According to final results from the MAGNITUDE trial, niraparib plus abiraterone acetate and prednisone (AAP) improved the time to symptomatic progression, time to cytotoxic chemotherapy, and patient-reported outcomes, with a favorable overall survival, among patients with BRCA-mutant metastatic castration-resistant prostate cancer.

These data were first presented by Kim Nguyen Chi, MD, BC Cancer and Vancouver Prostate Centre at University of British Columbia, Vancouver, British Columbia, Canada, at the 2023 European Society for Medical Oncology (ESMO) Annual Congress in Madrid, Spain.

In the placebo-controlled, double-blind, phase 3 MAGNITUDE trial, 423 patients with metastatic castration-resistant prostate cancer with HRR gene alterations were enrolled. Patients were randomized on a 1-to-1 basis to receive AAP plus either niraparib (n = 212) or placebo (n = 211) in the first-line setting. It has been previously reported that niraparib plus APP significantly improved the radiographic progression-free survival among BRCA-mutant patients with metastatic castration-resistant prostate cancer. This final analysis shares the secondary end points of overall survival, time to cytotoxic chemotherapy, and updates the end points of time to symptomatic progression and patient-reported outcomes in patients with BRCA mutations, and safety in all patients with HRR gene alterations.

In this final analysis, 224 patients with BRCA mutations were evaluated, of which 113 received niraparib plus AAP. The median follow-up duration was 35.9 months. Overall survival favored the niraparib arm compared to the placebo arm (hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.55 to 1.12; nominal P = .18). There was also a continued improvement seen in time to symptomatic progression and time to cytotoxic chemotherapy in the niraparib arm. Patient-reported outcomes of time to worst pain progression and time to pain interference progression also favored the niraparib arm. There were no new safety signals reported from the additional treatment exposure.

Second author on the study, Elena Castro, MD, Hospital University 12 de Octubre, Madrid, Spain, concluded, “We have seen an overall survival benefit from the combination [of niraparib plus AAP] for patients with BRCA1 and BRCA2 mutations. This is very important because we know these patients have very poor outcomes when conventionally treated with taxanes or hormonal agents.”

Dr Castro added, “We should make the effort of identifying all our patients with BRCA mutations to offer them treatment with a PARP inhibitor as soon as possible.”

Source:

Chi KNN, Castro E, Attard G, et al. Niraparib (NIRA) with abiraterone acetate plus prednisone (AAP) as first-line (1L) therapy in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) and homologous recombination repair (HRR) gene alterations: Three-year update and final analysis (FA) of MAGNITUDE. Presented at 2023 ESMO Annual Congress; October 20-24, 2023; Madrid, Spain. LBA85

Castro E. Niraparib Plus Abiraterone Acetate and Prednisone for Metastatic Castration-Resistant Prostate Cancer With HRR Gene Alterations. Oncology Learning Network. 2023. https://www.hmpgloballearningnetwork.com/site/onc/videos/niraparib-plus-abiraterone-acetate-and-prednisone-metasatic-castration-resistant