Sometimes, hope can be found in the strangest places.

For Sarepta Therapeutics (SRPT - Get Report) , a paragraph tucked inside an obscure Food and Drug Administration guidance document provides a reason to believe the frustrations and delays with the ongoing regulatory review of eteplirsen might actually support approval of the Duchenne muscular dystrophy drug this spring.

An interpretation of this FDA document suggests the eteplirsen review period was extended by three months from February to May because new clinical data submitted by Sarepta in January addressed the agency's concerns sufficiently to allow the drug to be approved.

It's important to insert a gigantic caveat right here: Nothing involving the FDA and the drug-review process is definitive. There's just too much subjectivity to state with absolute confidence that this FDA document clears a path for eteplirsen's approval.

But there's hope, perhaps more than many investors realize given the steep decline in the value of Sarepta's stock price since January.

The FDA document is titled "PDUFA Reauthorization Performance Goals and Procedures Fiscal Years 2013 Through 2017." You can download it here.

Basically, this is a report written by FDA to the pharmaceutical industry outlining the agency's procedures and timelines for reviewing new drugs. The rules FDA uses to review, approve or reject new drugs are encoded in a federal law negotiated and reauthorized every few years by Congress.

Section III of this document deals with performance timelines for the FDA during the first cycle of a drug review. On page 12, the FDA states:

If the applicant submits a major amendment(s) ... and the review division chooses to review such amendment(s) during that review cycle, the planned review timelines initially communicated will generally no longer be applicable. Consistent with the underlying principles articulated in the GRMP guidance, FDA's decision to extend the review clock should, except in rare circumstances, be limited to occasions where review of the new information could address outstanding deficiencies in the application and lead to approval in the current review cycle.

The latter part of the paragraph is most interesting and hopeful for Sarepta. Here's why:

On Jan. 8, Sarepta submitted a clinical update to the FDA covering six-minute walk performance and loss of ambulation data extending to four years for the 12 eteplirsen-treated patients in the company's clinical trial. These new data were compared against historical controls. You can see some of that data submitted by Sarepta here.

The FDA accepted the new eteplirsen data and deemed the submission to be a "major amendment" to the eteplirsen review. As such, the deadline for the review cycle was extended by three months from Jan. 26 to May 26.

With this in mind, read the FDA guidance again with my comments strategically inserted:

FDA's decision to extend the review clock (which it did for Sarepta) should, except in rare circumstances, be limited to occasions where review of the new information (the four-year eteplirsen data) could address outstanding deficiencies in the application (known from the FDA's briefing document posted in January) and lead to approval in the current review cycle (by the new, May 26 approval decision date.)

"Could address" is a potential problem with this optimistic eteplirsen review scenario. The FDA "could" determine the newly submitted eteplirsen data do not address outstanding deficiencies.

Keep that in mind.

From the FDA's review of eteplirsen made public in November, we know reviewers had significant doubts about the drug's ability to produce functional dystrophin, which in turn, raised doubts about the drug's purported mechanism of action. To my knowledge, Sarepta did not submit any new data to FDA to bolster the argument for eteplirsen's ability to produce functional dystrophin. However, Sarepta did try to correct and rebut some of the conclusions reached by FDA about eteplirsen and dystrophin in its Jan. 8 resubmission.

You can ponder all this while waiting for FDA to reschedule the eteplirsen advisory committee meeting.

 

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; click here to send him an email.