A-BRAVE trial: a phase III randomized trial with anti-PD-L1 avelumab in high-risk triple-negative early breast cancer patients

Background: The A-BRAVE trial evaluated the efficacy of avelumab, an anti-programmed death-ligand 1 (PD-L1) antibody, as adjuvant treatment of patients with early triple-negative breast cancer (TNBC) at high risk. Patients and methods: A-BRAVE is a phase III study that randomly assigned patients with high-risk early TNBC to 1 year of avelumab versus observation, after completion of standard surgery and (neo)adjuvant chemotherapy. High-risk was defined as either: (i) ≥pN2/any pT, pN1/pT2, or pN0/pT3 after primary surgery (stratum A); or (ii) invasive residual disease (breast and/or nodes) after neoadjuvant chemotherapy (stratum B). Coprimary endpoints were disease-free survival (DFS) in the intention-to-treat (ITT) and stratum B populations. Secondary endpoints were overall survival (OS) and DFS in PD-L1-positive patients. PD-L1 was evaluated in treatment-naïve tumor samples by immunohistochemistry (73-10 RUO assay, Agilent Technologies) and digital pathology. Results: From June 2016 to October 2020, 466 patients were randomly assigned: 383 entered stratum B (82%) and 83 entered stratum A (18%). At a median follow-up of 52.1 months, avelumab did not significantly improve DFS in the ITT population [hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.61-1.09, P = 0.172; 3-year DFS estimates were 68.3% for avelumab versus 63.2%], or in stratum B (HR 0.80, 95% CI 0.58-1.10, P = 0.170; 3-year DFS estimates were 66.9% for avelumab versus 60.7%). In a descriptive analysis, avelumab reduced the hazard of OS events: HR 0.66, 95% CI 0.45-0.97. The 3-year OS estimates for avelumab and control arm were 84.8% (95% CI 79.5% to 88.8%) and 76.3% (95% CI 70.1% to 81.3%), respectively. PD-L1 status was prognostic but not predictive for avelumab benefit in terms of DFS (test for interaction P = 0.155). Conclusions: For patients with TNBC at high risk of relapse who complete standard treatment with surgery and (neo)adjuvant chemotherapy, 1 year of adjuvant avelumab versus observation did not improve DFS. However, a descriptive analysis suggests a potential favorable impact on OS.