Refametinib

Refametinib (BAY 86-9766, RDEA119) is a potent, highly selective and ATP non-competitive inhibitor of MEK1 and MEK2 with IC50 of 19 nM and 47 nM, respectively. Refametinib potently inhibited MEK activity as measured by phosphorylation of ERK1/2 across several human cancer cell lines of different tissue origins and BRAF mutational status with EC50 values ranging from 2.5 to 15.8 nM. RDEA119 inhibits anchorage-dependent growth of human cancer cell lines harboring the gain-of-function V600E BRAF mutant with GI50 values ranging from 67 to 89 nM. Refametinib (BAY 86-9766) exhibited potent antiproliferative activity in HCC cell lines with half-maximal inhibitory concentration values ranging from 33 to 762 nM. BAY 86-9766 was strongly synergistic with sorafenib in suppressing tumor cell proliferation and inhibiting phosphorylation of the extracellular signal-regulated kinase (ERK). Refametinib (BAY 869766, RDEA119) exhibits complete suppression of ERK phosphorylation at fully efficacious doses in mice. Refametinib (BAY 869766, RDEA119) shows a tissue selectivity that reduces its potential for central nervous system-related side effects.