The U.S. Food and Drug Administration is planning to ask Sarepta Therapeutics to voluntarily stop all shipments of its gene therapy Elevidys, a source familiar with the matter told Reuters on Friday.

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.

The company had previously halted shipments to certain older patients following the deaths of two teenagers treated with the therapy, Elevidys.