The FDA has granted Breakthrough Therapy Designation to niraparib (Zejula), an orally-administered poly ADP-ribose polymerase (PARP) inhibitor, for the treatment of patients with BRCA ½ gene-mutated metastatic castration-resistant prostate cancer (mCRPC) who have received prior taxane chemotherapy and androgen receptor (AR)-targeted therapy. Data that led to this designation were recently presented at the European Society for Medical Oncology (ESMO) 2019 Annual Congress as a late-breaking abstract.

The Breakthrough Therapy Designation is based on findings from the GALAHAD study, a phase 2, multicenter, open-label clinical trial evaluating the efficacy and safety of niraparib in the treatment of adult patients with mCRPC and DNA-repair gene defects (DRD) who were treated with next-generation androgen-receptor targeting therapies and docetaxel.

BRCA1/2 mutations are the most common DRD in patients with mCRPC. Patients with a DRD in BRCA1/2 are at an elevated risk for both prostate cancer occurrence and more aggressive disease.

A Breakthrough Therapy Designation is granted in order to expedite the development and regulatory review of an investigational medicine intended to treat a serious or life-threatening condition. In order to qualify for Breakthrough Therapy Designation, a drug must have substantial improvement on at least 1 clinically significant endpoint over available therapy.

Reference
1. Janssen Announces U.S. FDA Breakthrough Therapy Designation Granted for Niraparib for the Treatment of Metastatic Castration-Resistant Prostate Cancer [press release]. Johnson & Johnson website. Published October 3, 2019. . Accessed October 4, 2019.