Pharma Focus Europe

FDA Approves Expansion of Gene Therapy for Duchenne Muscular Dystrophy

Friday, June 21, 2024

The U.S. Food and Drug Administration (FDA) recently expanded its approval of Elevidys (delandistrogene moxeparvovec-rokl), a gene therapy for Duchenne muscular dystrophy (DMD), to include ambulatory and non-ambulatory individuals aged 4 years and older with a confirmed mutation in the DMD gene.

Initially, Elevidys received accelerated approval for ambulatory DMD patients aged 4 to 5 years with a confirmed DMD gene mutation. This recent decision grants Elevidys traditional approval for ambulatory DMD patients aged 4 years and older with the same mutation, while non-ambulatory patients in the same age group receive accelerated approval. The FDA's decision was based on a thorough review of the therapy's benefits and risks, taking into account the severe nature of DMD and the critical need for effective treatments.

Duchenne muscular dystrophy is a rare genetic disorder characterized by progressive muscle weakness due to a defective DMD gene, which impairs the production of dystrophin, an essential protein for muscle cell integrity.

Elevidys functions by delivering a modified gene that leads to the production of micro-dystrophin, a shortened version of the dystrophin protein found in normal muscle cells (138 kDa compared to 427 kDa). It is administered as a single intravenous dose.

The FDA's decision to grant traditional approval was supported by data from multiple studies involving 218 male patients with confirmed DMD gene mutations. One large randomized study did not meet its primary endpoint of improvement in motor function (measured by the North Star Ambulatory Assessment), but secondary and exploratory endpoints showed significant clinical benefits such as improved mobility and reduced creatine kinase levels compared to placebo.

For non-ambulatory individuals, accelerated approval was based on evidence linking elevated micro-dystrophin levels with observed clinical improvements in younger ambulatory patients. Ongoing trials aim to further validate these findings.

Safety assessments indicated common side effects such as vomiting, nausea, acute liver injury, fever, and thrombocytopenia. Monitoring of liver function and troponin-I levels (indicative of heart muscle health) is recommended before and after treatment.

The FDA's approval of Elevidys reflects its dedication to advancing treatments for serious conditions like DMD, with the goal of improving quality of life and extending lifespan for affected individuals.



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