The 168-week eteplirsen clinical update from Sarepta Therapeutics (SRPT) - Get Report this morning can be viewed two ways.

The Duchenne muscular dystrophy (DMD) patients continue to walk more than three years after starting treatment with eteplirsen, with no significant side effects or tolerability issues. The drug appears to be slowing the progression of DMD.

The more skeptical view looks at the accelerated decline in walking ability at week 168 compared the previous update after week 144. All the DMD patients lost some walking ability. 

Here's how the updated eteplirsen phase II study results look graphed over time. Those are fairly flat lines for a disease like DMD which progressively robs patients of their ability to walk. This slide is included in Sarepta's new investor presentation for the J.P. Morgan Healthcare Conference. The company presents on Thursday.

Sarepta bulls and bears aren't likely to switch sides based on the new 168-week eteplirsen data. More importantly, Sarepta re-iterated guidance to complete the FDA approval submission in the middle of the year. Hopefully, that means no more delays, although some of the checklist items required for the eteplirsen submission appear to be behind schedule. Here's the company's latest regulatory update slide:

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Sarepta shares are down 10% to $12.49, near a 52-week low, on investor concerns about further delays to the eteplirsen FDA filing. The further declines in walking ability at week 144 are probably not helping the stock much either. Take your pick. 

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Sarepta's entire investor presentation can be seen here

Prosensa (RNA) (soon to be acquired by BioMarin Pharmaceuticals (BMRN) - Get Report ) is still expected to complete its FDA filing for drisapersen in DMD later this quarter, with the FDA scheduling an advisory committee meeting soon after.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

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