Pamiparib Monotherapy for Patients With Germline BRCA1/2-Mutated Ovarian Cancer Previously Treated With at Least Two Lines of Chemotherapy: A Multicenter, Open-Label, Phase II Study.

BACKGROUND Phase I results of this phase I/II study showed that pamiparib 60 mg BID had antitumor activity and an acceptable safety profile in Chinese patients with advanced cancer, including epithelial ovarian cancer (OC). METHODS This open-label phase II study was conducted in China and enrolled adult ({greater than or equal to}18 years) patients with platinum-sensitive OC (PSOC, disease progression occurring {greater than or equal to}6 months after last platinum treatment) or platinum-resistant OC (PROC, disease progression occurring <6 months after last platinum treatment). Eligible patients had known or suspected deleterious germline BRCA mutation (gBRCAmut) and had previously received {greater than or equal to}2 lines of therapy. Pamiparib 60 mg PO BID was administered until disease progression, toxicity, or patient withdrawal. The primary endpoint was objective response rate (ORR) assessed by independent review committee (IRC) per RECIST version 1.1. RESULTS In the total patient population (N=113; PSOC, n=90; PROC, n=23), median age was 54 years (range, 34-79) and 25.6% of patients received {greater than or equal to}4 prior systemic chemotherapy lines. Median study follow-up was 12.2 months (range, 0.2-21.5). Eighty-two PSOC patients and 19 PROC patients were evaluable for efficacy. In PSOC patients, 8 achieved a complete response (CR) and 45 achieved a partial response (PR); ORR was 64.6% (95% CI, 53.3-74.9). In PROC patients, 6 achieved a PR; ORR was 31.6% (95% CI, 12.6-56.6). Frequently reported grade {greater than or equal to}3 adverse events (AEs) were hematologic toxicities, including anemia and decreased neutrophil count. CONCLUSIONS Pamiparib 60 mg BID showed antitumor activity with durable responses in patients with PSOC or PROC with gBRCAmut, and had a manageable safety profile.