Notes: PF-04449913 is an orally available Hedgehog pathway inhibitor that acts by binding Smoothened (Smo) and blocking signal transduction (IC50 = 5 nM).{33585} It has been shown to attenuate leukemia stem cell self-renewal and cell cycle progression in primary acute myeloid leukemia cells and in an in vivo Drosophila model.{33586,33584}