Good morning, ladies and gentlemen, and welcome to the Sarepta Therapeutics Limb Girdle Muscular Dystrophy Type 2E Functional Results Call. At this time, all participants' lines are in a listen only mode. After the speakers' presentation, there will be a question and answer As a reminder, today's program is being recorded. And now I'd like to introduce your host for today's program, Ian Estapan, Senior Vice President, Chief of Staff and Corporate Affairs. Please go ahead.
Thank you, Crystal. Thank you all for joining today's call. Joining me today are Doug Ingram, Bo Cumbo, Doctor. Luis Rodino Klapac. After our formal presentation, we'll open up the call for Q and A.
I'd like to note that during this call, we will be using a number of forward looking statements. Please take a moment to review our slide on the webcast, which contains our forward looking statements. These forward looking statements involve risks and uncertainties, which could materially differ from the objective results, results of operations, trading prices, Sarepta's common stock. For a detailed description of applicable risks and uncertainties, we encourage you to review the company's most recent quarterly report on Form 10 Q filed with the Securities and Exchange Commission as well as other company's other SEC filings. The company does not undertake any obligation to publicly update its forward looking statements.
With that, let me turn the call over to our CEO, Doug Seindrum, for opening remarks.
Thanks, Ian. Good morning, and thank you all for joining us. As you will recall, earlier this year, we reported expression, safety and other biomarker results from our first pre patient cohort for our gene therapy intended to treat Limb Girdle muscular dystrophy type 2E. Today, our Head of Gene Therapy, Doctor. Louise Rodino Klapac will provide an update with 9 month functional results for these 3 patients.
And with that, I will turn the call over to Doctor. Klapac.
Thank you, Doug. Good morning, everyone. For today's call, I will be giving you an overview of Limb girdle muscular dystrophy type 2E and I'll be reminding you of the expression data that we showed earlier this year. And then the new data that I'll be showing will be the updated functional data from 9 months for the FMD2E trial. To remind you, limb girdle muscular dystrophy, are devastating group of neuromuscular diseases.
They're monogenic and they're rare. There's over 34 types of limb girdle accounting for 100,000 of patients worldwide. There are dominant and recessive forms with the recessive forms being 90% of all cases. Slim girdles are progressive, debilitating muscle wasting diseases. They affect both males and females equally.
So this is different than Duchenne muscular dystrophy, it only affects boys. They affect skeletal muscle, cardiac muscle and have elevated creatine kinase levels. To remind you, creatine kinase is an enzyme that's leaked into the serum upon significant muscle damage. In LGMD2E as well as other limb girdles, we see significantly elevated levels of creatine kinase. Symptoms in LGMD2E often begin before the age of 10, often very early between the ages of 3 to 5, but definitely before the age of 10 with a loss of ambulation in teens.
This is a more severe form and it's Duchenne like in the fact in its severity of early onset as well as a significant proportion of patients having cardiomyopathy and respiratory complications. Deaths can often result before the age of 30. If we look across our limb girdle portfolio, we have 5 internal limb girdle programs, with 3 of them being the sarcoglycans. Beta sarcoglycans, which is the protein that is missing or non functional in LGMD2E is one of the sarcoglycan proteins. These are integral in the membrane.
They're forming a complex with the membrane that also interacts with dystrophin. And so this is an important link when beta sarcoglycan is absent, you see a reduction in the other sarcoglycan proteins as well as dystrophin. Correspondingly in dystrophinopathies, when you see absence of dystrophin, you see a lack or reduction in the sarcoglycan protein. So these forms all forms together to form the dystrophin associated protein complex. The other 2 little programs that we're working on are Dysferlin and Enoctamin-five, and these are important for failed regeneration or muscle membrane repair.
So we're focusing in today on beta sarcoglycan, which is important. It forms the core of the sarcoglycan complex and binds to beta dystroglycan, which is an important protein in the complex as well. To remind you of our preclinical data, we did studies to look at dosing levels to see what amount of beta sarcoglycan was important to improve function very early on. And using vascular delivery at a low dose of 5x1012 spectrogel per kilogram, we see about 20% of the fibers expressing beta sarcoglycan. And this led to significant improvement in function in preclinical models.
And this really determined the threshold for success in our first Phase 1 trial that we'll talk to you about today. Okay. So now I'll go and remind you of the results from that we previously showed you on expression levels in our 2E trial. To remind you, this is an open label trial designed for 6 subjects with LGMD2E between the ages of 4 to 15. Our first cohort was at low dose of 5x1013 bacteriograms per kilogram using systemic delivery.
So this is a single IV delivery. This is a single site with Doctor. Mundell, Nationwide Children's SDPI. The inclusion criteria were confirmed sarcoglycan mutations, beta sarcoglycan mutations in both alleles, patients had to be negative for antibodies to RA 74 and be greater than 40% of normal on the 100 meter walk test. There were muscle biopsies at baseline and at 60 days post gene therapy.
To remind you, limb girdle patients are not on steroids as standard of care. But in this case, to preclude any potential immune reaction, patients were put on prednisone at 1 milligram per kilogram one day prior to gene transfer were maintained for 30 days before being tapered. This was a Phase 1 trial, so the primary endpoint is safety, but we also had expression primary endpoint with a threshold for success being determined as greater or equal to 20% beta sarcoglycan expression. We had various secondary endpoints, which included a decreased increase in kinase and then functional endpoints, which includes the NorthStar assessment for limb girdle muscular dystrophy. This is a 54 point scale.
So it's different than the North Star assessment that we use for Duchenne and that there are additional measures that account for a 54 point scale in total. The 100 meter walk test, 10 meter walk test, 4 stairs and time to rise, and we'll be going through each of these in detail when we show you the results. All right. So if you look at our first three subjects, again, this cohort 1 of low dose, these are the subject demographics at baseline. We had a wide range in age that ranged from 4 to 13 years of age, and also a large white range from 17 to 55 kilograms.
So we've dosed larger patients in the trial. These are the largest patients that we've dosed throughout for gene therapy within our trials. These mutations were in exons 3 or 4. Beta sarcoglycan is a small gene and is only encoded by 6 exons total. Exons 3 through 6 encode the extracellular domain and mutations of these exons lead to a complete absence of severely reduced expression of beta sarcoglycan.
And that corresponds to a severe phenotype that includes cardiomyopathy. Now as I previously mentioned, increase in kinase levels are increased in LGMD2E. As you can see here, normal is about 150 units or less, whereas in these 3 LGMD2E patients, we see significant elevations between 10,012,000 and relatively consistent between the three patients. And next, this is the expression data that we saw in our 3 subjects. So we're showing at baseline at the top three images, you can see almost a complete absence of beta sarcoglycan, whereas post treatment in all three subjects we see robust widespread distribution of beta sarcoglycan that's correctly localized at the membrane.
We quantify expression by immunofluorescence in multiple ways. 1 is just counting the number of fibers, and when we did that, we saw a mean of 51% of fibers expressing beta sarcoglycan. We also looked at intensity. So this is the amount of beta sarcoglycan at the membrane. And when we compare that to normal, we see, as you would expect, 47% compared to normal.
In the next slide, I will show you the subject level data by both the percentage of beta sarcoglycan positive fibers and mean intensity. And what you can notice, by looking at all three subjects is we see relatively consistent levels between the 3 subjects ranging from 42% to 63% for beta sarcoglycan positive fibers and between 38% 57% in terms of intensity. We also looked at restoration of the beta sarcoglycan complex. As I previously mentioned, restoring beta sarcoglycan is important, but you also want to restore the entire dystrophin associated protein complex in order to infer function. And so what we've seen here, we're looking at alpha sarcoglycan expression, another component of the DAP C.
At the top, you can see again that there's almost a complete absence of alpha sarcoglycan, whereas post treatment, you see a significant upregulation of alpha sarcoglycan at all three patients following treatment. To take it a step further, we looked in more detail and stained the biopsies for both beta sarcoglycan and alpha sarcoglycan at the same time. And as you can see in the merged image, these proteins are localizing together at the muscle membrane, proving that this is indeed restoring the protein complex. We also quantified the amount of beta sarcoglycan by western blot analysis to look at the total amount of protein. We quantified this using a standard curve using a recombinant beta sarcoglycan protein and looked at biopsies both pre and post for all three patients.
As you can see, we saw high levels of expression. This is the full length protein. This is not a modified version in any way. So this is a full length beta picoglycan protein. We can see a mean of 36.1% compared to normal.
And again, when we look across all three subjects, you see a consistency between the patients in terms of the amount of expression that we see. So next, this is just summarizing the expression data that I showed you so far, but then also we looked at vector genome copy number and this is the amount of copies of the vector that are present in the muscle and this just infers and really answers the question, did it get there in the 1st place. What we see is 0.6 copies per nucleus, as a mean across our 3 patients. And what this really indicates that this copy number that we see robust expression and speaks to the power of the promoter and construct that we're using in terms of the corresponding expression of 51% of normal. So now I will start to show you the new data and this is the functional data from 9 months of the trial.
And this again is our 1st cohort at low dose of 3 patients. So first, I'd like to start out by talking about the natural history for LGMD2E. This is data that was shared with us by Linda Loews and Lindsay Alfano at Nationwide Children's Hospital showing the natural history for LGMD2E patients in the age range of our subjects in this current trial. This is the NorthStar ambulatory assessment for limb girdle muscular dystrophy. And remember, this is a 54 point scale.
And so what you notice here is that between the ages of 4 to 8, we see a relative consistency of our plateauing of function in these LGMD2AE patients. Whereas around the age of 10, we start to see a significant and dramatic decline in patients between the ages of 10 to 14 and the age range that we see in our trial. This is a small data set. We have to further confirm this with additional patients. But it's really set the stage for what we would expect in this LGMD2E population.
So first, we looked at creatine kinase levels across our patients. So what we're showing here is data from baseline all the way out to day 270. And what you can appreciate is that we see a significant and consistent decrease in CK over the course of these 9 months. At 9 months, we've seen 82% mean reduction increase in kinase. What you noticed is that we did in one case on subject 3 at day 180, we saw a peak of CK level that came back to baseline, but this was associated with activity.
And this is consistent with what we have seen in Duchenne as well that as patients feel better and they start to be more active, that you start to see transient spikes in CK. But what's important is that it comes right back down to baseline of the next time point with the resting CK. So overall, these data dramatic and consistent throughout the course of the study in every single patient. So next, this is a busy slide, but this is showing the summary of our clinical data at 9 months. The take home message that I'll show you throughout this slide is that at every single measure, for all three patients, we see significant improvement, in all of the functional tests that we conducted.
But we'll walk you through it. So first is the NorthStar ambulatory assessment. What you remember is that this is a 54 point scale and from the natural history, during the ages that we looked at, you would expect about a 6 to 8 point decline in the NSA B score. And what you'll see here to point out, is that we're seeing significant increases in the score. If we look at patient 2 in particular, we saw a 6 point gain in his NSA D score.
To remind you, this is the max score. So he's essentially reached the normal level reached normal for the North Star, so he cannot increase in any additional way. We also saw a 6 point gain in subject 3. When we look at all of the time measured functions, time to rise, 4 stairs, 100 meter, 10 meter, To remind you, you're looking for a decline in time in all of these functions. So again, here we're seeing dramatic decreases in the amount of time to conduct these activities.
If we focus on subject 1, for example, her 100 meter has improved by 6 seconds. This is a dramatic improvement in this 13 year old patient. And we'll show you a video that really exemplifies this dramatic change that we're seeing on the timescale. So to put this in further context, we're going to do some comparisons to natural history, but then also I think the video speaks a 1,000 words in terms of showing how these improvements in these measures translate into real life. So to look at the demographics of our age matched natural history group, they are between the ages of 4 to 15.
And generally, what you see in this population is that they're overall slightly younger than our treated patients and also milder as well. So what we're looking at in this slide is the age matched natural history cohort. This is taking the same patients that we showed you previously and looking at the mean reduction or mean change from baseline and then an NSAD score in subjects between the ages of 4 to 15. And what you can see is a average 6 point drop over the course of 6 months. Now if we overlay our pre treated patients on this, we see a significant increase in the ENXAAD score over the course of 9 months.
So dramatically different than what we would expect from the natural history controls that we have. So next, we'll show you the videos which really speak a 1,000 words. So we'll start out by showing you patient 1. And to remind you, this patient had a 6 point improvement on her 100 meters scale. So let's start with the 1st baseline video.
And what you can appreciate in this video, is the patient has a gait with difficulty with flexibility and limited hip extension and flexion, while she is running. Now if we turn to the next video at 9 months post gene therapy, what you notice is this dramatic difference in the quality of her movements and the speed as well. So we can see she's running much faster and she has very good hip extension and inflection, which is really leading to faster time. The dramatic improvement, again, this is a 6 second improvement on her 100 meter walk run test.
Now if
we go to our next patient, patient 2. What we try to do is select videos across all of these functional measures. So in particular this patient we're looking at 1 of the NorthStar ambulatory assessment measures which is getting up from the floor. Our patients who are youngest patients at baseline has significant difficulties getting up from the floor. Got a lot of instability in his trunk muscles and core trunk control and is unable to get up unassisted.
Now if we turn to the 9 months post gene therapy, I think you can appreciate the dramatic difference. He gets right off the floor and I wish you could see his face because he's got a very nice sense of satisfaction on his face and he's very happy with getting up consistently. And now for our 3rd patient. This is another component of the NorthStar ambulatory assessment where a patient is asked to get up from a seating position without using assistance of their hands. So this 3rd patient, if you look at baseline, has difficulty getting up and actually can't do the function, if you could see her face or she's saying that she's not performed the function.
Now 9 months later, as we look at the same patient, she can get write up without any assistance. So a very dramatic difference. And this is a good example of not being able to do a function to being able to do it without assistance. This would equate to a 2 point change on the Northstar ambulatory assessment. So taken together, what you can appreciate is that we're very encouraged by these early results from these first three patients that are low dose of 5x1013 vector genomes per kilogram.
If we look at our safety assessments, since our last update, we've not had any additional safety events since our last update at 90 days. To remind you, we did have 2 subjects that had elevated liver enzymes early on. One of these was designated as an SAE, as that subject had transient associated increase in bilirubin. Both of these events occurred when the subjects were tapered off of oral steroids. But as soon as oral steroids would readminister, the elevated liver enzymes returned to baseline and symptoms resolved within a few days.
And then all patients were subsequently tapered off steroids completely by 90 days. So the patients have all been off steroids for at least 6 months at this point. So the patients had transient mild nausea and this was generally within the 1st week when they just had steroids added. This did not correlate with liver enzyme elevations or other abnormalities. There were no other clinically significant laboratory findings, no decreases in platelets.
Just to summarize this data so far, the construct that we're using for LGMD has been optimized. And what you notice using our platform across approach, we see a lot of similarities between our microdystrophin program and this LGMD2E program. We're using rh74, which we found efficiently transduced all muscle types, which includes skeletal muscle, diaphragm, heart. We know that rh74 has low pre existing immunity across both the Duchenne and Limb girdle population. We specifically chosen this MHTK7 promoter.
This allows for high expression in the heart and skeletal muscle leading to these high levels that we've been demonstrating not only in this 2E trial, but also our micro dystrophin trial. These preliminary results are very encouraging, but across a systemic dose of 5x1013 secondtograms per kilogram, we're seeing expression levels that are reaching 51.51 percent of normal. And these expression levels are restoring the DAPC complex leading to a substantial reduction in CK, and this is leading to consistent improvement across all three patients in all functional measures. And the safety profile we've seen so far supports dose escalation. So what are our next steps for this program?
Next step is to conduct a fourfold increase to do our Cohort 2, which is at a dose of 4 times, which is equivalent to the dose that we're using in our micro dystrophin trial. From those two doses, we'll select the final dose for our registration trial. And coincidentally, we are also or in parallel, we're engaging with global regulatory agencies to discuss pivotal trial designs. LGMD2E is a rare population and we want to make sure that we're taking advice from the agencies on how best to design these trials in a smaller population. So finally, just to remind you of our pipeline, we have a robust pipeline in LGMD.
We have 5 internal programs and we're using a platform approach again where we're using the same rh74 vector, the MHTK7 promoter, in all but few cases, but using a muscle specific promoter and the others. And really what we can say is that this, 1st LGMD2E program is pioneering the way, for success with these other programs. And the learnings can subsequently be applied to accelerate the pathway for the rest of these programs. And with that, I will stop and we can take questions.
Thank you. And our first question comes from Salveen Richter from Goldman Sachs. Your line is open.
Good morning. Thanks for taking my question. So just in regard to the registrational pathway here and I recognize that you're in discussions with the FDA, but is there flexibility here that you could use various components or composites of the functional endpoints that you presented today? Maybe you
could just walk us through that and
I have a follow-up.
This is Doug. So real quickly, let me say that it is our intention to meet with the agency in the near future and to have a discussion about the development pathway first, of course, for our 2E program and then beyond that to the rest of our limb girdle program. We have views about ways in which one might be able to accelerate the development of these programs, given the fact that we are dealing with a serious monogenic disease and the gene therapy it issues replaces the actual native protein. But until we have those discussions, I think it will be premature to speculate on the exact development pathway. We certainly think there's opportunities to shorten development or to accelerate development, but that's going to require some discussions with the agency before we can discuss that with a sense of confidence.
Thanks. And then with regard to the other Limb girdle muscular dystrophy programs, could you just give us a sense of when you might start those, and take them into the clinic? And how you might design those trials given the read through here?
So we are there is a lot of read through between the programs. 5 of the 6 limb girdle programs, as Doctor. Luis Rodino Klapac noted, use the same vector and many of them use the same promoter. And all of them express the native protein. We will come back early next year and discuss the development pathway for not only this GUE program, but for the rest of our limb girdle programs, we have a lot of work to do in that regard.
And we obviously want to work with a sense of urgency that matches the urgency that these families with these various limb girdles feel. But we need to think about a few things. As always the case with gene therapy, we need to work on manufacturing. We are doing work right now. And I would say we're making very good progress on manufacturing process for the limb girdle programs with our partner Paragon and with our own internal expertise, both in process development and analytical development as well.
And then of course, we also need to come to some views on the development regulatory pathway and that is going to require an informed discussion with the agency to take their input and guidance. And then we'll get that all together and we will come back and provide additional guidance on the pathway forward and the timelines in 2020.
Great. Thank you.
Thank you. Our next question comes from Martin Auster from Credit Suisse. Your line is open.
Hi, this is Mark on for Marty. Congrats on the encouraging data. I guess two questions from me. First, would you be able to disclose how many patients you've dosed at the high dose at this time? And then in terms of the decision on which dose to use in the pivotal study, will it be based on the biopsy data and safety data?
Or are you also planning to wait for some functional data from those high dose patients? Thank you.
So, Theresa, answer the second question.
Yes. So the dose will be selected. What we want to see is the maximum tolerated dose. We're very happy and encouraged with what we're seeing at the low dose so far. We'll explore the higher dose.
We'll look and evaluate both safety and function. And that's how we'll base our selection for the pivotal trial.
And then on the dosing, remember we're going to do one additional 3 patient cohort as Doctor. Rodino Klavec noted, it will be at one additional higher dose, actually 4 times higher at 2 times E to the 14. And then on that basis, as Luis just said, we'll make the decision on which of the 2 doses has the right combination of tolerability and expression efficacy. And we'll dose those patients. We intend to dose those patients as soon as possible.
We're actually screening patients even as we speak. So that should all occur fairly rapidly.
Thank you. Our next question comes from Alethia Young from Cantor Fitzgerald. Your line is open.
Hi. This is Eileen on for Alethia. Thanks so much for taking the question and congrats on the data. Just one, if you could comment on how the data impacts your view on the use of gene therapy in DMD, particularly as we think about older patients with the 2 13 year olds in the study?
In a lot of ways, it encourages us and makes more powerful to look at both older patients, larger patients. Just looking at what we'd expect from these 2 13 year olds, we really would expect a decline during this time frame. And what we're seeing is a reversal. We're seeing an improvement. We're not seeing just the stabilization of baseline.
We actually saw improvement. So I think this, although we can't directly I think, gives I think gives us a lot of confidence leading into that, that we're going to see in terms of the results, positive results and then also as far as safety.
And then we also get remember, there is a lot of similarities between these various constructs both the cast and rh74 as well as the promoter, MHCK7 is heavy chain promoter that Luis and Doctor. Jerry Mendel chose to use with these constructs. So this is additional evidence that suggests again that it appears that we can dose at high levels even in larger children safely and that we get very good expression. I will remind you that the dose here was one quarter of the dose that we used with Duchenne muscular dystrophy, notwithstanding that we got very robust expression, 51% on protein based fibers and 36.5% on Western blot. So I think there is we can't take it too far, but there is a significant amount of potential read through to the micro dystrophin program, giving us additional confidence there.
And there's a lot of read forward to the other limb girdle programs, which 5 or 6 of which share the same capsid, at least 2 of the other ones share the same promoter, and all of them share the same designers.
Thank you. Our next question comes from Brian Abrahams from RBC Capital Markets. Your line is open.
Hi there. Thanks for taking my questions and congratulations on the data. Two quick ones for me. Any more specifics you can give us on where you stand with respect to commercial scale up and timetable for supplying the market in limb girdle? And then I'm sort of curious how your ongoing experience with Golodirsen has influenced your thoughts on the potential for an accelerated path in limb girdle?
Thanks.
So on the first one, we are making good work on process development and analytical development on the limb girdle programs generally. I'll have additional updates on that in 2020, early in 2020 hopefully. And remember, because the processes are merely identical between these programs, both the micro dystrophin program and the limb girdle programs, as we're doing the same thing in all the programs. We're evolving from hyper stacks over to Icellus units, both the Peragon and Brammer. The learning that we get from micro dystrophin will significantly read through the limb girdle process development as well.
So the short answer is, I'll come back and provide additional updates early next year, but we're making very good progress across all of these programs, in the most advanced of which from a manufacturing perspective is, of course, our micro dystrophin program. We're making good headway there and I'll come back with updates next year. There is no read through from the in what my view, there's no read through from the Gullitterson CRL to the views on any of these issues here. This is an entirely different part of the agency and an entirely different issues that issue really was unique to Golodirsen with some read through to casimersen as well, but it doesn't really read through in any way to this. Now again, I don't want to get out ahead of our skis and start suggesting that we have the answer and the exact pathway for these limb girdle programs.
We do need to have discussions with the agency, and they need to be evidence based discussions and we'll come back and talk to the community once we have those. But I will note a couple of things. Note first that this is a as is the case with Duchenne muscular dystrophy, a serious monogenic disease that results from a single missing protein that is extremely serious, life limiting and very, very often life ending. And that the gene therapy here is replacing the actual native protein, the absence of which is causing the death of these children in this extremely rare disease. With that said, I think there will be the opportunity to have discussions with the agency about the pathway forward and how one can be thoughtful about accelerating the pathway forward if we have robust expression and good correlates between that native protein and the restoration of function and benefit.
But we'll come back and have full discussion about that next year.
Thanks, Doug, and congrats again.
Thank you so much.
Thank you. Our next question comes from Debjit Chattopay from H. C. Wainwright. Your line is open.
Hi, thanks for taking my call. This is Aaron on for Debjit. So I just have a couple of questions. So I'm sure you guys saw there was a recent study of 395 QK based CMD patients and they were able to classify patients into different progression trajectories based on their baseline NSAA scores, rise from floor and 10 meter walk run. So do you think there could be a similar story with LGMD?
And do you think you might incorporate some of these findings into clinical trial designs?
Limb girdle is a there's certainly differences in finding. So as the North Star assessment was adapted for this population, additional measures were added. Certainly, one of the things that we're considering is looking at trajectories in patient given the population and something that we'll continue to take guidance on. But we're looking at all of that in our as we assess our clinical development plan and certainly looking at the Duchenne data that's relevant, but also within a mind's eye that there are important differences in limb girdle.
Okay. Thanks. And just real quick, do you have could you tell us anything about the commercial supply study for micro dystrophin? Like you're still planning on having the initiating the study prior to unveiling the data for the ongoing clinical supply study in first half twenty twenty?
Yes. Our plans remain exactly as they were last time we talked and we've made additional progress in that direction. As one might recall, at our last earnings call, if I'm not mistaken, we increased the end on what we call Study 2 to 40 patients, increasing the powering of that to nearly 95%. We're working on that this year. And then our goal, since we have additional time, our goal was to commence Study 3 in the first half of twenty twenty and all of that remains on track.
Thank you. Our next question comes from Matthew Harrison from Morgan Stanley. Your line is open.
Hey, good morning. Thanks for taking the questions. 2 for me. 1, can you just talk about what the plan is to demonstrate an impact in cardiac tissue in these patients and how important you think that is, especially for some of the older patients who might already be declining? And then second question is just around natural history data.
I mean, you pointed out that the natural history data is maybe not as robust here as DMD. Just maybe remind us of the plan here and how important that is in terms of regulatory discussions? Thanks.
Yes. So in terms of the cardiac delivery and expression, we're obviously monitoring cardiac activity. As I said, we're doing cardiac MRIs at baseline and 1 year post. And really the impact of the cardiac success will be shown over the years as we start to look at these patients in more detail and realize that they're not succumbing or having the cardiac defects that we see in similar patients. So we're definitely monitoring that.
We can't do cardiac biopsies, but we're certainly monitoring cardiac activity through MRI. And we expect to see a significant improvement or absence of any cardiac defects in these patients. So it's a to your point in older patients, this is a really significant part of the disease. So really in a sense, not only are we doing a gene therapy trial for muscular dystrophy, but we're doing a cardiac, a cardiomyopathy trial in a sense as well. The second question was about the natural history data.
Yes, to your point that we don't have the robust in terms of numbers, amount of natural history with limb girdle in general and especially 2E. So this is something that we are certainly working with Nationwide Children's on collecting additional data, but then also in a broader sense, we'll be doing a larger natural history study, in not only LGMD2E, but then also multiple limb girdle subtypes, especially the ones that we're working on to really gather additional data to inform both our trial design and ways to limit the amount of patients that would have to be included to see significant effects.
The one thing I apologize if Doctor. Rodino Klapac has already said that, but I would just remind you and I think most people already know, which is while we can't take biopsies of the heart, it wouldn't be obviously ethical. There is a unique promoter being used here that was chosen specifically because of its preferential expression in the heart. As you may recall, in animal studies, we're seeing about 120% in the heart of whatever we see in the cardiac muscles. So it gives us a lot of confidence that even before we begin to see manifestations of the benefit in the cardiac muscle, can have very robust expression and very durable expression in the heart given what we're seeing in the skeletal muscle.
Thank you. Our next question comes from Tazeen Ahmad from Bank of America. Your line is open.
Hi, thanks for taking my questions. Maybe one about to the extent that you can comment, do you have a bit more color on how older patients in the study performed, let's say, before they started on gene therapy? Were they already showing signs of decline? And then maybe as a follow-up as well in relation to natural history, are there specific differences between exon 3 and exon 4 in how that impacts how the disease progresses? Thanks.
I'll answer the second question first. In terms of the exons 34, in the data sets that we have, we know in generally between exons 3 through 6 that we see a significant proportion of disease that is more severe than the others. So we don't have the specificity to look at 3 versus 4, but we know that we see almost a complete absence of expression and this corresponds to a more severe disease. So in terms of the patients that we look at, we don't have a long trajectory on all the patients that were enrolled in the trial. But what was clearly evident from the videos that we showed in their baseline scores is that these patients were significantly affected at baseline.
So these were not what you would expect, certainly divergent from what you would expect for their age. And when we look at the natural history, in line with what we expect actually more severe than natural history in terms of their baseline and the scores and their baseline function. I think you can just even appreciate from the videos these patients were definitely affected.
And you can see it objectively. If you go to the slide deck, you'll see the baseline, immunohistochemistry images for all 3 of these children. And as you'll see, they are basically entirely bereft of the protein of interest, which would certainly suggest that they're extremely severe versions of LINGR-two.
And so Doug, would you think that in your ADVANCE study you would want to have more of the severe patients enrolled? Or are you going to try to do it evenly across age?
We're not at a place where we've kind of made those decisions right now. We really need to sit with the agency. One of the dangers of choosing particular subsets, first of all, this is an extremely rare disease. So that would by itself assume that we would even have the luxury of choosing particular subsets of the TRDLE-two eighty. And then beyond that, of course, we've got to be careful not to choose subsets that end up creating issues for us from an access perspective.
And our goal here is obviously, if this therapy works, bring it to children around the world, children and adults around the world that have 2E and then the others and hurdles. And so we've got to sit with the agency and talk to the agency about the development pathway. But we will do that and we will come back next year and provide updates.
Thank you. Our next question comes from Ritu Baral from Cowen. Your line is open.
Hey guys, thanks for taking the question. Question on the next dosing cohort. Doug, can you confirm that you have the clinical supply for that dose manufactured? Or is that step for starting that higher dose cohort?
Yes, we haven't. So we have the supply. We're screening the children, so it should happen expeditiously. So we have no supply.
Okay. And then what is the steroid dosing plan for these patients? Are you going to keep the extended steroid plan? Are you going to up the dosing? Can you talk about that?
Sure. We're going to keep the same steroid dosing plan, 1 milligram per kilogram per day, and that we'll be closely monitoring it, extended as needed, as we did in the 1st cohort corresponding to any liver enzyme elevation. So we closely monitor and adjust as needed.
Is there any stopping criteria for liver enzyme changes?
No, there's no stopping criteria. Got it. And then as I
look at the data detail of the functional data, is there anything that
is there I guess is there
any pattern that stands out with the younger patient? I believe that was the 4 year old patient too. That patient had, I think, the most remarkable 100 meter run time improvement. How much could we think about that just being a 4 year old growing versus potential improvement in younger patients?
Yes. So I guess we can answer that in 2 ways. If you look at the natural history in the data set that we have, we would not expect improvements in this age group. And to your great point, I mean, this 4 year old did improve dramatically in his running times and also his NorthStar ambulatory assessment basically maxed out, so we cannot see any further improvements. So based on the natural history, we definitely would not expect these changes at this time point.
So and just thinking back to the video at baseline, you can see that definitely was dramatically affected, had very significant instability in his trunk, not able to get off the floor. So this certainly wasn't just a learning to test. This was a true improvement in strength that was able to make him get off from the floor without assistance.
Does this suggest to you that you may want to enroll younger patients in the next cohort or going forward?
I think overall looking at this cohort 4 to 13, we're very encouraged by the findings that we see in not only the young patients, but the older patients as well. And I think these are questions that we're begging to be answered. And I think that we're now starting to get the answers as these older patients can not only just stabilize but also improve. So I don't think that just enrolling younger patients will be the answer. I think we can have significant benefit for all patients.
No, one thing I wouldn't know, this is an early look, this is 3 patients. We need to be careful to not over interpret, but wouldn't know that every single patient, every single functional endpoint improved. And so frankly, these girls, these older patients should be in decline right now. So it would have been extraordinary if one could have arrested that decline. The fact that we're seeing functional improvements there is really exciting as well.
Great. Thanks for taking all the questions.
Thank you. Our next question comes from Christopher Marat from Nomura Instinet. Your line is open.
Good afternoon. Thanks for taking the question. Thinking about dosing the patients on the high dose arm and their screening, are you looking at wide age range of patients there? Are you still going to dose sort of the 13 year olds and beyond? And then just with respect to the preclinical data and dose response, just remind me if you saw a dose response, in same metrics like vector copy number in animal models?
And I have a follow-up. Thank you.
Got to take the second question. The second question was, are we seeing a direct to this response
in animals? Yes.
In our animal models, we definitely do see a dose response in terms of dosing and corresponding function. But importantly, why we chose our threshold of 20% is that we saw significant improvement at that dosing level. And then I'll start with the first question. We are enrolling the same between ages of 4 to 15 for the 2nd cohort. So we're not changing the age of enrollment at all.
Okay. And then just thinking about the functional endpoints, what sort of the clinically minimal clinically meaningful improvement on the North Star or other functional endpoints that you measured? And then does that change across age groups? And then maybe finally, just thinking about the 3 sarcoglycanopathies you're going after with your gene therapies here, I guess, 9,004, 9,005, would you consider a trial incorporating kind of all three, so 9,003, 9,004, 9,005, given the rarity of the disease and the fact that you're expressing the native protein and while phenotype probably looks pretty similar across the patients? Thank you.
I'll touch on the second one first to steadily say that is certainly one of the many things that we've pondered, and one of the things about developing rapidly these programs, but it will require us to have discussions with the agency before we have any confidence on that. And then I would say just touching briefly and then of course Doctor. Lucerne McClaybuck really unanswered the first question. But to the question, what level of improvement would be meaningful, I would at least argue that that might actually be a false statement because frankly in these older patients, they're supposed to be declining. Had we arrested decline or significantly slowed decline, one could have assumed that that would be very meaningful.
I can only imagine how much of a family want to get a child into a therapy that could stop the decline of this ferocious disease, but we're not seeing that. We're actually seeing improvement. So but with that said, at least do.
Yes. And I agree with Doug, and I just would add that in this early stage, we're still evaluating all that once we gather more natural history about a few more predictions, but just thinking about it from a practical level, 2 point change on Northstar is going from not being able to do one function to being able to do it and that in and of itself is significant. Being able to get off the floor without assistance, that's significant. So I think when you think about it and then we're returning towards evidence of these clinical trials, it's more real world that accounts to improvements in their daily living. So that from that perspective, those changes of just 2 points and above are significant in and of themselves.
Thank you. Our next question comes from Gena Wang from Barclays. Your line is open.
Hi. Thanks for taking our question. This is Peter for Gena. Just two quick questions from us. Understanding so first, understanding that natural history is pretty variable and you have limited data set.
For Slide 20, could you give a sense of how comparable these are in terms of the patients that were being treated versus these natural history? Do they like how do you have the confidence that these are representative countersets?
I think your question is that comparability of the natural history cohort and their severity versus the severity of the children in our study, I suspect. Sure.
Yes, I think as I mentioned that these patients, if you look at the overall mean of their age, they're slightly younger. And if we look at their NorthStar slightly milder in terms of their baseline characteristics.
I mean, do they have same sort of molecular characteristics?
They're missing the same protein. I think you're asking if they we know
No, same nicotinotype.
Yes, we don't have that information.
But we're not aware that there's a more severe phenotype than mutations on exons 3 through 6, right?
Right.
Thank you. And our next question comes from Vincent Chen from Bernstein. Your line is open.
Congrats on the data and thanks for taking the questions. A couple of them for me. The first is recognizing the natural history data is limited, what's your current sense for a range of variability in patients with LGMD2E and looking toward a pivotal trial, recognizes a range of potential path to approval. If you did have to power a trial for function, what would that imply for a number of patients needed to sufficiently power a LGMD2E pivotal trial as compared to a DMD trial? And the second is, thinking about the endpoints, just help us understand how does the NSAID and LGMD differ from the NSAID scale for DMD?
And in your discussions with KOLs, what's their sense for the potential degree of placebo effect in the 2 scales?
On the first one, let me say, again, I to be a broken record on this. We've really got to sit down with the agency and talk about the development pathway for 2e. There is certainly variability for this disease. And on top of that, this is a very, very rare disease. So the very fact that sort of pondering how it went by power, for instance, the placebo trial for 2E, it raises the very point that we've got to find a better, more thoughtful, more expeditious pathway for these patients.
And we will have discussions with the agency comp with views on that and come back to the community with the views. And then on the second to shoot.
Yes. Just in comparison of the traditional NSA that we use at DMD versus NSA D for limb girdle. The NSA D just includes additional measures. For example, some of those are getting up from a squatting position. Some of these are looking at left versus right.
So just additional measures in addition to the normal 34 point scale that we see in terms of this scale has been used similar scale in a significant cohort of discretolopathy patients, for example, and now it's being incorporated to many limb girdle history, natural history studies across the board. So it's definitely been endorsed by the larger community as appropriate for this limb girdle community.
And our next question comes from Joel Beatty from Citi. Your line is open.
Hi, thanks for the question. Could you discuss where the liver enzyme elevations in the 2 older heavier patients? And if so, what are the implications of that for the higher dose cohort?
Yes. The 2 liver enzyme elevation were in the larger patients. And as we said before, we'll just continue to monitor patients very closely and as soon as we see any elevations in the liver enzymes, we'll either increase steroids or if it's happening during potential taper period, we'll reintroduce steroids. But we're definitely monitoring and tapering over a longer period of time compared to the 1st quarter to make sure that we don't see that these increases in liver enzymes.
I will note again, I think everyone knows this, but this is this seems to be something that will occur at times with full body infusions. We've seen it in the micro dystrophin study and we've seen it here. But they all have responded to steroids, increases in steroids and would factor baseline. So while it's certainly something we have to take very seriously and monitor closely, it does appear to be a manageable aspect of these gene therapy trials.
Thank you. Our next question comes from Joseph Schwartz from SVB Leerink. Your line is open.
Great. Thanks very much. In which types of patients or in which ways do you think that a higher dose can offer a greater improvement above and beyond the benefits that you've seen now at the low dose? Are there certain functional areas or types of patients that you think have a particularly good opportunity to benefit more than others? Or is the goal of a higher dose more about providing longer lasting effects?
It's I'll broadly answer that. We would like to before we lock down the dose and proceed and get informed not only about 2E, but about some of the other limb girdle programs as well, because I believe this dose selection is going to have read through. We want to make sure that we have the most robust expression possible. We have the opportunity to do that with a higher dose, and so we're going to take that opportunity. I think, generally speaking, the answer on expression is more is always better, certainly.
And so before we lock that down, we want to have the most robust potential expression. We are frankly very excited about the fact that we certainly were early this year that even at what we thought was the lower dose, we got results that were multiples better than what we had predefined as success in the trial. But we don't want to just declare victory yet. Let's do one higher dose, compare expression and tolerability and safety and then make that dose selection between the 2. And it is interesting to know, why do we keep focusing on expression.
Conventional wisdom says focus on function, but I would remind you that this is a monogenic disease that results in the lack of protein and it is the only reason that these children are degenerating a diet. And so when we get if we can restore the actual native protein, then it is exceedingly logical that the functional benefits are going to flow because we've restored the very issue that exists. So getting the highest expressions that are reasonably possible with a good safety margin has to be our ultimate goal and that's the way we're going to look at these 2
tests.
Thank you. Our next question comes from Danielle Brill from Piper Jaffray. Your line is open.
Thanks guys. Congrats on the data. I'm curious what the ages of initial on set of symptoms were across the patients and also how variable were baseline symptoms like presence of muscle pain and macroglossia?
Did you have that answer?
We don't have that information as far as the age of onset in these patients. Certainly, our 4 year old, we know that the age of onset was significantly early, but we don't have that information for the 2 older patients.
Thank you. Our next question comes from Anupam Rama from JPMorgan. Your line is open.
Hi, all. This is Tessa filling in for Anupam this morning. Congratulations on the updates here from us. At the lower dose with data today, anything in terms of improvement you are seeing in patients that you don't think are captured by the scale you've used? And then just one question on the high dose cohort.
You are in the screening phase now. Will you aim to have these patients age matched to cohort 1? So 2 older patients, 1 younger patient and similar baseline for the comparison given variability in the population that has been previously noted? Thanks so much, guys.
Yes. So to answer the question, one is that we'll be doing again between ages of 4 to 15. So we don't have an age match exactly to our 1st cohort. I think to your other question, as far as beyond what we've seen with the functional scales, we have a lot of anecdotal data from the patients in ENDURANCE, I would say, it's something that definitely stands out for these patients from the families is that they're able to do activities for a much longer period of time and they certainly see differences at school. I think I remember hearing from Doctor.
Mendell that one patient in particular was able to carry her backpack for the first time and that sounds like something that maybe not meaningful, but being able to pick up your own backpack and carry it to school was significant for this family. So certainly, we definitely hear these stories about Endurance and being able to do activities they couldn't before.
And one of the values of these videos, arguably anecdotal that they are, is that one sees qualitative issues in the video that don't get captured by the necessary, stilted approach to taking, for instance, time tests and the like. You may recall with our Duchenne program of microdystrophin, when Doctor. Jerry Mendell spoke last year about those videos, he was able to comment, for instance, on the reciprocal climbing that the children could do that they could previously do or they exactly didn't use the rail, none of which is captured or even the way the quality of the way they run isn't captured. We're actually reflecting on some of these issues. And in addition to simply using videos and the like, we're actually pondering if there are ways it either an experimental measure or a secondary measure in the next trials that we do, if there's ways to capture that.
There are ideas out there, wearables and the like that we're going to think about, because I think that the by necessities, functional endpoints boil things down, for instance, to time test and the likes and sometimes miss some of the obvious qualitative issues. It's one thing to hear about NSAID, for instance. It's quite another to see the video of that boy who already at 4 years old cannot get up and then pops up with a massive smile on his face or that 13 year old woman could not stand up in a chair and if you had seen her face, you would see was embarrassed about the fact that she couldn't possibly do it and I had to tell them that she wasn't able to do it and then to see her actually being able to do it. We're going to try to find some objective way to capture what currently would be qualitative issues as we think about not only these limb girdles, but of course, our microdystrophin program.
And just to add, Doug has commented on videos 23, but if you think back to video 1 where the 13 year girl was running, but the quality of her movement was significantly improved as she has much more flexibility in her hips. And I think these are the types of things that aren't captured necessarily just on time scale of the quality of movement. So to Doug's good point, we're going to certainly evaluate ways that we could look at this and capture these measures as well.
Thank you. Our next question comes from Liisa Bayko from JMP Securities. Your line is open.
Hi, this is John on for Lisa. Thanks for taking the questions. Just one for me. I'm wondering, what do you hear from patients as far as what they care about as far as functional improvements and what could be measured in the study? I remember from the recent national conference that patients would say things like, I can walk just fine once I get going, but getting up is the real Yes.
I think you really you sort of hit the nail on the head and, Yes.
I think you really you sort of hit the nail on the head and things that we hear is getting up from a chair. To your good point, I hear that all the time from limb girdle patients and often they'll continue to stand because they don't want to sit down because they don't want to get back up again. So that's a really critical critically meaningful point to them. So our patient 3 that was able to get up from the chair, that is significant. And the other story that I told about picking up a backpack and taking that to school, that was important.
So those are the types of things that definitely matter to patient. That's what we've heard anecdotally.
I will say one thing. I just would remind us that the goal of this anyways is to replace the very protein in the absence of which is killing these children. So this is not a palliative therapy. And obviously, the palliative therapies, that's a really important thing to think about or asymptomatic therapy, that's an important thing to think about is this particular restoration of addressing of this particular symptom an important one. Here the goal is frankly much more ambitious.
The goal is to do full body infusions on children who have mutation on the gene that codes for beta sarcoglycan, the absence of which is going to cause them to degenerate they're already degenerating and then very likely to take their life. And our goal is to restore that in such abundance that we can arrest decline and at least in these early cohorts perhaps provide function that has even been lost already.
Thank you. Our next question comes from Tim Chiang from BTIG. Your line is open.
Hi, thanks. Louise, Doug, I was just looking at the clinical trial protocol for this study. I guess the upper limit for age is about what 15 years. Are there any non ambulatory patients
at that age with 2E?
I was just sort of wondering.
Yes. There are patients that are non ambulatory in that age group and so are the inclusion criteria of being able to walk greater than 40 percent on the 100 meter time test, excludes those patients that are non ambulatory unfortunately in this age cohort.
Just in some of the other limb girdles, would you consider enrolling non ambulatory patients?
The answer is yes to that. And let's be clear, we are talking only about dose selection for the next cohort. We don't intend to leave behind non ambulatory limb girdle to e patients either. So we have a criteria for the next cohort that does require ambulation. We will find an approach to our development path and come back and talk to you about it.
That will include non ambulatory patients, first with 2E and then with the rest of limb girdles. And as and I know you guys know this, but so we're clear and for micro dystrophin and Duchenne muscular dystrophy as well. The next trial that we do, what we call trial 3, will include non ambulatory patients. We're not going to leave them behind.
Thank you. Our next question comes from Hartaj Singh from Oppenheimer and Co. Your line is open.
Great. Thank you for the question. I just had a quick question. Maybe here I'm just confused and I apologize for that if I am because I think your protocol originally had 6 patients in this next cohort, right? 3 at the higher dose potentially, 3 placebo, and you were going to report that 9 patients in total.
Did that change? Are you just going to the high dose cohort or are you still planning on including the 3 placebo patients? And then how will that help you sort of, with your discussions with the FDA once all the 9 patients have read out? Thank you.
Yes. Originally, the protocol did anticipate a placebo patient in the 2nd cohort, but we've modified the protocol and we're just doing 3 patients at high dose, well, a total of 6 patients in this trial, 3 at the low dose, which we've already done and 3 additional at the high dose.
Thank you. Our next question comes from Tim Lugo from William Blair. Your line is open.
Hey, this is Lachlan on for Tim. Thanks for taking the questions. I was just wondering given the variability in CK, if you have any plans to look at other biomarkers to assess durability and obviously there are limitations as to how frequently you can conduct a biopsy, but do you have plans to rebiopsy at some point to look at the durability of expression?
We are not looking at doing another biopsy in the near term for the simple reason that borders on challenging from an ethical perspective to put these kids through another biopsy, simply because there is no evidence from any of the preclinical models that would suggest in any way that you would have any diminution in durability over any of these reasonable period of times. If you look at animal models, in the mouse model, we would see durability for the entire life of the normal life of a mouse. In the Golden Retriever models, we've been able to see full durability for as long as we've been able to look, which is 8 years. This is obviously I'm being a little bit agnostic. It's not Lynn Curdle 2E, but it's the neuromuscular generally.
In the non human primate, it's gone out much longer even still. So the issue is simply that this is not where we would the timeframes we're talking about are not timeframes where we would rationally even worry about durability. So rebiopsy in these kids would be a burden that would be unjustified.
And just to add to that, you mentioned particularly CK and CK is variable, but if you look at the data that we presented, we actually see consistent drop in CK over the course of the study in all three patients and remembering that these patients are off steroids, there's no confounding factor at all. So we did see very consistent results using CK as a biomarker in this study.
Thank you. And I am showing no further questions from our phone lines. And I'd like to turn the conference back over to Doug Ingram for any closing remarks.
Well, thank you all for joining us today. I want to thank, obviously, Doctor. Luis Rodino Klapac. But I would also be remiss if I did not take a moment to thank Doctor. Jerry Mendell at Nationwide Children's Hospital.
He is the principal investigator for the Slim Girdle trial. He is the principal investigator for our current microdystrophin Duchenne trial. He was the investigator for the SMA program at AveXis. And I think I don't think I'm going to be hyperbolic when I say that because of Doctor. Mendel's dedication and unbelievably hard work, Families of rare neuromuscular disease have real evidence based reason for hope.
And if successful, many lives will be saved. So I really want to make sure that we linger and thank Doctor. Jerry Mendell today as well as Luis. So with that said, we're very pleased to see the consistent functional improvements across all these patients correlated as they are with robust restoration of missing full length protein in this monogenic and life limiting and often life ending disease. As Doctor.
Rodino Klapac noted previously, we do believe it has the potential read through to the rest of our limb girdle portfolio. It's further confirmation of our DMD microdystrophin approach, and it is another important step in our strategy to build an enduring gene therapy engine that can expeditiously develop therapies to treat serious rare diseases including these neuromuscular diseases. As I've said during the call and answer the questions, we will provide a further update next year on our development plans across our entire Limb girdle pipeline and portfolio. With that, have a good day everyone.
Ladies and gentlemen, thank you for participating in today's conference. This does conclude the program. You may all disconnect. Everyone, have a wonderful day.