Cobimetinib (GDC-0973, XL-518) is a MEK inhibitor being developed by Exelixis and Roche. It is being studied in combination with BRAF inhibitors to treat several cancers. Early data showed that administration of Cobimetinib in combination with the BRAF inhibitor vemurafenib increased progression-free survival in melanoma patients with a BRAF V600 mutation by 3.7 months compared to vemurafenib alone. Phase 3 clinical trials are ongoing and expected to complete by 2017. After good results in 2014 the combination has been submitted to EC and FDA for marketing approval.