Human Genome Sciences Announces Multiple Abstracts Related to BENLYSTA® and Systemic Lupus Erythematosus to Be Presented at the 2012 EULAR Annual European Congress of Rheumatology

Human Genome Sciences, Inc. (Nasdaq: HGSI) announced today that several abstracts related to BENLYSTA® (belimumab) and systemic lupus erythematosus (SLE) will be presented at the EULAR Annual European Congress of Rheumatology, being held in Berlin, Germany from June 6 to June 9, 2012. A total of seven abstracts – all posters – have been accepted for presentation, five clinical trial data abstracts and two health economics and outcomes research (HEOR) abstracts.

Belimumab is the first in a drug class known as BLyS-specific inhibitors. Belimumab was approved by the U.S. Food and Drug Administration (FDA) on March 9, 2011 for the treatment of adult patients with active, autoantibody-positive systemic lupus erythematosus (SLE) who are receiving standard therapy. Limitations of use: The efficacy of belimumab has not been evaluated in patients with severe active lupus nephritis or severe active central nervous system lupus. Belimumab has not been studied in combination with other biologics or intravenous cyclophosphamide. Use of belimumab is not recommended in these situations. Belimumab is currently administered as a one-hour intravenous infusion given at 2-week intervals for the first 3 doses and at 4-week intervals thereafter.

In Europe, belimumab was approved by the European Commission on July 13, 2011. It is indicated as an add-on therapy in adult patients with active autoantibody-positive systemic lupus erythematosus, with a high degree of disease activity (e.g., positive anti-dsDNA and low complement), despite standard therapy. The summary of product characteristics (SmPC) lists patient groups which have not been studied with belimumab, including severe active CNS lupus and severe active lupus nephritis. Use of belimumab is therefore not recommended to treat these conditions. Caution should be exercised if belimumab is co-administered with other B-cell targeted therapy or intravenous cyclophosphamide, as it has not been studied in combination with these agents.

The clinical abstracts examine the impact of BENLYSTA on patients with SLE, including its efficacy and safety, its early clinical improvement and its impact in patients also being treated with mycophenolate mofetil and/or corticosteroids. In addition, predictors of moderate-to-severe SLE flares were evaluated from the placebo groups in the phase 3 BLISS trials. The HEOR analyses explore the prevalence of SLE in Europe as well as the impact of lupus on healthcare utilization following early diagnosis versus late diagnosis.

For complete information on all presentations and abstracts, please visit the EULAR website at www.eular.org.

IMPORTANT SAFETY INFORMATION

CONTRAINDICATION

BENLYSTA is contraindicated in patients who have had anaphylaxis with belimumab.

WARNINGS AND PRECAUTIONS

MORTALITY

There were more deaths reported with BENLYSTA than with placebo during the controlled period of the clinical trials. Out of 2133 patients in 3 clinical trials, a total of 14 deaths occurred in the following groups: 3/675 in placebo, 5/673 in BENLYSTA 1 mg/kg, 0/111 in BENLYSTA 4 mg/kg, and 6/674 in BENLYSTA 10 mg/kg. No single cause of death predominated. Etiologies included infection, cardiovascular disease, and suicide.

SERIOUS INFECTIONS

Serious and sometimes fatal infections have been reported in patients receiving immunosuppressive agents, including BENLYSTA. Caution should be exercised when considering use in patients with a history of chronic infections. Patients receiving therapy for a chronic infection should not receive BENLYSTA. Consider interrupting BENLYSTA therapy in patients who develop a new infection while receiving BENLYSTA. The most frequent serious infections included pneumonia, urinary tract infection, cellulitis, and bronchitis.

MALIGNANCY

The impact of treatment with BENLYSTA on the development of malignancies is not known. As with other immunomodulating agents, the mechanism of action of BENLYSTA could increase the risk of malignancies.

HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS) AND INFUSION REACTIONS

Hypersensitivity reactions, including anaphylaxis and death, have been reported with BENLYSTA. Delay in the onset of acute hypersensitivity reactions has been observed. Patients with a history of multiple drug allergies or significant hypersensitivity may be at increased risk. Some patients received premedication; however, there is insufficient evidence to determine whether premedication diminishes the frequency or severity of these reactions.

Healthcare providers should be aware of the risk of hypersensitivity reactions, which may present as infusion reactions, and monitor patients closely. Manifestations of hypersensitivity included hypotension, angioedema, urticaria or other rash, pruritus, and dyspnea. In the event of a serious hypersensitivity reaction, discontinue BENLYSTA immediately and administer appropriate medical therapy. Infusion-associated adverse events were also reported. Serious infusion reactions included bradycardia, myalgia, headache, rash, urticaria, and hypotension. In the event of an infusion reaction, the infusion rate may be slowed or interrupted.

Patients should be informed of the signs and symptoms of a hypersensitivity reaction and instructed to seek immediate medical care should a reaction occur.

DEPRESSION

In clinical trials, psychiatric events (primarily depression, insomnia, and anxiety) were reported more frequently with BENLYSTA than with placebo. Serious psychiatric events, serious depression, and two suicides were also reported. It is unknown if BENLYSTA treatment is associated with increased risk for these events. Instruct patients to contact their healthcare provider if they experience new or worsening depression, suicidal thoughts, or other mood changes.

IMMUNIZATION

Live vaccines should not be given for 30 days before or concurrently with BENLYSTA. BENLYSTA may interfere with the response to immunizations.

USE WITH BIOLOGIC THERAPIES OR IV CYCLOPHOSPHAMIDE

BENLYSTA has not been studied in combination with other biologic therapies, including B-cell targeted therapies, or IV cyclophosphamide. Therefore, use of BENLYSTA is not recommended in combination with these therapies.

ADVERSE REACTIONS

The most commonly reported adverse reactions (≥5%) were nausea, diarrhea, pyrexia, nasopharyngitis, bronchitis, insomnia, pain in extremity, depression, migraine, and pharyngitis.

OTHER IMPORTANT INFORMATION

USE IN SPECIFIC POPULATIONS

Pregnancy: Category C. BENLYSTA should be used during pregnancy only if the potential benefit outweighs the risk. Women of childbearing potential should use adequate contraception during BENLYSTA treatment and for at least 4 months after the last dose.

Effect in black/African American patients: In exploratory analyses of 2 Phase III trials, response rates were lower for black patients (N=148) in the BENLYSTA group relative to black patients in the placebo group. In the Phase II trial, black patients (N=106) in the BENLYSTA group did not appear to have a different response than the rest of the study population. Although no definitive conclusions can be drawn from these analyses, caution should be used when considering BENLYSTA for black/African American patients.

ABOUT THE HGS/GSK COLLABORATION

HGS and GlaxoSmithKline (GSK) are developing belimumab under a definitive co-development and co-commercialization agreement entered into in 2006. Under the agreement, HGS had responsibility for conducting the belimumab Phase 3 trials, with assistance from GSK. The companies share equally in Phase 3/4 development costs, sales and marketing expenses, and profits of any product commercialized under the current agreement.

ABOUT HUMAN GENOME SCIENCES

Human Genome Sciences exists to place new therapies into the hands of those battling serious disease. For more information about HGS, please visit the Company’s web site at www.hgsi.com. HGS, Human Genome Sciences and BENLYSTA are trademarks of Human Genome Sciences, Inc. Other trademarks referenced are the property of their respective owners.