Metabolism, excretion and pharmacokinetics of [14C]glasdegib (PF-04449913) in healthy volunteers following oral administration

1. The metabolism, excretion and pharmacokinetics of glasdegib (PF-04449913) were investigated following administration of a single oral dose of 100 mg/100 mu Ci [C-14]glasdegib to six healthy male volunteers (NCT02110342). 2. The peak concentrations of glasdegib (890.3 ng/mL) and total radioactivity (1043 ngEq/mL) occurred in plasma at 0.75 hours post-dose. The AUC(inf) were 8469 ng.h/mL and 12,230 ngEq.h/mL respectively, for glasdegib and total radioactivity. 3. Mean recovery of [C-14]glasdegib-related radioactivity in excreta was 91% of the administered dose (49% in urine and 42% in feces). Glasdegib was the major circulating component accounting for 69% of the total radioactivity in plasma. An N-desmethyl metabolite and an N-glucuronide metabolite of glasdegib represented 8% and 7% of the circulating radioactivity, respectively. Glasdegib was the major excreted component in urine and feces, accounting for 17% and 20% of administered dose in the 0-120 hour pooled samples, respectively. Other metabolites with abundance <3% of the total circulating radioactivity or dose in plasma or excreta were hydroxyl metabolites, a desaturation metabolite, N-oxidation and O-glucuronide metabolites. 4. Elimination of [C-14]glasdegib-derived radioactivity was essentially complete, with similar contribution from urinary and fecal routes. Oxidative metabolism appears to play a significant role in the biotransformation of glasdegib.