UNC Research Contributes To FDA Approval Of New Drug For Rare Genetic Disorder

A clinical trial at UNC led by Joseph Muenzer, MD, PhD, paves the way for a first-of-its-kind treatment that can slow the progression of Hunter syndrome.

A drug tested in a clinical trial at UNC, led by renowned UNC pediatric biochemical geneticist Joseph Muenzer, MD, PhD, has been approved by the U.S. Food and Drug Administration.

The decision marks a major breakthrough for children diagnosed with Hunter syndrome and families affected by the rare genetic disease.

“I was just phenomenally excited when I heard that it got approved because we have a drug now that can treat both the brain disease and the physical disease with one infusion,” said Dr. Muenzer, Director of the Muenzer MPS Research and Treatment Center, the Bryson Distinguished Professor in Pediatric Genetics, Department of Pediatrics, UNC School of Medicine, Chapel Hill, NC.

Kim Stephens, DBA, Executive Director of the Muenzer MPS Research and Treatment Center, is also the mother of a patient who has been in Dr. Muenzer’s care for more than thirteen years. Her son Cole is 15 now. Hunter syndrome stole his ability to speak, laugh, and sing.  She is thrilled to hear of the FDA approval for the new drug.

“This is his last chance, and I knew it was. This is it,” Stephens said.  “I knew it was working because I would see the kids in the trial  and, we were just watching it and watching it, and saying, ‘Is the approval coming in time for Cole?’ Because he was at that age when most boys with Hunter syndrome pass, and it did come, and Cole will be on it.”

The FDA approved Avlayah, a first‑of‑its‑kind treatment developed by Denali Therapeutics, on March 25. The drug is designed to reach the brain and body and slow the most devastating effects of the disorder. The initial results of a clinical trial on the drug were published in the New England Journal of Medicine in January 2026 with Dr. Muenzer as the first author.

The drug approval marks the first major advance in the care of Hunter syndrome in 20 years and reflects the global impact of Muenzer’s work at UNC.