Niraparib on the PBS

Niraparib is now available on the Pharmaceutical Benefits Scheme (PBS). It is listed for the treatment of high-grade stage III/IV epithelial ovarian, fallopian tube or primary peritoneal cancer in patients with a class 4 or 5 BRCA1 or BRCA2 gene mutation. Prior to commencing niraparib, patients must also be in response (partial or complete) to platinum-based chemotherapy.

Niraparib is an inhibitor of the poly (ADP-ribose) polymerase (PARP) enzymes, PARP-1 and PARP-2. These enzymes play a role in DNA repair, genome stability, and apoptosis of cancer cells.

The PRIMA trial investigated the efficacy of niraparib in treating newly diagnosed advanced ovarian cancer. The primary efficacy endpoint of progression-free survival was significantly longer in the niraparib group compared to placebo (13.8 months versus 8.2 months). Analysis shows that 42% of patients in the niraparib group were alive without disease progression 18 months after randomisation, compared to 28% of patients in the placebo group. The NOVA trial, conducted in patients with recurrent ovarian cancer, also demonstrated significantly longer progression-free survival for niraparib compared to placebo.

A meta-analysis was conducted to evaluate the safety of niraparib as a maintenance therapy for epithelial ovarian cancer. Nausea was the most common adverse event, reported in 73.6% of patients taking niraparib. Administering the once-daily dose at bedtime may reduce the impact of this. Commonly reported high-grade adverse effects include thrombocytopenia (33%), neutropenia (18%) and anaemia (15%). These effects can be largely controlled through individualised dose modification.