NEW YORK – The US Food and Drug Administration on Thursday granted accelerated approval to Sarepta Therapeutics' Elevidys (delandistrogene moxeparvovec), making it the first gene therapy for Duchenne muscular dystrophy (DMD).
Sarepta had submitted a biologics license application (BLA) seeking approval for Elevidys as a treatment for patients of all ages with the progressive muscle disease and a confirmed mutation in the DMD gene. However, after reviewing the evidence Sarepta submitted, the FDA opted to limit Elevidys' indication to DMD patients between 4 and 5 years old.
Elevidys is contraindicated in patients with deletions in exon 8 or exon 9 in the DMD gene.
Industry observers were eagerly awaiting the FDA's decision on Elevidys since the agency's advisory panel only narrowly voted in favor of accelerated approval. Meanwhile, Peter Marks, head of the FDA's Center for Biologics Evaluation and Research, had repeatedly expressed a desire to shepherd more gene therapies for rare diseases to market through the accelerated approval pathway.
"The FDA remains committed to facilitating the development of innovative new therapies to reduce the impact of debilitating diseases and to improve outcomes and quality of life for those affected," Marks said in a statement announcing Elevidys' approval.
Most existing DMD treatments address symptoms of the disease and not its underlying genetic cause, according to the FDA. Elevidys, an adeno-associated virus vector-based gene therapy, delivers a gene that encodes for microdystrophin, an engineered protein developed by Sarepta that the firm says can carry out the normal functions of dystrophin. Patients with certain DMD gene mutations lack the dystrophin protein.
Sarepta plans to price Elevidys at $3.2 million, according to a presentation the company shared with market analysts Thursday. Sarepta said the drug could be cost-effective at $5 million to $13 million when compared to standard care.
The FDA granted Sarepta accelerated approval for Elevidys based on data from a Phase II trial that demonstrated patients 4 to 5 years old experienced increased microdystrophin expression 12 weeks after they received the gene therapy. Sarepta has not demonstrated a clinical benefit for Elevidys, although the FDA deemed the surrogate endpoint of microdystrophin expression "reasonably likely" to predict one. As a condition of accelerated approval based on Elevidys' effect on microdystrophin as a surrogate endpoint, the FDA has asked the firm to complete a confirmatory study to verify that the drug improves physical function and mobility. The ongoing and fully enrolled Phase III EMBARK study is to serve as that confirmatory study, and Sarepta said it expects to release top-line results late this year.
"If EMBARK confirms the benefits seen in our prior trials, Sarepta will move rapidly to submit a BLA supplement to expand the approved label as broadly as good science permits," Sarepta President and CEO Doug Ingram said in a statement.