Bristol Myers, SystImmune report global Phase 1 results of Iza-bren

SystImmune and Bristol Myers (BMY) Squibb announced the oral presentation of the first disclosure of the safety and efficacy data from the global phase I US-Lung-101 study of iza-bren, a potentially first-in-class EGFR x HER3 bispecific antibody-drug conjugate, at the European Society for Medical Oncology Congress 2025 in Berlin, Germany. Iza-bren is jointly developed by SystImmune and Bristol Myers Squibb under a collaboration and exclusive license agreement in territories outside of Mainland China. In August 2025, iza-bren was granted breakthrough therapy designation by U.S. FDA for patients with previously treated EGFR-mutated NSCLC based on the data from China studies and this global study. This study evaluated the safety and efficacy of iza-bren in global patients with heavily pre-treated metastatic or unresectable advanced non-small cell lung cancer and other solid tumors. At the data cut-off of July 23, 2025, iza-bren has demonstrated: Promising antitumor activity in heavily pre-treated patients across multiple tumor types, including EGFR mutant and wildtype NSCLC; Manageable safety profile, with hematologic adverse events effectively managed by standard medical measures, and no interstitial lung disease was observed In the study, 107 patients with advanced solid tumors were treated, including non-small cell lung cancer patients with and without EGFR mutations. Most had received several prior therapies. The most common side effects were blood-related, such as neutropenia. These were generally manageable and rarely led to dose reductions or serious complications. No new safety concerns were identified, and no cases of interstitial lung disease were seen. Mandatory preventive measures for neutropenia have been added in ongoing global studies. For patients receiving 2.5 mg/kg, 55% showed a confirmed response, with a median progression-free survival of 5.4 months. Confirmed responses were also seen in both the subgroup with EGFR-mutated NSCLC and those without the mutation. Global registrational studies of first line metastatic TNBC, second line metastatic EGFRmt NSCLC and second line metastatic Urothelial Cancer are ongoing, with studies in other indications planned.