Trametinib dimethyl sulfoxide, an allosteric inhibitor of MEK1 and MEK2 kinases, was approved in 2013 after the results of the METRIC trial for BRAF V600E– or BRAF V600K–positive advanced melanoma.26 Trametinib vs chemotherapy (paclitaxel or dacarbazine) showed a 6-month overall survival of 81% with trametinib vs 67% with chemotherapy (HR, 0.54; P = .01), even with 47% of patients receiving chemotherapy crossing over to trametinib treatment.26 The gene discussed is MAP2K2; the disease is melanoma.