Effect of Diltiazem Administration on CP-945,598 Pharmacokinetics

A recently completed clinical drug interaction study of CP-945,598 with ketoconazole, a potent CYP3A inhibitor, showed that coadministration of CP-945,598 with ketoconazole results in an approximately 5-fold increase in CP-945,598 total exposure (AUC) and 4-fold increase in Cmax. Therefore, the sensitivity of CP-945,598 pharmacokinetics (PK) to less potent CYP3A inhibitors needs to be characterized to support labeling and registration. Diltiazem is a known substrate and moderate mechanism-based inhibitor of the CYP3A enzyme system and was chosen as the moderate CYP3A inhibitor for this study as it is a clinically relevant medication likely to be prescribed concomitantly with CP-945,598 given the increased risk of hypertension and cardiovascular disease in the obese patient population.