Rucaparib camsylate (CO-338, AG-014699, PF-01367338) is a potent PARP-1, PARP-2, 
and PARP-3 inhibitor. Phase I and II studies demonstrated clinical efficacy in 
both BRCA-mutated (inclusive of germline and somatic) ovarian tumors and ovarian 
tumors with homologous recombination deficiency (HRD) loss of heterozygosity 
(LOH). Rucaparib has received the US Food and Drug Administration (FDA) approval 
for patients with deleterious BRCA mutation (germline and/or somatic)-associated 
advanced ovarian cancer who have been treated with two or more chemotherapies. 
There is evidence to suggest that rucaparib has clinical efficacy against 
ovarian tumors with high HRD-LOH. Rucaparib's companion diagnostic 
FoundationFocus™ CDx BRCA test is the first FDA-approved next-generation 
sequencing-based companion diagnostic test designed to identify patients likely 
to respond to rucaparib. This article reviews the mechanisms of action, safety, 
approval, and indications for use of the PARP inhibitor rucaparib as well as 
future trials and use of rucaparib's companion diagnostic test.