Metabolism and Excretion of a Potent p38 Mitogen-Activated Protein Kinase Inhibitor N-cyclopropyl-3-(1-(2,6-difluorophenyl)-7-methyl-6-oxo-6,7-dihydro-1H-pyrazolo[3,4-b]pyridin-5-yl)-4-methylbenzamide

Compound I (N-cyclopropyl-3-(1-(2,6-difluorophenyl)-7-methyl-6-oxo-6,7-dihydro-1H-pyrazolo[3,4-b]pyridin-5-yl)-4-methylbenzamide) is a potent mitogen activated protein kinase P38α inhibitor.  The metabolic disposition of I was investigated to identify appropriate species for toxicity testing, to assess the clinical drug-drug interaction (DDI) potential, and to inform a circulating metabolite(s) strategy for the first-in-human (FIH) study.  The in vitro metabolite profile in hepatocytes of rat and cynomolgus monkey included the products of oxidation and amide hydrolysis and was qualitatively similar to human hepatocyte metabolism.  The major metabolite in hepatocytes of all species was the product of amide hydrolysis (M7).  In human hepatocytes the turnover of I was inhibited approximately 50% by the CYP3A inhibitor ketoconazole (1 ΅M).  Following a single oral administration of 1 mg/kg [¹⁴C] I to male bile-duct cannulated Sprague-Dawley rats, drug related radioactivity was predominantly recovered as metabolites consistent with the in vitro data.  Based on plasma collected at 1 hr post dose, compound I was the major circulating drug related radiolabeled component (62%) and metabolite M7 accounted for 21% of the total drug related radioactivity.  Analysis of plasma from multiple dose rat and cynomolgus monkey non-GLP toxicology studies indicated the exposure ratio of M7 to I was approximately 0.5.  The in vitro metabolite profiles supported the use of rat and cynomolgus monkey as preclinical tox species.  Metabolite M7 was also a circulating metabolite of potential toxicological importance in rat and monkey (>10% of total drug related material in plasma) and is therefore a candidate for further exposure assessment in FIH and GLP toxicology studies.