Janssen's niraparib, an orally-administered poly ADP-ribose polymerase (PARP) inhibitor received breakthrough designation from the US FDA. The drug is indicated in patients suffering from BRCA1/2 gene-mutated metastatic castration-resistant prostate cancer (mCRPC); who were previously treated with taxane chemotherapy and androgen receptor (AR)-targeted therapy.
The approval was based on GALAHAD study, a Phase 2, multicenter, open-label clinical trial.
BRCA1/2 mutations are the most common DNA-gene defects. The primary endpoint was the objective response rate. The study included 46 patients with BRCA mutation and 35 patients with non-BRCA mutated mCRPC. Overall response rate was 41%, CRR was 63% in BRCA mutated patients. Objective response rate was 5.5 months. In non-BRCA patients, CRR was 17%, objective response was reported in two patients and the duration was 3.8 and 6.5 months.
The results were reported in ESMO2019.