ACE-031 Reference

Plain English

What it is

ACE-031, also called ramatercept, is a lab-made protein built to block myostatin, a natural body signal that limits how much muscle you build. It is a research compound, not an approved medicine. The US FDA has never approved it.

What people use it for

A company tested it as a possible treatment for boys with Duchenne muscular dystrophy, a disease that slowly weakens muscles, to see if blocking myostatin would help them keep and build muscle. Because it acts on the muscle-growth pathway, it has also drawn outside interest from people focused on muscle size. It never reached the market.

What the science shows

The main human test was a small, early trial in boys with Duchenne muscular dystrophy. It showed only weak hints of more lean muscle and steadier walking ability, and those results were not statistically meaningful. The study was stopped early, and there was no later or larger trial.

The catch

The trial was halted after some boys had nosebleeds, gum bleeding, and small dilated blood vessels in the skin, a safety signal tied to how the drug affects blood vessels. The company then discontinued the program, so it was never proven safe or effective. It is also banned in sport at all times by the World Anti-Doping Agency.

Reference summary

Campbell 2017 Muscle Nerve published the abbreviated Phase 2 dataset (24 ambulatory boys with DMD). Despite the early termination, the trial reported a non-significant trend toward increased lean body mass and 6-minute walk distance; the safety signals (epistaxis, telangiectasia) drove the program halt. There is no Phase 3 trial and no later follow-up program.

Regulatory and posture

Categories

Growth Factor

Aliases

Ramatercept, Soluble activin receptor type IIB-Fc (ACVR2B-Fc) fusion protein, Acceleron Pharma development code

Evidence posture

human - Phase 2 trial halted early due to vascular-pattern safety signals; development discontinued.

Regulatory status

Not FDA-approved. Development discontinued. ACE-031 was a soluble activin receptor type IIB-Fc fusion protein developed by Acceleron Pharma as a systemic myostatin pathway inhibitor for muscular dystrophy. The Phase 2 trial in ambulatory boys with Duchenne muscular dystrophy was halted in 2010 due to non-clinical safety signals (epistaxis, gum bleeding, telangiectasia) consistent with off-target effects on vascular biology. Acceleron discontinued the program. WADA-prohibited at all times as a myostatin-pathway agent (S4).

Content review status

research reference

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