Multinational phase 3 trial of adjuvant atezolizumab for early-stage triple-negative breast cancer

The multinational phase 3 ALEXANDRA/IMpassion030 trial evaluated addition of one year of atezolizumab to 20 weeks of adjuvant chemotherapy after surgery for high-risk triple-negative breast cancer (TNBC). The primary endpoint was invasive disease-free survival (IDFS). After inclusion of 2199 of 2300 planned patients, the trial was stopped early for futility with IDFS events in 12.8% of patients in the atezolizumab-chemotherapy group versus 11.4% of patients in the chemotherapy-alone group (HR 1.11; p=0.38). Compared with chemotherapy alone, atezolizumab plus chemotherapy was associated with higher frequency of grade 3 or 4 treatment-related adverse events (44% versus 54%). The authors conclude that the addition of atezolizumab to adjuvant chemotherapy after surgery for high-risk TNBC did not result in IDFS benefit (visual abstract).