SB 590885 is a potent B-Raf inhibitor with Ki of 0.16 nM, 11-fold greater selectivity for B-Raf over c-Raf, no inhibition to other human kinases.

B-Raf is a MAP kinase kinase kinase, which functions downstream of Ras family GTPases to activate MEK1/2 and ERK1/2 signaling.Mutations of B-Raf, particularly at Val600, are common in melanomas and melanocytic nevi.SB 590885 is a potent inhibitor of B-Raf (Kd = 0.3 nM).It less effectively inhibits c-Raf (Ki = 1.72 nM) and has little effect at 46 other kinases.SB 590885 blocks activation of ERK1/2 and anchorage-independent cell proliferation of melanoma cells with either wild type or V600E B-Raf at nanomolar concentrations.Melanoma cells expressing the B-RafV600E mutation can drive invasion through alternative pathways in the presence of SB 590885, suggesting that combination therapy is needed to completely block cell invasion.SB 590885 has also been used to study the role of B-Raf in cerebral ischemia.