
What Is Duchenne Muscular Dystrophy? Duchenne Muscular Dystrophy is a rare, X-linked genetic disorder that primarily affects boys. It is caused by mutations in the DMD gene, which encodes for dystrophin, a protein essential for muscle integrity. Without dystrophin, muscle fibers progressively weaken and break down. Symptoms typically emerge in early childhood. Babies may miss developmental milestones such as holding their head up or crawling. By age 12, most patients require a wheelchair. As the disease progresses, it leads to serious complications, including respiratory failure or cardiomyopathy, often resulting in death during adolescence or early adulthood. At present, there is no cure. |
Sarepta Therapeutics: Sarepta Therapeutics is currently the only biotech company with FDA approval for a gene therapy targeting Duchenne. The treatment received accelerated approval in June 2023 for ambulatory patients aged 4 to 5. In 2024, the FDA granted full approval for use in ambulatory children aged four and older, even though the therapy did not meet its primary efficacy endpoint in a key Phase 3 trial. Use of the therapy in non-ambulatory (wheelchair-using) patients remains under investigation, and was not part of the approved indication at the time of the reported fatalities. The Fatalities: The two deaths involved boys aged 15 and 16, both of whom were non-ambulatory. Within 90 days of receiving the gene therapy, both suffered acute kidney failure. It is believed both may have had underlying or recent kidney infections at the time of treatment, which may have contributed to the adverse outcomes. Because non-ambulatory teens have significantly reduced muscle mass, higher doses of the gene therapy may have been required to target remaining muscle tissue. This increased dosage likely heightened the risk of toxicity. While the therapy has been associated with liver enzyme elevation in clinical studies, the link to kidney failure is now under scrutiny. There is now growing concern that these patients received the therapy outside of approved guidelines. The case raises urgent questions about off-label use, appropriate patient selection, and how best to balance hope with risk in experimental gene therapies. These tragic outcomes highlight the delicate balance between innovation and safety in gene therapy. While the new treatment may be a shining light for infants, the accelerated approval meant that the drug was sadly mis-prescribed and perhaps approved of too soon. Stock market shares for the biotech company have plummeted, and it remains to be seen whether this treatment will remain an option even when it is used appropriately. |