affected in a number of ways, including:

•

we and our collaborators may not be able to initiate or continue clinical trials of product candidates that are under development;

•

we and our collaborators may be delayed in submitting applications for regulatory approvals for our product candidates; and

•

we and our collaborators may not be able to meet commercial demands for any approved products.

If we were required to change manufacturers, it may require additional clinical trials and the revalidation of the manufacturing process and procedures in accordance with applicable current good manufacturing practices and may require FDA or EMEA approval. This revalidation may be costly and time-consuming. If we are unable to arrange for third-party manufacturing of our product candidates, or to do so on commercially reasonable terms, we may not be able to complete development or marketing of our product candidates.

We have no sales, marketing or distribution experience and will depend significantly on third parties who may not successfully sell our product candidates following approval.

We have no sales, marketing or product distribution experience. If we receive required regulatory approvals to market any of our product candidates, we plan to rely primarily on sales, marketing and distribution arrangements with third parties, including our collaborators. For example, as part of our agreements with Merck Serono, MedImmune, Nycomed and TRACON, we have granted these companies the right to market and distribute products resulting from such collaborations, if any are ever successfully developed. We may have to enter into additional marketing arrangements in the future and we may not be able to enter into these additional arrangements on terms that are favorable to us, if at all. In addition, we may have limited or no control over the sales, marketing and distribution activities of these third parties, and sales through these third parties could be less profitable to us than direct sales. These third parties could sell competing products and may devote insufficient sales efforts to our product candidates following approval. As a result, our future revenues from sales of our product candidates, if any, will be materially dependent upon the success of the efforts of these third parties.

We may seek to co-promote products with our collaborators, or to independently market products that are not already subject to marketing agreements with other parties. If we determine to perform sales, marketing and distribution functions ourselves, then we could face a number of additional risks, including:

•

we may not be able to attract and build an experienced marketing staff or sales force;

•

the cost of establishing a marketing staff or sales force may not be justifiable in light of the revenues generated by any particular product;

•

our direct sales and marketing efforts may not be successful; and

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•

we may face competition from other products or sales forces with greater resources than our own sales force.

Additional Risks Related to This Offering

Management will have broad discretion as to the use of the proceeds from this offering, and we may not use the proceeds effectively.

We have not designated any portion of the net proceeds from this offering to be used for any particular purpose. Accordingly, our management will have broad discretion as to the application of the net proceeds from this offering, and could spend the proceeds in ways that do not necessarily improve our operating results or enhance the value of our common stock.

You will experience immediate dilution in the book value per share of the common stock you purchase.

Because the price per share of our common stock being offered is substantially higher than the book value per share of our common stock, you will suffer substantial dilution in the net tangible book value of the common stock you purchase in this offering. After giving effect to the sale by us of 14,000,000 shares of common stock in this offering, and based on a public offering price of $5.00 per share in this offering and a pro forma net tangible book value per share of our common stock of $0.60 as of March 31, 2009, if you purchase shares of common stock in this offering, you will suffer immediate and substantial dilution of $3.55 per share in the net tangible book value of the common stock. If the underwriters exercise their over-allotment option, you will experience additional dilution. See “Dilution” on page S-23 for a more detailed discussion of the dilution you will incur in connection with this offering.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying prospectus, including the documents that we incorporate by reference herein and therein, contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These forward-looking statements can generally be identified as such because the context of the statement will include words such as “may,” “will,” “intends,” “plans,” “believes,” “anticipates,” “expects,” “estimates,” “predicts,” “potential,” “continue,” “likely,” “unlikely” or “opportunity,” the negative of these words or words of similar import. Similarly, statements that describe our future plans, strategies, intentions, expectations, objectives, goals or prospects are also forward-looking statements. Discussions containing these forward-looking statements may be found, among other places, in the “Business” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections incorporated by reference from our most recent Annual Report on Form 10-K, as well as any amendments thereto reflected in subsequent filings with the SEC. These forward-looking statements are based largely on our expectations and projections about future events and future trends affecting our business, and are subject to risks and uncertainties that could cause actual results to differ materially from those anticipated in the forward-looking statements. The risks and uncertainties include, among others, those noted in “Risk Factors” above and those included in the documents that we incorporate by reference herein.

In addition, past financial and/or operating performance is not necessarily a reliable indicator of future performance and you should not use our historical performance to anticipate results or future period trends. We can give no assurances that any of the events anticipated by the forward-looking statements will occur or, if any of them do, what impact they will have on our results of operations and financial condition. Except as required by law, we undertake no obligation to publicly revise our forward-looking statements to reflect events or circumstances that arise after the filing of this prospectus supplement or the filing of the accompanying prospectus or documents incorporated by reference herein and therein that include forward-looking statements.

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USE OF PROCEEDS

We estimate that the net proceeds from the sale of the 14,000,000 shares of common stock we are offering will be approximately $65.2 million, or approximately $75.0 million if the underwriters exercise their over-allotment option in full. “Net proceeds” is what we expect to receive after paying the underwriting discount and other expenses of this offering payable by us.

We intend to use the net proceeds from this offering for preclinical and clinical development of our drug candidates, for discovery research for new drug candidates and for general corporate purposes, including working capital. In addition, we may use a portion of the proceeds to acquire drugs or drug candidates, technologies, businesses or other assets. The timing and amount of our actual expenditures will be based on many factors, including the timing and success of our clinical trials, whether we partner any of our development programs, and whether we choose to curtail some of our research activities. We will retain broad discretion in determining how we will allocate the net proceeds from this offering.

Until we use the net proceeds of this offering, we intend to invest the funds in short-term, investment grade, interest-bearing securities.

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DILUTION

Our net tangible book value on March 31, 2009 was approximately $26.0 million, or $0.51 per share of common stock. “Net tangible book value” is total assets minus the sum of liabilities and intangible assets. “Net tangible book value per share” is net tangible book value divided by the total number of shares of common stock outstanding.

After giving effect to the sales on May 19, 2009, May 26, 2009, June 10, 2009 and June 15, 2009 of an aggregate of 1,420,568 shares of our common stock to Kingsbridge Capital Limited, or Kingsbridge, pursuant to a Common Stock Purchase Agreement dated as of December 1, 2008, at an average price of $3.70 per share, our pro forma net tangible book value, as of March 31, 2009, would have been approximately $31.3 million, or $0.60 per share of common stock.

After giving further effect to the sale of 14,000,000 shares of common stock offered by us in this offering at a price of $5.00 per share, less the underwriting discounts and other expenses of this offering payable by us, our pro forma as adjusted net tangible book value on March 31, 2009 would have been approximately $96.4 million, or $1.45 per share of common stock. The adjustments made to determine pro forma as adjusted net tangible book value per share are the following:

an increase in total assets to reflect the net proceeds of the offering as described under “Use of Proceeds”; and

the addition of the number of shares offered by this prospectus supplement to the number of shares outstanding as of March 31, 2009 (as adjusted to reflect the shares issued in connection with the Kingsbridge transaction described above).

The following table illustrates the pro forma as adjusted increase in net tangible book value of $0.86 per share and the dilution (the difference between the offering price per share and pro forma net tangible book value per share) of $3.55 per share to new investors in this offering:

Public offering price per share	$	5.00
Pro forma net tangible book value per share on March 31, 2009	$	0.60
Increase in pro forma net tangible book value per share attributable to offering	$	0.86
Pro forma as adjusted net tangible book value per share on March 31, 2009, after giving effect to the offering	$	1.45
Dilution per share to new investors in the offering	$	3.55

Assuming the underwriters exercise their over-allotment option in full, the pro forma as adjusted increase in net tangible book value would be $0.95 per share and the dilution (the difference between the offering price per share and pro forma net tangible book value per share) would be $3.45 per share to new investors in this offering.

The following table shows the difference between existing stockholders (which includes the sale of 1,420,568 shares of our common stock to Kingsbridge) and new investors with respect to the number of shares purchased from us, the total consideration paid and the average price paid per share.

	Shares Purchased					Total Consideration					Average Price
	Number		Percent			Amount		Percent			Per Share
Existing stockholders		52,333,249		78.9	%	$	225,471,000		76.3	%	$	4.31
New investors		14,000,000		21.1	%	$	70,000,000		23.7	%	$	5.00
Total		66,333,249		100.0	%	$	295,471,000		100.0	%	$	4.45

The above discussion and tables are based on 50,912,681 common shares outstanding at March 31, 2009, and do not include, as of that date:

7,514,532 shares of common stock issuable upon the exercise of outstanding options, with a weighted average exercise price of $3.72 per share;

8,222,416 shares of common stock issuable upon the exercise of outstanding warrants, with a weighted average exercise price of $3.92 per share; and

3,498,506 shares of common stock reserved for future issuance under our stock-based compensation plans, consisting of 2,850,073 shares of common stock reserved for issuance under our 2003 Amended and Restated Equity Incentive Plan, 443,614 shares of common stock reserved for issuance under our 2006 Equity Incentive Award Plan and 204,819 shares of common stock reserved for issuance under our Employee Stock Purchase Plan.

S-23

UNDERWRITING

We are offering the shares of common stock described in this prospectus supplement through a number of underwriters. Piper Jaffray is acting as the sole book-running manager of the offering and as representative of the underwriters. RBC Capital Markets Corporation and Merriman Curhan Ford are acting as co-managers for this offering. We have entered into a firm commitment underwriting agreement with the underwriters. Subject to the terms and conditions of the underwriting agreement, we have agreed to sell to the underwriters, and each underwriter has severally agreed to purchase, at the public offering price less the underwriting discount set forth on the cover page of this prospectus supplement, the number of shares of common stock listed next to its name in the following table:

Underwriter	Number of Shares
Piper Jaffray & Co.		9,450,000
RBC Capital Markets Corporation		3,850,000
Merriman Curhan Ford		700,000
Total		14,000,000

The underwriters are committed to purchase all the shares of common stock offered by us if they purchase any shares, other than those shares covered by the over-allotment option described below. The underwriting agreement also provides that if an underwriter defaults, the purchase commitments of non-defaulting underwriters may also be increased or the offering may be terminated.

The underwriters propose to offer the common stock directly to the public at the initial public offering price set forth on the cover page of this prospectus supplement and to certain dealers at that price less a concession not in excess of $0.1625 per share. After the offering, these figures may be changed by the underwriters. Sales of shares made outside of the United States may be made by affiliates of the underwriters.

The underwriters have an option to buy up to 2,100,000 additional shares of common stock from us to cover sales of shares by the underwriters which exceed the number of shares specified in the table above. The underwriters may exercise this option at any time and from time to time during the 30-day period from the date of this prospectus supplement. If any shares are purchased with this over-allotment option, the underwriters will purchase shares in approximately the same proportion as shown in the table above. If any additional shares of common stock are purchased, the underwriters will offer the additional shares on the same terms as those on which the shares are being offered.

The underwriting fee is equal to the public offering price per share of common stock less the amount paid by the underwriters to us per share of common stock. The following table shows the per share and total underwriting discount to be paid to the underwriters assuming both no exercise and full exercise of the underwriters’ option to purchase additional shares.

	Without over-allotment exercise		With full over-allotment exercise
Per Share	$	0.325	$	0.325
Total	$	4,550,000	$	5,232,500

We estimate that the total fees and expenses payable by us, excluding underwriting discount, will be approximately $300,000, which includes $100,000 that we have agreed to reimburse the underwriters for the fees incurred by them in connection with the offering.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute to payments that the underwriters may be required to make in respect of those liabilities.

We and each of our directors and executive officers are subject to lock-up agreements that prohibit us and them from offering for sale, pledging, assigning, encumbering, announcing the intention to sell, selling, contracting to sell, granting any option, right or warrant to purchase, or otherwise transferring or disposing of, any shares of our common stock or any securities convertible into or exercisable or exchangeable for shares of our common stock for a period of at least 60 days following the date of this prospectus supplement without the prior written consent of Piper Jaffray as the representative of the underwriters. The lock-up agreement does not prohibit our directors and executive officers from transferring shares of our common stock for bona fide estate or tax planning purposes, subject to certain requirements, including that the transferee be subject to the same lock-up terms, or pursuant to Rule 10b5-1 trading plans in existence as of the date of this prospectus supplement. The lock-up agreement does not prohibit us from issuing shares upon the exercise or conversion of securities outstanding on the date of this prospectus supplement. The lock-up provisions do not prevent us from selling shares to the underwriters pursuant to the underwriting agreement, or from granting options to acquire securities under our existing stock option plans or issuing shares upon the exercise or conversion of securities outstanding on the date of this prospectus supplement.

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The 60-day lock-up period in all of the lock-up agreements is subject to extension if (i) during the last 17 days of the lock-up period we issue an earnings release or material news or a material event relating to us occurs or (ii) prior to the expiration of the lock-up period, we announce that we will release earnings results during the 16-day period beginning on the last day of the lock-up period, in which case the restrictions imposed in these lock-up agreements shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, unless Piper Jaffray waives the extension in writing.

Our shares are quoted on the Nasdaq Global Market under the symbol “MITI.”

To facilitate the offering, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of the common stock during and after the offering. Specifically, the underwriters may over-allot or otherwise create a short position in the common stock for their own account by selling more shares of common stock than we have sold to them. Short sales involve the sale by the underwriters of a greater number of shares than they are required to purchase in the offering. The underwriters may close out any short position by either exercising their option to purchase additional shares or purchasing shares in the open market.

In addition, the underwriters may stabilize or maintain the price of the common stock by bidding for or purchasing shares of common stock in the open market and may impose penalty bids. If penalty bids are imposed, selling concessions allowed to syndicate members or other broker-dealers participating in the offering are reclaimed if shares of common stock previously distributed in the offering are repurchased, whether in connection with stabilization transactions or otherwise. The effect of these transactions may be to stabilize or maintain the market price of the common stock at a level above that which might otherwise prevail in the open market. The imposition of a penalty bid may also affect the price of the common stock to the extent that it discourages resales of the common stock. The magnitude or effect of any stabilization or other transactions is uncertain. These transactions may be effected on the Nasdaq Global Market or otherwise and, if commenced, may be discontinued at any time. The underwriters may also engage in passive market making transactions in our common stock. Passive market making consists of displaying bids on the Nasdaq Global Market is limited by the prices of independent market makers and effecting purchases limited by those prices in response to order flow. Rule 103 of Regulation M promulgated by the Commission limits the amount of net purchases that each passive market maker may make and the displayed size of each bid. Passive market making may stabilize the market price of the common stock at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

This prospectus supplement and the accompanying prospectus in electronic format may be made available on the web sites maintained by the underwriters and the underwriters may distribute prospectuses and prospectus supplements electronically.

From time to time in the ordinary course of their respective businesses, the underwriters and certain of their respective affiliates have engaged, and may in the future engage, in commercial banking or investment banking transactions with us and our affiliates.

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LEGAL MATTERS

Selected legal matters with respect to the validity of common stock offered by this prospectus supplement will be passed upon for us by Cooley Godward Kronish LLP, Reston, Virginia. Certain legal matters in connection with the common stock offered in this prospectus supplement will be passed upon for the underwriters by Goodwin Procter LLP, New York, New York.

EXPERTS

The consolidated financial statements of Micromet, Inc. appearing in Micromet, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2008, and the effectiveness of Micromet, Inc.’s internal control over financial reporting as of December 31, 2008, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated by reference in this prospectus supplement and the accompanying prospectus. The consolidated financial statements of Micromet, Inc. at December 31, 2007 and for the year then ended appearing in Micromet, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2008, have been audited by Ernst & Young GmbH WPG, independent registered public accounting firm, formerly known as Ernst & Young AG and Ernst & Young Deutsche Allgemeine Treuhand AG WPG, as set forth in their report thereon, included therein, and incorporated by reference in this prospectus supplement and the accompanying prospectus. Such consolidated financial statements have been incorporated herein and therein by reference in reliance upon such reports given on the authority of such firms as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC registration statements on Form S-3 under the Securities Act with respect to the shares of common stock we are offering under this prospectus supplement. This prospectus supplement and the accompanying prospectus do not contain all of the information set forth in the registration statements and the exhibits to the registration statements. For further information with respect to us and the securities we are offering under this prospectus supplement, we refer you to the registration statements and the exhibits and schedules filed as a part of the registration statements. Statements contained in this prospectus supplement as to the contents of any contract or any other document referred to are not necessarily complete, and in each instance, we refer you to the copy of the contract or other document filed as an exhibit to the registration statements. Each of these statements is qualified in all respects by this reference. We also file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy the registration statement, as well as any other material we file with the SEC, at the SEC’s Public Reference Room at 100 F Street, NE, Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information on the Public Reference Room. The SEC maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC, including Micromet. The SEC’s Internet site can be found at http://www.sec.gov.

Our Internet address is www.micromet-inc.com. There we make available free of charge, on or through the investor relations section of our website, annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. The information found on our website is not part of this prospectus supplement or any other report we file with or furnish to the Securities and Exchange Commission.

IMPORTANT INFORMATION INCORPORATED BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information we file with it, which means that we can disclose important information to you by referring you to those documents. Information incorporated by reference is part of this prospectus supplement. Later information filed with the SEC will update and supersede this information. The SEC’s Internet site can be found at http://www.sec.gov.

We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act until this offering is completed:

our Annual Report on Form 10-K for the year ended December 31, 2008, filed with the SEC on March 16, 2009;

the information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2008 from our definitive proxy statement on Schedule 14A (other than information furnished rather than filed) filed with the SEC on April 30, 2009 and additional definitive materials filed on the same date;

our Quarterly Report on Form 10-Q for the quarter ended March 31, 2009, filed with the SEC on May 11, 2009;

our Current Reports on Form 8-K (other than information furnished rather than filed) filed with the SEC on January 14, 2009, February 23, 2009, March 12, 2009 and July 10, 2009;

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the description of our common stock, which is registered under Section 12 of the Exchange Act, in our registration statement on Form 8-A, filed with the SEC on October 24, 2003, including any amendments or reports filed for the purpose of updating such description; and

the description of our Series A Junior Participating Preferred Stock Purchase Rights (the “Rights”) contained in our registration statement on Form 8-A registering the Rights under Section 12 of the Exchange Act, filed with the SEC on November 12, 2004, including any amendments or reports filed for the purpose of updating that description.

You may request a copy of these filings, at no cost, by contacting us at:

Micromet, Inc.

Attention: Investor Relations

6707 Democracy Blvd., Suite 505

Bethesda, MD 20817

Telephone number: (240) 752-1420

In accordance with Rule 412 of the Securities Act, any statement contained in a document incorporated by reference herein shall be deemed modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement.

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PROSPECTUS

$80,000,000

Common Stock, Preferred Stock,

Debt Securities,

Warrants and Units

From time to time, we may offer up to $80,000,000 of any combination of the securities described in this prospectus, either individually or in units. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

This prospectus provides a general description of the securities we may offer. Each time we sell securities, we will provide specific terms of the securities offered in a supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.

This prospectus may not be used to consummate a sale of any securities unless accompanied by a prospectus supplement.

Our common stock is traded on the Nasdaq Global Market under the symbol “MITI.” On July 2, 2009, the last reported sales price of our common stock was $4.88 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing on the Nasdaq Global Market or any securities market or other exchange of the securities, if any, covered by the prospectus supplement.

We will sell these securities directly to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts or over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

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Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.

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NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

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The date of this prospectus is July 2, 2009.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS	i
SUMMARY	1
RISK FACTORS	5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	5
FINANCIAL RATIOS	6
USE OF PROCEEDS	6
DESCRIPTION OF CAPITAL STOCK	6
DESCRIPTION OF DEBT SECURITIES	12
DESCRIPTION OF WARRANTS	19
DESCRIPTION OF UNITS	21
LEGAL OWNERSHIP OF SECURITIES	22
PLAN OF DISTRIBUTION	26
LEGAL MATTERS	27
EXPERTS	27
WHERE YOU CAN FIND MORE INFORMATION	27
INCORPORATION BY REFERENCE	28
DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITY	29

ABOUT THIS PROSPECTUS

This prospectus is a part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total dollar amount of $80,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in any documents that we have incorporated by reference into this prospectus. You should read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find More Information,” before investing in any of the securities offered.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

You should rely only on the information that we have provided or incorporated by reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you. We have not authorized any dealer, salesman or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus. This prospectus, any applicable supplement to this prospectus or any related free writing prospectus do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus, any applicable supplement to this prospectus or any related free writing prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find Additional Information.”

SUMMARY

This summary highlights selected information from this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.

Unless the context indicates otherwise, as used in this prospectus, the terms “Micromet,” “the Company,” “we,” “us” and “our” refer to Micromet, Inc., a Delaware corporation, and its subsidiaries. We use Micromet®, BiTE®, and the Micromet logo as trademarks in the United States and other countries. All other trademarks or trade names referred to in this prospectus are the property of their respective owners.

Our Company

We were incorporated in Delaware in 1998 under the name CancerVax Corporation. In May 2006, we changed our corporate name to Micromet, Inc. Our principal executive offices are located at 6707 Democracy Blvd., Suite 505, Bethesda, Maryland 20817, and our main telephone number is (240) 752-1420. Our website is located on the world wide web at http://www.micromet-inc.com. We do not incorporate by reference into this prospectus the information on, or accessible through, our website, and you should not consider it as part of this prospectus.

The Securities We May Offer

We may offer shares of our common stock and preferred stock, various series of debt securities and warrants to purchase any of such securities, either individually or in units, with a total value of up to $80,000,000 million from time to time under this prospectus, together with any applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of the offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

·	designation or classification;

·	aggregate principal amount or aggregate offering price;

·	maturity, if applicable;

·	original issue discount, if any;

·	rates and times of payment of interest or dividends, if any;

·	redemption, conversion, exchange or sinking fund terms, if any;

·	conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange;

ranking;

·	restrictive covenants, if any;

·	voting or other rights, if any; and

·	important United States federal income tax considerations.

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

This prospectus may not be used to consummate a sale of securities unless it is accomplished by a prospectus supplement.

We may sell the securities directly to investors or through underwriters, dealers or agents. We, and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

·	the names of those underwriters or agents;

·	applicable fees, discounts and commissions to be paid to them;

·	details regarding over-allotment options, if any; and

·	the estimated net proceeds to us.

Common Stock. We may issue shares of our common stock from time to time. The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of our common stock are entitled to receive ratably such dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any then outstanding shares of preferred stock. Our common stock does not carry any preemptive rights enabling a holder to subscribe for, or receive shares of, any class of our common stock or any other securities convertible into shares of any class of our common stock, or any redemption rights.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our certificate of incorporation, our board of directors has the authority to designate up to 10,000,000 shares of preferred stock in one or more series and to determine the designations, voting powers, preferences and rights of each series of the preferred stock, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series, any or all of which may be greater than the rights of the common stock. Convertible preferred stock will be convertible into our common stock or exchangeable for our other securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.

To date, our board of directors has designated 75,000 of the 10,000,000 authorized shares of preferred stock as Series A Junior Participating Preferred Stock. The preferred stock is described in greater detail in this prospectus under “Description of Capital Stock – Preferred Stock.”

If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or our other securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.

The debt securities will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. Forms of indentures have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. Forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental warrant agreements and forms of warrant certificates will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

We will evidence each series of warrants by warrant certificates that we will issue. Warrants may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

Units. We may issue, in one or more series, units consisting of common stock, preferred stock, debt securities and/or warrants for the purchase of common stock, preferred stock and/or debt securities in any combination. In this prospectus, we have summarized certain general features of the units. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of units being offered, as well as the complete unit agreement that contains the terms of the units. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement and any supplemental agreements that describe the terms of the series of units we are offering before the issuance of the related series of units.

We will evidence each series of units by unit certificates that we will issue. Units may be issued under a unit agreement that we enter into with a unit agent. We will indicate the name and address of the unit agent, if applicable, in the prospectus supplement relating to the particular series of units being offered.

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus, before deciding whether to purchase any of the securities being registered pursuant to the registration statement of which this prospectus is a part. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference contain forward-looking statements. These are based on our management’s current beliefs, expectations and assumptions about future events, conditions and results and on information currently available to us. Discussions containing these forward-looking statements may be found, among other places, in the Sections entitled “Business,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” incorporated by reference from our most recent Annual Report on Form 10-K and in our Quarterly Reports on Form 10-Q, as well as any amendments thereto, filed with the SEC.

Any statements in this prospectus, or incorporated herein, about our expectations, beliefs, plans, objectives, assumptions or future events or performance are not historical facts and are forward-looking statements. Within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Exchange Act, these forward-looking statements include, but are not limited to, statements regarding the efficacy, safety and intended utilization of our product candidates, the development of our BITE antibody technology, the conduct, timing and results of future clinical trials, the availability of financing, plans regarding regulatory filings and future research and plans regarding partnering activities. You can identify these forward-looking statements by the use of words or phrases such as “believe,” “may,” “could,” “will,” “possible,” “can,” “estimate,” “continue,” “ongoing,” “consider,” “anticipate,” “intend,” “seek,” “plan,” “expect,” “deem,” “should,” “would” or “assume” or the negative of these terms, or other comparable terminology, although not all forward-looking statements contain these words. Among the factors that could cause actual results to differ materially from those indicated in the forward-looking statements are risks and uncertainties inherent in our business including, without limitation, the progress, timing and success of our clinical trials; difficulties or delays in development, testing, obtaining regulatory approval for producing and marketing our product candidates; regulatory developments in the United States or in foreign countries; the risks associated with our reliance on collaborations for the development and commercialization of our product candidates; unexpected adverse side effects or inadequate therapeutic efficacy of our product candidates that could delay or prevent product development or commercialization, or that could result in recalls or product liability claims; our ability to attract and retain key scientific, management or commercial personnel; the loss of key scientific, management or commercial personnel; the size and growth potential of the potential markets for our product candidates and our ability to serve those markets; the scope and validity of patent protection for our product candidates; our ability to establish and maintain strategic collaborations or to otherwise obtain additional financing to support our operations; competition from other pharmaceutical or biotechnology companies; successful administration of our business and financial reporting capabilities; and the other risks discussed in our Annual Report on Form 10-K for the year ended December 31, 2008, filed with the SEC on March 16, 2009, and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2009, filed with the SEC on May 11, 2009, as well as “Risk Factors” sections of future filings made under the Exchange Act following the date of this prospectus. Given these risks, uncertainties and other factors, many of which are beyond our control, you should not place undue reliance on these forward-looking statements.

Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to revise any forward-looking statements to reflect events or developments occurring after the date of this prospectus, even if new information becomes available in the future.

FINANCIAL RATIOS

We have incurred $11.4 million in fixed charges from January 1, 2004 through March 31, 2009. Fixed charges represent interest expense including the interest component of rent expense. We have incurred losses $21.9 million in 2004, $9.7 million in 2005, $33.6 million in 2006, $25.2 million in 2007, $26.1 million in 2008 and $4.9 million for the first quarter of 2009.

USE OF PROCEEDS

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. Except as described in any applicable prospectus supplement or in any free writing prospectuses that we may authorize to be provided to you in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered hereby for general corporate purposes, which may include research and development, capital expenditures, working capital and general and administrative expenses. We may also use a portion of the net proceeds to invest in or acquire businesses or technologies that we believe are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus. Pending these uses, we intend to invest the net proceeds in investment-grade, interest bearing securities.

DESCRIPTION OF CAPITAL STOCK

As of the date of this prospectus, our certificate of incorporation authorizes us to issue 150,000,000 shares of common stock, par value $0.00004 per share, and 10,000,000 shares of preferred stock, par value $0.00004 per share. As of June 18, 2009, 52,578,875 shares of common stock were outstanding and no shares of preferred stock were outstanding. Our board of directors has designated 75,000 of the 10,000,000 authorized shares of preferred stock as Series A Junior Participating Preferred Stock, which series is described below under “Rights Plan.”

The following summary description of our capital stock is based on the provisions of our certificate of incorporation, including the certificate of designation for our Series A Junior Participating Preferred Stock, as well as our bylaws, our stockholder rights plan and the applicable provisions of the Delaware General Corporation Law. This information is qualified entirely by reference to the applicable provisions of our certificate of incorporation, bylaws, stockholder rights plan and the Delaware General Corporation Law. For information on how to obtain copies of our certificate of incorporation, bylaws and stockholder rights plan, which are exhibits to the registration statement of which this prospectus is a part, see “Where You Can Find Additional Information.”

Common Stock

The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders. The holders of our common stock do not have cumulative voting rights in the election of directors. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably such dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive rights and no right to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to our common stock.

Additional shares of authorized common stock may be issued, as authorized by our board of directors from time to time, without stockholder approval, except as may be required by applicable stock exchange requirements.

The rights of the holders of our common stock are subject to, and may be adversely affected by, the rights of holders of shares of any preferred stock that we may designate and issue in the future.

Preferred Stock

Pursuant to our amended and restated certificate of incorporation, or the Restated Certificate, our board of directors has the authority, without further action by the stockholders (unless such stockholder action is required by applicable law or Nasdaq rules), to designate and issue up to 10,000,000 shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, to fix the designations, powers, preferences, privileges and relative participating, optional or special rights and the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption and liquidation preferences, any or all of which may be greater than the rights of the common stock, and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding.

The board of directors, without stockholder approval, can issue preferred stock with voting, conversion or other rights that could adversely affect the voting power and other rights of the holders of common stock. Preferred stock could be issued quickly with terms designed to delay or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of the common stock and may adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation.

Future Preferred Stock. Our board of directors will fix the designations, voting powers, preferences and rights of the each series, as well as the qualifications, limitations or restrictions thereof, of the preferred stock of each series that we sell under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that series of preferred stock. This description will include:

the title and stated value;

the number of shares we are offering;

the liquidation preference per share;

the purchase price per share;

the dividend rate per share, dividend period and payment dates and method of calculation for dividends;

whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

our right, if any, to defer payment of dividends and the maximum length of any such deferral period;

the procedures for any auction and remarketing, if any;

the provisions for a sinking fund, if any;

the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

any listing of the preferred stock on any securities exchange or market;

whether the preferred stock will be convertible into our common stock or other securities of ours, including depositary shares and warrants, and, if applicable, the conversion period, the conversion price, or how it will be calculated, and under what circumstances it may be adjusted;

whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange period, the exchange price, or how it will be calculated, and under what circumstances it may be adjusted;

voting rights, if any, of the preferred stock;

preemption rights, if any;

restrictions on transfer, sale or other assignment, if any;

whether interests in the preferred stock will be represented by depositary shares;

a discussion of any material or special United States federal income tax considerations applicable to the preferred stock;

the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

any limitations on issuances of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock being issued as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

any other specific terms, rights, preferences, privileges, qualifications or restrictions of the preferred stock.

The General Corporation Law of the State of Delaware, the state of our incorporation, provides that the holders of preferred stock will have the right to vote separately as a class (or, in some cases, as a series) on an amendment to our certificate of incorporation if the amendment would change the par value or, unless the certificate of incorporation provided otherwise, the number of authorized shares of the class or change the powers, preferences or special rights of the class or series so as to adversely affect the class or series, as the case may be. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

Registration Rights

We have entered into a registration rights agreement with Kingsbridge Capital Limited, or Kingsbridge, in connection with the committed equity financing facility, or CEFF, that we entered into with Kingsbridge on December 1, 2008 pursuant to which we agreed to file and keep effective a registration statement under the Securities Act registering the resale of up to 10,104,109 shares of common stock issuable under the CEFF as well as 420,000 shares of common stock issuable upon exercise of warrants issued to Kingsbridge in connection with the CEFF and a prior CEFF.

Antitakeover Effects of Provisions of Charter Documents and Delaware Law

Charter Documents. Our Restated Certificate and Amended and Restated Bylaws, or Bylaws, each as amended to date, include a number of provisions that may have the effect of deterring hostile takeovers or delaying or preventing changes in control or management of our company. First, our board of directors is classified into three classes of directors. Under Delaware law, directors of a corporation with a classified board may be removed only for cause unless the corporation's certificate of incorporation provides otherwise. Our Restated Certificate does not provide otherwise. In addition, the Restated Certificate provides that all stockholder action must be effected at a duly called meeting of stockholders and not by a consent in writing. Further, our Bylaws limit who may call special meetings of the stockholders. Our Restated Certificate does not include a provision for cumulative voting for directors. Under cumulative voting, a minority stockholder holding a sufficient percentage of a class of shares may be able to ensure the election of one or more directors. Finally, our Bylaws establish procedures, including advance notice procedures, with regard to the nomination of candidates for election as directors and stockholder proposals. These and other provisions of our Restated Certificate and Bylaws and Delaware law could discourage potential acquisition proposals and could delay or prevent a change in control or management of our company.

Delaware Takeover Statute. We are subject to Section 203 of the General Corporation Law of the State of Delaware, or DGCL, which regulates acquisitions of some Delaware corporations. Section 203 generally prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years following the date of the transaction in which the person became an interested stockholder, unless:

the board of directors of the corporation approved the business combination or the other transaction in which the person became an interested stockholder prior to the date of the business combination or other transaction;

upon consummation of the transaction that resulted in the person becoming an interested stockholder, the person owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding shares owned by persons who are directors and also officers of the corporation and shares issued under employee stock plans under which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

on or subsequent to the date the person became an interested stockholder, the board of directors of the corporation approved the business combination and the stockholders of the corporation authorized the business combination at an annual or special meeting of stockholders by the affirmative vote of at least 66-2/3% of the outstanding stock of the corporation not owned by the interested stockholder.

Section 203 of the DGCL defines a “business combination” to include any of the following:

any merger or consolidation involving the corporation and the interested stockholder;

any sale, transfer, pledge or other disposition of 10% or more of the corporation’s assets or outstanding stock involving the interested stockholder;

subject to exceptions, any transaction that results in the issuance or transfer by the corporation of any of its stock to the interested stockholder;

any transaction involving the corporation that has the effect of increasing the proportionate share of its stock owned by the interested stockholder; or

the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, Section 203 defines an “interested stockholder” as any person who, together with the person’s affiliates and associates, owns, or within three years prior to the determination of interested stockholder status did own, 15% or more of a corporation’s voting stock.

Section 203 of the DGCL could depress our stock price and delay, discourage or prohibit transactions not approved in advance by our board of directors, such as takeover attempts that might otherwise involve the payment to our stockholders of a premium over the market price of our common stock.

Rights Plan

On November 3, 2004, our board of directors adopted a Stockholder Rights Plan, or the Rights Plan. In connection with the Rights Plan, the board of directors declared a dividend of one preferred share purchase right, or Rights, for each outstanding share of common stock, par value $0.00004 per share, of the Company outstanding at the close of business on November 15, 2004, or the Record Date. Each Right entitles the registered holder thereof, after the Rights become exercisable and until November 15, 2014 (or the earlier redemption, exchange or termination of the Rights), to purchase from the Company one one-thousandth (1/1000th) of a share of Series A Junior Participating Preferred Stock, par value $0.00004 per share, at a price of $95.00 per one one-thousandth (1/1000th) of a share of Series A Junior Participating Preferred Stock, subject to certain anti-dilution adjustments, or the Purchase Price.

Until the earlier to occur of (i) 10 days following a public announcement that a person or group of affiliated or associated persons has acquired, or obtained the right to acquire, beneficial ownership of 15% or more of our common stock (such acquiring person, entity or group of affiliated or associated persons being called an Acquiring Person) or (ii) 10 business days (or such later date as may be determined by action of the board of directors prior to such time as any person or group of affiliated persons becomes an Acquiring Person) following the commencement or announcement of an intention to make a tender offer or exchange offer the consummation of which would result in the beneficial ownership by a person or group of 15% or more of the Common Shares (the earlier of such dates being called the Distribution Date), the Rights will be evidenced, with respect to any of the certificates for common stock outstanding as of the Record Date, by such common stock certificate. The Rights will be transferred with and only with the common stock until the Distribution Date or earlier redemption or expiration of the Rights. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights, or Rights Certificates, will be mailed to holders of record of the common stock as of the close of business on the Distribution Date and such separate Rights Certificates alone will evidence the Rights. The Rights will at no time have any voting rights.

Each share of Series A Junior Participating Preferred Stock purchasable upon exercise of the Rights will be entitled, when, as and if declared, to a minimum preferential quarterly dividend payment of $1.00 per share but will be entitled to an aggregate dividend of 1,000 times the dividend, if any, declared per share of common stock. In the event of liquidation, dissolution or winding up of the Company, the holders of the shares of Series A Junior Participating Preferred Stock will be entitled to a preferential liquidation payment of $1,000 per share plus any accrued but unpaid dividends but will be entitled to an aggregate payment of 1,000 times the payment made per share of common stock. Each share of Series A Junior Participating Preferred Stock will have 1,000 votes and will vote together with the outstanding shares of common stock. Finally, in the event of any merger, consolidation or other transaction in which shares of common stock are exchanged, each share of Series A Junior Participating Preferred Stock will be entitled to receive 1,000 times the amount received per share of common stock. The Series A Junior Participating Preferred Stock will not be redeemable. These rights are protected by customary anti-dilution provisions. Because of the nature of the Series A Junior Participating Preferred Stock’s dividend, liquidation and voting rights, the value of one one-thousandth of a share of Series A Junior Participating Preferred Stock purchasable upon exercise of each Right should approximate the value of one share of common stock.

In the event that a person becomes an Acquiring Person, or if the Company were the surviving corporation in a merger with an Acquiring Person or any affiliate or associate of an Acquiring Person and the shares of common stock were not changed or exchanged, each holder of a Right, other than Rights that are or were acquired or beneficially owned by the Acquiring Person (which Rights will thereafter be void), will thereafter have the right to receive upon exercise that number of share of common stock having a market value of two times the then current Purchase Price of one Right. In the event that, after a person has become an Acquiring Person, the Company were acquired in a merger or other business combination transaction or more than 50% of its assets or earning power were sold, proper provision shall be made so that each holder of a Right shall thereafter have the right to receive, upon the exercise thereof at the then current Purchase Price of the Right, that number of shares of common stock of the acquiring company which at the time of such transaction would have a market value of two times the then current Purchase Price of one Right.

At any time after a person becomes an Acquiring Person and prior to the earlier of one of the events described in the last sentence in the previous paragraph or the acquisition by such Acquiring Person of 50% or more of the then outstanding shares of common stock, the board of directors may cause the Company to exchange the Rights (other than Rights owned by an Acquiring Person which have become void), in whole or in part, for shares of common stock at an exchange rate of one common share per Right (subject to adjustment).

The Rights may be redeemed in whole, but not in part, at a price of $0.01 per Right, or the Redemption Price, by the board of directors at any time prior to the time that an Acquiring Person has become such. The redemption of the Rights may be made effective at such time, on such basis and with such conditions as the board of directors in its sole discretion may establish. Immediately upon any redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price.

The Rights will expire on November 15, 2014, unless earlier redeemed, exchanged or terminated. American Stock Transfer & Trust Company, LLC is the Rights Agent.

The Purchase Price payable, and the number of one one-thousandths of a share of Series A Junior Participating Preferred Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of, the shares of Series A Junior Participating Preferred Stock, (ii) upon the grant to holders of the Series A Junior Participating Preferred Stock of certain rights or warrants to subscribe for or purchase Series A Junior Participating Preferred Stock or convertible securities at less than the current market price of the Series A Junior Participating Preferred Stock or (iii) upon the distribution to holders of the Series A Junior Participating Preferred Stock of evidences of indebtedness, cash, securities or assets (excluding regular periodic cash dividends at a rate not in excess of 125% of the rate of the last regular periodic cash dividend theretofore paid or, in case regular periodic cash dividends have not theretofore been paid, at a rate not in excess of 50% of the average net income per share of the Company for the four quarters ended immediately prior to the payment of such dividend, or dividends payable in shares of Series A Junior Participating Preferred Stock (which dividends will be subject to the adjustment described in clause (i) above)) or of subscription rights or warrants (other than those referred to above).

Until a Right is exercised, the holder thereof, as such, will have no rights as a stockholder of the Company beyond those as an existing stockholder, including, without limitation, the right to vote or to receive dividends.

Any of the provisions of the Rights Agreement dated as of November 3, 2004 between the Company and the Rights Agent, or the Rights Agreement, may be amended by the board of directors for so long as the Rights are then redeemable, and after the Rights are no longer redeemable, the Company may amend or supplement the Rights Agreement in any manner that does not adversely affect the interests of the holder of the Rights.

One Right was distributed to stockholders of the Company for each share of common stock owned of record by them on November 15, 2004. As long as the Rights are attached to the shares of common stock, the Company will issue one Right with each new share of common stock so that all such shares will have attached Rights. The Company has reserved 75,000 shares of Series A Junior Participating Preferred Stock initially for issuance upon exercise of the Rights.

The Rights have certain anti-takeover effects. The Rights are designed to assure that all of the Company’s stockholders receive fair and equal treatment in the event of any proposed takeover of the Company and to guard against partial tender offers, open market accumulations and other potentially abusive tactics to gain control of the Company, while not foreclosing a fair acquisition bid for the Company. The Rights will cause substantial dilution to a person or group that acquires 15% or more of the Company’s stock on terms not approved by the board of directors. The Rights should not interfere with any merger or other business combination approved by the board of directors at any time prior to the first date that a person or group has become an Acquiring Person.

Transfer Agent And Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company, and its address is 6201 15th Street, Brooklyn, NY 11219. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the prospectus supplement for that series.

Listing on the Nasdaq Global Market

Our common stock is listed on the Nasdaq Global Market under the symbol “MITI.”

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplements or free writing prospectuses, summarizes the material terms and provisions of the debt securities that we may offer under this prospectus. We may issue debt securities, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any future debt securities we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement or related free writing prospectus. The terms of any debt securities we offer under a prospectus supplement may differ from the terms we describe below. However, no prospectus supplement shall fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness. As of the date of this prospectus, we have no outstanding registered debt securities. Unless the context requires otherwise, whenever we refer to the “indentures,” we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue any senior debt securities under the senior indenture that we will enter into with the trustee named in the senior indenture. We will issue any subordinated debt securities under the subordinated indenture that we will enter into with the trustee named in the subordinated indenture. We have filed forms of these indentures as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The indentures will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We use the term “trustee” to refer to either the trustee under the senior indenture or the trustee under the subordinated indenture, as applicable.

The following summaries of material provisions of the senior debt securities, the subordinated debt securities and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indentures that contains the terms of the debt securities. Except as we may otherwise indicate, the terms of the senior indenture and the subordinated indenture are identical.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and set forth or determined in the manner provided in an officers’ certificate or by a supplement indenture. Debt securities may be issued in separate series without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the debt securities of any series. We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

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the title;

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the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

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any limit on the amount that may be issued;

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whether or not we will issue the series of debt securities in global form, and, if so, the terms and who the depositary will be;

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the maturity date;

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whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a United States person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

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the annual interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

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whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

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the terms of the subordination of any series of subordinated debt;

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the place where payments will be payable;

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restrictions on transfer, sale or other assignment, if any;

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our right, if any, to defer payment of interest and the maximum length of any such deferral period;

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the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

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the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option, to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

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whether the indenture will restrict our ability or the ability of our subsidiaries to:

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incur additional indebtedness;

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issue additional securities;

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create liens;

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pay dividends or make distributions in respect of our capital stock or the capital stock of our subsidiaries;

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redeem capital stock;

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place restrictions on our subsidiaries’ ability to pay dividends, make distributions or transfer assets;

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make investments or other restricted payments;

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sell or otherwise dispose of assets;

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enter into sale-leaseback transactions;

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engage in transactions with stockholders or affiliates;

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issue or sell stock of our subsidiaries; or

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effect a consolidation or merger;

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whether the indenture will require us to maintain any interest coverage, fixed charge, cash flow-based, asset-based or other financial ratios;

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a discussion of any material or special United States federal income tax considerations applicable to the debt securities;

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information describing any book-entry features;

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provisions for a sinking fund purchase or other analogous fund, if any;

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the applicability of the provisions in the indenture on discharge;

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whether the debt securities are to be offered at a price such that they will be deemed to be offered at an “original issue discount” as defined in paragraph (a) of Section 1273 of the Internal Revenue Code of 1986, as amended;

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the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

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the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars; and

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any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, including any additional events of default or covenants provided with respect to the debt securities, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock, our preferred stock or other securities (including securities of a third party). We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock, our preferred stock or other securities (including securities of a third party) that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indentures will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor to or acquirer of such assets must assume all of our obligations under the indentures or the debt securities, as appropriate. If the debt securities are convertible into or exchangeable for our other securities or securities of other entities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the debt securities into securities that the holders of the debt securities would have received if they had converted the debt securities before the consolidation, merger or sale.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indentures with respect to any series of debt securities that we may issue:

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if we fail to pay interest when due and payable and our failure continues for 90 days and the time for payment has not been extended;

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if we fail to pay the principal, premium or sinking fund payment, if any, when due and payable at maturity, upon redemption or repurchase or otherwise, and the time for payment has not been extended;

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if we fail to observe or perform any other covenant contained in the debt securities or the indentures, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive notice from the trustee or we or the trustee receive notice from the holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

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if specified events of bankruptcy, insolvency or reorganization occur.

We will describe in each applicable prospectus supplement any additional events of default relating to the relevant series of debt securities.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the unpaid principal, premium, if any, and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indentures, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity or security satisfactory to it against any loss, liability or expense. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

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the direction so given by the holder is not in conflict with any law or the applicable indenture; and

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subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

The indentures provide that if an event of default has occurred and is continuing, the trustee will be required in the exercise of its powers to use the degree of care that a prudent person would use in the conduct of its own affairs. The trustee, however, may refuse to follow any direction that conflicts with law or the indenture, or that the trustee determines is unduly prejudicial to the rights of any other holder of the relevant series of debt securities, or that would involve the trustee in personal liability. Prior to taking any action under the indentures, the trustee will be entitled to indemnification against all costs, expenses and liabilities that would be incurred by taking or not taking such action.

A holder of the debt securities of any series will have the right to institute a proceeding under the indentures or to appoint a receiver or trustee, or to seek other remedies only if:

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the holder has given written notice to the trustee of a continuing event of default with respect to that series;

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the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, and such holders have offered reasonable indemnity to the trustee or security satisfactory to it against any loss, liability or expense or to be incurred in compliance with instituting the proceeding as trustee; and

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the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities, or other defaults that may be specified in the applicable prospectus supplement.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indentures.

The indentures provide that if a default occurs and is continuing and is actually known to a responsible officer of the trustee, the trustee must mail to each holder notice of the default within 45 days after it occurs, unless such default has been cured or waived. Except in the case of a default in the payment of principal or premium of or interest on any debt security or certain other defaults specified in an indenture, the trustee shall be protected in withholding such notice if and so long as the board of directors, the executive committee or a trust committee of directors, or responsible officers of the trustee, in good faith determine that withholding notice is in the best interests of holders of the relevant series of debt securities.

Modification of Indenture; Waiver

Subject to the terms of the indenture for any series of debt securities that we may issue, we and the trustee may change an indenture without the consent of any holders with respect to the following specific matters:

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to fix any ambiguity, defect or inconsistency in the indenture;

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to comply with the provisions described above under “Description of Debt Securities — Consolidation, Merger or Sale”;

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to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act;

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to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

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to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided under “Description of Debt Securities — General,” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

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to evidence and provide for the acceptance of appointment thereunder by a successor trustee;

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to provide for uncertificated debt securities and to make all appropriate changes for such purpose;

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to add to our covenants such new covenants, restrictions, conditions or provisions for the benefit of the holders, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred to us in the indenture; or

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to change anything that does not adversely affect the interests of any holder of debt securities of any series in any material respect.

In addition, under the indentures, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, subject to the terms of the indenture for any series of debt securities that we may issue or otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may only make the following changes with the consent of each holder of any outstanding debt securities affected:

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extending the stated maturity of the series of debt securities;

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reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption or repurchase of any debt securities; or

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reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

Each indenture provides that, subject to the terms of the indenture and any limitation otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

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replace stolen, lost or mutilated debt securities of the series;

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maintain paying agencies;

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hold monies for payment in trust;

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recover excess money held by the trustee;

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compensate and indemnify the trustee; and

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appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we otherwise specify in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indentures provide that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company or another depositary named by us and identified in a prospectus supplement with respect to that series. See “Legal Ownership of Securities” below for a further description of the terms relating to any book-entry securities.

At the option of the holder, subject to the terms of the indentures and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indentures and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will make no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

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issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

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register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture and is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur. However, upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

Ranking Debt Securities

The subordinated debt securities will be unsecured and will be subordinate and junior in priority of payment to certain of our other indebtedness to the extent described in a prospectus supplement. The subordinated indenture does not limit the amount of subordinated debt securities that we may issue. It also does not limit us from issuing any other secured or unsecured debt.

The senior debt securities will be unsecured and will rank equally in right of payment to all our other senior unsecured debt. The senior indenture does not limit the amount of senior debt securities that we may issue. It also does not limit us from issuing any other secured or unsecured debt.

DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplements and free writing prospectuses, summarizes the material terms and provisions of the warrants that we may issue under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be issued independently or together with common stock, preferred stock or debt securities offered by any prospectus supplement, and may be attached to or separate from those securities. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants that we may offer in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, if any, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering before the issuance of the related series of warrants. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms relating to a series of warrants being offered, including:

the offering price and aggregate number of warrants offered;

the currency for which the warrants may be purchased;

if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

if applicable, the date on and after which the warrants and the related securities will be separately transferable;

in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at which, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which, and the currency in which, these shares may be purchased upon such exercise;

the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

the terms of any rights to redeem or call the warrants;

any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

the dates on which the right to exercise the warrants will commence and expire;

the manner in which the warrant agreements and warrants may be modified;

a discussion of any material or special United States federal income tax consequences of holding or exercising the warrants;

the terms of the securities issuable upon exercise of the warrants; and

any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

Outstanding Warrants

As of June 18, 2009, there were outstanding warrants to purchase 8,222,416 shares of our common stock, of which 23,000 have an exercise price of at least $32.34 per share, 55,316 have an exercise price of at least $12.07 per share, 555,556 have an exercise price of $5.00 per share, 2,823,585 have an exercise price of $4.63 per share, 135,000 have an exercise price of $4.44 per share, 285,000 have an exercise price of $3.21 per share, and 4,344,959 have an exercise price of $3.09 per share. Certain of the outstanding warrants may be exercised for cash or on a cashless basis, in which case we will deliver, upon exercise, the number of shares with respect to which the warrant is being exercised reduced by a number of shares having a value equal to the aggregate exercise price of the shares with respect to which the warrant is being exercised.

DESCRIPTION OF UNITS

The following description, together with the additional information we may include in any applicable prospectus supplements, summarizes the material terms and provisions of the units that we may offer under this prospectus. While the terms we have summarized below will apply generally to any units that we may offer under this prospectus, we will describe the particular terms of any series of units in more detail in the applicable prospectus supplement. The terms of any units offered under a prospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from a current report on Form 8-K that we file with the SEC, the form of unit agreement that describes the terms of the series of units we are offering, and any supplemental agreements, before the issuance of the related series of units. The following summaries of material terms and provisions of the units are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and any supplemental agreements applicable to a particular series of units. We urge you to read the applicable prospectus supplements related to the particular series of units that we sell under this prospectus, as well as the complete unit agreement and any supplemental agreements that contain the terms of the units.

General

We may issue units comprised of one or more debt securities, shares of common stock, shares of preferred stock and warrants in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including:

the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

any provisions of the governing unit agreement that differ from those described below; and

any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The provisions described in this section, as well as those described under “Description of Capital Stock,” “Description of Debt Securities” and “Description of Warrants” will apply to each unit and to any common stock, preferred stock, debt security or warrant included in each unit, respectively.

Issuance in Series

We may issue units in such amounts and in numerous distinct series as we determine.

Enforceability of Rights by Holders of Units

Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act as unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as holder under any security included in the unit.

Title

We, the unit agents and any of their agents may treat the registered holder of any unit certificate as an absolute owner of the units evidenced by that certificate for any purpose and as the person entitled to exercise the rights attaching to the units so requested, despite any notice to the contrary. See “Legal Ownership of Securities.”

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee or depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Global securities will be registered in the name of the depositary or its participants. Consequently, for global securities, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities that are not issued in global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of an indenture, or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

how it handles securities payments and notices;

whether it imposes fees or charges;

how it would handle a request for the holders’ consent, if ever required;

whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “—Special Situations When A Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued as a global security, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations For Global Securities

As an indirect holder, an investor’s rights relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only as global securities, an investor should be aware of the following:

an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

an investor may not be able to pledge his or her interest in the global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in the global security;

we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in the global security, nor will we or any applicable trustee supervise the depositary in any way;

the depositary may, and we understand that DTC will, require that those who purchase and sell interests in the global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in the global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When A Global Security Will Be Terminated

In a few special situations described below, a global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.

A global security will terminate when the following special situations occur:

if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

if we notify any applicable trustee that we wish to terminate that global security; or

if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the prospectus supplement. When a global security terminates, the depositary, and neither we nor any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

at a fixed price or prices, which may be changed;

at market prices prevailing at the time of sale;

at negotiated prices.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

the name or names of any underwriters, if any;

the purchase price of the securities and the proceeds we will receive from the sale;

any over-allotment options under which underwriters may purchase additional securities from us;

any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

any public offering price;

any discounts or concessions allowed or reallowed or paid to dealers; and

any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters who are qualified market makers on the Nasdaq Global Market may engage in passive market making transactions in the securities on the Nasdaq Global Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon by Cooley Godward Kronish LLP, Reston, Virginia.

EXPERTS

The consolidated financial statements of Micromet, Inc. appearing in Micromet, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2008, and the effectiveness of Micromet, Inc.’s internal control over financial reporting as of December 31, 2008, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. The consolidated financial statements of Micromet, Inc. at December 31, 2007 and for the year then ended appearing in Micromet, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2008, have been audited by Ernst & Young AG WPG, independent registered public accounting firm, as set forth in their report thereon, included therein, and incorporated herein by reference. Such consolidated financial statements have been incorporated herein by reference in reliance upon such reports given on the authority of such firms as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a registration statement we filed with the Securities and Exchange Commission, or SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. You should rely only on the information contained in this prospectus or incorporated by reference. We have not authorized anyone else to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of common stock.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy the registration statement, as well as any other document filed by us with the SEC, at the SEC’s Public Reference Room at 100 F Street NE, Washington, D.C. 20549. You can also request copies of these documents by writing to the SEC and paying a fee for the copying cost. You may obtain information on the operation of the Public Reference Room by calling the SEC at (800) SEC-0330. The SEC maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC, including Micromet. The address of the SEC website is www.sec.gov.

We maintain a website at www.micromet-inc.com. Information contained in or accessible through our website does not constitute a part of this prospectus.

INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The SEC file number for the documents incorporated by reference in this prospectus is 0-50440. The documents incorporated by reference into this prospectus contain important information that you should read about us.

The following documents are incorporated by reference into this document:

our Annual Report on Form 10-K for the fiscal year ended December 31, 2008, filed with the SEC on March 16, 2009;

the information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2008 from our definitive proxy statement on Schedule 14A filed with the SEC on April 30, 2009 and additional definitive materials filed on the same date;

our Quarterly Report on Form 10-Q for the quarter ended March 31, 2009, filed with the SEC on May 11, 2009;

We also incorporate by reference into this prospectus all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the initial registration statement and prior to effectiveness of the registration statement, or (ii) after the date of this prospectus but prior to the termination of the offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. Requests should be directed to: Micromet, Inc., Attn: Investor Relations, 6707 Democracy Blvd., Suite 505, Bethesda, MD 20817, telephone: (240) 752-1420.

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.

DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR

SECURITIES ACT LIABILITY

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or persons controlling the registrant pursuant to the foregoing provisions, the registrant has been informed that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

14,000,000 Shares

MICROMET, INC.

Common Stock

PROSPECTUS SUPPLEMENT

Piper Jaffray
RBC Capital Markets
	Merriman Curhan Ford

July 30, 2009