WASHINGTON -- Terri and Bill Ellsworth of Coraopolis expected their son to be in a wheelchair by now. Instead, 13-year-old Billy is hiking, jogging and dancing thanks to an experimental drug that's helping him and 11 other boys in a clinical trial for a drug to treat Duchenne, a rare and fatal form of muscular dystrophy mainly affecting boys.
The drug is helping all of them and it has no significant side effects, but the country's other 20,000 boys with Duchenne can't receive it because it hasn't yet gotten approval from the Food and Drug Administration.
Drug developers and Duchenne parents, who have been frustrated by the FDA's stop-and-go approval process, got a dose of good news Monday.
Approval of the new intravenous drug eteplirsen is still uncertain, but the FDA has offered a potential path forward for the drug.
In an agreement with regulators, the developer, Sarepta Therapeutics of Massachusetts, will conduct two additional studies even as the FDA considers its application for accelerated approval. That means the drug could be on the market by summer 2015. Sarepta also agreed to use a newer and more precise method of measuring dystrophin, the essential muscle protein that Duchenne boys lack.
Sarepta CEO Chris Garabedian said he believes the current data are sufficient to warrant approval but he understands the FDA wants additional information to bolster their confidence in the safety and efficacy of the drug. The additional data will make the new-drug application stronger, he told investors and other stakeholders on a conference call Monday morning.
Ed Kaye, Sarepta chief medical officer, said he would move expeditiously to begin the additional trials.
Eteplirsen works by correcting a genetic mutation that affects 13 percent of Duchenne patients. Approval would open the door to development of other drugs to treat Duchenne boys with other genetic mutations.
This year has been an emotional roller coaster for parents who are waiting for a drug to help their children. Last April, all signs seemed to point to swift approval by the FDA, but the agency became concerned after a failed trial of a drisapersen, another Duchenne treatment based on similar science.
The FDA has expressed concerns about the size and scope of Duchenne clinical trials and about techniques scientists used to measure results. But researchers and clinicians say the delay is confounding given that no significant side effects emerged after two effective clinical trials.
Billy is one of a dozen boys in an eteplirsen trial that his mother believes is keeping him out of a wheelchair and prolonging his life. Duchenne boys typically need wheelchairs by age 12 and die before reaching 30.
After three years on eteplirsen, Billy can walk on his own while other Duchenne boys his age are taking their last steps.
Mrs. Ellsworth, one of several mothers lobbying the federal government to expedite approval, has said that Billy's progress has been bittersweet because she knows other Duchenne boys, including friends' children, don't have access to eteplirsen, and the FDA had seemed in no hurry to make it available.
But Monday she was celebrating.
"This is huge and surreal," she said in a text message minutes after hearing the long-awaited news.
It's even better news for Liam O'Brien of Arlington, Va., who is likely to qualify for one of the new trials and might begin receiving the drug in the fall. His symptoms weren't severe enough to qualify him for the initial trial, which studied boys on the verge of becoming nonambulatory.
"This will allow him to walk in college instead of rolling through," said his mother, Noreen O'Brien.
Because of eteplirsen, Liam may be part of the first generation of boys to survive Duchenne.
"I felt in my heart that this would eventually get here and that the drug would eventually be approved. I just didn't know whether it would be in time for Liam," Mrs. O'Brien said. "We're not at full approval yet, but we're closer. We have something more concrete."
Mr. Garabedian credited parents for pressuring the FDA to offer clearer guidance and a path forward. A group of mothers launched a campaign this spring that included media interviews, a petition drive and meetings with regulators and members of Congress.
Mothers Tracy Seckler and Jenn McNary, who led the Race to Yes petition effort, said they've been waiting a long time for clear direction from the FDA.
"This is good news that gives our children a fighting chance, but it's only one lap in a long race and we have a long way to go to get to the finish line. Too much time has already been lost and, in that time, boys have continued to get sicker and die," said Ms. Seckler of Alford, Mass., whose 13-year-old son Charley has Duchenne.
"We are in a race to save the lives of boys around the world who have not had much hope for the future. The FDA must be more sensitive to those patients' needs and held accountable for delays in the process," said Ms. McNary of Pembroke, Mass., who has two children with Duchenne.
Sarepta investors on a conference call Monday also were gratified by the news, and the market responded. Stock shot up 34 percent Monday to $33.98 per share.
The publicly held company has no other drugs on the market but has seven more in the works to target other genetic mutations.
Eteplirsen has been shown to dramatically increase dystrophin production, to improve pulmonary function and to stabilize ambulation.
Still, it is not a cure.
"We're not creating healthy boys ... but we continue to be encouraged by the stability," Mr. Garabedian said. "Keeping these boys on their feet is what we hope to see."
Bureau chief Tracie Mauriello: email@example.com, 1-703-996-9292 or on Twitter @pgPoliTweets.