Trastuzumab Rezetecan Plus Bevacizumab in Platinum-Sensitive Recurrent Ovarian Cancer

This study is a prospective, multicenter, single-arm, open-label phase II clinical trial. It is planned to enroll 53 subjects with HER2-expressing (IHC 1+, 2+, or 3+) partially platinum-sensitive recurrent epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer (defined as disease recurrence occurring ≥6 months and \<12 months after the completion of the last platinum-containing therapy). The study adopts a two-stage sequential treatment strategy: Stage 1: All enrolled subjects will receive Trastuzumab Rezetecan (4.8 mg/kg IV, Q3W) combined with Bevacizumab (7.5 mg/kg IV, Q3W). Trastuzumab Rezetecan will be administered for a maximum of 1 year, or until disease progression, unacceptable toxicity, or other protocol-defined discontinuation criteria are met, whichever occurs first; Bevacizumab will be continued until disease progression, unacceptable toxicity, or other protocol-defined reasons. Stage 2: Upon confirmed disease progression in Stage 1, subjects will enter Stage 2 to receive platinum-based chemotherapy (e.g., Carboplatin + Paclitaxel, Carboplatin + Liposomal Doxorubicin, or Carboplatin + Gemcitabine ± Bevacizumab; Cisplatin or Nedaplatin may replace Carboplatin in cases of intolerance, including but not limited to these regimens, determined by the investigator) until subsequent disease progression or unacceptable toxicity. The primary objective is to evaluate progression-free survival 1 (PFS1) of SHR-A1811 combined with bevacizumab based on RECIST v1.1. Secondary objectives include objective response rate (ORR), disease control rate (DCR), progression-free survival 2 (PFS2), overall survival (OS), and safety and tolerability.