PIK3CA and neoplasm: All enrolled patients received study treatment and were stratified into three biomarker‐defined subgroups based on analysis of archival tumor tissue: PIK3CA‐mutated subgroup (mITT N = 8; SAF N = 9), PTEN loss subgroup (mITT N = 2; SAF N = 3,) and wild‐type subgroup (mITT N = 11; SAF N = 13) (please refer to patients and methods section for detail on the molecular strata).