Multicenter phase 2 trial of first-line ivonescimab plus chemotherapy for advanced triple-negative breast cancer

Ivonescimab is a PD-1 and VEGF targeted bispecific antibody. A multicenter phase 2 trial in China evaluated first-line ivonescimab plus chemotherapy for locally advanced unresectable or metastatic triple-negative breast cancer (TNBC). Patients received intravenous ivonescimab 20 mg/kg every two weeks and intravenous paclitaxel 90 mg/m² or nab-paclitaxel 100 mg/m² on days 1, 8, and 15 of 4-week cycles. Primary endpoints were safety and investigator-assessed objective response rate (ORR). A total of 36 patients were enrolled, with a median follow-up duration of 22.1 months. The primary endpoints were met. Treatment-related adverse events (TRAEs) occurred in all patients, and grade 3 or 4 TRAEs in 21 patients (58.3%); there were no grade 5 TRAEs. Immune-related adverse events occurred in 15 patients (41.7%); grade 3 or 4 events in four patients (11.1%). Among 35 evaluable patients, the ORR was 80% (95% CI 63.1-91.6), including two (5.7%) complete responses. The authors conclude that ivonescimab plus chemotherapy demonstrated encouraging antitumor activity as first-line therapy for advanced TNBC.