Potent and selective B-Raf inhibitor (IC50 = 0.13 nM against purified B-Raf V600E). Activity reduces phospho-ERK (pERK) levels (IC50 = 63 nM in the Malme-3M cell line). Inhibits the Raf/MEK/ERK signaling pathway in V600E B-Raf mutant cell lines. Does not activate apoptotic pathways in A375 or Colo205 cell lines. Orally bioavailable.