(NEW YORK) -- Jenn McNary, a mother of six from Saxtons River, Vt., is desperate. Both her boys have Duchenne muscular dystrophy, but only her 10-year-old Max has access to a wonder drug that appears to be reversing the symptoms of this deadly disease.
His 13-year-old brother Austin is languishing in a wheelchair while Max has been able to take the drug eteplirsen through a highly successful clinical trial.
After 60 weeks on an IV infusion, Max was able to participate in a three-mile Halloween walk.
"It's the first time ever -- he's never been able to walk that far. He's always gone with a wheelchair, even as a toddler," said McNary, 32. "He actually doesn't look like a Duchenne kid at all. And his balance is great."
"People all over the world are calling it a miracle," she said of the drug.
Now, McNary has written petitioned the Food and Drug Administration to give accelerated approval of the medication -- the fastest way to help Austin and other boys with the disease.
Both boys have the same gene mutation that the drug targets and it will eventually kill them. Austin was diagnosed at 3 and Max at 3 months.
There is no cure for Duchenne muscular dystrophy. Until now, doctors have only been able to use steroids, which just temporarily delay the inevitable loss of muscle strength.
Austin was not allowed to participate in the clinical trial because one of the inclusion criteria was that he be able to complete a six-minute walk.
"This has been a bitter-sweet journey for us," McNary wrote in a letter to the FDA this week. "As we watch Max get better, we also watch his older brother, Austin, 13, get worse. He suffers, silently, as his disease progresses."
Duchenne muscular dystrophy affects one in 3,500 male births, about 20,000 children in the United States and 300,000 worldwide, according to Cure Duchenne, one of three organizations that have funded the clinical trial.
The muscular disease strikes between the ages of 3 and 5 as boys progressively lose their ability to walk. Eventually, they are wheelchair bound, their upper body strength fails, and, like Austin, they eventually cannot raise their arms to feed themselves.
Later, their breathing is affected and they require tracheotomies and breathing assistance. Eventually, the heart and lungs fail.
Parents of children who were in the clinical trial of eteplirsen at Nationwide Children's Hospital in Columbus are calling it a "wonder drug."
According to McNary, all 12 children in the double-blind study received "some benefit" from the drug. It has no known side effects.
"Even two boys who stopped walking before taking it have stronger upper bodies and their hearts are strong," she said. "They have progressed to stable."
If this exon-skipping drug is approved, she estimates 15 percent of boys with Duchenne could be helped, those with the type that skips exon 51. As a class of drugs, they could help up to 85 percent of boys with the disease.
Copyright 2012 ABC News Radio