SystImmune And Bristol Myers Squibb Present Promising Global Phase I Results For Iza-bren In NSCLC At ESMO 2025

SystImmune Inc. and Bristol Myers Squibb unveiled the first safety and efficacy results from the global Phase I US-Lung-101 study (NCT05983432) of iza-bren (BL-B01D1), an EGFR x HER3 bispecific antibody-drug conjugate (ADC), at the European Society for Medical Oncology (ESMO) Congress 2025 in Berlin. Iza-bren, co-developed under a global collaboration (excluding Mainland China), recently received U.S. FDA Breakthrough Therapy Designation in August 2025 for patients with previously treated EGFR-mutated non-small cell lung cancer (NSCLC) based on strong data from China and global studies.

"The first global presentation of iza-bren builds on the compelling data initially observed in Chinese patients, showing consistent efficacy in a heavily pre-treated global population," said Jonathan Cheng, M.D., Chief Medical Officer, SystImmune. "These results support iza-bren's potential as a bispecific ADC treatment option across multiple tumor types, and we are excited to continue advancing this important program through our global collaboration with Bristol Myers Squibb."

The study assessed iza-bren’s safety and efficacy in heavily pre-treated patients with advanced or metastatic NSCLC and other solid tumors. As of July 23, 2025, the ADC demonstrated notable antitumor activity across multiple tumor types, including EGFR-mutant and wildtype NSCLC, with a manageable safety profile. Most treatment-related side effects were hematologic, such as neutropenia, which were manageable with standard interventions. Notably, no cases of interstitial lung disease were reported.

"We are committed to developing first-in-class and best-in-class medicines that can meaningfully improve outcomes for patients with difficult-to-treat cancers," said Anne Kerber, Senior Vice President, Head of Development, Hematology, Oncology and Cell Therapy, Bristol Myers Squibb. "The encouraging activity observed with iza-bren in this early global study reinforce our confidence in its potential, and we look forward to the ongoing registrational studies across lung, breast, and urothelial cancers."

Among patients receiving 2.5 mg/kg (Days 1 and 8 every 3 weeks), 55% (11 of 20) achieved confirmed responses, with a median progression-free survival (PFS) of 5.4 months. Responses were observed in both EGFR-mutated (3 of 10) and EGFR-wildtype (3 of 4) subgroups. The companies are advancing global registrational trials — IZABRIGHT-Breast01 for metastatic triple-negative breast cancer, IZABRIGHT-Lung01 for EGFR-mutated NSCLC, and IZABRIGHT-Bladder01 for urothelial cancer — alongside additional studies in other solid tumors.