Cobimetinib Products | Cleanchem - Cobimetinib is a targeted therapy drug used to treat melanoma in combination with vemurafenib, particularly in patients with BRAF V600E or V600K mutations. It works by inhibiting MEK1/2, enzymes in the MAPK pathway that are involved in cell proliferation and survival. Cobimetinib is often used in advanced or metastatic melanoma treatment. Side effects may include diarrhea, nausea, and skin rash.