Sarepta Therapeutics stock soared over 30% after the pharmaceutical company said it would lay off about 500 employees. It will also add a black-box warning to its controversial gene therapy Elevidys.Shares of Sarepta were up 34% to $24.

Following the death of two teenage patients with Duchenne muscular dystrophy following Elevidys treatment, Sarepta Therapeutics adds a black box warning to the gene therapy for acute liver injury and failure and parts with more than a third of employees.