Late-breaking results to be presented in an oral presentation at ESMO 2026
With two positive Phase 3 trials in breast cancer, these data reinforce the potential of iza-bren to further redefine treatment across breast cancer subtypes
Iza-bren, a potentially first-in-class dual-targeting EGFRxHER3 bispecific antibody-drug conjugate, has now demonstrated clinical benefit in five distinct tumor types
SystImmune, Inc. (SystImmune), a clinical-stage biotechnology company, and Bristol Myers Squibb (NYSE:BMY) today announced that SystImmune’s parent company Sichuan Biokin Pharmaceutical, Ltd. (Biokin) reported positive results from a prespecified interim analysis of the randomized Phase 3 PANKU-Breast01 study (NCT06343948) evaluating izalontamab brengitecan (iza-bren), an investigational, potentially first-in-class, dual-targeting EGFRxHER3 bispecific antibody-drug conjugate (ADC), versus chemotherapy in patients with unresectable locally advanced, recurrent or metastatic hormone receptor-positive (HR+)/HER2-negative (HER2-) breast cancer who have failed at least one prior line of chemotherapy. Results will be presented today in a late-breaking oral presentation at the European Society for Medical Oncology (ESMO) 2026 Annual Congress taking place October 23–27 in Madrid, Spain, and simultaneously published in The Lancet.
With a median follow-up for progression-free survival (PFS) of 15.2 months, results showed iza-bren (n=190) reduced the risk of disease progression or death, the study’s primary endpoint, by 59%, with median PFS vs. chemotherapy (n=193) of 8.2 months vs. 4.0 months as assessed by Blinded Independent Central Review (BICR) [HR: 0.41; 95% CI: 0.33-0.53, p<0.0001]. Overall survival, a key secondary endpoint of the study, was immature at the time of interim analysis. Confirmed objective response rate (cORR) by BICR was 40.5% with iza-bren vs. 20.2% with chemotherapy, and median duration of response (mDOR) was 6.9 months vs. 4.2 months, respectively.