Locally Acting ACE-083 Increases Muscle Volume in Healthy Volunteers.

Introduction: ACE-083 is a locally acting follistatin-based therapeutic that binds myostatin and other muscle regulators and has been shown to increase muscle mass and force in neuromuscular disease mouse models. This first-in-human study examined these effects. Methods: In this phase 1, randomized, double-blind, placebo-controlled, dose-ranging study in healthy postmenopausal women, ACE-083 (50-200 mg) or placebo was administered unilaterally into rectus femoris (RF) or tibialis anterior (TA) muscles as 1 or 2 doses 3 weeks apart. Results: Fifty-eight postmenopausal women were enrolled, 42 ACE-083 and 16 placebo. No serious adverse events (AE), dose-limiting toxicities, or discontinuations resulting from AEs occurred. Maximum (mean +/- SD) increases in RF and TA muscle volume were 14.5% +/- 4.5% and 8.9% +/- 4.7%, respectively. No significant changes in mean muscle strength were observed. Discussion: ACE-083 was well tolerated and resulted in significant targeted muscle growth. ACE-083 may have the potential to increase muscle mass in a wide range of neuromuscular disorders.