Multinational phase 2 study of niraparib in patients with mCRPC and DNA repair gene defects

Metastatic castration-resistant prostate cancer (mCRPC) is enriched for DNA repair gene defects (DRDs) that can be susceptible to synthetic lethality through inhibition of PARP proteins. The multinational phase 2 GALAHAD study evaluated the PARP inhibitor niraparib in heavily pretreated patients with mCRPC and DRDs. The study found that niraparib was tolerable and had antitumor activity, particularly in patients with BRCA alterations (ORR 34.2%; 95% CI 23.7-46.0).