Niraparib for Advanced Breast Cancer with Germline BRCA1 and BRCA2 Mutations: the EORTC 1307-BCG/BIG5-13/TESARO PR-30-50-10-C BRAVO Study

Purpose: To investigate the activity of niraparib in patients with germline-mutated BRCA1/2 (gBRCAm) advanced breast cancer. Patients and Methods: BRAVO was a randomized, open-label phase III trial. Eligible patients had gBRCAm and HER2-negative advanced breast cancer previously treated with <= 2 prior lines of chemotherapy for advanced breast cancer or had relapsed within 12 months of adjuvant chemotherapy, and were randomized 2:1 between niraparib and physician's choice chemotherapy (PC; monotherapy with eribulin, capecitabine, vinorelbine, or gemcitabine). Patients with hormone receptor-positive tumors had to have received <= 1 line of endocrine therapy and progressed during this treatment in the metastatic setting or relapsed within 1 year of (neo)adjuvant treatment. The primary endpoint was centrally assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS), PFS by local assessment (local-PFS), objective response rate (ORR), and safety. Results: After the pre-planned interim analysis, recruitment was halted on the basis of futility, noting a high degree of discordance between local and central PFS assessment in the PC arm that resulted in informative censoring. At the final analysis (median follow-up, 19.9 months), median centrally assessed PFS was 4.1 months in the niraparib arm (n = 141) versus 3.1 months in the PC arm [n = 74; hazard ratio (HR), 0.96; 95% confidence interval (CI), 0.65-1.44; P = 0.86]. HRs for OS and local-PFS were 0.95 (95% CI, 0.63-1.42) and 0.65 (95% CI, 0.46-0.93), respectively. ORR was 35% (95% CI, 26-45) with niraparib and 31% (95% CI, 19-46) in the PC arm. Conclusions: Informative censoring in the control arm prevented accurate assessment of the trial hypothesis, although there was clear evidence of niraparib's activity in this patient population.

Automated summary

The study investigated the activity of niraparib in patients with gBRCAm advanced breast cancer, showing clear evidence of its activity in this patient population. However, informative censoring in the control arm prevented accurate assessment of the trial hypothesis. The centrally assessed PFS was slightly better in the niraparib arm compared to the physician's choice chemotherapy arm, with some advantages in certain endpoints.