Sarepta Therapeutics announced it has laid off more than one-third of its workforce, a drastic cost-cutting move following the deaths of two teenagers administered its gene therapy for Duchenne muscular dystrophy.

A Cambridge-based company developing gene therapies for rare diseases is laying off more than a third of its workforce.

Sarepta Therapeutics’ stock has dropped precipitously as questions swirl around the safety of its gene therapies. Meanwhile, the Duchenne patient community fears losing access to Elevidys while the regulator considers more drastic action.

The favorable market reaction indicates investor relief at management’s swift measures to rectify the company's worsening financial situation.

The drop comes the day after the drugmaker said it would add a so-called black-box warning to its gene therapy Elevidys after two teenage boys receiving the treatment died earlier this year.

British biopharmaceutical company GlaxoSmithKline will lay off 150 employees in its Cambridge operations by the end of March 2026, the company said in a notice to the state.