Izalontamab brengitecan (Iza-bren) met its dual primary endpoints of progression free survival (“PFS”) and overall survival (“OS”) in an interim analysis of a Phase 3 trial (NCT06382142) conducted in China

BL-B01D1-307 is the third Phase III study in which iza-bren has achieved its primary endpoint(s)

SystImmune, Inc. (SystImmune), a clinical-stage biotechnology company, and Bristol Myers Squibb (NYSE: BMY) today announced that SystImmune’s parent company, Sichuan Biokin Pharmaceutical Co., Ltd. (Biokin), reported positive topline results from a pre-specified interim analysis of a Phase III study (BL-B01D1-307) evaluating izalontamab brengitecan (iza-bren), an EGFR×HER3 bispecific antibody-drug conjugate (ADC), in patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) whose disease progressed following prior taxane therapy.

In the pre-specified interim analysis, topline results showed that iza-bren demonstrated statistically significant and clinically meaningful improvement in both progression-free survival (PFS) and overall survival (OS) compared to chemotherapy of physician’s choice, meeting both dual primary endpoints.

This Phase III study represents the third Phase III trial in which iza-bren has achieved its primary endpoint(s). It is the first bispecific ADC in a Phase III study to report dual positive PFS/OS results in the treatment of triple-negative breast cancer.

“Patients with advanced triple-negative breast cancer who progress after standard therapies face an urgent need for more effective options,” said Dr. Yi Zhu, Chief Executive Officer of Biokin “These topline results further strengthen our confidence in iza-bren’s potential to deliver meaningful clinical benefit across multiple cancers.”

“These results underscore the potential of bispecific ADC technology targeting both EGFR and HER3 to meaningfully change outcomes in difficult‑to‑treat cancers,” said Cristian Massacesi, Executive Vice President, Chief Medical Officer and Head of Development at Bristol Myers Squibb. “We look forward to advancing the science and development of ADCs, with the hope of uncovering new options for people living with cancer.”

These data will be presented at an upcoming medical meeting.

The BL-B01D1-307 study is sponsored by SystImmune’s parent company, Sichuan Biokin Pharmaceutical Co., Ltd. (Biokin), in Mainland China. Outside of China, iza-bren is jointly developed by SystImmune and Bristol Myers Squibb (BMS) under a collaboration and exclusive license agreement.

The Center for Drug Evaluation (CDE) under China’s National Medical Products Administration (NMPA) granted Breakthrough Therapy Designation (BTD) to iza-bren for the treatment of seven indications, and the U.S. FDA has granted BTD to iza-bren for previously treated NSCLC patients with an EGFR mutation. The New Drug Applications (NDAs) for two indications of iza-bren, for the treatment of locally advanced or metastatic nasopharyngeal carcinoma and for the treatment of recurrent or metastatic esophageal squamous cell carcinoma, have been accepted by the CDE and included in the priority review process.

About BL-B01D1-307
BL-B01D1-307 is a Phase III, randomized, open-label, multi-center clinical study in China, evaluating iza-bren in patients with unresectable locally advanced or metastatic triple-negative breast cancer whose disease progressed following prior taxane therapy. The study includes dual primary endpoints of progression-free survival (PFS) and overall survival (OS). For more detailed information, please visit clinical.trials.gov (NCT06382142).

About iza-bren
SystImmune, in collaboration with BMS outside of China, is developing iza-bren (BL-B01D1), a bispecific antibody-drug conjugate (ADC) that targets both EGFR and HER3, which are highly expressed in various epithelial cancers and are known to be associated with cancer cell proliferation and survival. Iza-bren's dual mechanism of action blocks EGFR and HER3 signals to cancer cells, reducing proliferation and survival signals. In addition, upon antibody mediated internalization, iza-bren's therapeutic novel Topo1i payload is released causing cytotoxic stress that leads to cancer cell death.

About SystImmune
SystImmune is a clinical-stage biopharmaceutical company located in Redmond, WA. It specializes in developing innovative cancer treatments using its established drug development platforms, focusing on bi-specific, multi-specific antibodies, and antibody-drug conjugates (ADCs). SystImmune has several assets in various stages of clinical trials for solid tumor and hematologic indications. Alongside ongoing clinical trials, SystImmune has a robust preclinical pipeline of potential cancer therapeutics in the discovery or IND-enabling stages, representing cutting-edge biologics development.

About Bristol Myers Squibb
Bristol Myers Squibb is a global biopharmaceutical company whose mission is to discover, develop and deliver innovative medicines that help patients prevail over serious diseases. For more information about Bristol Myers Squibb, visit us at BMS.com or follow us on LinkedIn, X, YouTube, Facebook and Instagram.

SystImmune Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding the potential clinical benefits of iza-bren, the timing and outcomes of regulatory interactions, and the future development and commercialization of iza-bren. Forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially. SystImmune undertakes no obligation to update any forward-looking statements contained herein, except as required by law.

Bristol Myers Squibb Cautionary Statement Regarding Forward-Looking Statements
This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 regarding, among other things, the research, development and commercialization of pharmaceutical products. All statements that are not statements of historical facts are, or may be deemed to be, forward-looking statements. Such forward-looking statements are based on current expectations and projections about Bristol Myers Squibb’s future financial results, goals, plans and objectives and involve inherent risks, assumptions and uncertainties, including internal or external factors that could delay, divert or change any of them in the next several years, that are difficult to predict, may be beyond our control and could cause our future financial results, goals, plans and objectives to differ materially from those expressed in, or implied by, the statements. These risks, assumptions, uncertainties and other factors include, among others, that the expected benefits of, and opportunities related to, the collaboration with SystImmune may not be realized by Bristol Myers Squibb or may take longer to realize than anticipated, that iza-bren (BL-B01D1) may not receive regulatory approval for the indications described in this release in the currently anticipated timeline or at all, any marketing approvals, if granted, may have significant limitations on their use and, if approved, whether such product candidates will be commercially successful.

No forward-looking statement can be guaranteed. Forward-looking statements in this press release should be evaluated together with the many risks and uncertainties that affect Bristol Myers Squibb’s business and market, particularly those identified in the cautionary statement and risk factors discussion in Bristol Myers Squibb’s Annual Report on Form 10-K for the year ended December 31, 2025, as updated by our subsequent Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings with the Securities and Exchange Commission. The forward-looking statements included in this document are made only as of the date of this document and except as otherwise required by applicable law, Bristol Myers Squibb undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise.

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