Enlarge / Dr. Peter Marks, Director of the Center for Biologics Evaluation and Research within the Food and Drug Administration on March 18, 2021 in Washington, DC. (credit: Getty | Susan Walsh)

The Food and Drug Administration (FDA) on Thursday announced expanded approval for a gene therapy to treat Duchenne muscular dystrophy (DMD)—despite the fact that it failed a Phase III clinical trial last year and that the approval came over the objections of three of FDA's own expert review teams and two of its directors.

In fact, the decision to expand the approval of the therapy—called Elevidys (delandistrogene moxeparvovec-rokl)—appears to have been decided almost entirely by Peter Marks, Director of the FDA's Center for Biologics Evaluation and Research.

Elevidys initially gained an FDA approval last year, also over objections from staff. The therapy intravenously delivers a transgene that codes for select portions of a protein called dystrophin in healthy muscle cells; the protein is mutated in patients with DMD. Last year's initial approval occurred under an accelerated approval process and was only for use in DMD patients ages 4 and 5 who are able to walk. In the actions Thursday, the FDA granted a traditional approval for the therapy and opened access to DMD patients of all ages, regardless of ambulatory status.

Enlarge / Opal Sandy (center), who was born completely deaf because of a rare genetic condition, can now hear unaided for the first time after receiving gene therapy at 11-months-old. She is shown with her mother, father, and sister at their home in Eynsham, Oxfordshire, on May 7, 2024. (credit: Getty | Andrew Matthews)

There are few things more heartwarming than videos of children with deafness gaining the ability to hear, showing them happily turning their heads at the sound of their parents' voices and joyfully bobbing to newly discovered music. Thanks to recent advances in gene therapy, more kids are getting those sweet and triumphant moments—with no hearing aids or cochlear implants needed.

At the annual conference of the American Society for Gene & Cell Therapy held in Baltimore this week, researchers showed many of those videos to their audiences of experts. On Wednesday, Larry Lustig, an otolaryngologist at Columbia University, presented clinical trial data of two children with profound deafness—the most severe type of deafness—who are now able to hear at normal levels after receiving an experimental gene therapy. One of the children was 11 months old at the time of the treatment, marking her as the youngest child in the world to date to receive gene therapy for genetic deafness.

On Thursday, Yilai Shu, an otolaryngologist at Fudan University in Shanghai, provided a one-year progress report on six children who were treated in the first in-human trial of gene therapy for genetic deafness. Five of the six had their hearing restored.