Sarepta sustains high hopes for DMD drug eteplirsen with more PhII data

Sarepta Therapeutics ($SRPT) spotlighted continued benefits of treatment with its lead drug eteplirsen today in one of the most closely watched Phase IIb studies in the biotech industry. The data come as industry-watchers await word on whether the FDA will allow the company to pursue accelerated approval of the candidate in patients with a form of Duchenne muscular dystrophy, a rare genetic disease that wipes out muscle function in boys and leads to premature death.

In the latest update on the 12-patient trial Friday morning, the Cambridge, MA-based biotech reported 74-week results of a 6-minute walk test (6MWT), showing a 65.2-meter benefit for 6 patients in a modified intent-to-treat group. As Adam Feuerstein explains, those 6 boys who have been on the therapy since the start of the trial showed a decrease in 2.2 meters of walking distance compared with 64.6 meters less in those four patients who began on placebo and switched to eteplirsen after 24 weeks of the trial.

Through week 74, the company said, there have been no serious adverse events related to eteplirsen or new safety issues since a previous update at week 62 that showed one patient suffered from a short case of protein in his urine.

Sarepta has a lot riding on this small study, which the company hopes U.S. regulators will accept as qualifying evidence for a rapid pathway to approval for eteplirsen. Founded in 1980, the company aims to make the RNA-based therapy the first disease-modifying treatment for DMD approved in the U.S. Investors have swooned at earlier results from the Phase IIb trial, sending the company's shares up 468% over the past 12 months, according to Yahoo! Finance. The continued momentum for the stock could hinge on whether Sarepta gets in line for an early FDA approval or has to wait until after a lengthy Phase III study to seek a market nod.

The company is in a race with a rival DMD therapy from GlaxoSmithKline ($GSK) in Phase III. During development of GSK's therapy called drisapersen, four patients were hospitalized because of thrombocytopenia and several patients with severe proteinuria were also sent to the hospital, The Street reported in February. Glaxo licensed drisapersen from Prosensa, a 2012 Fierce 15 company.

CEO Chris Garabedian

"It's always nice to be first to market but I do not believe that it is critical to be first to market," Sarepta CEO Chris Garabedian told FierceBiotech in an interview on Thursday, before the company revealed the 74-week results this morning. "I do think it's critical to be best in class, and I do believe that we have a best-in-class drug in DMD."

"The reason I say it is not as critical" to be first to market "in this disease is that it's a long-term lifetime chronic disease," Garabedian added. "The safety profile and tolerability of a drug becomes much more important if you have two drugs that are working and one that is much easier to take, much easier to tolerate, doesn't have safety issues that might lead to hospitalizations or discontinuations. Then it makes a more compelling argument that, once a better therapy becomes available, to switch to that therapy."

Garabedian has kept the dialogue his company had with the FDA last month under wraps until after he and his team get the official minutes from the meeting. Everyone watching eteplirsen is now awaiting the update from Sarepta on potential accelerated approval later this month.

- here's the release
- see The Street's article

Special Report: Prosensa – 2012 Fierce 15