Regulatory Update from Sarepta Therapeutics

Posted by: Christine McSherry on July 24, 2013

Early this morning, the long anticipated regulatory update came from Sarepta Therapeutics. As parents, and advocates for eteplirsen, we were pleased to hear that the CEO expressed that the FDA was receptive and had a deep appreciation for the agency’s collaboration and involvement.  The most progressive points we heard were:


1. The FDA gave the nod to file an NDA

2. The FDA deems the dystrophin data to be reviewable

3. Timeline for the next set of exons

4. Confirmatory trial first Quarter of 2014

5. Enough eteplirsen to supply those amenable to exon 51 by the end of 2014


The company was given the good news that their data, collected from the eteplirsen trial, is sufficient to be considered for an NDA (New Drug Application) submission.  This means that the FDA will review the data given to them by Sarepta – and will decide under which approval pathway it will be considered.  There are two options, Full  (Traditional) Approval and Accelerated Approval.


While the timelines for both approvals are about equal, the difference is whether the FDA approves the drug on a biological marker, in this case dystrophin, or on a clinical endpoint – the 6MWT.  In the press issued just before the call, the company noted that the FDA did not accept dystrophin as a surrogate marker, however they did note in the call that they would be working with the FDA to help them get a better understanding of how this truncated dystrophin was working within the muscles of the boys and how it is reasonably likely to predict clinical benefit.  So, the FDA is still looking for this information and a way to support it. In a recent call that we (Jenn, Mindy and I) had with Dr. Woodcock, when asked if there was some concern about dystrophin as a surrogate, she specifically told us that she didn’t think that at all – they were just trying to figure a measurable way to quantify it. The FDA is willing to work with the sponsor to identify the best way to support dystrophin as a surrogate marker.  In our call,  Dr. Woodcock described the process in which a marker is considered a surrogate, noting that until it is accepted, there is often discussion going back and forth, and that the agency is looking for quantification, they need to have some kind of delta that has been achieved.  We feel encouraged that the FDA and the sponsor will be communicating and working on this together, we know that the FDA feels that the data is very compelling – and based on the information we heard this morning, we should expect that dystrophin will be considered in the upcoming trials.


The company gave a description and timeline for their upcoming trials for 53, 50, 45 and for 44 exon skipping.  Again, as done at the World Orphan Drug Conference, the CEO described an innovative type of trial design.  It is reassuring to know that they are on the fastest timeline to get to these other exons.  They will be recruiting in 2014 – and using this population as a placebo arm for the confirmatory (Phase 3) trial in eteplirsen – if a placebo is required by the FDA.  which will consist of 60 ambulatory patients who are amenable to skipping exon 51.  The placebo enrolled patients would then roll directly into their own exon skipping trial (53,50,45 &44), as soon as the compound that would be amenable to them was ready, probably the first quarter of 2015.  The company would have collected data on all of these boys previous to starting on the drug, giving a very clear picture of the progression or lack of progression of the disorder.


Can dystrophin, as a surrogate marker make these trials go even faster?  We need to look at every possible way to decrease the timelines…


Lastly, there has been a lot of talk about manufacturing, and it was refreshing to hear that the company is able to produce a small –to- mid scale product without problems.  We also heard that the company feels they will be able to supply the entire population amenable to exon 51 with drug – by the end of 2014.


We are one step closer to gettng this drug to our boys – we are will not stop pushing to make this process event faster, but we are very happy with what has been accomplished thus far.

Parents should reach out to the company to get clearer timelines on the trials for other exons.

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