This is a single-arm, multicenter, Phase II clinical study aiming to explore the efficacy and safety of Sacituzumab Govitecan combined with Bevacizumab as a second-line or later treatment for patients with metastatic triple-negative breast cancer (mTNBC). The study will be conducted in 6-8 centers in China.
The study is divided into two phases: a Safety Run-in Phase and a Dose Expansion Phase.
In the Safety Run-in Phase (3-12 patients), three dose levels are planned to determine the recommended dose. The starting dose (Level 1) is Sacituzumab Govitecan 10 mg/kg (Days 1, 8) plus Bevacizumab 7.5 mg/kg (Day 1) every 21 days. Based on the occurrence of Dose-Limiting Toxicities (DLT) in the first cycle, the Safety Monitoring Committee (SMC) will decide whether to continue the current dose or de-escalate to Level 2 (Sacituzumab Govitecan 10 mg/kg + Bevacizumab 5 mg/kg) or Level 3 (Sacituzumab Govitecan 7.5 mg/kg + Bevacizumab 5 mg/kg).
In the Dose Expansion Phase, 40-50 patients will be enrolled to receive the combination therapy at the recommended dose determined in the run-in phase. Efficacy will be evaluated every 2 cycles according to RECIST 1.1, and safety will be assessed continuously until disease progression or intolerable toxicity.