FDA broadens sanction for initial gene treatment in unique muscular dystrophy variant.
Last year, the drug Elevidys, manufactured by Sarepta Therapeutics, received regular approval to treat ambulatory individuals aged 4 and über who have a confirmed mutation in the DMD gene, a genetic anomaly linked to muscle strength, and associated with Duchenne muscular dystrophy (DMD), a severe form of inherited muscular dystrophy. Additionally, the drug was granted accelerated approval for non-ambulatory individuals aged 4 and above with the same mutation, despite insufficient safety data for children under 4.
The price tag for Elevidys, administered as a one-time intravenous infusion, amounts to approximately $3.2 million per patient. Although substantial, this is not unexpected for one-time gene therapies, some of which have exceeded $3 million per patient in recent years, making Elevidys the second most expensive drug globally, following the $3.5 million hemophilia treatment Hemgenix.
Elevidys was initially approved under the FDA's accelerated approval pathway, which expedites the approval of drugs for critical health conditions based on evidence suggesting clinical benefits. The drug has been under close observation since its initial approval, and in October, Sarepta Therapeutics reported results from a confirmatory trial. Although the trial missed its primary objective – assessing motor function – it achieved success on several secondary measures.
The approval of Elevidys addresses "an urgent unmet medical need," representing a significant advancement in the treatment of Duchenne muscular dystrophy, a debilitating condition with limited treatment options that leads to progressive deterioration over time, according to Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.
This is the first instance of a one-time treatment that delivers a functional gene copy to counteract the defective one causing disease, being approved under the accelerated approval framework. This decision was made following emotional testimonials from families during an FDA advisory committee meeting.
Duchenne muscular dystrophy causes progressive muscle weakness that can render children wheelchair-bound by their teenage years, and Unless treated, many individuals don't survive into their 30s. It predominantly affects boys due to its inheritable nature, affecting approximately 1 in 3,300 boys.
The Muscular Dystrophy Association supports the FDA's decision, which considers the risks and benefits of the drug, said Dr. Sharon Hesterlee, the association's chief researcher.
"Ultimately, what we aim for is the right balance between risks and benefits for our patient community," she said.
Potential risks associated with Elevidys include increased levels of specific liver enzymes and acute severe liver injury. Common side effects of the drug include vomiting, nausea, increased liver function tests, and fever.
However, a significant advantage of Elevidys is that it offers another treatment option for individuals with Duchenne muscular dystrophy, and it's administered just once.
There is currently no cure for Duchenne muscular dystrophy, and outside of Elevidys, treatment options are limited. Other strategies might include steroid medications, certain drugs that modify how muscle cells process the mutated gene, physical therapy, or surgery to correct spinal curvature, Hesterlee explained.
"Right now, the primary standard of care for Duchenne is corticosteroids, such as prednisone, although there are some newer drugs available. These kids are often on chronic doses of steroids for extended periods," she said, noting that the side effects of corticosteroids, such as weight gain, behavioral issues, and increased bone fracture risk, are less than ideal.
Treating Duchenne muscular dystrophy can be challenging, Hesterlee acknowledged, but having more effective treatment options remains crucial.
“Muscle constitutes a significant portion of your body mass. So when you have a disease like this, it's significantly impacting a lot of your tissue. Anything you do, you’re aiming to either reverse or halt a disease process that’s affecting the body throughout, and since it's a progressive disease, you continue to lose more and more muscle over time," she said.
"That’s made it challenging, but we've certainly learned a lot. You can't overlook the fact that these boys are living much longer and doing much better. Even 20 years ago, they were dying in their teens, and many of them are now living into their 30s. They're going to college; they have girlfriends; some of them have even gotten married. These are things that weren't happening years ago. So we've made a tremendous amount of progress.”
CNN’s Meg Tirrell contributed to this report.
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The FDA's decision to broaden the sanction for Elevidys is significant for individuals with specific mutations in the DMD gene, as it expands the drug's use to non-ambulatory patients aged 4 and above.
Given the high cost of Elevidys, health care providers and insurance companies will need to consider the drug's benefits and potential risks in light of its substantial price tag.
