Combined BRAF and MEK inhibition improves the response rate (RR) and progression-free survival for patients with V600 BRAF-mutant metastatic melanoma over single-agent BRAF inhibition, with the advantage of causing fewer cutaneous squamous cell carcinomas (cuSCCs). 1 In addition to the superior efficacy, the decrease in oncogenic toxicities favor its use over singleagent BRAF inhibitors in both metastatic and adjuvant patients, particularly with recent case reports of propagation of preexisting RAS-mutant leukemia, 2 gastric and colonic polyps, 3 and the possible increased risk of new BRAF wild-type primary cutaneous melanomas4 with single-agent BRAF inhibitors. Herein, we report the first case of a new KRAS-mutant adenocarcinoma diagnosed in a patient while treated with the combination of dabrafenib and trametinib for V600 BRAF–mutant metastatic