Three months after a blizzard delayed a key meeting to consider a Duchenne muscular dystrophy treatment, patient advocates hope next Monday to orchestrate one of the biggest crowds ever at a US hearing on a proposed new drug.
More than 1,200 people are expected to be on hand when an influential Food and Drug Administration advisory committee convenes to review a drug application submitted by Cambridge’s Sarepta Therapeutics Inc.
Advocates say the panel’s recommendation on the experimental drug, called eteplirsen, could be a precedent for approaching other treatments for potentially fatal diseases affecting small numbers of patients. Companies developing therapies for such conditions say they can’t afford to conduct the kind of lengthy placebo-controlled trials that are used for more common ailments because that would leave rapidly declining patients without a chance for relief.
While more than two dozen drugs are in clinical trials, there is still no treatment for Duchenne, a muscle-wasting genetic disorder that strikes roughly one in every 3,500 boys.
FDA staffers, in a Jan. 15 briefing document, questioned the methodology of Sarepta’s small clinical study of eteplirsen, which addresses a genetic mutation affecting about 13 percent of Duchenne patients. But a Feb. 24 letter signed by 36 leading scientists and doctors said boys in the study have shown better results than they typically see with muscular dystrophy patients.
“We really want to make sure that patients’ voices matter,” said Jenn McNary, a Pembroke mother registered to attend the meeting and testify along with her two sons, 17-year-old Austin and 14-year-old Max, who both suffer from muscular dystrophy. “This is going to set the stage for how the FDA handles rare disease drug approvals in the future.”
The advisory panel, made up of independent medical experts, was scheduled to review eteplirsen on Jan. 22, but its meeting was postponed because of a severe snowstorm. A coalition of Duchenne advocacy groups has used the intervening months to organize an international contingent of patients and their families to attend the meeting and testify about the benefits of the experimental drug and the importance of offering hope for boys with muscular dystrophy. They hope to number about 860 people at the meeting.
While the original session was to be at its White Oak campus in Rockville, Md., the FDA has moved the rescheduled gathering to a bigger facility in the Marriott Hotel and Conference Center in Hyattsville, Md. — and extended the hours of the meeting — to accommodate the larger crowd that is expected from across the country and abroad. In addition to patients and their families, many pediatric neuromuscular specialists and researchers have registered to testify.
FDA officials, criticized in the past for not listening to patients, have opened dialogues with numerous patient groups in recent years and regularly invite patients to testify at advisory committee hearings. But the 85 patient advocates that have signed up to speak Monday, including 15 boys with muscular dystrophy, may be the largest number yet.
Regulators value the insights of Duchenne patients, said FDA spokeswoman Sandy Walsh.
“Patients, supported by their families, and caregivers, continue to provide us with information about the symptoms that matter most to patients, the impact the disease has on patients’ daily lives, and their experiences with currently available treatments,” Walsh wrote in an e-mail. “These perspectives are critical to helping us more fully understand the experience of patients with [Duchenne] and complement the scientific advice from the committee.”
Sarepta, which has about 230 employees, is expecting an FDA decision on eteplirsen by May 26. The agency frequently relies on the recommendations of its advisory panels when deciding whether to approve a new drug, but there have been instances when it hasn’t.
Eteplirsen produces dystrophin, a protein missing in boys with muscular dystrophy. Sarepta’s clinical study determined 10 of 12 boys in its trial continued to walk after four years. There was no comparison data from a placebo, but the company examined an external “control group” of boys who hadn’t taken the drug and found only one of 11 was walking in a similar period.
The drug maker’s case was bolstered by the February letter written by the codirector of the Center for Duchenne Muscular Dystrophy at the University of California Los Angeles and signed by 34 other Duchenne specialists. Taking issue with the FDA staff briefing document, the specialists said eteplirsen showed evidence of slowing the disease’s progression.
Still, in a recent note to investors, Joseph Schwartz, an analyst for Boston investment bank Leerink Partners, urged caution. He noted FDA staffers had concluded the clinical study results are “prone to big variations arising from the small patient sample.”
Tracy Seckler, a mother living in the Berkshire County town of Alford, said she will testify in favor of eteplirsen even though her 15-year-old son Charley has a different Duchenne-causing mutation. If the FDA creates a “regulatory pathway” for approving such experimental drugs, she said, Sarepta and other companies will develop drugs addressing other mutations.
“We’re working 24/7 to make sure the FDA understands the realities” of the disease and the difficulty testing the treatments on small groups of patients, she said.
Robert Weisman can be reached at email@example.com. Follow him on Twitter @GlobeRobW.