Mahtomedi family asks FDA to accelerate approval of ‘life-changing’ muscular dystrophy treatment

Life-changing genetic therapy

Life-changing genetic therapy

The odds said Brecken Kinney, 9, would be in a wheelchair by now. That’s not the case.

Kinney, who lives with his parents and two younger brothers in Mahtomedi, has Duchenne muscular dystrophy, a genetic disorder that causes his muscles to deteriorate and sets his life expectancy at his early 20s.

5 EYEWITNESS NEWS met Kinney Monday and witnessed as he kicked the soccer ball around in the yard, cheering and running as he scored a point on his brother, Avery. Parents Marit Sivertson and James Kinney attribute the drastic change in Kinney’s physical abilities to an experimental gene therapy, and they are asking the FDA to accelerate its approval in hopes of changing the expected outcomes for other young boys.

It means a lot to me,” Kinney said. “The stairs just don’t feel like an obstacle anymore.”

Rewind four years, and Brecken’s life was drastically different.

“I felt like I couldn’t go up the stairs, and I didn’t have that much stamina to go up,” Kinney explained.

“Watching your child start to go downhill in front of you, it’s devastating, and you feel hopeless,” Sivertson remembered.

There is no cure for her son or thousands of other boys in the U.S. living with Duchenne muscular dystrophy.

Doctors can slow muscle degeneration by a year or two with steroids, but as neuromuscular neurologist Dr. Crystal Proud explained, “inevitably, they lose that ability,” typically by 13 years old.

“They subsequently have difficulties with breathing, they have heart failure, and unfortunately, they typically pass away in their 20s,” Dr. Proud said.

Proud is on the ground floor of changing that expectation. She’s one of the lead clinical investigators for the trial Kinney got accepted into when he was five years old.

The therapy, created by Sarepta Therapeutics, is called delandistrogene moxeparvovec (or SRP-9001). Essentially, it’s a one-time IV infusion that includes a small version of the dystrophin gene.

“It is packaging a small version of the of the dystrophin gene into a viral particle, but that viral particle is not able to cause infection. Instead, it allows for that miniature version of the gene that you want to deliver to be able to get to other tissues, in this case, cardiac and muscle tissues throughout the body,” Proud explained.

“Then it allows for that piece of DNA to produce protein that then is able to work within those muscles to hopefully stabilize those muscles and maintain their strength.”

Kinney got into the clinical trial at Nationwide Children’s Hospital in Columbus, Ohio, four years ago.

“I was a trooper the whole time,” he recalled.

A few weeks later, Sivertson said there were noticeable differences.

These days, “He’s not just walking up the stairs; he’s running up the stairs. He’s swimming, he’s diving, he’s playing with his brothers outside,” Sivertson shared.

“When we went to the Columbus Zoo, he was able to walk with us the whole park. We didn’t use a stroller or anything,” James Kinney added. “And so just that stamina to be able to do that post-transfer, that’s what I remember most about the whole thing.”

There’s still a lot to be learned about the treatment as Kinney’s parents — and several other families — asked an FDA advisory committee to give thousands of other families the same chance.

“There are thousands of other boys across the country whose families are waiting and watching as their sons continue to deteriorate,” Sivertson said.

She shared the story of a Minneapolis friend whose sons are within a year of Kinney’s age and were both diagnosed with Duchenne’s around the same time. That family did not make it into the clinical trial.

“She has seen significant decline in her sons, and just the other day, they went wheelchair shopping,” Sivertson said.

“A big narrative that came out of that was time is muscle, right?” James Kinney added.

“There are risks with gene therapy; maybe it affects some boys a little differently than others. You know, maybe it doesn’t work for some boys as well. But the alternatives right now are do nothing or take a chance at the gene therapy.”

For Brecken Kinney, it’s about the chance to ‘be like the other boys.’

“Well, if they got the treatment, then they would feel happy that they can go upstairs and they can be inclusive with other kids,” he said.

The FDA committee ultimately agreed with the families and, after a 9-hour meeting, recommended the accelerated approval of the drug.

The FDA is expected to make that decision by the end of the month, according to Proud, who said, what she and other neurologists saw in video testimony was “a clear distinction from what we know to be possible in our boys with Duchenne.”

“I’m optimistic that this is going to revolutionize what we know to be natural history in this really tragic disease,” she added.