Niraparib maintenance confers prolonged survival in advanced ovarian cancer

Maintenance therapy with niraparib appears to increase progression-free survival (PFS) in patients with advanced ovarian cancer, irrespective of postoperative residual disease or biomarker status, according to data from the phase III PRIME study.

PRIME INCLUDED 384 patients with newly diagnosed advanced ovarian cancer who underwent primary or interval debulking surgery and responded to treatment with first-line platinum-based chemotherapy. These patients were randomly assigned to receive either niraparib (n=255, median age 53 years) or placebo (n=129, median age 54) with an individualized starting dose (200 mg/d for those with a body weight of <77 kg and/or platelet count of <150 ×103/μL at baseline; 300 mg/d otherwise). The median follow-up duration was 27.5 months.

The primary endpoint was blinded independent central review (BICR)-assessed PFS in the intention-to-treat (ITT) population. Analysis was performed by germline BRCA variant status, tumour homologous recombination deficiency status, neoadjuvant chemotherapy, and response to first-line platinum-based chemotherapy.

Of the patients, 375 (65.9 percent in the niraparib group, 34.1 percent in the placebo group) received treatment at a dose of 200 mg per day. Median PFS was significantly longer with niraparib vs placebo (24.8 vs 8.3 months; hazard ratio [HR], 0.45, 95 percent confidence interval [CI], 0.34–0.60; p<0.001) in the intention-to-treat population.

In the subgroup analyses, niraparib was consistently associated with better PFS compared with placebo for patients with germline BRCA variants (not reached vs 10.8 months; HR, 0.40, 95 percent CI, 0.23–0.68), those without germline BRCA variants (19.3 vs 8.3 months; HR, 0.48, 95 percent CI, 0.34–0.67), homologous recombination-deficient patients (not reached vs 11.0 months; HR, 0.48, 95 percent CI, 0.34–0.68), homologous recombination-proficient patients (16.6 vs 5.5 months; HR, 0.41, 95 percent CI, 0.22–0.75), those with optimal debulking (24.8 vs 8.3 months; HR, 0.44, 95 percent CI, 0.32–0.61), and those with suboptimal debulking (16.5 vs 8.3 months; HR, 0.27, 95 percent CI, 0.10–0.72).

No significant difference was seen in the proportion of niraparib- and placebo-treated patients who discontinued treatment due to treatment-emergent adverse events (6.7 percent vs 5.4 percent).