Operator
Good afternoon, and welcome to the Sarepta Therapeutics ELEVIDYS FDA accelerated approval call. [Operator Instructions] As a reminder, today's program is being recorded. At this time, I'll turn the call over to Doug Ingram, President and CEO of Sarepta Therapeutics. Please go ahead.
Douglas Ingram
Thank you, Victor. And thank you all for joining us for this call to discuss the approval and launch of the first and only approved gene therapy for Duchenne muscular dystrophy. Mary, next slide. I will be making some forward-looking statements. Please refer to our public filings for the various risks and uncertainties that exist with statements and predictions about the future. Next slide. As you know, earlier today, the FDA approved RP SRP-9001, Dilimystrigene moxiparvovec Roca for the treatment of Duchenne patients. The division has initially approved the therapy for Duchenne patients aged 4 through 5 years with our ongoing Phase III trial EMBARK, acting as the confirmatory study for the approval. And if the study meets its objectives for label expansion, I will discuss later our plans to move rapidly to expand the label to treat the majority of Duchenne patients. Before I move on, I am excited we can now move out of stealth mode and announce the brand name for SRP-9001. So let me officially introduce you to ELEVIDYS which is how I will be referring to this therapy for the remainder of today's presentation. Next slide.
As the first gene therapy of its kind, the approval of ELEVIDYS is a historical milestone in the translation of genetic science to genetic medicine. It is also a monumental moment for those patients who will have access with this approval and an important step toward our paramount and near-term goal of providing a potentially transformative therapy to the vast majority of patients living with Duchenne. Next slide, please. To contextualize the importance of ELEVIDYS, let's briefly review this ferocious lead of disease Duchenne. Duchenne is caused by a mutation on the gene that codes for the structural protein dystrophin. Dystrophin acts as a shock absorber that protects our muscles as we move. Boys with Duchenne do not possess this dystrophin shock absorber and thus, they damage themselves literally every time they contract their muscles. Every hour of every day, they irrepably lose muscle and are relentlessly losing milestones. Duchenne damages then from birth and beyond. Typically, they begin to struggle in their very early years. By 11, they will struggle to walk. By their early teens, they are typically consigned to a power wheelchair.
In their mid-teens, they are struggling to use their upper limbs, struggling to breathe, and perhaps on a part time or even a full-time ventilator. And then often by their late teens to mid-20s, this disease will kill them. And this is what we're up against, a relentless, ferosously degenerative and lease. ELEVIDYS is a gene therapy that works by delivering a muscle around the body at gene cassette that codes for a shortened but fun of the shock absorbing dystrophin that these boys and young men are missing. The goal is to halt the otherwise irreversible muscle damage caused by Duchenne. That is why this approval is so important for the boys who are permitted access to it today, and it is why we must move as rapidly as science and our regulators will permit to expand this label and make ELEVIDYS available to all those whose muscles are being irreparably ravaged by this disease every single hour of every day.
Next slide, please. With our approval in hand, we are well prepared to launch ELEVIDYS and make it successful. Sarepta is the undisputed leader in serving the Duchenne community. We have previously launched 3 Duchenne therapies, which without a single price increase have collectively achieved about a 40% compounded annual growth rate since 2016. So we have the knowledge, the expertise and operational acumen to launch and make ELEVIDYS a success, first with patients covered by this approval and soon after should EMBARK meet its objectives with the vast majority of Duchenne patients. Next slide. I am, of course, confident that there is no team more capable than the Sarepta team to make this launch a success. Given the evidence set for ELEVIDYS, we expect arable demand, both from patients and their caregivers and from physicians. But with that said, I do want to set some expectations about the initial launch and its ramp.
First, of course, we have been preparing for a label that would serve all ambulatory patients. Our Age limited label will make the initial launch more measured than we had planned for. And second, it is important to consider the patient journey. The similarities to our oligonucleotides, but also some of the things that make gene therapy unique. Next slide. In addition to all of the early work that must be done with payers to get medical policies in place, we imbursement codes established and the like. The typical patient journey for one of our oligonucleotide therapies goes from diagnosis to console to prescription, to payer authorization, infusion coordination, infusion, reimbursement and eventually to an ongoing reauthorization process. Next slide, please. For gene therapy, one has nearly all of these steps, accepting the authorization. But then we must add to this the unique aspects for a onetime gene therapy, including initially the unique aspects of the distribution model, then referral to a gene therapy infusion site screening for neutralizing antibodies, site procurement and post therapy monitoring.
You will recall ELEVIDYS 51, for example, it took about 3 to 4 months before we began to see a significant launch ramp. And then we had a very substantial ramp in treatment and in revenue. This will be the same for ELEVIDYS, but it will be attenuated first by the size of the population and then by another few months for the additional gene therapy steps that must be executed. We will update the investment community on launch progress on upcoming earnings calls. But we do not intend to provide sales guidance for ELEVIDYS at this point, given we are at the beginning of a nearly one-of-a-kind launch to set expectations and as we have done with our prior therapies, we intend to reference net sales as the external metric for performance rather than things like patient numbers and the like. As it relates to our currently approved therapies, the launch of ELEVIDYS should have some cannibalizing impact on sales. However, we anticipate it will be modest in 2023 and and we remain comfortable guiding to $925 million for full year 2023 net product revenue from our 3 approved oligonucleotide therapies. Next slide. I have said many times that the cost of the health care system for ELEVIDYS will be much lower than the value that ELEVIDYS will bring to patients living with Duchenne muscular dystrophy.
So let us review that now. Sponsors pricing of their therapies in relation to a cost-effectiveness model can sometimes be opaque. We have gone much further than most, not nearly by referencing a cost-effectiveness analysis, but by publishing the elevates cost-effectiveness analysis in a highly respected peer-reviewed journal. On May 26 of this year, the Journal of Market Access and Health Policy published the article, Assessing the Value of Dilladystrigene Moxyparbovec SRP-9001 gene therapy in patients with Duchenne muscular dystrophy in the United States, a detailed cost-effectiveness model for SRP-9001, now, as you know, known as ELEVIDYS. The published cost-effectiveness analysis employed an established pharmacoeconomic model to project long-term health outcomes by extrapolating clinical trial data, leverage on health economic expertise and employing peer-reviewed scientific literature to assess the value of ELEVIDYS. The evaluation predicts that compared to corticosteroids alone, treatment with ELEVIDYS will add 26.4 undiscounted equal life years and 10 discounted equal life years gained to individuals with Duchenne. The publication concludes that ELEVIDYS is cost effectiveness at a price depending upon various assumptions of anywhere between $5 million and as much as $13 million.
Next slide. To avoid any debate that might delay access, the cost-effectiveness model use is a more traditional approach that looks only at the cost to the health care system without all of the adjustments necessary to capture the full value of a therapy like ELEVIDYS to society. On this slide, you will see reference to the broader value of the society that is not captured in traditional cost effectiveness tools. So for instance, the model doesn't capture the lost income from Duchenne -- a Duchenne patient, which over the life of a patient is approximately $1.91 million. It doesn't account for the impact on the lives and livelihoods of caregivers. It doesn't account for the risk-based investments required to develop therapy like ELEVIDYS . It doesn't account for the impact and approval will have on the innovation ecosystem. And the future benefits that will drive from compounding innovation. Next slide, all of which is to say that using a relatively conservative approach, ELEVIDYS would become effective in a range of around $5 million to $13 million. Now as we have said, our approach is to ensure that the cost to the health care system is less than the potential benefits of ELEVIDYS.
So we have set the wholesale acquisition cost or gross price of ELEVIDYS at $3.2 million. And remember, this is the gross price, not the actual price. Nearly all infusions will be subject to a statutory discount for Medicaid or 340B discounts. So with distribution and other discounts, you should be modeling a gross to net adjustment in the mid-20% range. Looking at the payer budget impact and applying the gross elevates price of $3.2 million for the approved Duchenne population, the cost per member per month would be about $0.25 at launch, and at about 11 at steady state or even lower when statutory discounts are applied. Now that per member per month cost for other therapies, particularly specialty therapies, can reach beyond $6, much higher than the estimated ELEVIDYS budget impact to payers. In short, we have achieved our goal of ensuring that the burden on the health care system is significantly lower than the potential benefits of elevates, and we have done this very transparently. Next slide.
Based on statutory and regulatory authority, president approval, the outcome of our advisory committee and the mechanism of action of elevates, we had submitted and have been preparing for a label without age restrictions. The approval of ELEVIDYS, however, is initially indicated for 4 through 5-year-old patients. This is an enormously important moment for those boys who can now be treated and it is an important milestone for the rest of the community. But our work is by no means done. We will make this launch a success. We will serve the patients available for treatment now, and at the same time, we will work rapidly to broaden the label to cover the majority of patients. The FDA has indicated to us that in addition to confirming the results of the initial BLA approval, if the readout of our next trial EMBARK meets its objectives the agency intends to entertain a nonage restricted expansion of this label.
We have also been assured that this will be done with maximal speed by the FDA. Our goal then is this. The last patient visit for our confirmatory trial Embark is in September of this year. As soon as we have the top line available, we will move quickly to supply it to the division. Even before, we have submitted our BLA supplement. So the division has an opportunity to begin its review immediately. Our goal is to submit a BLA supplement as soon as possible post embark and to expand the label to remove any restrictions or restrictions on the basis of ambulatory assessment consistent with all past Duchenne therapy approvals. And on the topic of nonambulatory patients I am happy to announce that we have commenced our nonambulatory study ENVISION or Study 303, and we are dosing now. This is important as it will provide us with additional safety and expression data to support the expansion of the label when Embark reads out, and it does support ex U.S. approvals as well.
Next slide. Now even with an expanded label, we would still be excluding those 13.9% of patients who will screen out for pre-existing antibodies. In addition to Envision, we will shortly commence multiple trials to explore the clearance of pre-existing antibodies. Our goal, if successful and if the evidence supports it is to expand the label to treat as much as 95% of the Duchenne population. Next slide. The approval of ELEVIDYS, the first gene therapy for Duchenne muscular dystrophy marks an important milestone in our journey to serve the broad Duchenne community with transformative therapies. Many have played a crucial role in getting to this point, and we feel a deep sense of gratitude for all of their contribution.
With Dr. Louise Rodino-Klapac and Jerry Mendell and their teams at Nationwide Children's Hospital, who started designing, testing, redesigning, testing, and optimizing what eventually became elevates literally 20 or so years ago. It includes all of our external advisers and our clinical investigators and their teams. It includes the unique cross-functional team of Sarepta professionals. This milestone speaks reams to the Sarepta culture, a fearless tenacious, patient-driven science-focused tribe of professionals who persist even in the face of resistance and have overcome countless obstacles to get to this moment. And I would like to end with a very special thank you to the Duchenne community and to the courageous families who chose to participate in our studies that support this approval. Their dedication, benefits the science of Duchenne and has brought hope of a brighter, longer richer future to the broader Duchenne community. While our approval to volume at all important one, our work goes on. We will continue to fight for every patient with Duchenne muscular dystrophy in the United States and around the world. And we will do so with the urgency that this fight requires. Regardless of obstacles, we will, as we say often, more into the day for Duchenne patients. And with that, Victor, let's open the line for Q&A.
Operator
[Operator Instructions] Our first question will come from the line of Tazeen Ahmad from Bank of America.
Tazeen Ahmad
And congrats on this initial launch, so my one question for you is just trying to understand how long you think it will take before insurance companies start to remember. I think that's probably the #1 inbound question I've been getting. Just given that Embark is so close to reading out why would payers start to pay now versus wanting to wait to see what the results of that pivotal study show.
Douglas Ingram
We've had -- thank you very much for your question. thank you for your statement of congratulations. We had very good conversations with payers. In fact, we've had conversations with payers covering more than 200 million lives already. I think those conversations are going quite well. I think the work that we've done to support the pricing of this therapy is potentially a blueprint for others. So I think most conversations are going well. We're very confident about reimbursement, and I don't think it would be appropriate for patients to wait. In fact, I think there's a compelling in the age restriction of the initial label to get patients dosed as soon as possible, so we don't age out the label. With that said, I do want to make clear really unrelated to payers' appetite for reimbursement that there is going to be a process that we have to go through to get policies finalized and agreements finalized and the like I think there will be -- before we see a significant ramp, you ought to be looking out a few months.
But as it relates specifically to the payer Adesis, I think we've done an enormous amount of work over really the last few years to put ourselves in a position to have very constructive discussions with payers. And so far, the dialogue that we've had has been very positive.Dallan, is there anything I missed in that?
Dallan Murray
No, not at all. The dialogue has been positive. We've been engaging with commercial and Medicaid payers to ensure they're prepared for this launch. And our objective is to align these payer policies with the FDA indication. And we achieved this by engaging with payers to provide the clinical evidence supporting the treatment. So it's going well, and we'll continue to drive to support patient access as rapidly as possible.
Tazeen Ahmad
So just to clarify, you don't expect to need to wait for EMBARK to get reimbursed.
Douglas Ingram
That will not be the rate limiter. There are a lot of procedural issues we had to go through and policy is in place, there's a natural unit of these things. But I don't imagine that we're going to get significant resistance with the idea that we ought to be waiting for EMBARK to put a kit on the therapy. I think that -- and then frankly, first of all, we've never had a hint of that in our discussions with payers and it would be appropriate these kids need therapy today. One of the things I said in my prepared remarks was that, as we all know, with respect to Duchenne muscular dystrophy, time is muscle as we've heard others say and that these kids dosed in this therapy to the families as fast as we can. First with the labeled indication and then as fast as we can post embark on this label so that other patients can benefit from ELEVIDYS.
Operator
Our next question is come from the line of Brian Abrahams from RBC Capital Markets.
Brian Abrahams
Congratulations. So based on this label and your most recent regulatory discussions, I'm wondering, what do you believe you'll need to show and embark, particularly in the signaled patients there in order to get a broad age agnostic label. Does the trial just need to hit statistical significance or show strong trends overall? Do you need to show a specific type of trend within the 6- to 7-year-old population, statistical significance in that age group?
Douglas Ingram
Yes. Thank you very much for that question, Brian. First, let me say, I think the standard that the FDA uses to look at this data is the totality of the evidence. So I think first and foremost, once EMBARK reads out, the standard for the FDA is to look at the totality of evidence to determine if it's confirmed the therapy? And is it appropriate to expand the label to get rid of the age limitation that hasn't been present, by the way, in any other approved Duchenne therapy. With that said, I'll be clear about our expectations in the study itself, which is a which is a slightly different question about what the standard for approval is [indiscernible] of approval is clearly the totality of evidence. What do we expect out of the trial, we are very confident that EMBARK is powered well. We powered EMBARK to show a statistically significant and clinically meaningful benefit on our primary endpoint functionally, which is NSAA. We made some assumptions around the at the time that EMBARK was studied and we've done additional studies since then and have additional insight. And that additional insight actually makes us even more confident in our conviction around the outcome of EMBARK. So while the broad standard for the review is totality of evidence, we're very excited for the results of EMBARK and we have powered that study as the statistical significance on NSAA.
Operator
Our next question come from the line of Colin Bristow from UBS.
Colin Bristow
And a big congratulations on such a landmark approval. So first question is, what is your expectation for the average time it's going to take for a patient to receive 9001 it's prescribed. I saw the patient journey, I'm not sure if I heard that specific time line. And then also, as we think about sort of exon skippers, what's your expectation around use and reimbursement in patients who received 9001?
Douglas Ingram
Yes. Let me -- the second question first, and then I'm going to turn it over to Dallan for the first. So as it relates to post infusion, continuing use of an exit therapy like [ EXONDYS or bandanamandus ]. I think assumption right now is there's going to be significant cannibalization. And I think that, as we said many times, folks ought to model that. As it relates to 2023, in particular, I think that the cannibalization will be quite modest. And therefore, I think before our previous guidance has been $925 million, while there will be some modest cannibalization, we're still very comfortable with the guidance that is at $925 million. So it's a slight change in guidance. But we are comfortable with that. Now with respect to the length of time,Dallan, so there's 2 answers to this question. One is just getting up and running and all of the policy-related issues that have to occur before infusions occur and the ramp occurs. I think the specific question that Colin is asking is, assuming steady state post that those early days, what's the typical time between a start form and an infusion if you -- if we have a view on that?
Dallan Murray
Yes. Thanks, Doug. Yes. And as you say, it will be to get the policies in place, and it will be case by case until that is the case. But as we get to steady state, we'll be looking to -- especially because of the narrow age range we will be looking to get that time as short as possible. So it's very early days in the to really lean in on an exact time. We'll keep you updated as we go. You can look to the PMO launches as initial guidance, but obviously, in this narrower patient population, we're going to have to try to find faster.
Operator
Our next question will come from the line of Gena Wang from Barclays.
Huidong Wang
Also, congrats on the approval. I will also ask one question -- one more question regarding the payer discussion. Doug, you lay out the patient journey. So when we look through, I think at the beginning part, most of these has been down. So mainly will be wondering regarding the payer part, would that be pay for performance? Or would that there be any possibility for pay for performance? And if that's the case, would that be delaying the patient receiving the drug due to the more complex discussion with the payers?
Douglas Ingram
Yes. Thank you very much for that question, Gena, thank you for your statement. Congratulations. Duchenne, and particularly with a narrow population and then there were label and considering that Duchenne is a heterogeneous degenerative disease. Looking at some of the recent outcome-based agreements isn't something that's likely or possible for ELEVIDYS. And I think the payers, particularly sophisticated payers, who through our engagement over the last 6 years, who know Duchenne. Well, I think generally understand that and expect that. We have some intones that we're working on with payers. They would be different than an outcome based.
Any event, none of that will, in any way, delay or slow down a child's ability to get a therapy. I think it's going to be generally straightforward with the exception that you've got to get policies in place and contracts finalized. The good news is we're not -- we haven't been sitting back waiting for this approval and then we're going to jump into action. We started this process -- I mean I'm not exaggerating when I think we started our discussions with payers in literally mid-2018. Of course, we've moved through this journey as clinical development is has progressed and as data has come in, those discussions have become more and more concrete. I think very recently, Dallas' team has had conversations with payers that I think down.
Correct me if I've got these numbers wrong, but I think it's over 220 million lives in the United States covered by the payers that we've had discussions with. Now all of that has to translate into some more work and some policies in place we're in a very good place to complete those discussions and get kids on therapy. And to Dallan's point, while we keep speaking cautiously about the early days of the launch, I do want to be clear. We've got to move rapidly because one of the things that we need to assure doesn't happen as often as it might otherwise happen is that kids who are amenable to getting this therapy and are within the indication, age out of this indication and our denied therapy because of the labeled indication itself. So the team is going to work really hard and as fast as possible with that. And again, I mean I will say this at the risk of being a modest, there's no team, better prepared to work with payers and to bring this therapy to Duchenne patients than this team. I think this team, Dallan's team, our medical affairs organization, our distribution folks have proven time and time again over the last 6 years that they know how to work with payers, get access and deliver the therapies to kids that need it.
Operator
Our next question will come from the line of Judah Frommer from Credit Suisse.
Judah Frommer
Congratulations as well, another one on kind of broad time lines here. You mentioned helping FDA move as quickly as possible. Once you have EMBARK data. But do you have a sense for how quickly you might be able to achieve label expansion post BLA supplement submission with positive EMBARK data and then whether you'd have a similar multiway between getting that expanded label and administering drug to those older patients.
Douglas Ingram
Yes. So. First answer is the good news is that EMBARK last patient last visit will be in September of this year. And so our goal, our aspiration, and I think it's a very -- I think it's a reasonable one. is that we would have this label expanded in the first year, assuming that EMBARK reads out positively as we anticipate that it will, given all of our analyses. So we think, certainly in the first half of next year, we can expand the label, as I've said in my prepared remarks, our goal is not is to extend it to have no age limitation and the FDA has confirmed that, that is an appropriate goal and have no reference to ambulatory status. And then the good news is from a precedent person, none of the Duchenne therapies that have been approved to date to the best of my knowledge had those kinds of restrictions. So I think it's very consistent with precedent. As it relates to the next wave of launch when we have a broader label. I'm sure we'll try to dampen that expectations at that moment, but the fact is A lot of the work we're doing right now will near to the benefit, not only of the initial launch with our 4- to 5-year old boys but to the broader patient population as well. So the policies and all of that work is going to benefit both of these launches. And so we should be able to move even faster with our broader label assuming that it all works out, we get that early next year.
Operator
Our next question is come from the line of Gil Blum from Needham.
Gil Blum
Good afternoon, everyone, and allow me to also add my congratulations. Maybe a bit of a hypothetical -- so do you expect any pushback from payers on longer-term reimbursement if patients who are receiving the gene therapy will require further treatment, let's say, with the next on skipping drug.
Douglas Ingram
Well, I think that our working -- I don't think that is going to be a significant discussion at launch because I think the working assumption is that children that have opportunity to get ELEVIDYS are going to result in signification of PMOs. So I don't think that that's going to be any kind of pushback on the use of ELEVIDYS and the reimbursement and access for levers. I think that the idea of a combination use of ELEVIDYS and then followed up with a PMO, I think, would require an enormous amount of discussion with payers. And that's why, as I've said earlier, I think you ought to plan for over time significant cannibalization of PMO use with elevates. And again, I know I'm repeating myself, but just to make very clear from a 2023 perspective, there will be some modest cannibalization with the success of elevates, but it will be modest. And as I've said, our guidance for the year is $925 million that we're big right now.
Again, just -- and can be completely transparent, so everyone understands, that's for our 3 oligonucleotide therapies alone. That's EXONDYS and MODIS and VYONDYS that does not include any revenue net sales associated with ELEVIDYS.
Operator
Our next question will come from line of Neena Bitritto-Gard from Citi.
Neena Bitritto-Garg
As on the update. I just wanted to clarify some of the commentary on the potential for label expansion. And just confirm that, it sounds like the ENVISION study would be needed for expansion into nonambulatory patients. But in ambulatory patients, I just wanted to clarify again what the bar for kind of that expansion would be whether or not you do need to see success in both age subgroups. And then, I guess, a separate question. If you see, let's say, statistical significance just in the overall analysis, but not in the 4- to 5-year-old subgroup, have you had a discussion with FDA and what that would imply about the label?
Douglas Ingram
So we are -- the goal of EMBARK and it's not it's the placebo-controlled trial, as you know, about 125 patients, 1:1 placebo control is to confirm the mechanism of action of ELEVIDYS which would then be applicable across ages and it's been powered to show that across the ages that are being studied, which is 4 through 7 years old. Once that mechanism of action has been established, then it's pretty straightforward that we ought to get a broad label that has no age bound restrictions in it. We expect that has been the subject of our discussions with the FDA, and I think that's consistent with our discussions with the FDA. As it relates -- go back to your first part of your question as it relates to Envision and the need for ENVISION to support the nonambulatory part. I want to be very clear about that. What we what is valuable about vision for expansion for nonambulatory is to get even more -- we already have good exposure for nonambulatory and older patients out of our prior studies, ENVISION gives us even more of that, and we'll take a cut of that to confirm and even more patients, the expression and safety associated with elevates in the older and nonambulatory patients.
That's what we need. I don't want people to match that we would anticipate having to wait for the conclusion of a vision to get to nonambulatory patients. That is not at all our assumption. So ENVISION serves a very important sort of a number of important goals, one of which is to get from that subset of patients, sufficient additional evidence to comfortably expand the label to older nonambulatory patients. And we would have that in time to have that label expansion with our BLA supplement post Embark. And then the other scale out of Envision as well is that it's the label for ex U.S. as well.
Operator
Our next question comes from the line of Ritu Baral from Callon.
Ritu Baral
Let me add my congratulations on the approval. Just to rewind on Doug, I just want to make sure I know how the pricing works. The label mentioned that revenue is going to be provided in kit form with a number of vials per patient depending on patient weight. The $3.2 million growth that you mentioned, is that the kit price regardless of the number of vials? Or will this essentially be priced per vial? And if it is a kit, by the way, if it is a kit, are we looking at a different kit pricing upon potential age expansion and the dynamics around that?
Douglas Ingram
Well, thank you for your congratulations, and thank you for this question because Interestingly, we've made the presention that folks would know this. And so it does give us an opportunity. So the pricing for ELEVIDYS is a single price per kit is not going to vary by numbers of vials. So as additional vials may be required for heavier patients, the price would remain at $3.2 million gross and then, of course, subject to 340B and Medicaid discounts and other distribution-related discounts that are in, as I said, in the mid-20% range. And then as it stands today, we don't anticipate modifying that as the label expands.
Operator
Our next question will come from the line of Mike Ulz from Morgan Stanley.
Unknown Analyst
Congratulations on the approval as well. Just a quick question from us in terms of the patient population here given the narrow label. Just how should we think about that initial addressable patient number ambulatory patients 4 to 5 years old?
Douglas Ingram
Yes. Thank you very much for that, Mike. One of the things I said and I do want to be cautious because we are going to avoid discussing patient numbers because we don't want to use that as the metric for success. We're really going to use 1 metric. It's the one we've been using for the last 6-plus years, which is net sales themselves. I think you can get guided by the fact that broadly speaking, there are about 400 new Duchenne patients in the United States.
This year, there are some epi literature that would suggest there might be a tad higher than that. But I think for our purposes, we use $400 million, that should guide you a bit on the potential addressable patient population?
Operator
Thank you. One moment for our next question. Our next question will come from the line of Salveen Richter from Goldman Sachs.
Salveen Richter
Congratulations. When I look at the last 3 gene therapy launches, it's taken at least 6 months from approval to first patient getting infused here. So could we kind of think of that as really an expectation as we think about your launch? And are there any infrastructure logistical we should be aware of here? And just a second question, does Embark put the current accelerated approval for 4 to 5 year olds at risk if it were not to be successful?
Douglas Ingram
Well, I'll answer the second question first. I mean we're going to be successful with the mark, and we're not particularly concerned about that. So I'll be honest with you, we're very excited about that. And as it relates to sort of -- I'd say 2 things that I'm sort of the attention with one another and answering your first part of your question. The one thing I would say is that there is going to take some time to get policies in place and codes and all of that. So it's going to take a bit of time, and that's why really before you see any real significant ramp, you ought to anticipate it's going to be some months to really see a significant ramp. From an infrastructure perspective, there are a lot of logistical issues, but we have been working hard on them. And I will tell you that Dale and his team have an obsessive attention to detail on these issues. So I think we're in good shape. And the second thing I would say again the significant risk of being a modest is that generally speaking, I probably wouldn't use precedent approvals as a metric for how we're going to do.
I think there's going to be an enormous amount of demand, and I think obsessive attention to detail by our team to get this therapy to patients we're already getting. And I can tell you, since we've had this approval just a few hours ago, the amount of attention and focus and pressure from not just the patient community, but the physician community has been significant. And frankly, even some positive statements from the payer community. So I think we're going to do quite well. But I don't want to start creating the impression that it's not going to take some time to really see a ramp. It's going to take some time.
Operator
Our next question will come from the line of under Pam Rama from JPMorgan.
Anupam Rama
And congrats on the approval. Maybe following up on the last question, where are you in terms of like site activation and sites being ready to administer SRP-9001 and obviously, work through all of those logistical things that you guys have been talking about on the call.
Douglas Ingram
Yes. I'm going to turn this over to Dallan, I say's, let me say a couple of things. We've been working on signed activation for a long time now, probably a lot of planning before about a year ago and then really working into working with these sites to get them up and running. There are a few things that you have to wait to do until you get the approval. Now we have it, those last few things will get done. Just to remind you to kind of contextualize what the sort of site activation and site readiness, remember a couple of things. One, now that the vast majority of sites that will be infusing elevates have significant experience because of [ Zolgensma ]. So we really do benefit from the prior approval of Zolgensma. Also now with respect to Duchenne muscular dystrophy, about 50 total sites already cover 80% of the Duchenne population. And then also finally, remember that we had until very recently been planned a broad label and all of our site activation and site work was on that basis. So we were in place right now. But with that, Dallan, do you want to kind of provide any of the numbers behind any of that?
Dallan Murray
Yes. Thank you, Doug. Yes, those 50 sites and the 80% covering 80% of the population are key ones. And thanks for the question. In the last several months, we've actively engaged with well over 100 HCPs across this site network and who do intend to dose patients with ELEVIDYS. So we have, as we sit here today, post PDUFA site activation and label education meeting set up with nearly all of those 50 sites. And we're going to be training the team on the final label tonight and tomorrow. And we already have 5 of those site activation visits Friday. So we'll already be doing this on Friday, and we have another several scheduled on Monday. So the team is, as Doug said, from the moment that they got the green light have moving forward.
Operator
One moment for our next question. Our next question come from the line of Kristen Kluska from Cantor Fitzgerald.
Kristen Kluska
Congratulations to the entire Sarepta team. Can you remind us other additional endpoints and color you might share with the agency after you have the data later this year? And then would you also plan to continue sharing some of the longer-term data you've been from the earlier conducted trials?
Douglas Ingram
Yes. As it relates to the second question, of course, we're always looking for appropriate medical meetings to share additional information and updates I assume as it relates to the first question, you're really asking what other endpoints are we looking at besides our primary endpoint, such as with time test and the like, Louise, do you have a what I sort of make a few comments on some of the other endpoints that we have.
Louise Rodino-Klapac
Sure. I think the question was what we shared with FDA. And certainly, we would share all of the complete data set, including all of the secondary and exploratory which will be the time test expression, et cetera. So yes, all of that data will be shared on an ongoing basis with the FDA.
Douglas Ingram
I'm sorry. Yes, of course. We're -- we have both an obligation and to ourselves and to the agency to share everything with them as we get it, and we certainly do all of that. We have an interesting one. We have an interesting exploratory endpoint. While I don't think it's going to form the basis for label expansion on its own. I think it's really interesting, we've got with respect to embark some novel concepts like wearables and the like. All of that will be interesting data that went over time.
Operator
Our next question will come from the line of Tim Lugo from William Blair.
Tim Lugo
Congratulations. It's obviously a great day for the community. Can you expand a bit on your strategy for those patients with preexisting antibodies? I think there might be two strategies that you're exploring and maybe tigers a strategy as well? I'd just love to know when we could hear some progress for these patients.
Douglas Ingram
Yes, our goal. So we have 2 different approaches. The great news is I think a lot of folks are looking at ways to knock down pre-existing antibodies. And I think a lot of folks are looking at ways to empower redosing as well. I'm excited about all of that. We are also very excited about it as well. And there's 2 approaches that we are going to take with the goal of starting both of these studies this year. One is in partnership with a company called [indiscernible] is the use of ELEVIDYS to cleave preexisting antibodies to empower redosing. And the second is to use apheresis to explore the ability to clear antibodies and then allow for redosing. We have really very encouraging preclinical data that gives us some hope around that. So we're going to get going on that because this is an extraordinarily important issue, about 13.9% of children with Duchenne muscular dystrophy will screen out of our therapy because of pre-existing antibodies, which that's our best estimate today. And while that is a very low percentage relative to other serotypes and other AAV capsids, it's still too high.
And in fact, I think I've said this before, I've had parents more than one parent say to me that the second worst day MOIs was hearing that their child screened out of the ability to get ELEVIDYS, the first being original diagnosis. So we're going to get on that. We're going to start these trials this year. And then if they're successful, we're going to move as fast as we can to get that in the labels and we do so safely so that patients that are NAV positive can get this therapy. And then, of course, our goal with all of this, if we're ultimately successful is to extend this therapy to many as 95% of kids in the share, and we want to do that as fast as we can.
Operator
Our next question will come from the line of Eka Gigauri from Oppenheimer.
Eka Gigauri
Hello. This is Eka on for Hartaj Singh today. Congratulations to Sarepta team as well as the addition community for this milestone. We have a question on the competition. Can you just talk about your confidence level in ELEVIDYS launch in the context of the competitors pivotal trial in Duchenne that is going to be reading out in late 2023 or early 2024 at the time when you are going to be in the middle of the launch and also potentially looking at broadening the addressable patient population.
Douglas Ingram
Yes. I'm going to try not to get excessively competitive. So let me just say, we are very confident. We're enormously confident. We have a very, very significant competitor right now, and that is Duchenne muscular dystrophy. And while we are enormously excited about this launch, we need to move as fast as possible to confirm things through embark and get this get this therapy to more kids before more damage is done. That's our razor-focused issue right now. And to be honest, competition -- commercial competition is an important one because it's great for patients. It fuels us to move fast as it sits right now, the biggest issues in front of us right now are not other organizations, but really is a fight against time trying to get this therapy to kids with Duchenne muscular dystrophy before more damage is that -- so in the broadest sense, let me just say, we're confident.
Operator
Next question will come from the line of Brian Skorney from Baird.
Brian Skorney
I know I pushed on this a few times offline, but I wanted to maybe push again online around the powering assumptions for EMBARK. I know the Paris Mullen talked about specifics around the assumption, but I think that actually created more confusion than color. And you said before that EMBARK was designed on what you saw on Study 102. Can you give us more specifics here, like if embarked 1.7 treatment mean improvement from baseline in the 0.9 point placebo mean improvement from baseline with a standard deviation of 2.7. Would that result in a statistically significant effect in EMBAARK? Or can you detail exactly what your assumptions are around standard deviation on these mean changes?
Douglas Ingram
Yes. And that was -- sorry about that, Brian, didn't mean to interrupt. I will say notwithstanding the fact that we were required to discuss it at the advisory committee. We've been pretty careful for competitive reasons to avoid going into a lot of detail about our powering assumptions. One of the things I will say that while the information provided at the advisory committee was accurate at the time that we did our powering assumptions. The updated data gives us additional confidence and it actually makes it even higher powered. We could have changed those assumptions and still had a very, very powerful very well-powered study, including everything from standard deviation and the like. So I think we feel we're in great. We felt good about the powering. We take what was really the highest number at the time that we could choose without being at risk of overpowering the study, and it's only improved since then of the various numbers we could approve. We picked 120. We've actually over-roll to about 125 patients right now. So we feel like we're in great shape. I think the study has performed very well, at least from an enrollment perspective. And the last patient last visit will be in September.
And then we'll rapidly unblind that and have that data out both to the FDA. We're going to give that to shares we have at QC. We're going to give it to the FDA. Our goal is to give it to the FDA before we even are able to provide compiled BLA supplement. So that to the extent the has the appetite for it and a commitment to patients, they'll start that review as soon as possible, and then we'll submit the BLA supplement. And then hopefully, as early as possible next year, we'll expand the level. So that's sort of where we are right now. We haven't given a lot more detail on powering assumptions beyond that. Is there anything else you'd like to say on that, Louis or I hit the high points.
Louise Rodino-Klapac
You've got you captured it well. Thank you.
Operator
Our next question will come from the line of Joseph Schwartz from Marc Partners.
Joseph Schwartz
Hats off to everyone at Sarepta, Doug. This is cause for applause. So I was wondering, oftentimes, we see trials not result in a clear win or loss but something in between with divergent results in different subgroups. So I was wondering what happens if EMBARK isn't a clear win or there's different results in the 2 different subgroups. Is your statistical analysis plan set up in a manner or prespecified in a manner that is strategic at all and you can analyze the data in a manner that maximizes the probability that embark fulfills its objectives with the FDA?
Douglas Ingram
Yes. Thank you for your comments, and your congratulations. That really means a lot to the team. This has been a long -- there's been a lot of hard work and tenacity by a lot of folks. So I really do appreciate that. And again, let me say, I mean we're very confident in the PARI study and the outcome. Obviously, in the end, the goal is to look at the totality of evidence. We'll have to see what that looks like when we see it. I mean, I do think we've been strategic in the way we've powered this study. We -- as you know, one of the things that there are numbers of different ways that you go into statistical analysis plans I think we have managed our staff, our statistics in a way, I think, that maximizes the potential for success, and that is by powering the study to see a statistically significant and clinically meaningful effect across the entire patient population.
If we started dividing that up in smaller segments, you might lose power. So we've got -- as our primary endpoint, statistical significance across this entire patient population. Now when I say entire patient population, I do want to remind you that it's a very -- it is a much are patient population than the patients we're going to serve. So this isn't as if we take in patients between the age of 4 and 12, and we're looking across that group. This is a fairly tight range of 4 through 7 year olds. And so we feel very good about it.
Operator
Our next question will come from the line of Danielle Brill from Raymond James.
Danielle Brill
Allow me to extend my congrats as well for getting 9001 across the finish line. I just wanted to clarify what proportion of the population had mutations in exon 8 and 9.
Douglas Ingram
Yes. Thank you for that something I should comment on. So as you know, we had the commencement of study of EMBARK, what we've always called 301 before that. We had conservatively excluded patients. Any patient can have mutations in 1 through 17. We've done another updated study to narrow those mutations into where the issues that appear real risk. And that's -- as you know, that is contraindicated if they have any mutation that covers either 8 or 9 or 8 and 9 which is unfortunate that any patients get left behind, but that's probably 5% or so of patients at most. So it is a fairly, fairly small percentage of patients that are subject to that contraindication.
Operator
Our next question will come from the line of Gavin Clark Gartner from Evercore ISI.
Gavin Clark-Gartner
You got some of the approval. So for your approved PMO products, these have broad labels whereas many of the large payer policies today, they have restrictions based on age and ambulation in the clinical trials. So I was just hoping you could describe your historical ability to secure access to these products outside of the published prior authorization criteria.
Douglas Ingram
Yes. So let me divide this up into 2 answers because I want to be very clear. I don't want to be misread here. So there's one question about whether you -- the extent to which you have a narrower payer policy than the approved label -- and I'll answer that. That's I think the question you're asking, and I'll answer that question. There's another concept, which is the extent to which you can get patients treatment to patients that are outside of the label. Let me answer that second first. I don't think this is the question you're asked but I want to be very clear about it. We will not promote or market our therapy outside label nor do I think that that's going to be a significant issue. And any of that because I think payers are going to restrict themselves to the labeled indication itself. So one should ENVISION that, that -- the label we have is going to be the label that we're going to market and promote and serve, and that should be the -- your assumption should be that for the group.
Now let me answer a different question, which is to the extent that a payer had a restriction that was more restrictive than the label itself. What it has the success rate been of this team and working with those payers to get therapy to kids that are outside the -- that are within the label, but outside of the payer policy. And the answer is extraordinarily -- extraordinarily well. They've done very, very well. As an example, you'll recall when EXONDYS was approved back in late 2016, given what was -- it turns out with the benefit of hindsight, an enormously unnecessary amount of controversy with that approval. There were large payers, Anthem being one that had issued a policy that restricted the use of EXONDYS at all in their patients. And by the end of 2017, I think all of the patients that were amenable to that therapy were on therapy. And that was through working with anti notwithstanding their policy and then working in medical affairs group, the medical affairs group to show them the data and justify it.
So this team, I will say, is well prepared to work with payers to ensure that to the fullest extent permitted vital label and appropriate kids with Duchenne muscle dystrophy are going to have access to ELEVIDYS. And initially, that means kids in the 4- to 5-year-old range. And then as we expand the label, if we're successful in doing that, it will mean the broader patient population. So this team knows how to work with payers.
Operator
Last question will come from the line of [indiscernible] from Mizuho Group.
Unknown Analyst
Hi, everyone. Thanks for squeezing me in. And I'd like to add my congratulations. Could you elaborate on the time line for the nonambulatory potential approval? Or I guess if it gets approved, Doug mentioned that you're going to submit the data from the ENVISION with the SBLA along with the EMBARK beta, is that correct?
Douglas Ingram
Yes. Thank you for your question, and thank you for your congratulations. So the -- yes, so what we're going to do is we're going to look to a subset of the ENVISION patients for both safety and expression we'll add that to what we already have from patients that we've dosed in other studies that are older and nonambulatory and that would support from our perspective, the expansion of this label beyond the 4- to 5-year-olds to all patients without restriction on age and without restriction on ambulatory status. And that would all occur at the same time. So our goal is to Barkell readout, hopefully, shortly after the last case and last visit sometime in the -- towards the back half of the year, we'll submit a very early in 2024 and then hopefully very shortly thereafter, we would have a broad label that would be unrestricted both on ambulatory status and age and I will know. Once again that, that would be consistent with every other approval for Duchenne Musredustrophy. So we have a lot of conviction around that. Thank you for your question.
Operator
Thank you. Now I would now like to turn the conference back to Doug Ingram for any closing remarks.
Douglas Ingram
Well, thank you very much. Thank you all for your questions this evening and for spending time with us. And I just want to say, once again, thank you for the community for supporting us. Thank you for the broader team, both externally and internally at Sarepta that have been razor-focused on getting to this moment at this time. This has been an enormous amount of work, and we're -- I'm just enormously fortunate to have such an extraordinary ecosystem. And we're also extraordinarily fortunate that the science is broken the right way for what I believe to be an unbelievably important therapy for the Duchenne community ELEVIDYS. With that said, I do want to be very clear about something that I think we are going to celebrate this moment because this is an enormous milestone for Sarepta with the Duchenne community and for the patients that get access to this therapy now. We have a lot of work to do. We are not going to stand on our laurels. We are not going to slow down. We have a ton to do right now. We're going to make this launch a success. We're going to serve the patients that are in front of us today and bring them a better life. And we are going to work to get this label expanded with the success of EMBARK, with EMBARK having last patient last vision in September.
And we're going to expand this label as soon as we are able to and when the science supports that so that we can bring this therapy to patients first in the United States and then around the world who have Duchenne muscular dystrophy. So I look forward to updating you all across the course of this year as we continue to execute. We will, as I said at the beginning, I'll say at the end, we're going to fight for patients with the ferocity and the urgency that this fight requires. And so thank you all very much for all of your support.
Operator
And with that, this concludes today's conference call. Thank you for participating. You may now disconnect. Everyone, have a great day.
Access This Content Now
Sign Up Now!
