Cambridge Biotech Approaches Crossroads with MD Drug

Posted by: Christine McSherry on July 31, 2013


This article is from the Boston Business Journal :

No one is watching discussions between Sarepta Therapeutics and regulatory officials about how to proceed with a muscular dystrophy drug more closely than Christine McSherry

The Pembroke resident went to Washington last week to urge congressmen to support the fastest possible approval of the drug, eteplirsen, by the U.S Food and Drug Administration.  She also helped gather support on Capitol Hill for letters from U.S. Rep. William Keating and Sen. Elizabeth Warren.

McSherry’s efforts paid off in part this week when the Cambridge firm announced it will submit the drug for approval in the first half of next year, with a chance for accelerated approval. The decision was based on meetings Sarepta has had with the FDA in recent weeks, and means that the drug could potentially be approved before the end of next year. It’s good news for both the company and patients, because it means the FDA will consider approving the drug without further trials.

The news sparked massive volatility in the company’s shares on Wednesday, but McSherry isn’t really worried about that.

McSherry isn’t a shareholder. She’s a mother who has watched her son, Jett, lose his ability to walk, and is now watching as he becomes unable to feed himself, due to DMD. Now, with a treatment that could halt the progression of the disease — often fatal by a patient’s early 20s — so close to approval, the prospect of a drug being available by the end of 2014 is a life-or-death matter. Jett was diagnosed with the disease more than a decade ago. Today he is almost 18.

“When this started 12 years ago, I knew this was going to happen,” she said of her son’s degenerative condition. “But how could I know there would be something so close, at the very end?”

Sarepta is developing so-called exon-skipping drugs, which target a specific genetic mutation in boys that causes a decrease in dystrophin, a protein vital to the creation of muscle. Eteplirsen targets the most common mutation, exon 51, the cause of the disease in about 15 percent of patients. The company has similar drugs in the works for the next most common mutations.

The 100-employee company’s fate is closely tied to this drug. In its most recent quarter, the firm reported $4.5 million in revenue from licensing fees, grants and research contracts but nothing from commercial drug sales. The commercialization of a muscular dystrophy drug would provide a significant boost. A Sarepta spokesman said that if the company is granted a priority review, final approval could come as soon as six months after the company submits the application.

The initial results of a year-long study of eteplirsen was a turning point for the company, shooting its stock from around $4 a share this time a year ago to a high of $45 a share last October. While the Phase 2 trial only included 12 patients, the data showed that after six months, the boys who received eteplirsen from the beginning were able to perform better on a test of distance walked in six minutes. Sarepta has continued to measure and report on the patients, showing continued progress after more than a year and a half. In the meantime, Sarepta’s stock value dipped to $22 a share last November, but has slowly crept back up to more than $46 as of this week.

Kimberly Lee, an analyst at Janney Montgomery Scott LLC, said the decision to pursue accelerated approval is “a big binary event” for the company. It means the difference between Sarepta being able to market the drug in as little as six months after submitting the application versus a couple years.

Lee said the political lobbying surrounding the drug is not uncommon for rare diseases, but she’s not convinced it will work. Her own company is maintaining a $34 price target, on the assumption that Sarepta will not win the designation. Lee said Sarepta’s future could also be affected by a rival drug, drisapersen, being developed by Prosensa, a Netherlands-based biotech affiliated with GlaxoSmithKline. While that company has not generated the same level of excitement as Sarepta, she said, drisapersen is now finishing up a Phase 3 trial involving 52 patients, four times larger than Sarepta’s.

McSherry said she favors Sarepta over Prosensa due to the drug’s safety and the company’s outreach to families. She said what’s happening with eteplirsen is crucial not only to Sarepta, but to the 500 or so boys born every year in the U.S. with DMD. “This is the first (drug) ever,” she said. “There’s so much riding on it.”


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