Abstract
Abstract only
5517
Background: Therapeutic paradigms for recurrent OC vary by geography. Maintenance following response to platinum-based chemotherapy (Plat) is standard in Europe, whereas in the US maintenance is considered following complete response (CR) vs treatment for partial response (PR). Niraparib is a highly selective PARP 1/2 inhibitor (PARPi). In preclinical studies it concentrates in the tumor relative to plasma, delivering > 90% durable PARP inhibition and antitumor effects. Niraparib demonstrated significantly longer PFS vs placebo (P) in pts with recurrent OC following a CR or PR to Plat in the randomized, controlled, double-blind phase 3 ENGOT-OV16/NOVA trial. Methods: Pts with recurrent OC, no prior PARPi use, ≥2 prior courses of Plat, and response to most recent Plat were eligible. Pts were assigned to 1 of 2 cohorts on the basis of g BRCA testing (g BRCAmut or non-g BRCAmut) and randomized 2:1 within each cohort to niraparib 300 mg or P qd until progressive disease (PD). Randomization occurred up to 8 weeks after last dose of the most recent Plat. Pts were stratified by time to progression after penultimate Plat (6 to < 12 months or ≥12 months), prior use of bevacizumab (yes/no), and response to most recent Plat (CR or PR). PFS was measured from time of randomization to death or earliest PD as assessed by independent review committee. Results: 49% of pts (niraparib: 67/138; P: 32/65) in the g BRCAmut and ~49% of pts (niraparib: 117/234 [50%]; P: 56/116 [48%]) in the non-g BRCAmut cohorts entered NOVA with a PR following their most recent Plat. At time of unblinding, 30 (45%) niraparib and 23 (72%) P pts in the g BRCAmut and 65 (56%) niraparib and 45 (80%) P pts in the non-g BRCAmut cohorts had PFS events. PFS hazard ratios (95% CI) were 0.24 (0.131–0.441) in g BRCAmut and 0.35 (0.230–0.532) in non-g BRCAmut cohorts for pts who had a PR to their most recent platinum regimen. This compared favorably to the overall NOVA study results, where PFS hazard ratios (95% CI) were 0.27 (0.173–0.410) in g BRCAmut and 0.45 (0.338–0.607) in non-g BRCAmut cohorts. Conclusions: Niraparib treatment provided significant benefit to pts with recurrent OC who achieved a PR following Plat. Clinical trial information: NCT01847274.