NOVA 6-year-old First U.S. Recipient of New Muscular Dystrophy Treatment

The Secrist Family. Photo Credit: Erin Luellen Photography

A local boy from Burke, Virginia, received a last-minute revolutionary treatment that changed his life in a matter of weeks.

The U.S. Food and Drug Administration approved Elevidys, the first gene therapy for patients who are 4 to 5 years old with Duchenne’s Muscular Dystrophy (DMD) in June of last year.

Up until then, the only treatment for DMD, a degenerative condition that weakens the skeletal muscles, had been steroids, according to Dr. Sarah Wright, a neuromuscular neurologist at Washington D.C.’s Children’s National Hospital.

Hiram Secrist received a one-time infusion the day before his sixth birthday, making him just barely eligible for the treatment. He was the first person in the country to receive it.

His mother, Kristen Secrist, says while the infusion process itself only lasted for about an hour, the family remained at Children’s National for about a day to monitor Hiram’s blood pressure and stay vigilant for any adverse reactions.

“At that age, it’s hard to explain. We just said [to Hiram], ‘Oh, you’re getting some medicine for your muscles to help your muscles get stronger,’” she says.

What is DMD?

Though Hiram, now 6 ½, loves Star Wars, LEGO and dinosaurs—like many boys his age—his diagnosis of DMD, a severe, hereditary neuromuscular disease, had made it challenging for him to navigate daily life.

A more rare form of muscular dystrophy (though not a rare condition itself), DMD affects one in every 3,600 male live-born infants. The condition is more common in males because the dystrophin gene is on the X chromosome, which males generally have one of—meaning the they won’t have a functioning backup copy on their other sex chromosome.

DMD can be challenging to detect early on, but the first indicators are usually missed developmental milestones for sitting, standing or walking. Boys with DMD will start to show signs of weakness in their legs at about two to three years of age.

In Wright’s specialty, she works closely with other doctors from pulmonology, cardiology and rehabilitation to treat DMD and conditions like it.

One particular sign Wright says these doctors look for in diagnosing DMD is called Gower’s sign, which is where a child will stand by “walking” their hands up their legs from a hands-and-knees position.

Other signs and symptoms of the disease include frequent falls, trouble running and jumping, toe-walking, the appearance of large calf muscles, muscle pain and weakness, learning disabilities and delayed growth.

People with DMD lose the ability to walk over time and are confined to wheelchairs, often dying from the condition by the age of 25—but the new gene therapy Hiram received is offering families hope.

How does it work?

For those looking for a more scientific explanation of the new treatment, Sarepta Therapeutics, the manufacturer of Elevidys, explains that it works by delivering a new gene to the targeted cells. This new gene is designed to correct or overcome the defective version of the gene that codes for the production of a functional dystrophin protein.

A promoter functions to activate or “turn on” the transgene, and both the transgene and the promoter are carried to the target cells by a viral vector (rh74) with an affinity for skeletal muscle cells.

These microscopic agents may be small, but the results are momentous, especially for Hiram and his family.

Just one week after Hiram received his treatment, Secrist says she and her husband, Benjamin, noticed their son doing something new—hopping.

“He’s able to jump, whereas before he couldn’t. He’d kinda do this one foot up, then the next foot, but now he’s, like, actually jumping. He has endurance that’s much greater. He’s able to run like he wants to run. You can tell he’s got more energy,” Kristen Secrist says.

“This is six months out, and that these are the things that he’s able to do, it’s been incredible.”

What do families need to know?

Kristen Secrist says her family hasn’t noticed any downsides to the treatment itself, however, the steroid course that Hiram had prior to the infusion did result in some behavioral challenges which have since subsided.

Currently, Elevidys is only approved for boys ages 4 and 5. Potential recipients also have to have mutations that don’t include exons 8 and 9, because those boys had a very serious adverse effect during the clinical trial that is not yet well understood, according to Wright.

Recipients also have to be able to receive the gene therapy though the viral vector that carries the treatment.

“Essentially, we just have to test to make sure they’ve never been exposed to this
particular virus (rh74) in the population so they don’t have immunity against it,” Wright says, explaining that immunity against the viral vector would make the therapy
ineffective.

Learn more with a guide to treatment and eligibility on elevidys.com.

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