Niraparib (PARP inhibitor) + abiraterone (CYP17 inhibitor) drives 38.6-mo rPFS in BRCA2+ Asian 1L mCRPC

Niraparib is an oral PARP inhibitor that exploits homologous recombination repair deficiency; here it was combined with abiraterone acetate + prednisone (AAP), an androgen biosynthesis (CYP17) inhibitor backbone, in the Phase 3, randomized MAGNITUDE trial (NCT03748641) in first-line mCRPC. In the exploratory Asian BRCA+ subgroup (n=35; all BRCA2+), niraparib+AAP improved BICR-assessed median rPFS to 38.6 months vs 8.3 months with placebo+AAP (HR 0.33, 95% CI 0.13–0.83; nominal p=0.0141) after ~35 months follow-up; time to PSA progression (HR 0.32) and time to cytotoxic chemotherapy (HR 0.098) also favored niraparib+AAP, while median OS was NR vs 24.0 months (HR 0.67, 95% CI 0.27–1.71). Against a practical SOC benchmark of abiraterone+prednisone alone in chemo-naïve mCRPC (COU-AA-302: median rPFS ~16.5 months; mOS 34.7 months), the placebo+AAP rPFS here looks unusually short, which makes the absolute rPFS delta eye-catching but also raises “small-n / subgroup” caution; safety in the Asian HRR+ population was reported as consistent with the global MAGNITUDE experience (no new signal highlighted).