Check out the companies making headlines after the bell Monday:
Sarepta shares surged in after-hours trading, after the Food and Drug Administration requested more data before making a decision on eteplirsen. Eteplirsen's approval has been mired in challenges, as regulators have debated whether the treatment for Duchenne muscular dystrophy, has had adequate clinical drug trial results amid changing guidelines for compassionate use.
Shares of Alexion Pharmaceuticals tumbled in extended trading after the company announced results from a study of one of its drugs. The company revealed that at week 26 of the study, a key efficacy measure missed its endpoint for statistical significance. The drug, Soliris, treats a neuromuscular disease that causes slurred speech, impaired swallowing and choking, double vision, weakness, disabling fatigue, shortness of breath and episodes of respiratory failure, according to the company.