A Phase IIb, single arm, multicenter trial of sacituzumab govitecan in Chinese patients with metastatic triple‐negative breast cancer who received at least two prior treatments

Abstract

AbstractRefractory or relapsing metastatic triple‐negative breast cancer (mTNBC) has a poor prognosis. Sacituzumab govitecan (SG) is a novel antibody‐drug conjugate, targeting human trophoblast cell‐surface antigen 2 (Trop‐2). This is the first report of SG's efficacy and safety in Chinese patients with mTNBC. EVER‐132‐001 (NCT04454437) was a multicenter, single‐arm, Phase IIb study in Chinese patients with mTNBC who failed ≥2 prior chemotherapy regimens. Eligible patients received 10 mg/kg SG on Days 1 and 8 of each 21‐day treatment cycle, until disease progression/unacceptable toxicity. The primary endpoint was objective response rate (ORR) assessed by the Independent Review Committee. Secondary endpoints included: duration of response (DOR), clinical benefit rate (CBR), progression‐free survival (PFS), overall survival (OS) and safety. Eighty female Chinese patients (median age 47.6 years; range 24‐69.9 years) received ≥1 SG dose with a median of 8 treatment cycles by the cutoff date (August 6, 2021). Median number of prior systemic cancer treatments was 4.0 (range 2.0‐8.0). ORR and CBR were reported 38.8% (95% confidence interval [CI]: 28.06‐50.30) and 43.8% (95% CI, 32.68‐55.30) of patients, respectively. The median PFS was 5.55 months (95% CI, 4.14‐N/A). SG‐related Grade ≥3 treatment‐emergent adverse events (TEAEs) were reported in 71.3%, the most common were neutrophil count decreased (62.5%), white blood cell count decreased (48.8%) and anemia (21.3%); 6.3% discontinued SG because of TEAEs. SG demonstrated substantial clinical activity in heavily pretreated Chinese patients with mTNBC. The observed safety profile was generally manageable.