Talazoparib versus chemotherapy in patients with germline BRCA1/2-mutated HER2-negative advanced breast cancer: final overall survival results from the EMBRACA trial.
Joanne L. Blum, M.D.
Litton, J.K., Hurvitz, S.A., Mina, L.A., Rugo, H.S., Lee, K.H., Gonçalves, A., Diab, S., Woodward, N., Goodwin, A., Yerushalmi, R., Roché, H., Im, Y.H., Eiermann, W., Quek, R.G.W., Usari, T., Lanzalone, S., Czibere, A., Blum, J.L., Martin, M. and Ettl, J. (2020). “Talazoparib versus chemotherapy in patients with germline BRCA1/2-mutated HER2-negative advanced breast cancer: final overall survival results from the EMBRACA trial.” Ann Oncol Aug 20;S0923-7534(20)42106-4. [Epub ahead of print.].
BACKGROUND: In EMBRACA, talazoparib prolonged progression-free survival versus chemotherapy (hazard ratio [HR] 0.542 [95% CI 0.413-0.711]; P < 0.0001) and improved patient-reported outcomes (PRO) in germline BRCA1/2 (gBRCA1/2)-mutated advanced breast cancer (ABC). We report final overall survival (OS). PATIENTS AND METHODS: This randomized phase III trial enrolled patients with gBRCA1/2-mutated HER2-negative ABC. Patients received talazoparib or physician's choice of chemotherapy. OS was analyzed using stratified HR and log-rank test and prespecified rank-preserving structural failure time model to account for subsequent treatments. RESULTS: 431 patients were randomized (287 talazoparib/144 chemotherapy) with 412 patients treated (286 talazoparib/126 chemotherapy). By September 30, 2019, 216 deaths (75.3%) occurred for talazoparib and 108 (75.0%) chemotherapy; median follow-up was 44.9 and 36.8 months, respectively. HR for OS with talazoparib versus chemotherapy was 0.848 (95% CI 0.670-1.073; P = 0.17); median (95% CI) 19.3 months (16.6-22.5) versus 19.5 months (17.4-22.4). Kaplan-Meier survival percentages (95% CI) for talazoparib versus chemotherapy: Month 12, 71% (66-76)/74% (66-81); Month 24, 42% (36-47)/38% (30-47); Month 36, 27% (22-33)/21% (14-29). Most patients received subsequent treatments: for talazoparib and chemotherapy, respectively, 46.3%/41.7% received platinum and 4.5%/32.6% received a poly(ADP-ribose) polymerase (PARP) inhibitor. Adjusting for subsequent PARP and/or platinum use, HR for OS was 0.756 (95% bootstrap CI 0.503-1.029). Grade 3-4 adverse events occurred in 69.6% (talazoparib) and 64.3% (chemotherapy) patients, consistent with previous reports. Extended follow-up showed significant overall improvement and delay in time to definitive clinically meaningful deterioration in global health status/quality of life and breast symptoms favoring talazoparib versus chemotherapy (P < 0.01 for all), consistent with initial analyses. CONCLUSIONS: In gBRCA1/2-mutated HER2-negative ABC, talazoparib did not significantly improve OS over chemotherapy; subsequent treatments may have impacted analysis. Safety was consistent with previous observations. PRO continued to favor talazoparib.