Welcome to the Sarepta Therapeutics First Quarter 2013 Earnings Call. My name is Donna, and I will be your operator for today's call. At this time, all participants are in a listen-only mode. Later, we will conduct a question-and-answer session. Please note that this conference is being recorded. I will now turn the call over to Erin Cox. You may begin.

Thank you, Donna, and thank you for joining today's call. Earlier today, we released our financial results for the first quarter of 2013. The press release is available on our website at www.sareptatherapeutics.com and our 10-Q will be filed on or before May 10. Joining me on the call today are Chris Garabedian, our President and Chief Executive Officer; and Sandy Mahatme, our Chief Financial Officer. Please note that we have slides posted in conjunction with the webcast, that supplements some of the information we will be discussing during today's call. These slides can be found on the Investor Relations section of our website. If you're following along, please turn to Slide 2. I would like to note that during this call, we will make a number of statements that are forward-looking, including statements about the safety, efficacy and potential of Sarepta's product candidates, timelines for clinical development activity, the potential and timing for regulatory submissions, and meetings with the FDA; the potential and timing for regulatory filings, review and approval of Sarepta's product candidates, including under Subpart H Accelerated Approval; Sarepta's ability to establish and protect intellectual property rights, Sarepta's timing and ability to scale its manufacturing capabilities, Sarepta's estimates regarding its future revenue, operating loss and expenses, expectations regarding future success and adequacy of financing and reserves on hand. Our ability to obtain continued funding from government and other sources, and our anticipated 2013 financial results. For a detailed description of risks and uncertainties we face, you are encouraged to review the official corporate documents filed with the Securities and Exchange Commission. With that, let me turn the call over to Chris Garabedian, our President and Chief Executive Officer. Chris?

Thank you, Erin. Good morning everyone and thank you for joining us today for our quarterly financial and corporate update for the first quarter of 2013. I will be updating you on our recent business activities, and Sandy Mahatme will review the company's financial results for the first quarter, before we take your questions during the Q&A portion of the call. We have slides that are accompanying the call, and we will be referencing them during this update. As you all know, 2012 was a transformative year for Sarepta, and we had a number of critical activities over the last few months, to keep the company on a critical path towards realizing the full potential of eteplirsen, our lead clinical candidate for Duchenne muscular dystrophy, as well as a broader pipeline of RNA-based therapeutics. If you refer to Slide 3, titled eteplirsen program status, I would like to begin by giving you an update on the activities that we are engaged in, with respect to our work on eteplirsen with the FDA to determine the feasibility of an Accelerated Approval NDA submission. As we disclosed earlier this month, we received meeting minutes from the FDA, summarizing our End of Phase II clinical meeting that occurred in the first quarter. One of our key objectives at this meeting, was to gain feedback on the feasibility of an Accelerated Approval NDA filing, with the existing eteplirsen dataset. As a reminder, the FDA has authority to grant Accelerated Approval, under what is known as Subpart H of Title 21, Part 314 of the code of Federal Regulations. This regulation states that the agency may speed up the approval of a new drug, for a serious and life threatening disease, based on the drugs effect on the surrogate endpoint that is reasonably likely to…

Thanks Chris. Good morning everyone. Please go ahead and turn to Slide number 10. This morning's press release provided detail for the first quarter of 2013, in both an adjusted or a non-GAAP basis, as well as a GAAP basis. Management believes that non-GAAP results are useful in evaluating the current underlying trends in our operations, and highlight the impact of our operations, on our cash balance, while also providing information relevant in comparing current results, with prior periods. We will be presenting non-GAAP results on this call, primarily, due to the significant non-cash impact that the revaluation our outstanding warrants has on our net results. These results also exclude the impact of stock based compensation and our ongoing corporate relocation to Cambridge. Please refer to our press release for a full reconciliation of GAAP to non-GAAP results. In the first quarter of 2013, we reported an adjusted loss of $13.3 million or $0.42 per share, compared to an operating loss of $6.1 million or $0.27 per share in the first quarter of 2012. The incremental loss is a result of a $6.7 million decrease in government contract revenue, and $0.5 million increase in operating expenses. Revenue for the first quarter of 2013 was $4.5 million, down $11.2 million versus the first quarter of 2012. The decrease was due to the August 2012 August 2012 stop-work-order and subsequent termination of the Ebola portion of the Ebola-Marburg U.S. government contract due to a lack of available U.S. government funding. These decreases are partially offset by revenue from the intramuscular administration contract with the U.S. government for the Marburg virus that started in 2012. Adjusted research and development expenses were $13 million for the first quarter of 2013, compared to $14.5 million for the first quarter of 2012, a decrease of $1.5…

Yeah, operator, we can open up the call for questions.

Thank you. We will now begin the question-and-answer session. [Operator Instructions]. Our first question comes from Christopher Marai from Wedbush Securities. Please go ahead.

Hi good morning guys. Thanks for taking my question. Congratulations on the quarter. I appreciate that you have licensed additional rights to exon-skipping candidates from the University of Western Australia. I was just wondering what your estimate is of your freedom to operate with respect to the (inaudible) exons in a worldwide environment and the U.S., specifically?

Yeah. So actually, well its one of the reasons why we believe it was an important agreement to finalize, and the original license that we had with the University of Western Australia patent estate, was with kind of the initial filing, which was good, but the rights we had were to eight identified exon targets, not the full complement of all of the rare exons that we would want to have protection to commercialize. And since the license of that original patent, there was another patent that provided even more optimized sequences, provided a broader footprint geographically, and we think most of the sequences that we would want to bring in, to development for subsequent exons, would come from the second, we call the DMD-II patent estate from the UWA, and so we have now license to the -- both of those patents. The second one includes a broader geographic footprint, and even more optimized sequences, and subsequent sequences that might even be further optimized, that can be linked back to those two patent estates would be covered as well. So we believe this really is what we needed to be confident in our freedom to operate around the globe, in countries that we specified. I had listed them out at the investment conference a week or so ago, of what that covered, and we gave you that information specifically. So again, we think this is what's needed where the sequence patents is essentially, how the real estate is divided up among the DMD space. As we have reported previously, we had an opposition challenge in Europe on eteplirsen and did not prevail on exon-51, exon-46 with European patent opposition. Just as an update, they have now posted the summary of that patent opposition hearing, which does start to clock for the potential for a request for appeal. So we are evaluating our options on that internally, currently, and we have four months to actually file, if we decide to appeal this. We have two months from the posting of that, to file a written appeal, request, and the summary briefing of the appeal would be within four months of that. But again, we think this was an important agreement to give us the confidence and the freedom to operate globally for our DMD program broadly.

Great. Thanks. Then, any insight into the timeline, with respect to pre-IND meetings with the FDA to discuss some of the other exon-skipping candidates, that you'd mentioned --?

Yeah. It's a good question. So we are planning two pre-IND meetings to occur this year, and we are not ready to disclose the timing of those, but I think it's fair to say that, as we approach the end of the year, we should have good insight in terms of the agency's view on the preclinical packages needed for not only our second exon-skipping drugs that would be brought into the clinic, but subsequent exon-skipping drugs. We expect that will be less burdensome, based on the both emerging eteplirsen dataset, and whatever commitments we make on the second exon-skipping drug, from a preclinical package. So these pre-IND meetings become important, because it really starts to set the stage for how the agency might be viewing the burden of proof for subsequent follow-on exon targets, after the first, second, third, and we hope, that that will lead to a more streamlined development program, that would not take the more onerous route of not leveraging the safety dose information, dystrophin data that we have been producing, both preclinically and clinically from eteplirsen to date.

Great. Thanks, and finally one just quick one, and I will jump back in the queue here. Are we anticipating any additional data from the extension study at World Muscle this year, or any other conferences that you could highlight for us? Thanks.

Yeah. We are likely to have a clinical and safety update on our extension study, at World Muscle, and we will be determining if there are appropriate communication points prior to world muscle. But we have submitted an abstract related to this extension study, and so whatever data we can compile and analyze and incorporate in that, at that time, we will do so.

Thank you. Our next question comes from Ted Tenthoff with Piper Jaffray. Please go ahead.

Great. Thanks. Can you hear me okay?

Yes Ted, I can hear you.

Great thanks. My question is on manufacturing. I know you guys have been focused on that and appreciate the update. Can you give us a sense of kind of where scale is now, what are the hurdles, maybe a little bit more detail, just in terms of where things are going, and what needs to still be done that really gets you to the level where you can either meet requirements for the confirmatory study, and/or commercial launch?

Yes. So Ted, what I've tried to do is provide updates that we are still on track for our plans to start dosing the confirmatory study in the first quarter of 2014. You won't hear me give blow-by-blow, week-to-week activities on our manufacturing. If anything were to trip up to that timing, then we would communicate that expeditiously to let people know. So all things and activities are on-track. To provide a little more color, we are doing -- the process of the scale up currently, and that contains a lot of elements. For example, reduction to practice runs, where we can learn, right, if there is any tweaks that are required before we go for those specific test runs at the -- let's call it midscale production batch. And so, we learn from that, to make sure we mitigate any risk, when we actually do the production runs that we would want to us for the clinical trial material. This is akin to training for an Olympic event. You know what you need to do, you know what the event is and what it looks like, and so you prepare, you try to practice, you try to improve, learn from any mistakes you find along the way. But at the end of the day, when you do those production runs, you don't know what you get until you do it, and so, we will not have that final insight on whether its yield, whether its stability, purity profile, until we do those runs, which would be sort of the latter part of this year, obviously, to start getting the stability data that we would submit to the FDA, to have drug released in the first quarter of 2014. But that's the extent of the kind of insight that we are ready to give, but again, rest assured, we believe we are on our timeline, and that if we learned anything that would move us off of that timeline, we would communicate that accordingly.

That's helpful color. I appreciate it Chris.

Thanks Ted.

Thank you. Our next question comes from Bill Tanner from Lazard Capital Markets. Please go ahead.

Thanks for taking the question. I have a few. Chris, just as it relates to the information that the company did provide to the FDA, can you give us a sense or the scope of what was provided, as compared with that submitted initially, and I guess, wondering the extent to which the topics were winnowed down to maybe a more smaller, more manageable number of them, and just trying to determine, is it possible that there will be another iteration, or do you think that you will actually get the decision after the FDA reviews these data?

Yeah Bill, so let me clarify. So we have not submitted those two documents, as we sit here today. But I can provide some color on what we provided previously, and what we are providing coming up. We are in the stages of finalizing those documents, and we decided that the importance of these documents was more important than getting it in a week or two earlier, and so we have really gone even deeper than we had previously of combing through the literature, talking to other experts on their thoughts and advice of making the most compelling arguments for dystrophin as a surrogate and how our clinical data would support that. You see some of the evidenced in the communication around the natural history studies, and what we would expect from this age cohort, and the six minute walks that we started out, prior to dystrophin production. So we believe the two issues have been sufficiently narrowed. In that I describe it as two sides of a coin. One is to show that the dystrophin that we are producing is functional and is of a quantity and quality that is meaningful, based on the Becker patient, and studies that have been done with the natural phenotype of Becker of which the dystrophin we are producing, the truncated dystrophin is akin to the Becker dystrophin that exists in those patients, as well as the preclinical studies, those that have been done in animal models of DMD, there is dystrophic mice, dystrophic dogs, both of which have used eteplirsen or other treatment modalities to show that dystrophin that's produced, of this kind, produces functional benefit in the animal. Then of course, our own clinical data, that suggests the clinical benefit that is produced from the dystrophin we are creating. And then…

That's helpful. Then just as it relates -- obviously there is really no data to support restoration of dystrophin and having prior to yours, perhaps, and having a clinical benefit. So what is your perception of the FDAs viewpoint on the need for there to be some correlation obviously would seem like, there should be some, I guess the question is, how tight do you think they are looking at that needing to be or how convincing, taking into account that you got small numbers of patients, and you've got different ages and heights and things of that nature?

Yes, Bill, we know that there have been other dystrophin producing drugs that are still currently in active late stage development. Of which, we have not seen the type of robust consistent dystrophin levels that we've produced in a controlled manner, and so we think that we have the most compelling argument, that we are producing meaningful level of dystrophin, and that the clinical outcomes we are seeing, right, are indicative that the dystrophin levels we are producing are meaningful, right. Now I think we have other drugs that are moving forward, without that level of evidence, and so, I think we are blazing the trail, for establishing dystrophin as an important marker in this disease, I think no one disputes the fact that restoring dystrophin is going to be essential to changing the natural course of Duchenne muscular dystrophy, it’s the main essential protein that's lacking. So we think we have sufficient evidence to do this, we think the FDA will see this after they review these more extensive documents, and we are hopeful that they see it, the way we see it. But we will have to see, based on their questions and their review of this and their comments, to come to that decision.

Thank you. Our next question comes from Robyn Karnauskas with Deutsche Bank. Please go ahead.

Hey great. Thanks. [Alicia] here for Robyn. Congrats on the progress during the quarter, first of all. And our question is, just can you help us understand that Prosensa gets approved prior to your drug, what impact could it have on an orphan drug exclusivity for your drug?

[Alicia], we don't think that it would have an impact. These are different molecules, these are different composition of matter. We have a different backbone chemistry. So when you look at the guidelines for similarity on orphan drug exclusivity, as it relates to two compounds. Other than mechanism of action, we really don't see similarity on many of the other criteria. So you have, obviously a different composition of matter, a different chemistry backbone. They look at things like, how the datasets suggest that these products are different or the same. Well, I think the fact that we were seeing very similar toxicities with -- there is a person, at 0.5 mg per kg from their reported dose escalation study, and we are now at 100 times that does, at 50 mgs per kg in our current clinical study, without any of the same lab signals, and toxicities. I think it's hard to argue that these are not different, right. Then efficacy datasets is another thing, and then there is even the idea that would it benefit patients to make the drug available in a serious disease like Duchenne. So that's not something that is at the top of our list as a potential concern.

Great. Thanks.

Thank you.

Thank you. Our next question comes from Ritu Baral from Canaccord. Please go ahead.

Thanks for taking the question guys. Mine is on the Phase III/IV confirmatory study. Just given the recent conferences, where you have had a lot of access to the KOLs and the patient community, could you bracket for us, the low end or the high end of potential size and duration of this trial, if you could just give us an idea what the range might be, and also, Ed, specifically, you and I have talked about all the different potentials for the comparator arm or comparator dataset of the trial, if you could give us your current thoughts. And the third part of that question is -- and this is for Sandy, potentially, what do you think the biggest levers are in that trial design for cost and duration of the trial, duration to data?

Yeah so Ritu, let me try to address on most of those questions and Ed is not on the call today. But basically, on the size, we've said repeatedly that we think a 60 to 80 patient treated study is sufficient. If you look at, let's say the PTC study that was 180 patients, they had two dose arms, so they had 60 patients treated versus a placebo 60-patient arm, with two dose cohorts. All right. Now, Prosensa has done a two to one randomization, so 120 to 60 patients. So we think with the data we have to-date, to guide are powering on both dystrophin and six minute walk results, and the consistency that we are seeing and the lack of variability. That is the sufficient treated population. Now the question you raise is, the control arm is the question that we want to resolve, with our discussion with the FDA. Obviously, it can range from a placebo arm to a non-exon-51 amenable population that would have the same inclusion criteria, but would avoid the challenges of and ethical considerations of doing a placebo study, with a kind of a known active agent like eteplirsen; then there is always the natural history comparison, because we have an emerging dataset on the natural history of this, which is getting easier to compare, as I just did in the call today on greater than seven years of age, and start cutting these date more specifically, to compare it to a treated cohort. The size of the overall study, if we had a control arm, then that depending on, if it's a one to one, right, that would be a 60 plus 60 or 80 plus 80. If its two to one, it would be a 60 plus 30 or 80 plus 40 population. So those details will be worked out in time, I will let Sandy comment, but I just wanted to highlight that the biggest cost driver of the confirmatory study, is the drug cost, and that is what we are incurring this year, essentially, and why our burn is what it is this year, is because we are producing much of the drug needed for the confirmatory trial, that we would begin dosing in 2014. Sandy, do you want to add anything on, how it's really not a major cost driver beyond the drug costs?

Chris, you are right about that. Its primarily the drug costs that we are focusing on and we have been in talks with various CMOs in the U.S. and the EU as well as in Asia, both in our subunits as well as in API, and we are looking at various arrangements, such as joint ventures or maybe even buying suites in these various manufacturers, putting our employees in the facilities that the CMOs own, so that we can get more control and ownership over the process, and we are certainly putting our financial resources in there to ramp up the manufacturing, which obviously would then drive down the price. As we have guided previously, this year, we're spending between $85 million to $115 million, a majority of that, [by this] accelerated or non-accelerated scenario, is in drug costs and manufacturing operations. So the whole goal is to make sure that not only do we have manufacturing, but also backup facilities, and production efficiency, which really goes to your question. So you cannot really guide specifically on what production efficiencies we can get to drive down the costs, but in every month or six weeks that goes by, we feel better and better in terms of the progress we have made, in terms of both manufacturing, as well as the manufacturing efficiencies, which is where we hope that we can contribute, in terms of containing the costs related to the Phase III trial.

Got it. So you are focused on getting six months to a year of supply for those 80 patients on treatment, that you are anticipating for the trial?

Well Ritu, it's a campaign, right. So you have constant drug production runs, but the setup costs, and the initial runs, which would be usable in the clinical trial, right, are a big part of that. But obviously, it's not to say we wouldn't be incurring, you know, manufacturing costs moving forward. I mean, this is a campaign that will continue to increase, as the scale increases, the cost of manufacturing will increase. But we get to a point where every vial that's produced, from mid-scale or large scale, is either going to drive value with an essential part of our clinical program, or is going to drive value in terms of a commercial sale, in the marketplace. So we see every investment in manufacturing as one of the best returns on investment that we can make at this point.

Thank you. Our next question comes from Heather Behanna from JMP Securities. Please go ahead.

Hey guys, thanks for taking the question. Just a follow-up slightly on the manufacturing vein. Can you give us any color on discussions you've had with FDA or internal agencies on which dose you will use moving forward?

Yeah, we have made our case for 30 mgs per kg based on the fact that the biochemical data supports that 30 mgs per kg is producing as much, and actually numerically more 48 weeks than the 50 milligram per kilogram dose. Again, the stability we see, even in the 30 mg patients now is very good and sufficient, and so again, that is our stance. Again, the confirmatory study design has not been finalized at this time, and so we expect further discussions with the FDA. But as I stated earlier, Heather, I mean, you can only accomplish so much in these FDA meetings. We have a very ambitious set of questions and topics that we'd like to cover. The FDA knows this, they are encouraging that there will be opportunities to discuss all of these issues, over the coming months and quarters, and so we expect to do that. So as we get more specific perspective on the dose, we will provide that to the market.

Thank you. Our next question comes from Brian Skorney from Baird. Please go ahead.

Yes good morning guys. Thanks for taking the question. I guess, just in regards to some of the question, the FDA has had in your initial meeting, I am just wondering, how focused are they on the ability to adequately quantify dystrophin on western blot and the actual relative differences in (inaudible) intensity produced in healthy patients. Becker patients with an (inaudible) lesion, ending with exon-51 and eteplirsen treated patients?

So Brian, we have collected dystrophin in a very specific way. As a reminder, we had to submit this protocol, going back to the summer of 2011 for a review with this division, where we outline this as our primary endpoint, and how we were going to be collecting the dystrophin etcetera. So we are summarizing for them again, why we selected the methodology we did. But we believe that it was selected with an informed view. This was after talking to a lot of experts in the field, this was after looking at the precedents that was established by those before us, PTC, Prosensa, GSK, who were using immunohistochemistry to help them identify the dystrophin that they were producing, and we do believe that the information gleaned from a specific muscle tissue that you can look at, specifically for dystrophin and looking at percent positive fibers, as well as intensity, as well as the localization and the uniformity of that across the samples. This is a lot of great information to have, when you are trying to interpret a muscle biopsy sample, across the musculature of the human subject. We have supportive data that we are showing the appropriate length of the protein by RT-PCR and we have a supportive evidence on Western blot, that the protein has been produced. We think all of this in totality, provides the evidence that is needed, to show that this dystrophin is meaningful and we believe the literature, the preclinical models show that its functional, and we believe that the clinical outcome show that its reasonably likely to predict clinical benefits. So I can't state for sure, what each mind of the agency, within the division are thinking specifically. But we believe we have outlined very clearly, our methodology, how we quantify…

Thank you. Our next question comes from Tim Lugo from William Blair. Please go ahead.

Thanks for taking the question. Can you give us an update on your plans for the non-ambulatory patients? Will you be sharing data from the Phase IIb and your white papers to the FDA. Will you include these patients in some sort of Phase IV or in maybe some sort of offshoot of the confirmatory studies?

Tim, it's a good question. We actually believe that we have good evidence in our existing study, with the two patients who rapidly lost ambulation, shortly after enrolling in our study. Just to put that in perspective, both of these twins were below 250 meters after four weeks on -- after enrolment in the study. Long before we would expect dystrophin to be produced, and the Mazzone study I referred to earlier had those patients who were below 250, had the highest risk of losing ambulation over a year to two year timeframe, from his natural history study. So we have now continued to treat those patients. They were two of the boys who showed increase in dystrophin from week 24 to week 48. We have shared some of the pulmonary function data, that we believe is, I guess, a stabilization on a measure that starts to more rapidly progress, once you lose ambulation, and we have other upper arm extremity tests and (inaudible) test and other things that are non-ambulatory measures. So we believe where we sit today, we have one of the most robust, non-ambulatory data sets that exists in DMD today, on these two patients. And we expect that there will be other experienced studies, whether that will be a companion study to our pivotal, that's not determined at this point. It could be that if any patient's, whether on placebo or some other control group, were to lose ambulation, we would likely continue them and continue to follow them on treatment, and look for those outcomes. So we think there is a lot of different ways, beyond what we have already collected to date, to support the non-ambulatory population. But going back to the proof of concept, there is no reason to suggest that we wouldn't be producing dystrophin in the same way, based on the results we have had to date, in any DMD boy, who is amenable to an exon-51 skip, and that dystrophin that we are producing, wouldn't lead to some level of functional benefit, and it's harder to determine the right measures of functional benefit in these other populations, outside of six minute walk tests in the type of population that we identify for our study.

Thank you. Our next question comes from Joe Schwartz from Leerink Swann. Please go ahead.

Great. Thanks and congrats with all the progress. Wanted to ask, how you expect your deliverables to be able to show a concurrence between the doses of that person administered with the functional changes being achieved in the dystrophin production? In some respects, there seems to be a lack of correlation, but we obviously have less data than you, so you expect that this will be a strong argument in your deliverables?

You know, it's not something that we have ever suggested, that we would be able to show some type of tight, linear, correlation. Now you are adding another criteria, which is does, right. So I think it's hard enough to suggest that, for example, 30% dystrophin positive fibers will translate to a benefit over an untreated patient of 50 meters. But if we show 45% dystrophin positive, if that goes up to 65 meter benefit, you are dealing with a sampling bias of a tissue sample that's representing the full musculature, and you are using an effort-dependent test, that is highly variable based on other phenotypic characteristics and age and demographics, and trying to correlate those two things, in a very linear type fashion. So that's not an expectation that we have even set, but we do believe that there is a threshold, and that we are above that threshold, for which we would expect clinical benefit to manifest itself, based on the levels of dystrophin we are producing. And that we believe, is the level of evidence we need to provide. It's unfortunate in diseases like this, where there is no clear biomarker, and there is no easy way to detect dystrophin levels other than muscle biopsies at this point, and we know there is new approaches, that might make it less invasive and easier to do that, and we look forward to those new methodologies. But when you are dealing with a disease like this, you can either throw up your hands and say, well, we can never approve drugs that might be really active against these diseases, because we just don't know enough information, and it's not as tightly correlated. So there is no pathway to approve these drugs. All we can say, let's work with the information we have, and is there sufficient evidence, and again, we like the Accelerated Approval pathway that the FDA has at their disposal, which is reasonably likely to predict, and that would be confirmed in a larger clinical outcome based study. And so, Tim this study -- this is where we have to -- or Joe, we have to lead ourselves, because we don't have that level of information for this particular disease.

Thank you. Our next question comes from Reni Benjamin from Burrill and Company. Please go ahead.

Hi good morning Chris. Thanks for taking the question. Just goes to the natural history slide. You mentioned that 330 meters of baseline maybe a good cutoff when enrolling in a study. Is there an upper limit that you have found, that may also be a good cut off, and can you remind us of the range of the baseline, six minute walk on the eteplirsen treated patients?

Yeah. So basically, we enrolled patients that could have qualified for the study, having a baseline of 200 to 400 meters at baseline. This is their first day one, what we call our screening visit, and we allow, on that first screening visit, a variable of plus 10%, meaning they could have been below 440 meters and still qualify for the study. Now, when we use maximum score, the reason the average value, that baseline or higher, when we use maximum mean scores, is because the second day, they could have been above that, or above 400 on average, and we had a few patients who qualified above 400. I think one, I don't recall specifically who might have been above that 440 mark on day two. But again, all of them were within that, let's call it, 250 to 450 range, that's the broader range, including the day two scores. I think on the upper end, I think we would look a little suspect at kids who are above, let's say 450 meters, at least on a consistent basis, over a couple scores. If that is not a healthier than normal DMD boy. We would also -- as we know, from the natural history studies, including boys that are less than seven years of age, and I think both PTC and Prosensa have made comments to this effect as well, that they are still improving, they are still growing. So doing studies in a population that includes patients below 7, can be very confounding, because you don't -- I think it's a lot more variable to interpret a potential treatment effect, when you have got a large swathe of patients, that might naturally be improving, whether they are on drug or not. So, we believe the population we selected, is exactly who we intended to, which is those that would not be healthy, would not be young, would not be expected to be improving and would be on a decline. So again, we think both our early treated group, which averaged in the 380s on six minute walk, and then the placebo group, with average below 330, at the time, we were producing dystrophin, both of those are levels of evidence, of stability that you would not expect to see in those populations.

Thank you. Our next question comes from Kim Lee from Janney Capital. Please go ahead.

Good morning. Thanks for taking the question. First one is, in your previous discussions with the FDA, kind of what are the things, concerns, if any were brought up, besides their requirement for showing that dystrophin does show clinical outcome. Is there any other color you can provide there? And what were the FDA thoughts on exclusion of certain data, like data from the twins? Thanks.

Yes. I mean, look, we have highlighted the most salient, relevant points that we feel, related to the FDA discussions. Again, we were encouraged that, we are not making an issue of the sample size, and it was more on, let's understand the quality and quantity of data that was collected from that sample size. So we were very encouraged by that. And again, they gave flexibility statement on the safety, is that if they did accept this for an Accelerated Approval filing, that we could then supplement that NDA filing with some initial experience from any confirmatory study, if we needed that to form the basis of an approval. So again, we have shared what we think are the most relevant outcomes of the FDA meeting, and again, we described and explained the twins, we think very sufficiently, and of course, they want to see all the data, right. They want to make their own interpretation and its though, they do this, when they do a review, and we expect that they are going to do a similar type of assessment, not to the same extent as they would after an NDA filing. But I expect they are going to review our data with a measured eye, and so we explained the twins as best we can, and we don't think that that would impede their decision on whether this is a feasible dataset for accelerated approval filing. Again, we think there is advantages, if there is a silver lining, we are collecting some excellent information in a non-ambulatory population, as a result of these two boys. So again, we are looking at this very favorably, and I believe, the FDA will look at this appropriately and pragmatically.

Thank you. Our last question comes from Debjit Chattopadhyay from Emerging Growth Equities. Please go ahead.

Good morning guys, and thank you for the questions. Just have two questions. First, I mean, what differences are you seeing with the other exon drugs versus eteplirsen, in terms of therapeutic dose and efficiency of exon-skipping? Number two is, if you compare the current Phase IIb patients, instead of looking at the natural history of DMD, and compare them with the most severe Beckers muscular dystrophy phenotypes, how do they stack up versus the second group, the severe phenotype of Beckers muscular dystrophy? Thank you.

Yeah absolutely. So Debjit, I am sorry, can you repeat the first question again?

Well I was just wondering if, in terms of the other exon-skipping drugs, what are you seeing in terms of --?

Yeah, okay. So on the other exon-skipping drugs, again, we are in preclinical development, and there are not -- there is no plans for specific exon targets. There was preclinical work. Any functional (inaudible) would be done in the dystrophic mouse model, the MDX, which is a surrogate, it's at exon-23 skip. So what we have is, we have optimized the sequences, for exon-45, 53, and 50 and have identified those lead candidates, and so what we can extrapolate at this point, this early stage, is that the exon-skipping efficiency is in the range, we would like to see it, and that would be predicted, based on what we know about eteplirsen and the sequent we have for exon-51, that these would have a similar ability to produce the dystrophin levels we are seeing with eteplirsen, at a standard dose, at a similar dose of, let's say 30 mgs per kg per week. So we won't know for sure, until we actually dose patients, collect some dystrophin from those new exon targets, to know if that's the case. Regarding your second question, Becker muscular dystrophy has a very milder course, and oftentimes, there is a wider range to Becker. So some would be described as a mile Duchenne patient, and that ranges from an almost normal healthy individual, which can live most of their life, without even knowing they have a muscular dystrophy, never requiring a wheelchair and living a kind of a full life expectancy. So, what we see right now, in these 10 boys that were still ambulant, is the stability that if we can continue that on an ongoing basis, that would be very encouraging, that if we started this drug in an earlier healthier population, we could really have an opportunity to change the natural course of Duchenne, and make it more akin to what we would see in Becker muscular dystrophy, which is a much milder phenotype, which allows ambulation to continue largely into adult life.

Thank you. I will now turn the call back to Chris Garabedian for closing remarks.

Okay. Thank you, operator, and thank you everybody for your interest and calling into this quarterly update. We are prioritizing this program in our interactions with the FDA, as well as the activities on clinical regulatory, and manufacturing. We understand the urgency of doing everything we can, to get this product to the patients who need it as quickly as possible, and we believe the FDA is a partner in trying to help us figure out, how to do that in the best way possible. So thank you, we look forward to giving you periodic updates along the way, and thank you for your interest in Sarepta.

Thank you. Ladies and gentlemen, this concludes today's conference. Thank you for participating. You may now disconnect.