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.

Sorafenib (BAY 43-9006), marketed as Nexavar by Bayer, is a drug approved for the treatment of advanced renal cell carcinoma (primary kidney cancer, hepatocellular carcinoma and for the treatment of patients with locally recurrent or metastatic, progressive, differentiated thyroid carcinoma (DTC) that is refractory to radioactive iodine treatment. It has also received "Fast Track" designation by the FDA for the treatment of advanced hepatocellular carcinoma (primary liver cancer), and has since performed well in Phase III trials. Sorafenib was shown to interact with multiple intracellular (CRAF, BRAF and mutant BRAF) and cell surface kinases (KIT, FLT- 3, VEGFR- 2, VEGFR- 3, and PDGFR- ß). Several of these kinases are thought to be involved in angiogenesis. Thus, sorafenib may inhibit tumor growth by a dual mechanism, acting either directly on the tumor (through inhibition of Raf and Kit signaling) and/or on tumor angiogenesis (through inhibition of VEGFR and PDGFR signaling). Sorafenib inhibited tumor growth of the murine renal cell carcinoma, RENCA, and several other human tumor xenografts in athymic mice. A reduction in tumor angiogenesis was seen in some tumor xenograft models.

PLX8394 is a potent and selective inhibitor of B-Raf V600E (IC50 14 nM for WT and 3.8 nM for V600E mutant). Unlike vermurafenib, sorafenib and dabrafenib, PLX8394 does not cause paradoxical MAPK pathway activation. PLX8394 is under investigation in phase I/II of clinical trial for the treatment patients with advanced unresectable solid tumors.

SB-203580 was originally prepared as inflammatory cytokine synthesis inhibitor that subsequently was found to be selective inhibitor of p38 MAP kinase. SB-203580 is a p38 MAPK inhibitor with IC50 of 0.3-0.5 uM in THP-1 cells, 10-fold less sensitive to SAPK3(106T) and SAPK4(106T) and blocks PKB phosphorylation with IC50 of 3-5 uM. SB203580 induces autophagy in human hepatocellular carcinoma (HCC) cells. Development of SB-203580 for cancer; postmenopausal osteoporosis; rheumatoid arthritis; septic shock has been discontinued.

LY-3009120 is an orally available inhibitor of all members of the serine/threonine protein kinase Raf family, including A-Raf, B-Raf, and C-Raf protein kinases, with potential antineoplastic activity. Upon administration, pan-RAF kinase inhibitor LY3009120 inhibits Raf-mediated signal transduction pathways, which may inhibit tumor cell growth. Raf protein kinases play a key role in the RAF/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway, which is often dysregulated in human cancers and plays a key role in tumor cell proliferation and survival. LY3009120 is being investigated in phase I clinical trial.

AZ-628 is a new pan-Raf inhibitor for BRAF, BRAFV600E, and c-Raf-1 with IC50 of 105 nM, 34 nM and 29 nM in cell-free assays. Specificity profliling indicates that AZ-628 also inhibits activation of number of tyrosine protein kinases including VEGFR2, DDR2, Lyn, Flt1, FMS and others. AZ-628 inhibits anchorage-dependent and -independent growth, causes cell cycle arrest, and induces apoptosis in colon and melanoma cell lines harboring B-RafV600E mutation. The profile of AZ-628 cross-reactivity suggests that similar to sorafenib, AZ-628 may be antiangiogenic based on inhibition of VEGFR2. AZ-628 is remarkably effective at inhibiting the growth of a specific subset of human cancer cell lines derived from melanomas, thyroid cancers, and colorectal cancers that harbor the BRAF V600E mutation. Preclinical evaluation is in progress.

Sorafenib (BAY 43-9006), marketed as Nexavar by Bayer, is a drug approved for the treatment of advanced renal cell carcinoma (primary kidney cancer, hepatocellular carcinoma and for the treatment of patients with locally recurrent or metastatic, progressive, differentiated thyroid carcinoma (DTC) that is refractory to radioactive iodine treatment. It has also received "Fast Track" designation by the FDA for the treatment of advanced hepatocellular carcinoma (primary liver cancer), and has since performed well in Phase III trials. Sorafenib was shown to interact with multiple intracellular (CRAF, BRAF and mutant BRAF) and cell surface kinases (KIT, FLT- 3, VEGFR- 2, VEGFR- 3, and PDGFR- ß). Several of these kinases are thought to be involved in angiogenesis. Thus, sorafenib may inhibit tumor growth by a dual mechanism, acting either directly on the tumor (through inhibition of Raf and Kit signaling) and/or on tumor angiogenesis (through inhibition of VEGFR and PDGFR signaling). Sorafenib inhibited tumor growth of the murine renal cell carcinoma, RENCA, and several other human tumor xenografts in athymic mice. A reduction in tumor angiogenesis was seen in some tumor xenograft models.