ACE-083 is a follistatin-based therapeutic agent known for its localized mechanism of action. It works by binding to myostatin and other muscle-regulating factors to enhance muscle mass. ACE-083 has undergone testing in various clinical trials for different neuromuscular diseases, yielding mixed results. Notably, in a Phase 2 clinical trial for FSHD, it increased muscle volume, but did not improve function, leading to the discontinuation of its use for FSHD treatment.