WASHINGTON – There is new hope for thousands of dying boys waiting for approval of a eteplirsen, a new intravenous drug known to stabilize the symptoms of a rare and fatal form of muscular dystrophy known as Duchenne.
Approval is still uncertain but parents and investors are celebrating an announcement this morning by Massachusetts-based Sarepta Therapeutics. Government regulators have offered a potential path forward for eteplirsen after they appeared to put the brakes on in November, Sarepta officials said today.
In an agreement with regulators, the company will conduct two additional studies even as the Food and Drug Administration considers its application for accelerated approval that could bring the drug to 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 Chief Executive Officer Chris Garabedian said he believes the current data is 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 this morning.
“We’re very pleased we received this guidance from the FDA. It provides us all the information we need to move our program forward,” he said. “We’re really excited about this news, and we think we will be in good shape to submit our [new drug approval application] by the end of the year.”
Sarepta Chief Medical Officer Ed Kaye 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 rollercoaster 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 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.
Thirteen-year-old Billy Ellsworth of Coraopolis is one of 12 boys participating in an eteplirsen trial that his mother Terri 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 is able to hike, jog and dance when other Duchenne boys his age are talking 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 today she is celebrating.
“This is huge and surreal,” she said in a text message after hearing the long-awaited news.
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.
“You have helped us better understand the urgency you live with every day in doing everything in your power to try to intervene and halt this relentless, progressive and irreversible disease. And in doing so you’ve enabled – or maybe demanded – that the FDA and Sarepta arrive at a possible step forward that gives us the chance to get eteplirsen to all of the [Duchenne] patients that can benefit,” Mr. Garabedian said.
He said the parents demonstrated that the parent voice deserves a seat at the table and that there are situations that warrant flexibility in the drug approval process.
Sarepta investors on a conference call this morning also were gratified by the news and the market responded. Stock shot up 48 percent today to $36.08 per share as of noon.
The publicly held company has no other drugs on the market but has seven more in the works to target other genetic mutations.
Eteplirsen works by directing the cellular machinery to skip exon 51, a small part of the dystrophin gene. That allows enough dystrophin production to essentially transform Duchenne muscular dystrophy to Becker, a less severe form of the disease.
It 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.”
Washington Bureau Chief Tracie Mauriello: firstname.lastname@example.org, 703-996-9292 or on Twitter @pgPoliTweets.