BIIB-024, also known as MLN2480, and AMG 2112819, is an oral, selective pan-Raf kinase inhibitor. The Raf kinases (A-Raf, B-Raf and C-Raf) are key regulators of cell proliferation and survival within the mitogen-activated protein kinase (MAPK) pathway. The MAPK pathway is frequently disregulated in human cancers, often via activating mutations of Ras or Raf. BIIB-024 inhibits MAPK pathway signaling in BRAF mutant and some RAS mutant preclinical cancer models at concentrations that are tolerated in vivo. BIIB-024 is most potent in BRAF mutant melanoma models but also has single agent activity in some RAS mutant models. The combination of BIIB-024 with TAK-733 inhibits the growth of a broader range of RAS mutant tumor models than single agent BIIB-024, including primary human tumor xenograft models of melanoma and CRC. BIIB-024 is in phase I clinical trials for the treatment of malignant melanoma and solid tumours.