European regulators said that a Duchenne gene therapy should not be approved, imperiling the treatment that is also facing scrutiny in the U.S.

The European Medicines Agency determined testing failed to prove Elevidys’ benefit and issued a negative opinion that could further jeopardize Sarepta’s financial future.

The U.S. Food and Drug Administration (FDA) is investigating the death of an eight-year-old boy who received Sarepta Therapeutics (NASDAQ: SRPT) gene therapy, Elevidys, for Duchenne muscular dystrophy (DMD).