Effectiveness, safety, and biomarker analysis of sacituzumab govitecan in Chinese metastatic breast cancer: a multicenter real-world study

Background: Sacituzumab govitecan (SG), an anti-Trop-2 antibody-drug conjugate (ADC), was approved for metastatic triple-negative breast cancer (mTNBC) with ⩾1 prior therapy and hormone receptor-positive (HoR+) breast cancer progressing on cyclin-dependent kinase 4/6 inhibitor and chemotherapy. However, little real-world evidence is available in China, and the potential predictive biomarker of SG has not been fully investigated. Objectives: Our study aimed to evaluate the effectiveness, safety, and biomarker of SG in Chinese metastatic breast cancer (MBC) patients. Design: A total of 165 MBC patients treated with SG between June 2023 and December 2024 in 4 institutions nationwide were included in this study. SG was administered intravenously at a dosage of 10 mg/kg on days 1 and 8 of a 21-day treatment cycle. Methods: Demographic and clinical data were retrospectively collected and analyzed. Clinical outcomes included real-world progression-free survival (rwPFS), overall survival (OS), objective response rate (ORR), disease control rate, and toxicity. Results: In 103 mTNBC patients, median rwPFS was 5.1 months (95% confidence interval (CI): 3.8–7.4) and median rwOS was 19.7 months (95% CI: 17.3–not reached); in 62 HoR+HER2− patients, median rwPFS was 5.8 months (95% CI: 4.7–7.9), and OS data were immature. Prior PD-1/PD-L1 inhibitors exposure in TNBC showed significantly shorter rwPFS ( p = 0.025) in multivariate analysis. Longer rwPFS was observed in patients receiving SG as front line (line 1–2) compared to later line (line ⩾3) in both populations. mTNBC patients harboring PIK3CA mutation were associated with reduced PFS of SG ( p = 0.034). No new safety signal was observed in this study. Conclusion: In conclusion, SG showed similar effectiveness with ASCENT and TROPiCS-02 study in heavily pretreated Chinese MBC patients. Given the compromised effectiveness in patients with prior PD-1/PD-L1 inhibitors or PIK3CA mutation, future investigations are warranted to explore SG-based combination regimens or novel therapeutic strategies in the above population.