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The first phase 3 win for a bispecific ADC, in triple-negative breast cancer, announced February 2026.
BL-B01D1-307, trial NCT06382142 sponsored by SystImmune and Bristol Myers Squibb and announced on 26 February 2026, delivered the first phase 3 win for a bispecific antibody-drug conjugate, izalontamab brengitecan, in previously treated locally advanced or metastatic triple-negative breast cancer. It randomised 418 patients in China to the EGFR by HER3 conjugate or chemotherapy and met its primary progression-free survival endpoint by blinded review and its interim overall survival endpoint with statistically significant and clinically meaningful improvements, with full data at ASCO 2026 and a parallel positive phase 3 in oesophageal squamous cell carcinoma. It has not been replicated outside China, and the global first-line IZABRIGHT-Breast01 trial will show whether the result travels, which is the open question.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
418 enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Progression-free survival (BICR)primary | Izalontamab brengitecan | 207 | 8.5 months | 0.29 (0.22 to 0.38) | <0.0001 | link |
| Chemotherapy (TPC) | 211 | 3.1 months | ||||
| Overall survival (interim, median follow-up 11 months)primary | Izalontamab brengitecan | - | 15.9 months | 0.6 (0.42 to 0.85) | 0.0019 | link |
| Chemotherapy (TPC) | - | 12.5 months | ||||
| Confirmed objective response rate (BICR) | Izalontamab brengitecan | - | 51.7% | - | - | - |
| Chemotherapy (TPC) | - | 20.5% |
Shares TNBC roadmap: from 'nothing to target' to ADC + immunotherapy first line, Bispecific ADC, Izalontamab brengitecan, Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.
Shares Bispecific ADC, Izalontamab brengitecan.