Vemurafenib
Melanoma cells without these mutations are not inhibited by vemurafenib; the drug paradoxically stimulates normal BRAF and may promote tumor growth in such cases.[5][6] Three mechanisms of resistance to vemurafenib (covering 40% of cases) have been discovered: At the maximum tolerated dose (MTD) of 960 mg twice a day 31% of patients get skin lesions that may need surgical removal.[25] In February 2012, the European Commission approved vemurafenib as a monotherapy for the treatment of adults with BRAF V600E mutation positive unresectable or metastatic melanoma, the most aggressive form of skin cancer.[26] In November 2017, the US Food and Drug Administration (FDA) approved vemurafenib for the treatment of people with Erdheim–Chester disease (ECD), a rare type of histiocytic neoplasm.[30] In a phase II clinical trial, Memorial Sloan Kettering is testing Vemurafenib, plus Obinutuzumab, in patients with previously untreated classical hairy cell leukemia.