Cytochrome P450 (CYP450) isozyme CYP3A4 is an important drug-metabolizing enzyme. PF-04981517 is a potent, time-dependent inhibitor of CYP3A4 (IC50 = 30 nM). It is less effective against CYP3A5 and CYP3A7 (IC50s = 17 and 70 μM, respectively). PF-04981517 will be useful for understanding the relative roles of CYP3A4 and CYP3A5 in drug metabolism.
