FDA approves ‘bittersweet’ version of ‘life-changing’ muscular dystrophy treatment
Families across the country celebrated the Food and Drug Administration’s accelerated approval of a new gene therapy treatment for Duchenne muscular dystrophy late last week.
The limited approval of the treatment — known as SRP-9001 among the thousands of families of young boys living with the genetic disorder that causes progressive muscle degeneration — was bittersweet, according to a Mahtomedi family that’s been at the forefront of fighting for expanded access.
“This is the first-ever gene therapy approved for Duchenne muscular dystrophy, and it’s a huge step forward for these little boys. But it’s a first step,” reacted Marit Sivertson, the Mahtomedi mother of 9-year-old Brecken Kinney, who was diagnosed as a toddler.
At his age, Brecken has defied what was known to be possible for someone with the disorder after his family took a chance on an SRP-9001 clinical trial a few years back.
The odds said Brecken should be nearing the need for a wheelchair by 9 years old. Instead, since the treatment, he has been able to walk, run, climb stairs, swim and even play soccer with his brothers.
“Yeah, I do think it changed my life,” Brecken said.
His family has been anxiously waiting for a final decision from the FDA after a committee in May, recommended the accelerated approval of the drug following a nine-hour meeting.
“This has been decades in the making to get to this point,” Sivertson said.
That long-awaited approval came down last week — but with a caveat: For now, the treatment is only approved for 4- and 5-year-olds, which means, according to Sivertson’s estimates, it’s available for about 400 kids in the U.S. out of around 15,000 who are living with Duchenne.
“So it is a bittersweet moment for us,” she said, adding Brecken was accepted into the clinical trial and received the one-time treatment at 6 years old.
“It was kind of sad that it wasn’t for all the kids because if it was for all the kids, all the kids could do the stuff that they’ve been wanting to do,” Brecken said.
“We were crushed,” said Sarah Kasner, a mother of two boys in Minneapolis with Duchenne.
Kasner and Sivertson bonded over having kids of similar ages living with the genetic disorder.
At 8 and 9 years old respectively, Kasner’s sons, Caleb and Duncan “Dunky” Kasner, are much less mobile than Brecken.
Kasner’s kids did not get into the clinical trial, and in the last year, they have both become reliant on mobility devices like scooters and wheelchairs to get around.
“They can still get where they need to go, but we can’t do anything without having a backup mobility device with us,” Kasner explained. “Stairs are not even an option.”
Meanwhile, the FDA continues to review trial results before considering expanding the therapy to older kids.
“That could be another year, though, before that happens,” Sivertson said.
SRP-9001, at this point, has only been administered to kids who are still ambulatory, Sivertson said, meaning in a year, it may no longer be an option for the Kasners.
“So we are going to continue to watch their disease progress, and we are days away probably from Caleb not being able to walk,” Kasner said.
“He will for sure be wheelchair-bound. Dunky, maybe a glimmer of hope,” she added. “Maybe.”
“Brecken got into the clinical trial, and her two boys didn’t, and now they’re on different trajectories, and that’s not right,” Sivertson said. “Sarah and I have this story where we were brought together by this awful disease, and I promised myself I wouldn’t stop fighting until her boys got the same opportunity that my son did.”
The push to make the gene therapy accessible wouldn’t stop at full FDA approval, Sivertson added.
“The access conversations need to start now with both the Medical Assistance Program here in Minnesota and private insurance companies to make sure that they will cover this life-changing drug for these boys,” she said.
“And then we also need to have a conversation about diagnosis at a young age. The average age of diagnosis is around age 5 to 6. So if we’re able to add Duchenne muscular dystrophy to the newborn screening panel in Minnesota, that means that children will be diagnosed at the time that they’re born and that they’ll be able to have access sooner to therapies like gene therapy.”