ACE-031

ACE-031 is a recombinant fusion protein that acts as a myostatin/activin type IIB receptor decoy, blocking inhibitory signals on muscle growth. It demonstrated substantial lean mass gains in clinical trials for Duchenne muscular dystrophy before development was halted due to vascular side effects at high doses.

• Significant lean muscle mass gain
• Reduction in body fat percentage
• Increased strength
• May benefit muscular dystrophy conditions
• Rapid onset of action

• Nosebleeds (epistaxis) — dose-dependent
• Gum bleeding
• Telangiectasias at high doses
• Potential vascular effects
• Limited long-term safety data

Phase 2 trial (NCT01099371) in Duchenne MD showed lean mass increases of 2.7 kg vs placebo over 3 months at 1 mg/kg. Development paused due to vascular side effects at higher doses.