Niraparib for the treatment of ovarian cancer

Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors are being developed in maintenance and recurrence treatment settings in ovarian cancer. They inhibit single-stranded DNA repair, inducing synthetic lethality in cells with underlying homologous recombination deficiency (HRD). Marked responses are seen in ovarian cancers with breast cancer gene 1 (BRCA1) or 2 (BRCA2) mutation, although up to 50% of high-grade serous ovarian cancers (HGSOC) have HRD may also benefit. Areas covered: This review focuses on niraparib (oral PARP I and II inhibitor), its clinical testing in ovarian cancer, including the Myriad MyChoice HRD test as a potential companion diagnostic. Future directions plus ongoing trials, including novel combinations are highlighted. Expert opinion: There is now level 1 evidence of efficacy from the first randomized placebo-controlled phase III trial using niraparib maintenance in women with platinum-sensitive recurrent HGSOC with complete or partial response post platinum-based chemotherapy. Niraparib improved progression free survival over placebo in all groups of women. The benefit was greatest in patients with germline BRCA1/2 mutation, followed by HRD positive tumors; however, absence of either does not exclude the possibility of benefit from niraparib maintenance. Additional studies are underway with niraparib in the first line maintenance, and 4^th/5^th line recurrence treatment settings.