Tucatinib has not yet been examined clinically against HER2-mutated cancers and lapatinib showed poor efficacy in a small basket trial (0/8 HER2-mutant NSCLC patients responded).41 The SUMMIT basket trial investigated neratinib in patients with solid tumours that had a HER2 or HER3 mutation.42 Of the 141 patients in this trial, encompassing 21 different cancer types, 125 had HER2 mutations and 16 had HER3 mutations. This evidence concerns the gene ERBB3 and non-small cell lung carcinoma.