A single ascending‐dose study of muscle regulator ace‐031 in healthy volunteers

Introduction ACE‐031 is a soluble form of activin receptor type IIB (ActRIIB). ACE‐031 promotes muscle growth by binding to myostatin and other negative regulators of muscle mass. Methods This double‐blind, placebo‐controlled study evaluated the safety, pharmacokinetics, and pharmacodynamics of ACE‐031 in 48 healthy, postmenopausal women randomized to receive 1 dose of ACE‐031 (0.02–3 mg/kg SC) or placebo (3:1). Results ACE‐031 was generally well‐tolerated. Adverse events included injection site erythema. Mean ACE‐031 AUC 0–∞ and C max increased linearly with dose; mean T ½ was 10–15 days. Statistically significant increases in mean total body lean mass (3.3%; P = 0.03, by DXA) and thigh muscle volume (5.1%; P = 0.03, by MRI) were observed at day 29 in the 3 mg/kg group. Statistically significant changes in serum biomarkers suggest ACE‐031 also improved bone and fat metabolism. Conclusions Single‐dose ACE‐031 treatment was generally well‐tolerated and resulted in increases in muscle mass in healthy postmenopausal women. Muscle Nerve [B]47[/B]: 416–423, 2013