Izalontamab Brengitecan (EGFRxHER3 ADC) Granted Breakthrough Therapy Designation by U.S. FDA for Patients with Previously Treated Advanced EGFR-Mutated Non-Small Cell Lung Cancer

• First Breakthrough Therapy Designation in the U.S. for SystImmune and Bristol Myers Squibb's Izalontamab brengitecan (Iza-bren) based on data from the BL-B01D1-101 (CN), BL-B01D1-203 (CN), and BL-B01D1-LUNG-101 (U.S.,/EU) studies

REDMOND, Wash. and PRINCETON, N.J., Aug. 18, 2025 /PRNewswire/ -- SystImmune Inc. (SystImmune), a clinical-stage biotechnology company, and Bristol Myers Squibb (NYSE: BMY) today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation (BTD) to izalontamab brengitecan (iza-bren) for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor (EGFR) exon 19 deletions or exon 21 L858R substitution mutations whose disease has progressed on or after treatment with an EGFR tyrosine kinase inhibitor (TKI) and platinum-based chemotherapy.

Iza-bren is a potential first-in-class bispecific antibody-drug conjugate (ADC) which targets both epidermal growth factor receptor and human epidermal growth factor receptor 3 (EGFRxHER3) with a topoisomerase 1 inhibitor payload. Iza-bren is being developed by Biokin in China and jointly developed by SystImmune and Bristol Myers Squibb under a collaboration and exclusive license agreement in territories outside of China.

The granting of BTD underscores the strength of these data and highlights the potential of iza-bren to address the significant clinical unmet need patients face after EGFR TKI and platinum-based chemotherapy treatment. While EGFR TKIs have shown clinical efficacy in the frontline setting, most patients eventually see their cancer progress after about 18 months. Subsequent treatment options often contain platinum-based chemotherapy, which are of limited efficacy and come with significant toxicities. Breakthrough Therapy Designation from the US FDA is intended to expedite the development and review of drugs that may demonstrate significant benefit over current standards of care.

The FDA's decision was based on efficacy and safety data from three ongoing clinical trials: BL-B01D1-101 and BL-B01D1-203, conducted in China by Sichuan Biokin Pharmaceutical Co., Ltd., and the global BL-B01D1-LUNG-101 study conducted by SystImmune across the United States, Europe and Japan. Across these trials, iza-bren demonstrated evidence to suggest improved efficacy with a manageable safety profile in patients with EGFR-mutant NSCLC who had progressed after third-generation EGFR TKIs and platinum-based chemotherapy.

"The FDA's granting of Breakthrough Therapy Designation underscores the potential of iza-bren to meaningfully improve clinical outcomes for patients with previously treated epidermal growth factor receptor mutation NSCLC," said Dr. Jonathan Cheng, Chief Medical Officer of SystImmune. "The data we have generated to date suggest that iza-bren could address a critical unmet need in patient care, and we look forward to working closely with the FDA to conduct the relevant clinical studies and seek regulatory approval."

About EGFRmt NSCLC
Non-small cell lung cancer (NSCLC) accounts for approximately 80% of all lung cancer cases, which remains the leading cause of cancer-related death worldwide. Among patients with NSCLC, 10% to 15% in Western populations and up to 50% in Asian populations harbor activating EGFR mutations. These tumors, most commonly of non-squamous histology, initially respond to EGFR TKIs such as osimertinib. However, resistance is nearly universal, often occurring after about 18 months, and treatment options beyond TKIs and platinum-based chemotherapy provide limited clinical benefit with significant toxicities, highlighting the critical need for new, effective therapies.

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 targets that 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 payload is released causing genotoxic stress that leads to cancer cell death.

About SystImmune
SystImmune is a clinical-stage biopharmaceutical company located in Redmond, WA and Princeton, NJ. 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
Any research and development information provided by SystImmune is intended for general information purposes only. Such information is not intended to provide complete medical information. We do not offer patient-specific treatment advice and if you have medical conditions, please see your medical doctor or healthcare provider.

This press release may contain forward-looking statements with the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, and the Private Securities Litigation Reform Act of 1995, which reflects the expectations regarding the company's goals, strategies, results of operations, performance, business prospects, and opportunities, including but not limited to the ability to gain Investigational New Drug status for the resulting new product and the ability to develop a successful formulation. Terms such as "anticipates," "believes," "expects," "estimates," "could," "intends," "may," "plans," "potential," "projects," "will," "would" and other similar expressions, or the negative of these terms, are generally indicative of forward-looking statements.

While SystImmune, Inc. believes that expectations expressed in the forward-looking statements are based on the company's reasonable assumptions and beliefs in light of the information available to the company at the time such statements are made, it cannot give assurance that such forward-looking statements will prove to have been correct. Such forward-looking statements are not fact and are subject to uncertainties and other factors that could cause actual results to differ materially from such statements. We undertake no obligation to update any forward-looking statements contained in this press release to reflect events or circumstances occurring after its date or to reflect the occurrence of unanticipated events.

For additional information about the company, please visit https://systimmune.com/.

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 described herein and the collaboration with SystImmune. 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 our 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 the therapeutic potential of Iza-bren (BL-B01D1) may change, that Bristol Myers Squibb may fail to discover and develop any commercially successful product candidates through the collaboration with SystImmune, that such product candidates may not receive regulatory approval for the indications described in this release 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, 2024, 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.

SOURCE SystImmune, Inc.