Izalontamab brengitecan for HR+/HER2- breast cancer in China (PANKU-Breast01): a randomised, phase 3 trial.

Izalontamab brengitecan improved progression-free survival versus chemotherapy in 383 Chinese women with pretreated HR+/HER2- breast cancer, with median 8.2 vs 4.0 months (HR 0.41).

• Why it matters: Heavily pretreated HR+/HER2- breast cancer has few options, and a new therapy is needed that can extend disease control beyond endocrine therapy, CDK4/6 inhibitors, and prior chemotherapy.
• What they did: In this randomised, open-label phase 3 trial across 72 hospitals in China, 383 patients received izalontamab brengitecan 2.5 mg/kg on day 1 and day 8 every 3 weeks or physician’s choice chemotherapy, with progression-free survival assessed by blinded independent central review per RECIST v1.1.
• The result: Grade 3+ treatment-related adverse events were more frequent with izalontamab brengitecan (85% vs 66%), and two treatment-related deaths occurred; overall survival data were immature and no OS benefit was established.