AIMSTo characterize pharmacokinetic parameters of MK-0916 and its safety and tolerability in lean, healthy male subjects following single and multiple oral doses. To assess (by stable-isotope labelling) the in vivo inhibition of cortisone-to-cortisol conversion following oral MK-0916. METHODSData are presented from two randomized, controlled, double-blind, rising-dose phase I studies. In the first study, subjects received single oral doses of 0.4-100 mg MK-0916 (n = 16). In the second study, subjects received 0.2-225 mg MK-0916 followed by daily doses of 0.2-100 mg for 13 days beginning on day 2 or day 15 (n = 80). Plasma and urine drug concentrations were measured for pharmacokinetic analysis. For pharmacodynamic analysis, concentrations of plasma [13 C4]cortisol were measured by high-pressure liquid chromatography and tandem mass spectrometry following a single oral dose of 5 mg [ 13 C4]cortisone. RESULTSDoses Ն3 mg were rapidly absorbed (time at which maximal concentration was achieved in plasma, 1.1-1.8 h). Exposure (measured as the area under the concentration-time curve from 0 to 168 h) increased approximately in proportion to dose. Values for the maximal plasma concentration and the plasma concentration at 24 h increased in excess of dose proportionality at doses <6 mg and roughly in proportion to dose at doses >6 mg. In subjects dosed with 6 mg MK-0916 once daily for 14 days, the mean trough plasma concentration was 240 nM and in vivo cortisone-to-cortisol conversion was inhibited by 84%. The relationship between plasma MK-0916 and hepatic 11b-hydroxysteroid dehydrogenase type 1 inhibition was well represented by a simple Emax model with an IC50 of 70.4 nM. Exposure to MK-0916 was generally well tolerated. CONCLUSIONSThese findings indicate that 11b-hydroxysteroid dehydrogenase type 1 is effectively inhibited in human subjects by doses of MK-0916 that are well tolerated. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• The intracellular enzyme 11b-hydroxysteroid dehydrogenase type 1 converts the inactive glucocorticoid cortisone into the active hormone cortisol in many tissues, including the liver and adipocytes. It is thought that increased conversion of cortisone to cortisol contributes to pathophysiology associated with the metabolic syndrome.• MK-0916 is an inhibitor of 11b-hydroxysteroid dehydrogenase type 1 that has been evaluated clinically as a potential therapy for type 2 diabetes, obesity or hypertension. WHAT THIS STUDY ADDS• In lean, healthy male subjects, MK-0916 was well tolerated when given in oral doses that were sufficient to provide profound inhibition of hepatic conversion of cortisone to cortisol.• Multiple-dose administration of 6 mg day -1 MK-0916 provided mean plasma concentrations >200 nM at all times, a plasma drug concentration that inhibited systemic 11b-hydroxysteroid dehydrogenase type 1 by 84%.

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Oral aprepitant 125 mg, an antiemetic and a moderate inhibitor of the metabolism of oral midazolam, was assessed for interaction with intravenous midazolam in 12 subjects randomized to intravenous midazolam 2 mg +/- oral aprepitant 125 mg. The hypothesis was that midazolam AUC would not change by more than 2-fold (consistent with no more than weak inhibition) when midazolam + aprepitant was compared with midazolam alone. An AUC geometric mean ratio (midazolam + aprepitant/midazolam) with 90% confidence interval upper bound< or =2.0 (an increase in midazolam felt to be of modest clinical significance in the highly monitored perioperative period) was prespecified. Aprepitant increased intravenous midazolam AUC(0-infinity) 1.47-fold (90% confidence interval, 1.36-1.59), which fell within the prespecified criterion.

The observed effects of MK-0767 on adiponectin, free fatty acids and lipids, even after single doses, demonstrate that this prototypical dual PPAR alpha/gamma agonist has clinically meaningful activity in vivo.

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