How does ACE-031 differ from follistatin?

ACE-031 is a decoy receptor that traps myostatin and related ligands in circulation, whereas follistatin directly binds and neutralizes myostatin. Both reduce myostatin signaling but act through different mechanisms.

Why was clinical development of ACE-031 stopped?

Trials in Duchenne muscular dystrophy were discontinued after safety concerns including nosebleeds and small dilated blood vessels, despite signs of muscle benefit.

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Muscle Growth

Preclinical

ACE-031

Also known as: ACE-031

ACE-031 is a soluble decoy receptor (ActRIIB-Fc fusion) studied as a myostatin inhibitor to increase muscle mass and strength.

Mechanism of Action

ACE-031 is a fusion protein combining the extracellular domain of activin receptor type IIB (ActRIIB) with an IgG1 Fc region. It acts as a ligand trap, binding circulating myostatin (GDF-8), activin A, and other TGF-beta superfamily ligands before they can engage ActRIIB on muscle cells. By preventing receptor activation, it blocks downstream SMAD2/3 signaling that normally restrains muscle growth, leading to muscle hypertrophy and increased bone density in animal and early clinical models.

Half-life: Approximately 10 to 15 days (Fc-fusion, long-acting)
Administration Routes: subcutaneous
Research Status: Preclinical