The Application relates to the use of a B-Raf inhibitor in combination with a second inhibitor for the treatment of a patient suffering from a proliferative disease characterized by mutation in BRAF. Namely, the invention relates to reversing resistance to a B-Raf inhibitor for the treatment of a proliferative disease by obtaining a tumor sample from the patient and testing it for genetic alterations in a panel of genes comprising BRAF, CRAF, MAP2K1, MAP2K2, NRAS, KRAS HRAS, and EGFR and administering a drug combination therapy comprising a B-Raf inhibitor of formula (I) and a Mek 1/2 inhibitor which is Compound B, which overcomes resistance to the B-Raf inhibitor, which second inhibitor is selected based on genetic alterations discovered in the tumor sample.
