762P Pamiparib combined with surufatinib as a neoadjuvant therapy for advanced ovarian cancer patients in the entire population: Preliminary results of a prospective, exploratory, single-arm phase II clinical study

Optimal tumor reduction surgery is crucial for for advanced ovarian cancer (OC) prognosis. Neoadjuvant chemotherapy can increase surgery chances for OC, but the benefit to patients (pts) is limited. PARP inhibitors combined with anti-angiogenic drugs have significant benefits in the first-line maintenance and recurrence treatment of OC. This study aims to evaluate the efficacy and safety of Pamiparib combined with Surufatinib neoadjuvant therapy (NAT) for advanced unresectable OC in the entire population. This is a single-center, single-arm, phase II study following Simon's two-stage design. 20 pts with newly diagnosed unresectable (Fagotti score ≥ 8 or upper abdominal CT score ≥ 3) FIGO III-IV OC were recruited. Enrolled pts will receive NAT with Pamiparib (40 mg bid q3w for 3 cycles) combined with Surufatinib (250mg bid q3w for 2 cycles), followed by interval debulking surgery (IDS) and4 cycles of platinum-containing chemotherapy. The primary endpoint is complete resection rate (R0), and secondary endpoints include objective response rate (ORR), pathologic complete response(pCR) rate, progression-free survival, overall survival, and safety. As of Aug 30, 2023, of the 20 enrolled pts, 16 had completed genetic testing, and 14 were homologous recombination deficiency (HRD) positive, with 9 cases of BRCA1/2 mutations. By Aug 30, 2023, 17 pts completed NAT and IDS with an ORR of 100%. 15 pts achieved R0 surgery (88.24%), and 2 pts achieved R1. All 20 pts were evaluable by GCIG CA125 criteria, and CA125 response was all observed (100%). Grade 3 or 4 treatment-related adverse events that occurred are neutropenia, thrombocytopenia, anemia, and hepatic dysfunction. Pamiparib combined with Surufatinib as a new neoadjuvant "chemotherapy-free" regimen showed extremely high R0 and ORR rates with manageable toxicity profiles. Currently, the experiment is still ongoing and further analysis and reporting of more data will be conducted.