Sacituzumab Govitecan for Endocrine-Refractory Metastatic Breast Cancer

In a prior analysis of the industry-funded, international, randomized, open-label, phase 3 TROPiCS-02 trial, sacituzumab govitecan (SG) — a Trop-2–directed antibody–drug conjugate approved for the treatment of triple-negative metastatic breast cancer — conferred a significant improvement in progression-free survival compared with traditional single-agent chemotherapy in patients with endocrine-refractory HR+ and HER2− metastatic breast cancer (J Clin Oncol 2022; 40:3365).

Now, investigators report results of the protocol-specified final analysis of overall survival (OS) and other secondary endpoints of TROPiCS-02. The trial included 543 women (median age, 56; 90% white) who had received at least one previous endocrine therapy, a taxane, a CDK4/6 inhibitor in any setting, and two to four prior chemotherapy regimens. Patients were randomized to receive SG or physician's choice of chemotherapy (eribulin, vinorelbine, capecitabine, or gemcitabine).

At a median follow-up of 12.5 months, OS was significantly improved with SG versus chemotherapy (median 14.4 vs. 11.2 months; P=0.020); survival benefit was consistent across Trop-2 expression-level subgroups (high, intermediate, low). The objective response rate was improved with SG versus chemotherapy (21% vs. 14%; P=0.035), as was time to deterioration of quality-of-life (median 4.3 vs. 3.0 months; P=0.0059). No new safety concerns were identified.