Deforolimus

A potent, selective mTOR inhibitor with IC50 of 0.2 nM in HT-1080 cell line; displays significant antiproliferative activity a broad panel of cell lines with EC50 of 0.2-2.3 nM; potently and selectively inhibits VEGF production in a dose-dependent manner; exerts significant antitumor effects in mice bearing PC-3 (prostate), HCT-116 (colon), MCF7 (breast), PANC-1 (pancreas) or A549 (lung) xenografts.Breast Cancer Phase 2 Clinical(In Vitro):Treatment of HT-1080 fibrosarcoma cells with Ridaforolimus results in a dose-dependent inhibition of phosphorylation of both S6 and 4E-BP1, with IC50s of 0.2 and 5.6 nM, respectively, and EC50s of 0.2 and 1.0 nM, respectively. In HT-1080 cells, the EC50 for inhibition of cell proliferation (0.5 nM) is similar to the EC50s for inhibition of S6 and 4E-BP1 phosphorylation. Exposure to Ridaforolimus reduces the proliferation of cell lines representing a variety of tumor types. Administration of Ridaforolimus to tumor cells in vitro elicit dose-dependent inhibition of mTOR activity with concomitant effects on cell growth and division. Ridaforolimus exhibits a predominantly cytostatic mode of action, consistent with the findings for other mTOR inhibitors. Potent inhibitory effects on vascular endothelial growth factor secretion, endothelial cell growth, and glucose metabolism.(In Vivo):Ridaforolimus inhibits tumor growth in mice bearing PC-3 (prostate), HCT-116 (colon), MCF7 (breast), PANC-1 (pancreas), or A549 (lung) xenografts. Ridaforolimus inhibits tumor growth in a dose-dependent manner, with 0.3 mg/kg being the lowest dose that inhibits tumor growth significantly and 3 and 10 mg/kg doses achieving maximum inhibition.