Clinical benefit has been observed with poly(ADP-ribose) polymerase (PARP) inhibition in patients with metastatic castration-resistant prostate cancer (mCRPC) that carry HRR gene defects. Niraparib is a highly selective and potent PARP inhibitor, with activity against PARP-1 and PARP-2 deoxyribonucleic acid (DNA)-repair polymerases. In this session we aim to discuss the benefit of combining PARP inhibitor with ADT in mCSPC and discuss how to optimize treatment outcome in mCSPC.