AKT1 and neoplasm: PIK3CA/AKT1/PTEN tumor alterations were not detected in 35 patients (49.3%) receiving capivasertib–fulvestrant and 33 patients (52.4%) receiving placebo–fulvestrant, while tumor alteration status was unknown for 12 patients (16.9%) receiving capivasertib–fulvestrant and 8 patients (12.7%) receiving placebo–fulvestrant (Supplementary Table 1).