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. The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.