New PARP Inhibitor Approved for Ovarian Cancer Maintenance Treatment

On 27 March 2017, the US Food and Drug Administration (FDA) announced approval of niraparib (Zejula®, Tesaro), a poly ADP-ribose polymerase (PARP) inhibitor for use as maintenance therapy following partial or complete response to platinum-based chemotherapy in patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer. Niraparib is the third PARP inhibitor to be approved for advanced ovarian cancer, but the first to be approved for use in patients with and without germline BRCA (gBRCA) mutations.

This approval is based on results from the large randomized phase III NOVA trial (N = 553) that showed a significant improvement in progression-free survival (PFS) with niraparib maintenance compared to placebo in women with recurrent, platinum sensitive ovarian cancer regardless of the gBRCA mutation and homologous recombination deficiency (HRD) status. In patients with gBRCA mutations, maintenance treatment with niraparib 300 mg daily resulted in a median PFS of 21 months, compared to 5.5 months in patients receiving placebo (HR 0.26, P<.0001). Niraparib also significantly improved PFS in patients without germline BRCA mutations (9.3 months vs 3.9 months; HR 0.45, P<.0001). In the subgroup analysis of these patients, benefit was observed regardless of HRD status, though a larger benefit was seen in patients with HRD-positive tumors.

Niraparib was well tolerated with an adverse event profile consistent with other agents of this class. Patients receiving niraparib had higher rates of grade 3/4 hypertension (9%) than those receiving placebo (2%).