Oral niraparib, a highly-selective, potent poly(ADP-ribose) polymerase (PARP)-1 
and PARP-2 inhibitor, is approved in the USA for the maintenance treatment of 
adult patients with recurrent epithelial ovarian, fallopian tube or primary 
peritoneal cancer who are in a complete or partial response to platinum-based 
chemotherapy. It is also under regulatory review in the EU for use in 
maintenance treatment in patients with platinum-sensitive, recurrent epithelial 
ovarian cancer who are in response to platinum-based chemotherapy. In the 
multinational, phase 3 NOVA trial in adult patients with platinum-sensitive, 
recurrent ovarian cancer, niraparib significantly prolonged median 
progression-free survival, irrespective of the presence or absence of a germline 
BRCA (gBRCA) mutation and irrespective of the presence or absence of homologous 
recombinant deficiency. Niraparib is also in development for use in other solid 
tumours, including breast and prostate cancer. This article summarizes the 
milestones in the development of niraparib leading to its first global approval 
for the maintenance treatment of adult patients with recurrent epithelial 
ovarian, fallopian tube or primary peritoneal cancer.