SystImmune and Bristol Myers Squibb announce positive Phase III topline results for izalontamab brengitecan (iza-bren), an EGFR×HER3 bispecific ADC, showing significant PFS and OS benefits in taxane-pretreated advanced TNBC patients.
Written By: Pharmacally Medical News Desk
SystImmune, Inc., a clinical-stage biotech firm, alongside Bristol Myers Squibb, announced positive topline results from a pre-specified interim analysis of the Phase III BL-B01D1-307 study.
The trial evaluated izalontamab brengitecan (iza-bren), an investigational EGFR×HER3 bispecific antibody-drug conjugate (ADC), in patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) that progressed after prior taxane therapy.
Iza-bren met both dual primary endpoints, delivering statistically significant and clinically meaningful improvements in progression-free survival (PFS) and overall survival (OS) versus physician’s choice chemotherapy.
This marks the third Phase III trial where iza-bren has hit its primary endpoint(s) and the first bispecific ADC to report dual positive PFS/OS data in TNBC.
“Patients with advanced TNBC post-standard therapies urgently need better options,” said Dr. Yi Zhu, CEO of SystImmune’s parent company, Sichuan Biokin Pharmaceutical Co., Ltd. (Biokin). “These results bolster our confidence in iza-bren’s potential across multiple cancers.”
Bristol Myers Squibb’s Executive VP and Chief Medical Officer, Cristian Massacesi, added, “These findings highlight bispecific ADC technology’s promise in tackling hard-to-treat cancers. We’re excited to advance ADC development for cancer patients.”
Sponsored by Biokin in mainland China (NCT06382142), the randomized, open-label study underscores iza-bren’s dual action: it blocks EGFR/HER3 signaling to curb cancer cell proliferation and releases a novel Topo1i payload intracellularly for cytotoxic effects. Outside China, SystImmune and BMS co-develop the asset under an exclusive license.
Iza-bren has secured Breakthrough Therapy Designation from China’s NMPA CDE for seven indications and from the U.S. FDA for EGFR-mutated NSCLC post-prior treatment. NDAs for nasopharyngeal carcinoma and esophageal squamous cell carcinoma are under priority review by the CDE. Full data will be presented at an upcoming medical meeting.
This milestone reinforces iza-bren’s broad potential in EGFR/HER3-driven solid tumors, addressing high unmet needs in oncology.
References
SystImmune and Bristol Myers Squibb Highlight Positive Phase III Interim Topline Results for izalontamab brengitecan (Iza-bren) in Previously Treated Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer, 26 February 2026, https://systimmune.com/news—systimmune-and-bristol-myers-squibb-highlight-positive-phase-iii-interim-topline-results-for-izalontamab-brengitecan-iza-bren.html
SystImmune and Bristol Myers Squibb Highlight Positive Phase III Interim Topline Results for izalontamab brengitecan (Iza-bren) in Previously Treated Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer, 26 February 2026, Bristol Myers Squibb – SystImmune and Bristol Myers Squibb Highlight Positive Phase III Interim Topline Results for izalontamab brengitecan (Iza-bren) in Previously Treated Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer
A Study Comparing BL-B01D1 With Chemotherapy of Physician’s Choice in Patients with Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer, ClinicalTrials.gov ID NCT06382142, https://clinicaltrials.gov/study/NCT06382142