Pamiparib works well against platinum-sensitive, -resistant ovarian cancer

The selective oral PARP1/2 inhibitor pamiparib is well tolerated and demonstrates favourable antitumour activity with durable responses in the treatment of patients with platinum-sensitive ovarian cancer (PSOC) or platinum-resistant ovarian cancer (PROC) harbouring the germline BRCA mutation (gBRCA^mut), according to the results of a phase II trial.

The trial was conducted in China and involved 113 adult patients with PSOC (n=90; disease progression occurring ≥6 months after last platinum treatment) or PROC (n=23; disease progression occurring <6 months after last platinum treatment). These patients had known or suspected deleterious gBRCA^mut and had previously received at least two lines of therapy.

Pamiparib was administered to all patients at 60 mg orally twice a day 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.

The median age of the population was 54 years, and 25.6 percent of patients received four or more prior systemic chemotherapy lines. About 86.7 percent of patients had gBRCA1^mut and 13.3 percent had gBRCA2^mut. Most patients (95.6 percent) had serous epithelial tumours.

Over a median study follow-up of 12.2 months, 82 patients with PSOC and 19 patients with PROC were evaluated for treatment efficacy. In the PSOC group, eight patients achieved a complete response (CR) and 45 achieved a partial response (PR), with the ORR being 64.6 percent (95 percent confidence interval [CI], 53.3–74.9).

In the PROC group, on the other hand, six patients achieved a PR, yielding an ORR of 31.6 percent (95 percent CI, 12.6–56.6).

Frequently reported grade ≥3 adverse events were haematologic toxicities, including anaemia and decreased neutrophil count.