CEP-32496 is a highly potent and orally efficacious V600E mutant BRAF, WT BRAF and c-Raf inhibitor with Kd values of 14 nM, 36 nM and 39 nM, respectively.

In addition to BRAFV600E, CEP-32496 has exhibited high binding affinity for both wild-type BRAF and related CRAF, as well as certain receptor tyrosine kinases of known therapeutic utility, such as Abl-1, c-Kit, Ret, PDGFR-β, and VEGFR-2. However, CEP-32496 proved selective for the RAF members of the MAPK signal transduction pathway, as no significant affinity was observed for other key kinases of the MAPK pathway, including MEK-1, MEK-2, ERK-1, and ERK-2. This suggests that the observed cellular activity was driven primarily through inhibition of BRAFV600E, which is further supported by the observation that CEP-32496 exhibited selective cytotoxicity for tumor cell lines expressing mutant BRAF versus those expressing wild-type BRAF [1].

Oral administration of CEP-32496 to Colo-205 tumor xenograft-bearing mice resulted in significant inhibition of pMEK in tumor cell lysates [1].

References:
[1] Rowbottom MW1, Faraoni R, Chao Q, Campbell BT, Lai AG, Setti E, Ezawa M, Sprankle KG, Abraham S, Tran L, Struss B, Gibney M, Armstrong RC,Gunawardane RN, Nepomuceno RR, Valenta I, Hua H, Gardner MF, Cramer MD, Gitnick D, Insko DE, Apuy JL, Jones-Bolin S, Ghose AK, Herbertz T, Ator MA,Dorsey BD, Ruggeri B, Williams M, Bhagwat S, James J, Holladay MW. Identification of 1-(3-(6,7-dimethoxyquinazolin-4-yloxy)phenyl)-3-(5-(1,1,1-trifluoro-2 -methylpropan- 2-yl) isoxazol-3-yl) urea hydrochloride (CEP-32496), a highly potent and orally efficacious inhibitor of V-RAF murine sarcoma viral oncogene homologue B1 (BRAF) V600E. J Med Chem. 2012 Feb 9;55(3):1082-105. doi: 10.1021/jm2009925. Epub 2012 Jan 23.