Sarepta rockets up after mapping a shortcut to the FDA with DMD hopeful eteplirsen

After keeping investors on a roller coaster ride of speculation for months, Sarepta says it now plans to shoot for an accelerated approval of its Duchenne muscular dystrophy drug eteplirsen. The biotech says it will file for an early approval by the end of this year after launching a slate of new clinical trials to get the data that the FDA is looking for.

The company's shares ($SRPT) immediately rocketed up 75% on the news.

The new round of studies, following a successful but very small trial of eteplirsen, includes a clinical trial "with predefined efficacy endpoints for ambulatory patients between the ages of 7 to 16 years who can walk a minimum distance, and two additional clinical trials that will evaluate safety and biomarkers in DMD patients younger than 7 years and DMD patients who have advanced in their disease progression to a point they cannot walk a minimum distance or have become non-ambulant," the company noted in its press release. "Additionally, Sarepta plans to initiate a placebo-controlled study with one or more of its follow-on DMD exon-skipping drug candidates by the end of the year."

The quickly assembled mid-stage studies come after Sarepta held a series of talks with the FDA over the efficacy and safety data that would be needed to gain an accelerated approval of their drug.

Sarepta's shares rocketed up last year as the company and a few analysts fed investors' giddy expectations for the company if it could win an early approval for eteplirsen based on its micro-study. Then, last November, the stock fell back to earth after the biotech shared the agency's skepticism over its drug after another therapy from Prosensa ($RNA)--which uses a similar approach on exon-skipping to slow the disease--failed in a pivotal late-stage study.

Since then, though, there have been indications in subsequent discussions with regulators that Sarepta might yet blaze a shortcut to an approval--if it can add key positive outcomes.

Why all the hubbub over one drug? DMD currently can't be treated, leaving the boys afflicted with this lethal disease with no way to stop it or slow it down. Parents and families have mounted an intense public campaign demanding an early approval based on a tiny study at Sarepta with positive outcomes. But the agency has resisted, especially after seeing other once-heralded therapies tank in larger studies. Aside from Prosensa, PTC Therapeutics ($PTCT) has its own long-running DMD program for one group of patients but has only reported a mid-stage failure for all of its work in the field.

"We are excited to have guidance from the FDA that allows us to move quickly into additional clinical trials with eteplirsen to confirm our current understanding of eteplirsen's safety profile, its effect on dystrophin production, and its impact on clinical outcomes in DMD patients," said Dr. Edward Kaye, senior vice president and chief medical officer of Sarepta Therapeutics, in a statement. "We are particularly pleased that the FDA shares our interest in accelerating the clinical development of our follow-on exon-skipping drugs and we expect to initiate enrollment in this trial later this year."

- here's the release