– New global Phase 1 data from a randomized dose-expansion cohort of iza-bren in previously treated EGFR-mutated metastatic NSCLC demonstrate promising antitumor activity and a tolerable safety profile, supporting selection of 2.5 mg/kg D1D8 Q3W as the recommended Phase 3 dose

REDMOND, Wash., Sept. 12, 2026 /PRNewswire/ — SystImmune, Inc. (SystImmune), a clinical-stage biotechnology company, today announced an abstract for iza-bren (izalontamab brengitecan), a potentially first-in-class EGFRxHER3 bispecific antibody drug conjugate (ADC), will be presented in an oral presentation at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer (WCLC) taking place September 12 – 15 in Seoul, South Korea. Iza-bren is being developed under a license and collaboration agreement by and between SystImmune and Bristol Myers Squibb.

The global Phase 1 data being presented at WCLC 2026 evaluated iza-bren in a randomized expansion cohort across three dose levels in patients with EGFR-mutated metastatic NSCLC who had previously received a third-generation EGFR inhibitor. The randomized dose-expansion results demonstrate promising clinical activity, with higher efficacy observed at the 2.5 mg/kg dose level with a manageable safety profile, and support 2.5 mg/kg D1D8 Q3W as the recommended Phase 3 dose for IZABRIGHT-Lung01, the global registrational study of iza-bren in EGFR-mutated NSCLC following progression on a third-generation EGFR inhibitor. The data further demonstrated the consistent efficacy and safety profile in a global population as shown previously in Chinese patients. These findings further advance the global development of iza-bren in EGFR-mutated NSCLC and build upon the clinical activity reported across multiple tumor types at prior international medical meetings.

“The data being presented at WCLC provide important insights into the clinical profile of iza-bren in global patients with previously treated EGFR-mutated metastatic NSCLC,” said Jonathan Cheng, M.D., Chief Medical Officer of SystImmune. “We are encouraged by the promising antitumor activity observed in this randomized dose-expansion cohort, including the increased efficacy observed at the 2.5 mg/kg dose level. Together with the safety and pharmacokinetic findings, these results support 2.5 mg/kg D1D8 Q3W as the recommended Phase 3 dose and represent an important step forward as we advance the global registrational study, IZABRIGHT-Lung01, in patients with EGFR-mutated NSCLC following progression on a third-generation EGFR inhibitor.”

Details of the presentations at WCLC are below:‍‍

Phase 1 Global Study of Iza-bren in Patients with Metastatic EGFR-mutated NSCLC: Results of the Randomized Dose Expansion Cohort
Session Title: OA10 – Novel Antibodies and ADCs – Are They HERalding New Benchmarks?
Presentation: OA10.01
Speaker: Alexander Spira (United States)
Session Date & Time: Monday Sep 14, 2026 12:00 PM – 1:15 PM (KST)

About iza-bren
Iza-bren (BL-B01D1) is 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. Iza-bren is being developed under a license and collaboration agreement by and between SystImmune and Bristol Myers Squibb.

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.

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.

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SOURCE SystImmune, Inc.