Background:

PF-04449913 is an orally bioavailable inhibitor of smoothened with IC50 value of 5nM [1].

In the Hedgehog (Hh) signaling pathway, the combination of Hh ligands and their receptor Patched leads to the activation of smoothened and subsequently activation of three transcription factors Gli1, Gli2 and Gli3. It then leads to the proliferation of cells. As an antagonist of smoothened, PF-04449913 is developed for treatment of cancer [1].

PF-04449913 is found not to inhibit cytochrome P450 and is negative in Ames and micronucleus assays suggesting it as a safe drug. In the preclinical studies, PF-04449913 shows a half-life of 30 h and an oral bioavailability of 55% in humans. It also has low plasma clearance of 1.03 mL/min/kg and moderate volume of distribution (2.7 L/kg) [1].

参考文献:
[1] Munchhof MJ, Li Q, Shavnya A, Borzillo GV, Boyden TL, Jones CS, LaGreca SD, Martinez-Alsina L, Patel N, Pelletier K, Reiter LA, Robbins MD, Tkalcevic GT. Discovery of PF-04449913, a Potent and Orally Bioavailable Inhibitor of Smoothened. ACS Med Chem Lett. 2011 Dec 21;3(2):106-11.