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For Many Boys With Duchenne Muscular Dystrophy, Bright Hope Lies Just Beyond Reach

April 3, 2019

Scientists are testing nearly two dozen treatments that might stop the disease. But enrollment in the trials is very restricted, and few children qualify.

Lucas was 5 before his parents, Bill and Marci Barton of Grand Haven, Mich., finally got an explanation for his difficulties standing up or climbing stairs. The diagnosis: muscular dystrophy.

Mr. Barton turned to Google.

“The first thing I read was, ‘no cure, in a wheelchair in their teens, pass in their 20s,” Mr. Barton said. “I stopped. I couldn’t read any more. I couldn’t handle it.”

Then he found a reason to hope. For the first time ever, there are clinical trials — nearly two dozen — testing treatments that might actually stop the disease.

The problem, as Mr. Barton soon discovered, is that the enrollment criteria are so restrictive that very few children qualify. As a result, families like the Bartons often are turned away.

“There is so much hope, but it’s not for them,” said Kristin Stephenson, vice president of policy and advocacy at the Muscular Dystrophy Association in Chicago.

Even for the parents whose lucky child qualifies, good news may be followed by agonizing, life-or-death choices. What treatments seem most promising? Should he be enrolled in a trial with a placebo arm?

Should he be placed in a less risky study that aims to slow the progress of the disease but will not stop it? Should the parents take their chances with a trial now — or wait a year or two, as their child’s condition worsens, until something better comes along?

Often there is no easy way to decide.

“We talk to families every day,” said Debra Miller who founded the advocacy group, Cure Duchenne, after her son was diagnosed with the disease. “So many times they are looking at us and saying, ‘What do I do?’”

To help, her group has constructed detailed decision trees and leads families through them. Ms. Miller’s own son, who is 22, does not qualify for the new clinical trials.

Ryan and Brooke Saalman know how hard it can be to know what to do. “We did a lot of praying,” said Ms. Saalman, mother of two boys with Duchenne in Columbus, Ga.

They decided to enroll their oldest son, Jacob, 6, in a trial of a highly experimental drug. The trial requires weekly infusions at a site 100 miles from their home. He is one of the first boys to be treated.

The investigators are testing a strategy called exon skipping: putting a molecular bandage over a tiny mutation in a large gene. The Saalmans also considered a gene-therapy trial, in which scientists were attempting to insert a new gene that makes dystrophin.

But they discovered that gene therapy may be irreversible. And if it didn’t work, Jacob would be ineligible for an even more promising approach in the future: gene editing, to snip out the deadly mutation that causes Duchenne, an effort now in preclinical development.

Gene therapy and gene editing both depend on a disabled cold virus to deliver the treatment. Once exposed to that virus, the body makes antibodies to it. Essentially, patients like Jacob get one shot at genetic modification.

The Saalmans made a different decision for their younger son, Hudson, 2. He was offered a spot in two trials by companies that will accept younger boys.

The Saalmans could not decide what to do. Hudson’s disease is steadily progressing; muscle that he loses now is gone forever.

But they finally made the difficult decision to wait.

Hudson is still very young. If they wait, the Saalmans concluded, researchers will have learned more. Other trials are bound to begin.

About 15 out of every 100,000 males aged 5 to 24 have Duchenne muscular dystrophy, the most common kind. They all lack a functioning dystrophin gene, which is on the X chromosome, transmitted to boys by their mothers.

Without dystrophin — a protein that is important for maintaining the membrane of muscle cells — muscles atrophy. Patients usually lose the ability to walk by age 12, and die in their 20s.

“It’s a heavy thing,” said Leslie Porter of Blanchard, Okla., whose 8-year-old son has Duchenne. He does not qualify for any trials, and she dreads watching him deteriorate.

“I just want time to slow down,” she said.

According to Ms. Stephenson, of the M.D.A., drug trials are seeking 2,500 patients. But most only want to enroll boys between the ages of 4 and 7 who are affected by the disease but not yet too debilitated, and who meet other clinical criteria, such as having a mutation in the right place in the dystrophin gene.

The trials usually require functional tests, including one that measures how far a boy can walk in six minutes or how quickly he can get up from lying flat.

For many, the criteria are just too stringent. “There are not enough patients,” Ms. Miller said. “It will be difficult to fill all these clinical trials.”

The Bartons found out about a gene-therapy trial at Nationwide Children’s Hospital in Columbus, Ohio, testing a treatment by Sarepta Therapeutics.

They watched a miraculous video of a little boy struggling to walk up a flight of stairs before treatment — and then doing it easily afterward.

“This was what we were hoping for,” Mr. Barton said.

Lucas was the right age, and he seemed to qualify. But testing showed that he carries antibodies to the virus used to deliver the treatment. It would not work for him.

The Bartons were drained, devastated. And for now, there is no other trial that Lucas qualifies for.

“I had my put my hopes into this,” Mr. Barton said. “It was the miracle.”

Dr. Jeffrey Bigelow, a neurologist, and his wife, Alexis Bigelow, of Millcreek, Utah, hoped against hope that their son Henri, 8, would qualify for the only gene therapy trial that will accept boys his age.

Then the Bigelows found out that enrollees of Henri’s age have to be able to lie down and then stand up with their hands at their sides in less than 10 seconds.

It took Henri 10 seconds to do that last spring, when he was evaluated for another trial. Now it would probably take him 20 seconds, his father said.

“It feels like Henri is being punished for losing the ability to stand up from the ground too soon,” Dr. Bigelow said.

He also worries about older boys with Duchenne who are lucky enough to still walk. They are shut out from the trial because they are not yet in wheelchairs. And other trials won’t accept boys that old.

“These are boys who, like Henri, desperately need the treatment, and if they don’t get it in the next one to two years, likely will be confined to a wheelchair, to never walk again,” Dr. Bigelow said.

“This just feels unjust.”