The Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ASP3652 in First-in-Human and Ascending Multiple Oral Dose Studies in Healthy Subjects.

INTRODUCTION Inhibitors of fatty acid amide hydrolase (FAAH) increase the levels of endocannabinoids and have shown analgesic and anti-inflammatory activity in animal models. ASP3652 is a peripherally acting FAAH inhibitor in development for the treatment of chronic bladder and pelvic pain disorders. Here we describe the safety, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of ASP3652 administered in healthy non-elderly and elderly male and female volunteers. METHODS Study 1 was a combined single-ascending dose and food-effect study in which ASP3652 was given as single doses (1-600 mg) or matching placebo in healthy subjects. Study 2 was a multiple ascending dose study in which ASP3652 or matching placebo was administered in multiple oral doses (10-300 mg bid and 600 mg qd for 14 days) to healthy subjects. In both studies, the levels of ASP3652, FAAH, endocannabinoids (eCBs) and safety were evaluated. RESULTS ASP3652 was readily absorbed to reach Cmax at 1 h after a single dose. Steady state was reached within 3 days after the start of multiple dosing. The Cmax and AUC of ASP3652 increased in a slightly more than dose-proportional manner after a single dose of ASP3652 at 30-600 mg. There was some accumulation (15-38%) based on Cmax and AUC12h upon multiple doses. Cmax was 47% lower in combination with food. There was no significant effect of gender or age on the pharmacokinetics of ASP3652. FAAH activity was inhibited in a dose-dependent manner in all dose groups after single and multiple doses of ASP3652, paralleled by an increase in plasma levels of anandamide (AEA). The incidence of adverse events following multiple doses was similar across all treatment groups including the placebo group. CONCLUSIONS Single and multiple doses of ASP3652 were safe and well tolerated and increased endogenous cannabinoid plasma levels.