Morning, everyone. Lovely to see you all here. My name is Joanne Donovan. I'm Chief Medical Officer at Edgewise Therapeutics. I'd like to very much welcome everyone here in Halifax, both here in the room and possibly in other rooms, other places watching, and our virtual crowd online as well. But this has been a terrific meeting. It's wonderful to see everybody in person. And this morning, we are delighted at Edgewise to share with you information about targeting fast muscle myosin, which we believe is a novel approach to protecting muscle in the dystrophinopathies. First, I would show you a disclosure slide that has, I realize, quite fine print, that Alan and I are employees of Edgewise, and EDG-5506 is an investigational agent and not available in any territory at this point.
The agenda: Alan Russell is going to speak on preferential fast fiber injury and dystrophinopathies and targeting that to decouple injury from muscle contraction, both in Duchenne and Becker muscular dystrophy. Then Professor John Vissing is going to speak on mechanical stress-induced injuries and how we can look at biomarkers of dystrophic muscle during exercise in Limb-Girdle Muscular Dystrophy and Becker muscular dystrophy. Professor Craig McDonald is going to speak on clinical course of dystrophinopathies, focusing on Becker. And lastly, I'm going to give you an overview of clinical development of EDG-5506 in Becker and Duchenne muscular dystrophy and share some new data with you. So with that, I'll turn it over to Alan.
Thanks very much, Joanne. And imagine, if you can, that I am Lee Sweeney, because I should be Lee Sweeney, except for poor Lee had a nasty traffic accident a few weeks ago, and he's recovering right now. So I am Lee for the day. And I'll start with some general physiology, which is kind of something a bit different for you guys, just to kind of place dystrophin in the muscle and give you a bit more functional view of what it does before we talk about the mechanism of the compound. So in this review, I'll just give you an overview on how muscle force is controlled. This is kind of basic stuff, but I think I'll hopefully add a little color to it just so you can understand how complicated the whole thing is.
Some insights into why human anatomy is kind of bad news when you've got muscular dystrophy, and an overview of why we're interested in fast fibers and targeting those for muscular dystrophy. So here's your physiology 101. I'm going to start with motor units, which is kind of a weird place to start if you're thinking about dystrophin and dystrophinopathies. But it's really just to highlight that individual fibers receive individual neural signals. The motor unit is essentially a neural unit of 10-1,000 fibers. And I put an example there, the muscles in the hand and arm are approximately 113 motor units. And each motor unit essentially controls a like-minded population of fibers. And by that, I mean fast and slow. So we're a mix of fast and slow fibers.
Unlike things like mice and rats, our fibers are a mosaic, so they're not blocks of fast and slow fibers. Each one of those receives that separate innervation to control motion. And of course, slow fibers have the slower contraction kinetics. They tend to rely on oxidative metabolism, and they're slow fatiguing compared to the fast fibers that tend to use glycolysis for metabolism and have that fast fatiguing, fast contracting type of property. So if you're controlling force in an integrative way, you've got two ways of doing that. So in the first context, you've got the force-frequency relationship. It seems like an oversimplification, but this is what people tend to think of when they look at muscle force control. So as you stimulate the muscle with greater frequency, so force goes up to a tetanus from a twitch.
Of course, the muscle has other strategies, particularly large muscle units, and they use recruitment, so as force development is increased, what happens is different motor units have different thresholds for recruitment, and then they're brought into the mix such that not all motor units are firing at the same time, and the dogma is generally that the slower, smaller muscle units recruit before the faster ones, but this is somewhat activity dependent, so when you put it all together, you actually get a rather complicated picture of action, so what you're looking at in this paper from 2009 is essentially a whole bunch of separate motor units that are being tracked, and on the x-axis, you're looking essentially at torque, so as force development is going up and then going back down again, what you're looking at on the y-axis is the discharge rate for individual units.
And what you can see is some units come in real early, some units come in real late, some rate code more than others. And in doing so, it allows you that gradual grading of force development that allows you to do everyday motions and not have problems. And of course, we have to bear in mind that the human body is built to sustain all sorts of weird situations. So I put two examples there of temperature and nutritional deprivation. We do nasty things to ourselves. We're exposed to external environments. And this machine is essentially built to deal with all of those kind of perturbations. Now, human physiology is an interesting beast.
And my personal feeling is because we're upright rather than quadrupeds, our fiber architecture is actually quite a bit different from smaller mammals like mice and rats, which, of course, we do most of our preclinical work in. And I've given you an example here focusing on the sartorius muscle on the left-hand side. Now, this is the longest muscle in the body. It's actually about 60 cm long, if you can believe that. And what that kind of piano chord diagram is designed to illustrate is that most of the muscle fibers in the sartorius muscle actually span that entire muscle. So they can be up to 60 cm long and yet quite often have just one motor unit, one neuromuscular junction innervating that. And that's what the black dots on the figure are there.
I've highlighted subject one in the red box there just to show example fibers that span the entire muscle. Now, that's not entirely always the case. You can see in the sartorius, a number of the muscle fibers only span half of the muscle. That's because they've got these interfascicular junctions. They actually have a dystrophin-rich junction in the middle of the muscle that connects two fibers with two separate neuromuscular junctions. Now, that's much more common in preclinical species. You can see that reflected on the right-hand side there. What you're looking at there is an anatomical view of muscle fibers looking at the fiber length for fibers with one neuromuscular junction.
You can see if you're a mouse or a guinea pig or a rabbit, your fibers are much, much shorter than in the human condition with about a six- to seven-fold difference between a mouse and a human. You can imagine if there's just one neuromuscular junction, but your fibers are seven times longer, that's a lot more longitudinal stress that is potentially placed upon a muscle fiber in a human than it is in a mouse. It's perhaps one of the reasons why it's so easy to cure Duchenne in a mouse, and yet in a human, it's that much more challenging. What I'm going to do now is put that information all together in the context of dystrophin. What you're looking at there on the right-hand side is an animation. The green bands are essentially the dystrophin complexes.
It's the dystroglycan complexes linking into the Z-disc. What I'm showing you here is the canonical view of muscle contraction. This is what people, this is what we like to think of because it's nice and simple with this muscle contracting as a big block. Now, of course, that's not the case. I've just described to you we have motor units. It's quite possible to just have that one central fiber contracting. Then you can see the main function of the dystroglycan complex is to couple these fibers together such that when that muscle is contracting, it's supported. Now, if you don't have dystrophin, the body will make an effort to upregulate machinery to kind of cope with that. Of course, it doesn't do a very good job.
And what that leaves you is a scenario where the central fiber is completely unsupported from the surrounding fibers when it contracts. And that increases that longitudinal stress. So this kind of notion that you have these very long fibers. And when you get membrane stress, of course, you get calcium entry. That actually compounds the problem because calcium turns on contraction and then proteolytic machinery. And now what you're seeing is this kind of compounded longitudinal stress, which eventually ends up in activation of proteolytic enzymes, which chop the whole machine up into small segments to essentially ditch it off to the dustbin and start again by mobilization of stem cells on the basal lamina. Now, this is a normal process in exercise. Of course, if you've got Duchenne or Becker muscular dystrophy, this is turned up a notch so that your threshold for injury is that much lower.
You can see this kind of regional stress by MRI, so this is a paper from the Niks lab from 2021 just showing that in muscles where you don't have even longitudinal fat infiltration. This is in Becker individuals, and what they've done is nicely parse people by their fat content in their muscle. And you can see when individuals with Becker have intermediate fat levels, the location of the fat is actually at the distal ends of the muscle. It's actually not in the belly of the muscle, so these kind of regional areas of stress degrade faster, and then eventually, as the disease progresses, that fat fills in all the way along the muscle. Now, our approach is to target fast muscle, and I'll tell you a little bit about why that would be, and I'm going to start with healthy people before going into the disease setting.
It's been known for many years that fast fibers are more susceptible to injury than slow. I've just given this one example here from 1983 that uses a really nice EM strategy to look at muscle stress. I'll tell you how they've measured that in a second. What we're looking at here is healthy individuals doing 30 minutes of controlled eccentric exercise, so lengthening exercise. Then a muscle biopsy was taken. You're looking at some EMs of muscle. They conveniently in the paper showed a slow unit next to a fast unit. You can see that the fast unit is showing much more signs of stress than the slow unit. By that, I mean that the Z-disc is streaming. It's being pulled apart. You can see some of them have kind of a nice sharp delineation.
Some of them have this kind of fuzzy delineation as the muscle is being kind of stressed and pulled apart, and when you quantify that, it's roughly a three-to-one ratio of fast stress to slow stress when looking at the Z-disc. Something that people don't always appreciate is that the Z-disc is an extraordinarily complicated organelle that plugs straight into the dystrophin protein, and there's actually a really nice clear difference between fast and slow muscle fibers when it comes to Z-disc architecture, so on the left-hand side, that figure is just placing dystrophin, I mean, the Z-disc for you, so the thin filaments, the actin filaments of muscle plug right into the Z-disc, and you can see it has that kind of zigzag pattern.
On the top there is just a very interesting different view of the Z-disc in relaxed and contracted muscle showing that the Z-disc really senses stress. So you can see you have this kind of basket weave design of the Z-disc, which is actually deformed when muscle contracts. So it's actually a stress sensor of a sort. When the muscle is contracted and then it's under load, it actually feels that stress. And you can see there's a primary difference between fast and slow muscle fibers in the thickness and architecture of that Z-disc. So not only are fast fibers developing force slower, so the power output is lower, they're actually processing stress in a different way.
And I think the body has designed fast and slow muscle fibers in such a way so that when you do exercise and you have an adaptive load, that you actually have a population of fibers that adapts quite rapidly and then a population that adapts quite slowly. And in doing so, it allows you to adapt to exercise very rapidly without actually being disabled by that exercise load. Now, of course, that's different if you have Duchenne. And to a degree, Becker too. And this was a paper from 1988 from the lab of Helen Blau at Stanford. And what she did is she compared very young healthy kids to young kids with Duchenne. So you've got the healthy on the top there and the Duchenne on the bottom. And she used embryonic myosin heavy chain as a biomarker of muscle turnover.
So when muscles regenerate, they co-express embryonic myosin heavy chain. And she just used histology to ask a simple question, which is whether the fast fibers or the slow fibers were enriched for embryonic myosin heavy chain. And what you're looking for is the difference between the white bars and the shaded bars. And you can see that the black, which is the embryonic myosin heavy chain, is only present in the normal state pre-birth. Once you're out of the womb, that embryonic is pretty much gone. Whereas in the Duchenne state, it's largely co-located to the fast fibers in this very early stage. So in this very kind of cleanest stage of the disease, if you like, where there's not really any fibrosis, you can see it's very heavily balanced in favor of these fast fibers. You can see that in terms of biomarkers too.
This is some research that we did a couple of years ago looking at troponin levels in Duchenne and Becker muscular dystrophy. On the left-hand side, what we did is we took cross-sections of plasma from individuals in the healthy state, Becker or Duchenne, and looked at creatine kinase. That's your standard relationship. You've got high levels of CK in Duchenne, intermediate in Becker, and low levels in healthy. Now, when you compare that to the troponins, troponin is a protein in muscle. It's a structural protein. Much the same as CK, when you injure muscle, it leaks into the circulation. There's a marked difference between fast and slow troponin such that the fast troponin has the same relationship to disease as CK, whereas the slow troponin does not.
So it's a really interesting situation where slow fibers clearly pick up injury over time in Duchenne, but I don't think they do it primarily by leaking and these kind of membrane lesions that we're so familiar with in the dystrophic state. So in summary for this little subsection, I just want to emphasize that contraction of skeletal muscle is a complex process that relies on a combination of rate coding and recruitment. And as such, it's super flexible. The dystrophin complex stabilizes fiber contraction by providing support across fibers. It's often described as a shock absorber. I think that does the protein injustice to an extent because it's really a force transducer. It connects these fibers together and supports them. And when dystrophin is mutated, regional stress is placed on fibers, particularly fast fibers.
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I'll now segue into the therapeutic approach and a little bit of preclinical data before I hand it off to John, and he'll talk about some controlled exercise studies in the background of myopathy. So I just described fast fibers being susceptible to contraction injury. And in many ways, the primary concept of 5506, the compound that we're developing, is to protect those fast fibers from that contraction injury. And I'll show you the therapeutic hypothesis right now. And it's super simple. It has two elements to it. So contraction causes injury. Fast fibers are more susceptible. So if you can selectively stabilize those fast fibers by modulating their contraction, can you stop them from breaking down but allow them to function? So this, in many ways, returns to those themes of muscle flexibility and force control.
If you can just change the way that muscle contracts, can you stabilize it without losing functionality? The target that we looked for is fast myosin, which is really the primary modulator of force, ATPase, that hydrolyzes ATP in order to go through these cycles of attachment and detachment. Now, myosin is a large family, and that's illustrated there on the bottom right-hand side. There's a number of forms of them. But we've known for some time that you can make allosteric modulators of myosin and get quite nice specificity. And I'll show you how we did that in this example here. So this is EDG-5506. And a lot of graphs that are going to tell you one simple story that we designed an allosteric selective modulator of fast myosin that doesn't target the cardiac stroke slow form of myosin.
You can see that illustrated there, for instance, in the top left-hand side. So you're looking at ATPase by concentration. And you can see in a concentration-dependent way, EDG-5506 decreases fast fiber ATPase, but not slow or cardiac. So we have no direct effect on the heart or slow fibers. You can see in a skinned fiber system on the top right that causes a decrease in force without changing the calcium sensitivity of those fibers. So it's very much like taking an elevator down. The higher the concentration, the lower the maximal force generation of the fiber. It's a myosin inhibitor, and you can see that on the bottom left. So when you use an isolated S1 domain from myosin, it only inhibits the fast skeletal form and not the cardiac or the slow. Oh, and we have the smooth one in there as well, just for fun.
And then on the bottom right-hand side, that's live muscle ex vivo. So this is a mouse EDL muscle, a primarily fast muscle fiber muscle. And you can see again in the concentration-dependent way, you can decrease force. So this is what it all looks like together. I showed you that illustration. Now, this is kind of the real thing. So what you're looking at here are lumbrical muscles from the mouse. It's a very, very small muscle. And that gives you the luxury of being able to look right through the muscle while it's contracting. The left-hand side is an mdx muscle just in control buffer. On the right-hand side, we pre-treated. Ooh, look at that. That should be what? 0.3 micromolar, not millimolar, of EDG-5506. We pre-incubated it for one hour. And that decreases the contraction force by 15%.
So you're just taking the very top end off the force development of that muscle. Now, what you're seeing on the left-hand side around now is movement of the muscle when it should be relaxing. And what's happening is that membrane stress that I described is allowing calcium influx. And that's turning on the contraction machinery when the muscle should be relaxing. It's also turning on the proteolytic machinery. So the enzymes are now snipping up the Z-discs. And those fibers are now retracting as they're unanchored. So what you're seeing is accumulation of hypercontracted sarcomeres and pruning of injured fibers over time. On the right-hand side, essentially, you have the same dystrophic muscle. But in stabilizing that force and preventing that membrane stress, you pretty much cut out that process completely. So we're not changing the dystrophin status. It's only a one-hour pre-incubation.
But the compound is capable of fully stabilizing the muscle under situations of stress. You can measure that stress in other ways. And one is by looking at fluid uptake, so kind of an edema phenotype in humans. And on the left-hand side, this is using a dye. So this is ex vivo force development in the presence of compound. But what we've done is use this Procion dye, which is a vital dye that only goes into leaky fibers. And you can see that marked in red there. So in a concentration-dependent way, you can prevent water influx into the muscle. And that can also be done in vivo by using Evans Blue dye. So we're looking at whole body stain of Evans Blue.
So what you do in this case is you take an mdx mouse, you dose them for three weeks with compound, and then you give them an IV dose of Evans Blue. That's again a vital dye that's only taken up into the leaky fibers. And you can see it marking all of these fibers that are taking up fluid because of these membrane lesions. And you can see you can totally cut that out. So this is not in the background of exercise at all. This is just in habituating mice. Putting this all together in an integrative context, we can actually look at the effects of the compound on exercise, but also on muscle injury. So on the left-hand side here, what we've done is a single-dose study in mdx mice. In this case, what we're doing is giving those mice a rotar od challenge.
So this is kind of a stressful assay where they're put onto a spindle that's rotating at an increasing speed. And they have to try and keep on and not fall off. So they get stressed. It has an endurance and a coordination aspect to it. And you can see what we're doing is a single dose of compound orally from one to 10 mg/kg in healthy in black dots, and mdx in red dots. And just looking to see if it affects performance on the left-hand side there. And there's no effect on performance with this single dose of compound. So you do the dose. You wait three hours, and then you do the assay. Then what we do is we take a CK measure one hour after that assay. And what you can see is that, of course, the wild-type mice, their muscles aren't leaking.
But in the dystrophic state, you get this big spike of CK that then you can suppress in a dose-dependent way without affecting the exercise capacity. So you've modulated myosin. You've modulated how the muscle contracts. But you're not stopping the muscle from functionally doing what it needs to do. But you are changing the relationship with leak. We've also done experiments in Golden Retrievers with muscular dystrophy. So this is the most severe dog model of muscular dystrophy, largely because they're the biggest ones. And this is collaboration with Texas A&M. And we asked two simple questions in short dosing studies. Now, these are dogs that are older. So if you know anything about dog physiology in the context of Duchenne, they tend to start OK. And then as the dogs age up to about six months, they get progressively worse. And then after six months, they stabilize.
We actually started our studies at seven months. So these dogs were already dysfunctional. They were already weak. And on the left-hand side, we just asked a simple biomarker question. And that was, when we give the compound, what happens to CK? On the left-hand side there, that's a kind of average baseline over two weeks of what their CK was. And then during the dosing period, we took blood samples every two to three days. This is four dogs. And you can see about a 40%-50% decrease in CK. We heard reports during that time that the dogs appeared more active. So what we did is we came back and later did a study around eight months later using a collar-bound activity monitor. And you can actually measure the opposite relationship with activity. So these dogs are actually more active during the dosing period.
And that actually washed away when you took the compound out. So very interesting relationship in dogs where you decrease membrane leak, but you appear to facilitate activity. So just in summary, we've designed these allosteric inhibitors for skeletal muscle myosin for therapeutic benefit. Modest inhibition of myosin is sufficient to stabilize muscle membranes and just essentially remodel the relationship between contraction and injury. And those doses really don't appear to affect coordination and strength, which is a critical component, of course, if you're going into the clinic and treating people who are already weak. So thanks very much. I'm going to hand it off now to John. And he'll describe some really interesting studies doing controlled injury in the background of myopathy and how you can use biomarkers to kind of inform what's going on. Thanks, John.
Thank you, Alan. And good morning, brave people. Let's see here. Yeah.
So actually, I realized I didn't have a disclosure slide. And so we have received research funds for this experiment I'm going to talk to you about from Helse. And we'll also do two clinical trials with Helse. But otherwise, nothing really interesting to disclose. So I'm going to start off showing you this classical exercise experiment showing muscle injury, even with a small muscle group only exercising the forearm flexors in an eccentric way, two sets of 35 maximal contractions. And you see that in doing so and probably a lot of you have experienced this as well after trips to the fitness center after you haven't trained for a while, you see that this produces reduced strength, actually, to have normal strength in the day after. And in the days, a whole week after, actually, you are still recovering the same with this muscle soreness and reduced motion.
CK levels increase quite a lot, even with a small muscle group like this. When you do eccentric exercise, usually the CK response you get is somewhat delayed compared to if you do aerobic exercise and get an exercise increase in CK. Usually, that comes up after one day already. It peaks in one, two days. Here, you see the peak is after four days. Interestingly, and as Alan also alluded to, there are other biomarkers that you can use. This is from a study from nine years ago where the exercise paradigm was sort of similar to what we saw before. You see the CK, again, increases to a peak after four days. But also the fast troponin and the slow troponin to the right, you see that the fast troponin increases in a very similar pattern. But slow troponin doesn't.
And this is something that we have seen evidence of also in the muscular dystrophies that we have studied. We don't really have very clean results on the slow troponin yet. So I can't show the results. But it looks as if we see the same response in diseased muscles. And this is an example of a study we did some years back in patients with McArdle's disease and Becker muscular dystrophy, where we exposed them to a combined aerobic exercise at 95% of maximal oxygen uptake on a bike and then some leg presses. And you see that this kind of exercise did not really elicit any particular response in the controls. Those are the ones at the bottom. Actually, can we point here? I guess we can't. So the flat line there is the healthy controls.
And then you have the McArdle patients, which are the highest levels, and the Beckers. And there, again, you see that fast troponin has a quite similar response as what we see with myoglobin , which is the one there in the middle. So we wanted to better understand the muscle injury response in some muscular dystrophies. And the first line there, understanding whether there's a difference between the fiber types, I can't really show you today. But what we were interested in was whether there was a common proteomic signature for muscle injury in these patients. And therefore, we did this experiment, which was conducted by Dr. Mads Stemmerik. He's sitting here in the back. Mads gave me this picture. Actually, he's a very happy guy, I can tell you. And so what Mads did was, and actually, Mads, I think, gave a flash presentation on some of this.
So maybe you have seen a bit of this before. First of all, testing the maximal strength in the quadriceps and performing a maximal cycle test. And then he exposed the patients for a cycle exercise five times, four minutes at 95%. So essentially quite similar to the exercise paradigm I showed you in the slide before. And then some quadriceps exercises with 10 repetitions, doing this four times at 80% of the max. So that's quite a heavy exercise load for these patients. And this was done in healthy controls and in three different muscular dystrophies. So we measured blood samples at the times, you can see here, and performed proteomics on the blood samples. So the three different muscular dystrophies that we studied were affecting different compartments of the muscle. One was Becker muscular dystrophy patients, obviously, with the cytoskeletal dystrophin protein.
Another was the glycosylation of alpha-dystroglycan, so on the self-surface using Limb-Girdle Muscular Dystrophy R9 or 2I patients. Finally, patients with an Anoctamin 5 mutation, so Limb-Girdle Muscular Dystrophy R12 or 2L in the old classification. Of course, the Anoctamin 5 is thought to be involved in membrane repair. Relatively small cohorts, about nine patients in each group. You see that they were if you look at the oxygen uptake, that all three patient groups had much lower max levels. The same for the workload that they could perform was under half of what you saw in the healthy controls. To the far right, the quadriceps strength was also much less. They did achieve a maximal heart rate during exercise, as you can see there in the second last column. The proteomic approach we used was SomaScan, aptamer technology.
By aptamer-linked precipitation, we were able to look at 7,000 different proteins in the plasma. The data we got out here was not absolute values, but relative to healthy controls. It was fold changes we were looking at. In doing so, we found that there were 33 proteins out of these 7,000 that were shared among these three different muscular dystrophies. To your far right, you can see that about three-quarters of these proteins were muscle tissue proteins, not surprising. 32 of the proteins were elevated in the muscle diseases. One of them was universally decreased. If we look at how these proteins behaved when the patients were exercised, you can see here that 26 of the proteins increased further in the patients, whereas seven of the proteins were unresponsive.
They were elevated at baseline, but were unresponsive to the exercise challenge, which we thought was quite interesting, and you can see on the far right there the two examples of the most responsive protein and the least responsive protein, so trying to look at this proteomic signature, we wanted to look into Becker muscular dystrophy patients a little further, and since we had only nine patients in our cohort, we took the advantage of the Newcastle Tissue Bank, and there were 55 samples from that group, and in order to see whether they actually aligned with our data, we looked at the universal proteomic signature in these groups, and as you can see on the bar graph here on the right, they were indeed quite similar. Also, the age of the two groups down at the bottom to the left is, you can see, quite similar.
So interestingly, when we used these samples and we looked at the correlation to age, we saw that proteins that were responsive to exercise, so went up further with an exercise injury challenge, they decreased with age. As you know, creatine kinase in muscle diseases generally decreases with age. So this whole group of proteins behave like creatine kinase, probably because of the muscle mass with aging drops. But interestingly, the group that was unresponsive increased with age. So really, at least to me, quite surprising finding. And you see examples of this on the right side, where CK here at the top, you see there's a general drop in the Becker patients. And then at the bottom, you see a nonresponsive protein that increases with age.
So with this, we think we have, and actually, you can ask, were there any then proteins in some of the single diseases that stood out? Now, we've talked about common signatures. But were there really proteins that were particular and manifold increased in just one of these conditions? And this was not the case. So it does look like it is a quite common signature. So I think the really interesting thing is the responsive and the nonresponsive proteins to the muscle injury, how can we use these biomarkers in the future? I think it's likely that we can probably use the responsive biomarkers in interventional trials, those that are responsive to muscle injury. And the question is, what to do with the other biomarkers? Are they really biomarkers that are indicators of disease progression during the course of the disease in a patient?
We obviously need to study this further. But I think it's an interesting finding. So with that, I just want to acknowledge all the patients. First and foremost, Mads, who did the experiment, sitting there at the back, and Ben Patel, who's also sitting there in the back, who did a huge work in analyzing the SomaScan data. So with that, I will end. Thank you and hand over to Craig McDonald.
Thank you very much, John. I'm going to go over the clinical course of dystrophinopathies with really a focus on Becker muscular dystrophy. Just as a disclosure, like Professor Vissing, I'm an EDG-5506 investigator. So I think, importantly, we need to start by really coming up with a definition of really the spectrum of dystrophinopathy and specifically Becker muscular dystrophy.
There obviously is a tremendous heterogeneity and variability due largely to the amount and quality of the dystrophin protein. But I think it's important to point out this is a graphic on a draft FDA guidance where we're really trying to come up with concepts of Duchenne, Becker. And I think it's important to realize that there's a potential overlap between this spectrum of dystrophinopathies. I'd like to just point out this is our recently published results published in The Lancet in 2018 on the age at loss of ambulation in Duchenne muscular dystrophy. And historically, Becker muscular dystrophy, prior to the application of steroids, was frequently defined as continued ambulation past the age of 16. And indeed, if you look at our CINRG Natural History data on almost 400 subjects.
Those patients in the blue that have not been treated with steroids, largely all of those patients will lose ambulation prior to the age of 16. Whereas the steroid-treated patients, we can see a prolongation of ambulation by three and a half years. But really, very few of those patients are continuing to ambulate into the adult years past the age of 18. So if you look here in the blue, which would be perhaps more of a Becker phenotype, a Becker-like phenotype, and the green being more of a Duchenne phenotype, really in the era prior to application of steroids, median age of loss of ambulation in Duchenne was 10 years of age with a range of seven to 13. In the era of steroids, we really see ambulation continuing, in some cases, past the age of 16 and into 18.
But really, I think ambulation past the age of 18 in the era of steroids is really consistent with more of a Becker-like or milder phenotype. So for the purposes of the Edgewise clinical trials, the definition of Becker muscular dystrophy has been for adults, 18 years of age and greater with documented dystrophin mutations, a phenotype consistent with Becker muscular dystrophy, and a history of being ambulatory past 16 years of age without steroids or being ambulatory beyond 18 years of age with steroids. I think for the younger patients treated in the program, I think an in-frame mutation has been necessary for that definition. So the incidence of Becker muscular dystrophy worldwide is about one in 18,000. The global prevalence is about 1.6 per 100,000 patients, about a third the prevalence of Duchenne muscular dystrophy. Worldwide, the median survival of patients is 67 years of age.
I want to just point out this interesting study published by de Feraudy, really looking at the effects of very low dystrophin levels on muscular dystrophy phenotypes. And the objective here was to actually ask the question whether low residual quantity of dystrophin protein is associated with delayed or clinical milestones in patients with Duchenne muscular dystrophy and with Becker muscular dystrophy. They took a large number of samples, 80 muscle biopsy samples, which had really good clinical data available. And they actually, at the bottom there, they defined those groups. They actually classified them in three groups: those with complete absence of dystrophin protein on Western blot, those with residual but low levels of dystrophin somewhere between 0% and 5%, that was group B, and those with residual dystrophin levels greater than 5% were defined as group C.
If you look at the breakdown of these groups, in those that were group B that had 0%-5% dystrophin, some of those patients were treated with corticosteroids. Really, virtually none of the patients with dystrophin levels greater than five years of age or dystrophin levels greater than 5% were treated with corticosteroids. Actually, the phenotypes in these groups really differed quite dramatically. If you look at age at loss of ambulation, those with complete absence of dystrophin on the left actually lost ambulation well prior to 16 years of age. Interestingly, those with very low levels of dystrophin between 0% and 5% and those with greater than 5% levels, actually, many of those patients actually continued ambulating into the adult years.
What was further interesting is even if you looked at the group of patients with 0%-5% levels, those with 0.5%-5%, those with 0%-0.5% levels versus those with 0.5%-5% levels, there was a further differentiation between those groups in terms of age at loss of ambulation. I think the implication here is that I think this program, this EDG-5506 program, could potentially not only have applicability to Becker muscular dystrophy patients, but also to patients with Duchenne treated with dystrophin restoration strategies who actually achieve low levels of dystrophin. Interestingly, if you look at this dystrophin breakdown, just pointing to the middle there in terms of cardiomyopathy, those with low levels of dystrophin still have onset of cardiomyopathy into the late teens to early 20s.
Cardiomyopathy onset seems to occur even in these patients with low levels of dystrophin. As I mentioned, Becker is extremely heterogeneous. The symptom onset typically can range from five to 60 years of age. Some patients may just be asymptomatic with hyperCKemia. Typically, there will be onset between eight to 13 years of age. The walking problems usually noticed in the second decade of life. Most common cause of death in Becker is heart failure from cardiomyopathy. I just want to point out that there often is a discordance between the skeletal myopathy in Becker muscular dystrophy patients and the cardiomyopathy in Becker muscular dystrophy patients. We may see patients that are highly functional, Becker muscular dystrophy patients functionally in young adulthood with virtually no weakness that may actually present with severe cardiomyopathy.
This can even lead to treatment and to development in ambulatory patients of severe heart failure and cardiomyopathy leading to referral for destination ventricular assist devices or even cardiac transplantation. Many of the Becker muscular dystrophy patients, unlike Duchenne patients, will actually utilize assistive devices late in their life to maintain functional mobility. Upwards of 50% of patients will use assistive devices. Now, this actually is data I'd like to present just really showing probably the most comprehensive natural history published to date by Luca Bello. I'd like to just point people towards the figure on the right, which is the North Star Ambulatory Assessment. Specifically, the two columns in the middle represent patients with deletions extending to and including exon 51 and also deletions involving exon 48. Those patients actually have a very mild or even asymptomatic phenotype.
You can see their North Star values are really towards the ceiling value of 34 and don't really change over the course of a year between time zero and time 12 months. Whereas the other patients that actually have deletions that extend to exon 45, including additional Becker muscular dystrophy mutations, are shown in the green plot and the white plot on the right, and you can see there that there's actually measurable changes that occur over the course of a year, predictable changes that occur in the North Star Ambulatory Assessment in those patients that have some impairment on the North Star at baseline values below 32, and if you look at the data on the left, the six-minute walk data, you can see is really the baseline values are higher in the more mildly affected patients.
But you can see the six-minute walk distance data is really much more variable over the course of 12 months where the North Star really behaves much better. You can look at data in terms of proportion of patients continuing to be able to ambulate independently. And virtually over 80% of patients in the top graph will continue to ambulate upwards to 50 years of age. Similarly, you can look at the proportion of patients continuing to be able to run, which is really quite interesting data. And you can see the phenotypes that were consistent with the change in the North Star over the course of a year were also patients that ultimately lost the ability to run, which could be defined as essentially a 10-meter run walk time of less than three seconds or less.
Here is actually the longitudinal spaghetti plots from Luca Bello's natural history study. And here you can see that the NSAA shows a consistent decline in Becker muscular dystrophy patients who are already progressing. So those that actually have baseline NSAA values below the 33- 34 ceiling value, there's actually an estimated change of about 1.2 points over the course of 12 months in this Becker muscular dystrophy population. So the disease progression could actually be ascertained by the North Star Ambulatory Assessment. Similarly, the natural history data recently published from the Leiden group, I just want to point out the longitudinal change in the NSAA over the course of two years actually showed a change of minus 2.5 points. So again, very similar data, about 1.2 point changes on the North Star per year in that population.
Some of the other more classic endpoints used in dystrophinopathy also showed changes over time. This actually shows correlation plots between the endpoints. The larger circles correspond to a higher degree of correlation. The adult patients are shown on the right. The pediatric Becker patients are shown on the left, and in the adult Becker population, there's actually very nice correlations between the endpoints, so the timed function tests actually correlate nicely with six-minute walk distance as well as NSAA. The correlations with age, though, are really quite a bit lower, and there's more variability with regard to age changes, so these show those relationships. The column on the left, I'll point you to, is just the correlations between the run/walk, 10-meter run/walk, the six-minute walk distance, and the NSAA with age, and you can see there's much more variability and lower correlations with age.
If we look at the bottom row to really point out here, these are the correlations with the NSAA values with the Y-axis shown on the right with the 10-meter walk run time with the six-minute walk distance and with the age on the left. And you can see that those patients with those high NSAA values of 32- 34, those patients really don't change much over the course. They really don't begin to show sort of phenotypic divergence. Until you get six-minute walk distances below 400 meters or 10-meter run walk times of greater than five seconds, you'll start to see really some nice relationships between the NSAA and those time function tests as well as relationships between the six-minute walk distance and the NSAA values once you get to a critical threshold.
So patients at that high ceiling value aren't really changing in their North Star values over the course of a wide range of function. In terms of MRI and fat fraction, what we see really quite interestingly on the left is fat fraction values across a range of muscles in Duchenne muscular dystrophy patients, 50% who are ambulant. This is 10-year-old data on 10-year-old patients. The Becker data is shown below that. And what's really quite interesting is even among the ambulant Becker patients, you see these quite high values of fat fraction that actually exceed the fat fractions that we see in Duchenne patients in these patients who are continuing to be able to ambulate. So their proximal musculature, their vastus and quadriceps muscles are really quite fatty infiltrated and can be quite weak, but they display compensatory strategies to be able to continue to ambulate.
I think we've all been struck by seeing Becker muscular dystrophy patients who have antigravity knee extension strength, who have knee extension lags. You don't believe these patients could possibly stand and ambulate, but with locking out the knee and with compensatory strategies, they continue to walk really quite well. Here is some physical activity data we obtained. This is over a decade ago in Becker muscular dystrophy patients looking at total steps per day in a variety of adult neuromuscular diseases. The control data is shown on the left and the data among the Becker, Charcot-Marie-Tooth, FSHD, myotonic dystrophy, and limb-girdle dystrophy patients. We can see reductions in total steps per day taken, seen in the Becker muscular dystrophy population. They're showing about 3,000 steps per day. Really quite sedentary.
But what's really quite striking is if we look at steps at the high activity levels defined as greater than 30 steps per minute, there's even a greater decrement in activity in these patients. And definition of 30 steps per minute, these patients are not really maintaining continuous activity even sustained for a minute. This is a pretty modest definition of high activity of 30 steps per minute, but they have tremendous decrements in steps taken at the high activity levels. This is actually some interesting exercise training data from Professor Vissing's laboratory where they actually did endurance training in Becker muscular dystrophy patients who were patients 18-55 years of age. They actually participated in a 12-week aerobic exercise program at 65% of VO2 max aerobic capacity on a bicycle ergometer for 30 minutes five times a week.
There were six of the patients they actually continued on the exercise paradigm for a full 12 months at three times per week. They did muscle biopsies pre and post CK, and quality of life was assessed, but what was really quite striking is the patients actually showed some nice exercise responses, so despite their tremendous weakness, their VO2 max actually improved up to 47%. Their maximum workloads improved, and they showed some strength improvements as well, and those improvements were actually sustained between 12 weeks and 12 months of testing, so the initial improvement they showed actually was nicely sustained, and I think that they also reported improvements in quality of life. There were no negative changes in terms of heart rate, CK, histology, increased regeneration, or central nuclei.
So these patients actually responded well to an exercise paradigm, and those exercise improvements were sustained for a one-year time. So I think those studies actually support a more active approach. But also, I think it has important implications for the context of a therapy like EDG-5506 that there's really, I think, potential for a synergistic effect if we can improve capacity and improve activity. And in the community, these patients may actually get secondary benefits of that increased activity that could translate to functional benefits over time. I think in a clinical trial context, we also have to document the exercise practices of the patients. So just to conclude, low levels of dystrophin result in intermediate dystrophinopathy in Becker muscular dystrophy with ambulation past the age of 16 without steroids, up to 18 with steroids. There's variability in the disease.
The frameshift rule does not always apply in patients with deletions extending to exon 51 or a deletion of 48. They may have this mild or asymptomatic phenotype. I think that the traditional dystrophinopathy endpoints characterized disease progression are likely prognostic in Becker. The functional outcome data will be important for trials, particularly focusing on patients with NSAAs less than 32. The MRI is a promising biomarker in Becker dystrophy. Cardiomyopathy needs to really be carefully monitored. Sometimes there can be discordant features with the skeletal myopathy in Becker. Community activity monitoring is promising, and formal exercise and activity may also impact the functional progress of these patients. So thank you very much, and we'll turn the podium over to Dr. Donovan. Thank you.
Thank you. And I'd like to remind folks in the room and online that you can ask questions, and they are starting to pop up.
So I'm going to focus on how we are developing EDG-5506 for Duchenne and Becker muscular dystrophy. And as you well know, this is a spectrum, and it's a spectrum that's becoming increasingly blurred by dystrophin-targeted therapies as well. So what we've done in terms of clinical development is started with a phase I in which we were looking at healthy adults, but also included adults with Becker muscular dystrophy. Those patients continued on with other patients in an open-label study in Becker. And that's really given us the foundation for a phase II study in Becker muscular dystrophy and a phase II in Duchenne that I'll be telling you more about at the end. And as Alan talked about, this is a novel. It's a really orthogonal approach to others that have been tried.
Really looking at targeting the daily mechanical stress and with the hypothesis that if we can block that, then we can decrease muscle injury. We can then interrupt the progression to replacement of muscle with fat and fibrosis and ultimately avoid reducing muscle function. Our phase I in healthy volunteers was kind of a classic single and multiple ascending dose study for up to 14 days, and we got important information from that. The drug was well tolerated and actually has an extended half-life. We also included ambulatory subjects with Becker muscular dystrophy and dosed them for 14 days in a phase I unit, which was challenging. Certainly, we enormously appreciate their contributions in doing that. They were monitored for 14 days or 16 days as inpatients and then followed up for four weeks afterwards.
There, we also saw the drug was well tolerated, well absorbed, somewhat shorter half-life from healthy volunteers. These were our main points. The most common adverse events were somnolence and dizziness, which were generally mild and transient. We were able to demonstrate that the drug was absorbed well orally, both with and without food, and was appropriate for daily dosing. Importantly, we were able to demonstrate that the muscle concentrations were above the levels that we were targeting as potentially efficacious based on the animal studies, which Alan showed you a few. Now, while we only required the patients to be ambulatory, we saw that they were relatively advanced in their disease, mid-30s, but a prolonged 10-meter walk run rise from the floor median of 20, decreased serum creatinine, yet the CK was still elevated, indicating ongoing damage. Now, the muscle biopsies were very interesting.
We were able to do that both in the healthy volunteers as well as the patients with Becker. And we, as I mentioned from the preclinical studies, we knew that we wanted to reach a target of between one and 4,000 nanograms per gram. And even at the lowest dose, we were starting to be on the edge of that range and were well within it with the higher doses. For the patients with Becker muscular dystrophy, now these are quad biopsies. So as Craig mentioned, this is a highly involved muscle. In fact, you could see the fat on the biopsy specimen. So we're estimating these folks had muscle fat between 50%-70%. And when corrected for that, their concentration was well above. This represents in healthy volunteers a 100-to-1 ratio from plasma to muscle. So the drug is concentrating there.
It's getting to where it needs to be. And what that tells us is that the binding site of fast myosin is there in Becker muscular dystrophy. And it's there in these advanced patients who have at least as much fat as the late ambulatory Duchenne patients. So it's very encouraging overall. Now, we looked at some of these SomaScan markers that John has described. And in particular, we compared the patients with Becker to the healthy volunteers. And we picked out 125 proteins that were both elevated by more than 50% in the Becker patients as well as being statistically significant. So that's that group in the upper right, the red proteins, 125 proteins. It's basically a fingerprint of muscle injury.
When you look at what those proteins are, they are largely proteins that are markers of muscle injury, so reflecting the leaky state of the membrane in Becker. When we looked at these proteins in the patients over 15 days, on the left are the healthy volunteers. They didn't change much. Their muscles weren't perturbed at baseline. The placebo patients in the middle, they went down a little bit. Now, in the phase I unit, these folks are minimally exercising, shall we say. It's a 2,500 sq ft unit, and they're really not walking around very much. They did improve some. What we saw for the patients treated with EDG-5506 for two weeks is we saw a decrease, a statistically significant decrease in that cloud of markers. We're not just looking at one marker. We're looking at the whole cloud responding.
And the one that was most responsive in the green at the bottom was fast skeletal muscle troponin I, with CK in the pink closely followed. So we saw that both relative to the control group as well as relative to the placebo folks. And this shows another way. Basically, the red is the order of the proteins with the most elevated in Becker at the top, placebo, and the five treated with EDG-5506. And so this is a global response. It's a consistent response across individuals. And you'll see that borne out when we get to longer studies in Becker patients. And what we're seeing is really the greatest decrease is in the proteins that are most elevated at baseline. So on the x-axis, this is how elevated are they at baseline in healthy volunteers, between one and five times elevated.
And then you see, well, how much are those coming down? And the ones that are three, four, five-fold elevated in Becker patients compared to healthy volunteers, those are the ones that are responding the most. So it's really very interesting to look at this kind of a detailed panel of proteins. We also looked at the proteins that were exercise responsive from Mads and John's work. And we saw those steadily decreasing over the two weeks of therapy as well. So we are seeing a consistent response here. Now, we then included those patients and others for a total of 12 in an open-label study done at Han Phan's site in Atlanta. And these patients, again, had to be ambulatory, no other functional criteria for entry. And we looked at biomarkers, North Star, the NSAD, the North Star Assessment for Limb-Girdle Muscular Dystrophies.
We dropped down in dose and started them at 10 mg for two months, escalated to 15 mg for four months. The data that I'm going to show you are for all 12 patients at six months. At this point, they have been dose escalated further to 20 mg per day. Now, these 12, again, mid-30s, only half of them could perform the rise from floor at baseline. We also looked at DEXA, and that confirmed the decrease in serum creatine kinase, that they had a profound decrease in their lean muscle mass, with lean muscle mass constituting about 40% of total body weight. On the right is we compared at screening the North Star versus the NSAD. Now, that's not really surprising that these are highly correlated, R-squared of 0.98. They reflect patients with a North Star from four to 31.
But 17 of all of the measures in North Star are also incorporated in the NSAD. So what that scale does is it also includes some more difficult measures to increase the sensitivity at the high end as well as the low end as well. But in the range of the patients that we were looking at, those were highly correlated. Of interest, some other measures, the functional measures correlating with each other, the 100-meter timed test versus the North Star, highly correlated with each other versus serum creatinine. We don't look at that as much, but it is a, not surprisingly, it is a, and there are papers out there that look at that as a good biomarker as well. And lean body mass correlates with the NSAD as well. Now, I didn't mention safety as much for the short-term study.
Now we're looking at six months of dosing with these patients. And this separates the adverse events at two months on the lower dose and four months on the higher dose. Basically, it's been very well tolerated, no dose reductions, adjustments, no discontinuations due to adverse events. Again, the most common adverse events were dizziness and somnolence. We're giving the drug at night, and it is only an adverse event in the first few days of dosing typically. So it seems to be something that the patients adjust to quite quickly. Now, we reached, this shows the PK on the left. We reached plasma PK levels that were seen in the phase I study. And the dose, it's at steady state after two months. Interestingly, this is not an advanced step count or an accelerometer. We're just looking at step counts here.
But we did see, compared to the phase I in the gray, the first month of dosing, the patients have increased their step counts and very much a little bit above the range where Craig was showing for the Becker patients. And we'll be looking at this more in future studies. What we saw was that there was a sustained and really a profound decrease, both in creatine kinase as well as fast skeletal muscle troponin TNNI2. And it tells us that we have engaged the target. We're seeing a response. You see in the CK, every single patient is going down 39% after six months. The fast skeletal muscle troponin, again, we're seeing very consistent reduction, 75% on average in 91% median. And the individuals with the highest baseline values are showing the greatest biomarker effect.
So this supports that we are showing protection against contraction-induced or activity-induced damage. Now, with the SomaScan, we also looked at a different set of proteins. Now, this looked at proteins that were different at six months than at baseline or one month. So this is excluding the damage-induced changes that we saw at two weeks. And this identified another set of proteins that is slowly responding. And so we're seeing this slowly decrease over six months. And on the right, the black bar is the normal volunteers. Then the next two bars are at baseline in one month. They're elevated in the Becker folks compared to healthy volunteers. And then, very interestingly, you see this set of proteins responding over time and moving closer and closer to the baseline of healthy volunteers. So that's very interesting. And it seems as though those proteins are reflecting more inflammatory proteins.
You're starting to see long-term changes that reflect potentially decreases in inflammation remodeling as time goes on. Now, in terms of function, this study was primarily designed to look at PK safety over time, but we did look at function over time, and I just went backwards, and so you saw this. This is the trajectory of patients between four and 32. Those patients are consistently going down, yearly change of - 1.22. What we saw on the left with the North Star and on the right with the NSAD is we saw that the trend is up. The line and the shaded areas represent the linear regression with a 95% confidence interval. We're seeing durable improvements observed over six months of EDG-5506.
For the North Star, this contrasts with the expected natural history, where we would have expected that to trend down about 0.6 based on data from the literature. The North Star, the NSAD, we don't have a good comparison from natural history. We're also seeing that trend up very nicely. Now, what other things can we look at in these patients? One of them is the patient-reported outcomes, with pain being very important. That pain seems to be a more prominent symptom in Becker than it is in Duchenne, as you can see here, particularly in the ambulant patients. Measuring, looking at pain over the six months of dosing, we've seen a consistent trend better in the patients over this period of time, as well as a trend in other patient-reported outcomes. You'll be hearing more about that.
To put this in perspective of our overall development plan, there's a natural history study ongoing working with GRASP. We have a phase II in Becker, the Canyon study. With Professor Vissing, we're doing a phase II study, not in Becker, but also limb-girdle 2i and McArdle to look at exercise-induced biomarkers of muscle injury. That's going to be exciting to look at the potential in other muscular diseases. Lastly, in Duchenne, phase II study is looking at patients between 12 and 50 with a confirmed mutation, ambulatory, not on corticosteroids, 12-month placebo-controlled study, and looking at a variety of endpoints, including biomarkers, safety, MRI, functional assessments, and accelerometry. The LYNX study in boys with Duchenne will look at four- to nine-year-olds on corticosteroids and potentially also on approved exon-skipping therapies. This is a three-month placebo-controlled study followed by nine months of open label.
We can take advantage of this rapid change in biomarkers to look at the response, to look at PK, and determine doses for a phase III study with that. So that's going to be starting later this year as well. And we'll be collecting functional measures, but the focus is on safety and PK biomarkers to be able to determine doses for phase III. So with that, I'd like to thank you all for listening. I'd like to very much thank the patients and their families who have contributed. This work was done, the open-label at Rare Disease Research with Han Phan as principal investigator and her team. So thank you all for your attention. And we can take questions from the floor as well as I will get the ones online. Thank you.
Thank you. I have found the aging component of pathogenesis particularly fascinating.
During normal aging, you see preferential loss of fast fibers as well. And I wonder if there are shared molecular events that lead to damage and degeneration in the Becker BMD versus the normal aging. And if so, Edgewise's compound has potential to address both mechanisms in the older Becker patients. Can the panelists comment on this topic? Also, I have noticed that the aging has led to certain loss of correlation between different measure parameters. Is it because of additional mechanism during aging that's complicated the measurements, or are there contributing factors responsible? Thank you.
I can answer the first bit. I'm not sure I'll be able to answer the second bit. Aging is really interesting, right? You tend to get selective decreases in fast fiber size. Some people often think that you get kind of fiber type changes.
But if you actually look at some very nice data from Lars Larsson over in Sweden, it's more that the proportion of muscle size is decreased in the fast fibers. And that may be a combination of both kind of disuse and kind of selective stress on these larger fast muscle units. So as such, I think that is somewhat distinct from what you're seeing in the Becker, where you have this ongoing stress. But I do think what you often get in these myopathies is an accelerated aging phenotype on top of this kind of myopathy, right? But not entirely the same. Would EDG-5506 be good with age? I don't know. Maybe. It's going to be a long study that.
Thank you very much. Good morning, first of all. And Jordi Díaz-Manera from Newcastle. Nice presentation, interesting concept.
So, just to be sure that I get it correctly, so John identified kind of a fingerprint of biomarkers in blood after doing exercise, right? A specific program on exercising, healthy controls on patients. And then you treated the patients and looked at these markers. But did you look at the markers after exercising the patients?
Yeah, John.
Did we look at the markers after exercise?
Oh, when treated. Yeah. So we didn't do any exercise in the treatment study. So what you just looked at, but we did look at those subsets of markers. So Joanne had that data in the slide set. So we were very interested in setting the table in many ways with John to define this signature of injury. Like, what is a true injury biomarker? And that's where the controlled exercise comes in.
Because you don't really know if a biomarker is elevated at baseline, whether it's truly a muscle leaking from injured, a protein leaking from injured muscle, or if it's just elevated as a response to the disease state, right? So that annotation was very useful for us in ring-fencing these biomarkers and then seeing what happens with the compound. And they were the most responsive biomarkers with the compound. So what you're asking is actually what we're going to do now in the next experiments. Haven't been done yet.
Next year.
Yeah. Great presentations. Good morning, Benedikt Schoser from Munich. I'd like to ask you for the preclinical workup. Did you also have a comparison with steroid treatment on top or parallel to this? I think that would be very interesting, especially for the Duchenne topic.
That's a very timely question. Yeah.
So we've been spending the last year preclinically doing those kind of combinations, largely with deflazacort, just because that's the primary one used. We'll probably have a presentation on that at MDA next year. But just a kind of top line, preclinical species and steroids is somewhat of a controversial area because some people have suggested they don't particularly well model the human state. But we see really interesting temporal aspects to steroid treatment, where short-term they work real well, and then longer-term they have a bit of a problem, right? And what we've seen in the longer-term studies with the steroids and EDG-5506 is that the EDG-5506 just keeps steaming on. It works just the same in many ways as whether the steroid's there or not.
I actually think we have a great combination potential there where you get the benefits from the steroid, but then the additional protection from EDG-5506.
Hi, Julie from Colorado. Is there any effect on cardiomyocytes or were cardiac monitoring, was any kind of cardiac monitoring done in any of the patients?
Yes. We are looking with echoes and EKGs with the patients. And we'll be continuing to do that. But it is specific for fast skeletal. And as Alan showed you, there is not an effect on those. But you did look at fibrosis.
Yeah. So we've done studies in the DBA/2 mdx mouse. So this is the kind of more severe mdx mouse that has cardiac involvement as well. And in medium and long-term studies, we've seen improvements in cardiac fibrosis.
So even though we're not directly affecting the heart, perhaps there's a knock-on, I mean, that's a mouse versus a human. But that would be great if we could achieve that in people too.
Good morning, Meredith James from Newcastle. Thank you for the lovely presentations. Just a comment regarding the natural history and defining when patients are deteriorating. I think we need to be very careful saying that the patients are only deteriorating when the North Star is at less than 32. Our natural history to this date has had a clear ceiling effect. You can see from the NSAA scores that the patients who are more able are having a ceiling. And they need to be tested with more robust instruments that actually extend their ability, like NSAD in natural history.
So really pleased to see natural history studies giving that opportunity to remove that ceiling that has been present in the natural history cohorts that have been reported so far.
Yes. You're absolutely right. They're stuck at 34 because there's no place above that. But they're coming down. We just can't see it.
Absolutely.
So we've got NSAD and the 100-meter time test to now appropriately test those Becker patients who are more able.
There was also a question from there that how do you explain the severe fat degeneration in one muscle and completely preserved in others with this?
This is like one of my favorite topics, this one. So everyone loves to look at gracilis muscles, right? Why on earth would a gracilis muscle be saved and not other leg muscles, right? What's up with that?
And I often get asked, is that because they're full of slow fibers? And the answer is not entirely no. But I've kind of dug into this one kind of a lot. And I think what you're looking at in many ways is architectural differences between these different types of muscle. The gracilis is unique in that it has more of these intramuscular junctions. So it actually has shorter fibers versus the other leg muscles. So there's less longitudinal stress on that muscle, perhaps, than these other ones. Also, other muscles tend to be more pennate, so they don't necessarily span the entire muscle. They kind of fan out. And I think that longitudinal stress is a huge component in the speed and degeneration of muscle fibers. And on top of that, the gene expression pattern is also very different.
I mean, if you test all muscles up against each other, they may look like beef, all of them. But really, I mean, the gene expression pattern is huge.
Very good. There's no more questions. I don't see any more online. And I'd like to thank you all for coming out, for bravely coming out in the dark this morning. And it was a pleasure speaking with you all. Enjoy the rest of your day in the conference.