ACE-083 Reference

Plain English

What it is

ACE-083 is an experimental, lab-made protein (a follistatin-based "ligand trap") that was built to be injected straight into one muscle so that just that single muscle would grow. It is not approved by the FDA, and the company that made it stopped developing it, so it is not a real medicine you can get.

What people use it for

It was tested as a possible treatment for muscle-wasting diseases, including Charcot-Marie-Tooth disease and a form of muscular dystrophy. Because it can build up one targeted muscle, it has also drawn interest from people who simply want bigger muscles.

What the science shows

In two mid-stage human trials, the injected muscles did get measurably bigger, but the people did not get stronger or move and function any better than those given a placebo (a dummy treatment). After these results, the drugmaker discontinued the program.

The catch

ACE-083 is not FDA-approved, its development was discontinued, and it is not available as a legitimate medicine. As a muscle-pathway agent it is also banned in sport at all times by the World Anti-Doping Agency (WADA).

Reference summary

Thomas 2022 Neurology (CMT, n=44, intramuscular ACE-083 to tibialis anterior) and Statland 2022 Muscle Nerve (FSHD) are the two published Phase 2 datasets. Both reported MRI evidence of muscle hypertrophy at the injected site but no significant gains on functional endpoints (6-minute walk, foot-drop measures, FSHD functional composite). The program was discontinued before Phase 3.

Regulatory and posture

Categories

Growth Factor

Aliases

Locally-injected follistatin-Fc fusion protein, Acceleron Pharma development code

Evidence posture

human - Phase 2 trials showed muscle growth without functional benefit; development discontinued.

Regulatory status

Not FDA-approved. Development discontinued. ACE-083 was Acceleron Pharma's locally-injected follistatin-Fc fusion designed to produce focal muscle hypertrophy without the systemic vascular signals seen with ACE-031. Two Phase 2 trials were completed in Charcot-Marie-Tooth disease (Thomas 2022 Neurology) and facioscapulohumeral muscular dystrophy (Statland 2022 Muscle Nerve). Both reported MRI-measured muscle volume increases without translating into clinically meaningful functional improvement, and Acceleron discontinued the program in 2019. WADA-prohibited at all times as a myostatin-pathway agent (S4).

Content review status

research reference