GlaxoSmithKline receives EU marketing authorization for Mekinist GlaxoSmithKline announced Friday that the European Commission has granted marketing authorization for Mekinist as a single agent in the treatment of adult patients with unresectable or metastatic melanoma with a BRAF V600 mutation. Trametinib has not demonstrated clinical activity in patients who have progressed on a prior BRAF inhibitor therapy. Before taking trametinib, patients must have confirmation of a BRAF V600 mutation using a validated test. Mekinist was in-licensed by GSK in 2006. GSK holds the worldwide exclusive rights to develop, manufacture and commercialise Mekinist, while Japan Tobacco retains co-promotion rights in Japan.