CAMBRIDGE, Mass. ( TheStreet) -- Sarepta Therapeutics ( SRPT - Get Report) issued a boring, 74-week update from its mid-stage study of eteplirsen in boys with Duchenne muscular dystrophy. The boys in the study basically walked just as well as they did when measured at 62 weeks and no new adverse events were reported.

Boring, in this case, is very good news and will help Sarepta as it seeks U.S. approval of eteplirsen as quickly as possible.

After 74 weeks, the six boys treated with eteplirsen were able to walk, on average, 2.2 meters less over six minutes than they walked at the beginning of the study. By comparison, when the boys performed the same walking test after 62 weeks, their walking ability dropped by 4.2 meters.

"We are encouraged to see a continued stabilization of walking ability in patients treated with eteplirsen for nearly one and a half years," said Sarepta CEO Chris Garabedian, in a statement. "These data are particularly compelling when viewed in the context of published natural history studies, which showed substantial declines on the 6-minute walk test over this timeframe in a similar ambulatory DMD population.

"Stable" is also the operative word for the four DMD boys who began the study on a placebo and were switched over to eteplirsen after 24 weeks. On the same six-minute walk test conducted after 74 weeks, these four boys walked 64.6 meters less, on average, than they did when the study began. When the same test was performed at 62 weeks, the decrease in walking distance was 63.8 meters.

Like the boys treated with eteplirsen from the beginning of the study, the four boys in the "control" arm demonstrated stable walking ability from 62 weeks through 74 weeks.

The safety of eteplirsen continues to look promising with no new adverse events reported in the 74-week update. No patients were hospitalized or required treatment discontinuation, which sets eteplirsen apart from the safety questions raised about a competing DMD drug from GlaxoSmithKline.

Sarepta met with officials from the U.S. Food and Drug Administration late last month seeking permission to file an accelerated approval application for eteplirsen based on data from the small phase II study. Sarepta is expected to announce the outcome of this meeting later in April.

Sarepta shares opened Friday trading up 28 cents to $34.71.

-- Reported by Adam Feuerstein in Boston.

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