AST 487

AST487, also known as NVP- AST487, is a RET kinase inhibitor/FLT3 inhibitor. The RET kinase has emerged as a promising target for the therapy of medullary thyroid cancers (MTC) and of a subset of papillary thyroid cancers. NVP- AST487 has an IC (50) of 0.88 mumol/L on RET kinase, inhibits RET autophosphorylation and activation of downstream effectors, and potently inhibited the growth of human thyroid cancer cell lines with activating mutations of RET but not of lines without RET mutations. NVP- AST487 induced a dose-dependent growth inhibition of xenografts of NIH3T3 cells expressing oncogenic RET, and of the MTC cell line TT in nude mice. NVP- AST487 inhibited calcitonin gene expression in vitro in TT cells, in part, through decreased gene transcription.