Safety and efficacy of veliparib plus carboplatin/paclitaxel in patients with HER2-negative metastatic or locally advanced breast cancer: subgroup analyses by germline / mutations and hormone receptor status from the phase-3 BROCADE3 trial

• Published in: Therapeutic advances in medical oncology 2021-12, Vol.13
• Main Authors: Jean-Pierre Ayoub, Hans Wildiers, Michael Friedlander, Banu K. Arun, Hyo S. Han, Shannon Puhalla, Yaroslav Shparyk, Erik H. Jakobsen, Meijing Wu, Bruce A. Bach, Dai Feng, Christine K. Ratajczak, David Maag, Véronique Diéras
• Format: Article
• Language: English
• ISSN: 1758-8359
• DOI: 10.1177/17588359211059601

Purpose: To evaluate efficacy and safety of veliparib combined with carboplatin/paclitaxel in patients with advanced human epidermal growth factor receptor 2 (HER2)-negative, germline BRCA (g BRCA )-associated breast cancer defined by hormone receptor (HR) and g BRCA1 / 2 mutation status. Patients and Methods: In this phase-3, double-blind, placebo-controlled trial, patients ( N = 509) with advanced HER2-negative breast cancer and g BRCA1/2 mutations were randomized 2:1 to receive veliparib plus carboplatin/paclitaxel or placebo plus carboplatin/paclitaxel. Patients who discontinued chemotherapy prior to disease progression continued receiving blinded veliparib/placebo monotherapy. The primary endpoint was investigator-assessed progression-free survival (PFS). Subgroup analyses of PFS stratified by HR and g BRCA1/2 mutation status were prespecified. Results: In the intention-to-treat population, there were similar proportions of patients with g BRCA1 versus g BRCA2 mutations (51% vs 49%) and HR+ disease versus triple-negative breast cancer (TNBC) (52% vs 48%). Median PFS was longer in the veliparib arm compared with the placebo arm for all subgroups (HR+: 13.0 vs 12.5 months, hazard ratio (95% confidence interval (CI)): 0.69 (0.52, 0.93), p = 0.013; TNBC: 16.6 vs 14.1 months, hazard ratio (95% CI): 0.72 (0.52, 1.00), p = 0.052; g BRCA1 : 14.2 vs 12.6 months, hazard ratio (95% CI): 0.75 (0.55, 1.03), p = 0.073; g BRCA2 : 14.6 vs 12.6 months, hazard ratio (95% CI): 0.69 (0.50, 0.95); p = 0.021). Benefit was durable, with improved PFS rates at 2 years (HR+, 27.5% vs 15.3%; TNBC, 40.4% vs 25.0%) and 3 years (HR+, 17.5% vs 8.6%; TNBC, 35.3% vs 13.0%) in all subgroups. g BRCA status ( BRCA1 vs BRCA2 ) did not substantially affect the carboplatin/paclitaxel ± veliparib toxicity profile. Conclusion: Veliparib plus carboplatin/paclitaxel resulted in durable benefit in subgroups defined by HR status or by g BRCA1 versus g BRCA2 mutation. Overall, addition of veliparib to carboplatin/paclitaxel was tolerable, and there were no clinically meaningful differences in adverse events between the g BRCA1 versus g BRCA2 and HR+ versus TNBC subgroups. Trial Registration: NCT02163694, https://clinicaltrials.gov/ct2/show/NCT02163694