Olaparib is a poly(ADP-ribose) polymerase inhibitor approved for metastatic castration-resistant prostate cancer (mCRPC). Olaparib is approved by the US Food and Drug Administration (FDA) for the treatment of adult patients with deleterious or suspected deleterious germline or somatic HRR gene-mutated mCRPC who have progressed following prior treatment with enzalutamide or abiraterone and by the European Medicines Agency (EMA) for the treatment of adult patients with metastatic castration-resistant prostate cancer and BRCA1 and/or BRCA2 mutations (germline and/or somatic) who have progressed following prior therapy that included a new hormonal agent.1,2 These approvals were based on positive Phase 3 evidence from the PROfound trial – a prospective, randomized, open-label trial in patients with mCRPC who had ≥1 of 15 HRR gene alterations based on prospective tissue testing and who had experienced disease progression while receiving a new hormonal agent for metastatic prostate cancer or castrate resistant prostate cancer (Figure 1).3,4