Drugmaker Sarepta Therapeutics says it won’t comply with a request from U.S. regulators to halt all shipments of its gene therapy.

U.S. regulators asked Sarepta Therapeutics on Friday to voluntarily halt shipments of its Elevidys gene therapy after a muscular dystrophy patient who received a different, experimental treatment died,

The move follows the death of two teenagers who were administered the treatment, as well as the death of a 51-year-old man who received a similar product in a clinical trial for a different form of muscular dystrophy.