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

Purpose: Phase I outcomes of this phase I/II study demonstrated that pamiparib 60 mg two times each day had antitumor activity as well as an acceptable safety profile in Chinese patients with advanced cancer, including epithelial ovarian cancer.

Patients and techniques: This open-label phase II study was conducted in China and enrolled adult (=18 years) patients with platinum-sensitive ovarian cancer (PSOC disease progression occurring =6 several weeks after last platinum treatment) or platinum-resistant ovarian cancer (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 =2 lines of therapy. Pamiparib 60 mg orally twice a day 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 =4 prior systemic chemotherapy lines. Median study follow-up was 12.2 months (range, 0.2-21.5). Eighty-two patients with PSOC and 19 patients with PROC were evaluable for efficacy. In patients with PSOC, 8 achieved a complete response (CR) and 45 achieved a partial response (PR) ORR was 64.6% [95% confidence interval (CI), 53.3-74.9]. In patients with PROC, 6 achieved a PR ORR was 31.6% (95% CI, 12.6-56.6). Frequently reported grade =3 adverse events were hematologic toxicities, including anemia and decreased neutrophil count. Conclusions: Pamiparib 60 mg twice a day showed antitumor activity with durable responses in patients with PSOC or PROC with gBRCAmut, and had a manageable safety profile.