Sarepta rises after muscle disease drugs show promise in early-to-mid stage trials

Shares of drugmaker Sarepta Therapeutics SRPT.O rise 6.1% to $18.70 premarket

Co says early-to-mid stage studies of two experimental drugs for rare muscle diseases showed high levels of the treatment reaching muscle tissue with no serious safety issues

One of the drugs targets facioscapulohumeral muscular dystrophy, a rare inherited disorder that causes progressive muscle weakness, while the other targets myotonic dystrophy type 1, a common adult-onset muscle disorder that can affect the heart and breathing

Co says the treatments reduced harmful proteins or genetic material linked to the diseases after a single dose

Adds most side effects were mild to moderate, with no dose-limiting safety signals

Shares fell ~82% in 2025