Clinical Pharmacology of the Reversible and Potent P2Y12 Receptor Antagonist ACT‐246475 After Single Subcutaneous Administration in Healthy Male Subjects

Abstract

ACT-246475 is a selective and reversible P2Y12 receptor antagonist inducing inhibition of platelet aggregation (IPA). A randomized, double-blind, placebo-controlled, parallel-design study was performed to investigate the safety, tolerability, pharmacokinetics, and pharmacodynamics of escalating single subcutaneous doses of ACT-246475 (1, 2, 4, 8, 16, or 32mg) in healthy male subjects (N=8 per dose, 3:1 active:placebo ratio). Pharmacodynamic effects were assessed based on maximum platelet aggregation and P2Y12 reaction units using light transmission aggregometry and VerifyNow® assays, respectively. ACT-246475 was safe and well tolerated up to 32mg based on adverse event data and absence of clinically relevant changes in hematology, biochemistry, vital signs, and electrocardiogram variables. Median time to reach maximum plasma concentration was 0.5-0.75hours, and geometric mean terminal half-life ranged from 1.3 to 9.2hours across the tested dose range. Exposure to ACT-246475 was dose proportional across all dose groups. The maximal %IPA was reached within 30minutes after subcutaneous administration of ACT-246475. A dose-dependent duration and extent of effect were observed based on area under the effect curve and maximum effect data. Similar results were observed for maximum platelet aggregation and P2Y12 reaction units. The %IPA was≥85% at doses≥2mg. This level of %IPA was extended to at least 12hours in the 32-mg dose group. The safety and pharmacokinetic/pharmacokinetic profile with quick onset and adequate duration of IPA support further investigation in patients with coronary artery disease.