Good morning, ladies and gentlemen. Welcome to the Sarepta Therapeutics micro-dystrophin Gene Therapy Update Conference Call. As a reminder, today's program is being recorded. I'll now turn the call over to Doug Ingram, President and CEO of Sarepta Therapeutics. Please go ahead.
Good morning. Thank you all for joining us for an update on the clinical data from our four-patient phase I micro-dystrophin gene therapy program. On this call, we may provide forward-looking statements. I would refer you all to our public filings for the risks and precautions associated with our forward-looking statements. Before I turn the discussion over to Dr. Louise Rodino-Klapac, let me put this update in context and explain why we are making it. As you will all recall, at the World Muscle Conference in Mendoza, Argentina, in the fall of 2016, we provided an update on our four-patient phase I trial for gene therapy. We provided functional and biomarker results for the last date we had for each patient. You will also remember that those patients were treated in a staggered fashion.
The earliest treated patient had nine months data. The other patients had earlier last measures consistent with the date on which the patient received therapy. We are this morning presenting updated nine-month functional and CK-related results for all four patients. Many investors will also recall that I have repeatedly stated that as we are in the midst of a blinded, placebo-controlled study verifying the results we have seen in our first cohort, we do not believe it appropriate to provide ongoing updates on the first four-patient cohort. Why then are we updating? We have also said repeatedly that while we do not intend to update, it is possible that the principal investigator, Dr. Jerry Mendell, may decide to publish or otherwise present updated results in a medical meeting.
We have been informed that in a recent medical meeting, Dr. Mendell updated the data to include nine-month results for all patients. Accordingly, in the interests of full transparency, we think it only appropriate to provide an update consistent with Dr. Mendell's presentation. As you will see, the data remain very encouraging, with continuing improvement on functional endpoints, unprecedented biomarker results, and on safety as well. Finally, I do want to reiterate that we do not intend to continue to update the first patients to keep focused on completing our placebo-controlled trial. With that, I will turn the presentation over to Dr. Louise Rodino-Klapac.
Thank you, Doug. Good morning, everyone. I'm pleased to present the updated results from our first four patients in our micro-dystrophin trial, our Study 101. Just to remind you, this study was in DMD boys between ages of four to seven , and we enrolled four patients. Inclusion included confirmed DMD mutations, as well as the subject had to be negative for antibodies to rAAVrh74. This was a phase I safety study, so the primary endpoint is safety, but there are various secondary endpoints, which included micro-dystrophin expression, decreased in creatine kinase, the 100-meter time test, the North Star Ambulatory Assessment, as well as stair climbing, and time to rise. Just to orient you on the demographics at baseline for our four subjects. They range between the ages of four to six at baseline, and their creatine kinase or CK levels range between 20,000 and 35,000.
This is right in line what we would expect for DMD boys, which typically range between 20,000 and 40,000 at this age range for CK. We previously presented the biopsy data at World Muscle Society in Mendoza, and we'll just go through that today as well, because it's the same biopsy data that was previously reported. We had biopsies at baseline as well as at day 90, and these are the results of those biopsies. We quantified the amount of micro-dystrophin, and here we're looking at immunofluorescence staining. As you can see, widespread micro-dystrophin expression is correctly localized to the sarcolemma or the muscle membrane.
We quantify this by looking at both intensity, so this is the amount of micro-dystrophin present at the membrane, and we see that it is 96% compared to normal, which you can see a comparative normal control in the upper left-hand corner. We also quantified it by looking at the number of fibers, and here we see a mean of 81.2% of muscle fibers expressing micro-dystrophin across our four patients at 90 days post-treatment. We further quantified the amount of micro-dystrophin by Western blot, so this is looking at the total amount of micro-dystrophin protein. As you can see, we've shown gels for all four patients, and we see robust micro-dystrophin levels. We quantified this by adjusting for fat and fibrosis, and we get a mean of 95.8% expression compared to normal.
If you don't adjust for fat and fibrosis, it's at 74.3% of normal. This next slide is just a summary of the results I've shown you so far in terms of the amount of dystrophin-positive fibers at 81.2 Western blot, and also vector genome copy number. We see as a mean across the 4 patients greater than 10^5 copies per microgram of DNA. To put that another way, that's greater than three copies per nucleus, so three copies per cell. All of this biopsy data taken together is very consistent in terms of the number of copies we see and the amount of dystrophin present. We see high level widespread micro-dystrophin expression 90 days post biopsy. Now I will summarize the clinical data.
Just to remind you, previously disclosed nine-month data for patient 1, today we're updating you with nine-month data on patients two, three, and four . Start out with the North Star Ambulatory Assessment. To remind you, this is a functional scale looking at milestones that DMD boys will achieve. This is a 34-point scale, we're looking for increase that shows improvements over time. What we're showing here is baseline out to on the left all the way out to nine months or day 270 on the right. What you'll see is a consistent increase in the North Star Ambulatory Assessment score in all four patients. To look at it more closely, if we focus on patients one, two , and four these patients are the four to five -year-olds.
We know from natural history that four to five -year-olds do see an increase over this time when they're on steroids of about two points. If you look at our patients, they're increasing to eight points over the course of just nine months. Well beyond what we would predict from natural history. Looking at patient three, who was six years old at baseline. He was already doing quite well with a baseline of 26. He still improved with an increase of two points. We know that six and seven -year-olds from natural history data are actually declining over the course of a year by four points. We would expect that he would decline. Really the net delta in all of these patients reports to a mean of 6.5 points from baseline. Very consistent results.
Just to put this in some perspective, since this is a milestone scale, this is actually telling us that these patients can do three activities that other DMD boys in this age range can no longer do. Or put another way, they can do six activities independently that another DMD boy that's untreated cannot do. Very consistent and encouraging results, which gives great confidence as we enroll our Study 102 or our placebo-controlled trial of 24 patients. In this next slide, we're showing additional net functional measurements. We're showing time to rise, four-stair climb, and the 100-meter test. Just to give you some perspective on this slide, we're showing baseline measurement. We're showing the previous time points as closed, as designated with the asterisk, as well as day 270 or nine-month data.
For all of the time tests, we're actually looking for a decreased amount of time to do that activity. If you look across every single measure, we're seeing an improvement. For time to rise, it's a mean of 0.8 seconds improvement. For four stairs, 1.2 seconds improvement, 100 meter, almost eight seconds improvement. We're seeing consistent results across every single functional outcome measure that we've looked at. We've also continued to look at the biomarker CK. What we see is a continued trend for a drop in CK over time. CK can be variable, we know that it can vary within a day, it varies with activity. As we look at the data here across nine months, you'll see that we've seen a few spikes.
For example, day 90 for patient two, we know that this patient was doing activity prior to getting the measurement. For our protocol, we ask that the patients do resting CK, but we know that we've had protocol violations where this has not occurred, and we had several spikes. We can also see that for patient one at day 180 and patient three at day 270. There's some variability, but these kids are doing very well, and they're active. We know that this is an inherent variability due to CK. However, we're seeing an overall trend in the downward direction for CK, which is encouraging. If we look at in graphical form, I think this makes the point that we're seeing still a drastic decrease in CK over time, and this is still very unprecedented.
If you remember, we said that CK for DMD boys in this age range are between 20,000 and 40,000. If you look at this graph, the only point that we're looking at in that range is at the baseline. We're consistently seeing a drop in CK over time. What's important is when we look at the function. We've overlaid the North Star Ambulatory Assessment here just to make the point that we see consistent improvement in North Star over the nine months, and we see a consistent decline in CK. Really unprecedented results in terms of function. We're seeing durable improvement in function, and we're extremely encouraged as we enroll our placebo-controlled study. As far as safety, we've had no updates from our last report. The patients continue to do very well. Just to remind you, we've had no serious adverse events in the study.
Three patients did have elevated GGT, and they all resolved with steroids within one week. There were no other clinically significant laboratory findings. The subjects had transient nausea within the first week, but that was when the steroids were increased, and that did not correlate with liver enzyme elevations or any other abnormality. Just to summarize, all four of our open label patients are doing extremely well. The biomarkers, including CK and microdystrophin, have shown large magnitudes of effect within three months, and we're seeing continued functional improvement from baseline now to nine months.
All these results are showing that these patients are performing better than we would predict by natural history, and there continues to be a favorable safety profile. All of this is supportive of our current enrollment in our Study 102 or our 24-patient placebo-controlled study. With that, we will be happy to open up the call for questions.
Thank you. Ladies and gentlemen, if you have a question at this time, please press the star followed by the number one key on your touchtone telephone. If your question has been answered or you wish to remove yourself from the queue, please press the pound key. Once again, to ask a question, please press star and then one now. Our first question comes from Martin Auster from Credit Suisse. Your line is open.
Hi, everyone. This is [Markan] from Marty. Thanks for taking my questions and for all the color that you guys provided today. I guess my first question is big picture. What's a good way to monitor durability longer term? My second question is, I realize you don't plan to provide an update on this trial while the phase III is ongoing. That said, I was just looking for a clarification on the protocol design of the phase I study. Specifically, will there be 12-month biopsies taken? Thank you.
Thanks a lot for the question. A couple of things on durability. First of all, let me answer your last question first. There is not currently a planned 12-month biopsy for these children, and 1 of the reasons for that kind of relates to your initial question, which is how do we look at durability. The preclinical work, the animal models, and we're talking across our program, mouse models, the golden retriever model, and also the non-human primate. There is no basis to believe that there would be durability issues in this kind of timeframe. In fact, for the mouse, the mouse showed durability for as long as a mouse lives, normal age range of a mouse. In the golden retriever models with our partner, Genethon, we've seen that out to seven, eight years. Non-human primates has been out for years.
As long as we've looked, we've seen durability. The problem with having a biopsy at the end of one year is it's a very invasive procedure for these children without a real justification because one wouldn't see at this point diminutions in durability. Certainly given the level of expression that we're seeing in these first four children, there would be no reason to modify that. We would assume significant durability. We have a lot of work to do to just think about how to measure long-term durability in a way that's not overly invasive for these children, because we're going to need to be monitoring this in three and five years and the like. We have more work to do there. I think a couple of things. Certainly payers would like to see function.
If you want to know what payers want, they would love to see function. That might very well be a good measure. We need to look carefully at it to make sure that it's objective and that over the long term, so we don't find ourselves in disputes with payers over access and reimbursement-related issues in the long term. CK is not. CK is a great marker of the benefits of the therapy because, of course, CK is associated with muscle damage. When we see these significant drops like we've seen here, we can see that the therapy looks like it's working, and the functional results confirm that. The issue with CK, and you can see it here, is there's a number of confounding variables. The first confounding variable is if CK moves around too much. It moves around intraday.
As a good marker of durability, that alone is going to be a problem. The second thing we see in these kids, at least the first four kids, is that they do not act like you would expect in their age range for Duchenne muscular dystrophy kids. They appear to be significantly more active. Like we can get an anecdote about one of those kids and talking to their parents, who the day before he had a spike in his CK, was at the park doing things like handstands and somersaults. It's not surprising they're going to get spikes simply associated with the fact that the therapy appears to be, at least in this early study, very functional. Then the third issue we have right here is you get protocol violations.
It's very difficult to have these children assiduously abide by the resting CK protocol, and we've seen that a couple of times now, probably now three times in this scenario where the families haven't been able to follow the strict resting CK protocol. There was a spike, and as soon as they're reminded to go back on a resting protocol, they come back down, and then the CK drops to below what would be DMD-like in both of the two cases that we've seen, and then we'll see the third case. I suspect it'll be very similar to that. CK will be a challenge for durability, but certainly it's a good marker to show that the therapy is working.
The short answer is we have a lot of work to do to see if we can find either a good non-invasive marker for durability for the long term, or failing that, a good functional endpoint that payers and we agree is a good long-term marker as well.
Great. Thank you.
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. As we think about the different components of the NSAA, what's your view on the most challenging components and maybe which are the most clinically meaningful? Can you just help us think about the main drivers of this score between patients and over time? Thanks.
Sure. Thank you very much for that. I'm going to turn that question over to Louise to try to answer.
Sure. I can say, as we mentioned, the scale is of 17 different measures on two points per measure, and we're currently evaluating the subcomponents of the NSAA to look just at that to see which are more responsive. Maybe we could use that going forward. Right now, we don't have any sub-analysis to be able to speak to in terms of if there is a response in some areas versus others.
Okay. Thanks.
Thank you. Our next question comes from Debjit Chattopadhyay from H.C. Wainwright. Your line is open.
Hey, good morning. Just to follow up, the North Star Ambulatory Assessment compares obviously very favorably to age-adjusted DMD patients. Wondering if you have insights on what is the norm as far as the interesting 20% decline in time to rise, the 29% decline in the forced vital capacity, and I believe a 13% decrease in 100 meters to a similar age-adjusted cohort. What should the expectations be for those three markers? Thank you so much.
I'm going to turn this over to Louise, and maybe additionally, Ted, but remember, as Louise said during her presentation, in the age range of the four to five-year-olds cohort, any benefit that they might see in development over that course of that time would be a fraction of what we're seeing in the NSAA cohort here. Likewise, in the five to six-year-old range, you would see the opposite. Six and seven-year-old range, you would see the opposite. You would actually see these kids beginning to significantly decline over that period of time, and of course, in the one six-year-old we have, we're seeing the opposite. We're seeing a gain in function in NSAA. Louise, do you have any other insight into the natural history regarding some of the subparts of the NSAA? Or the time here, in particular, the one that Debjit referenced.
Just on the natural history data that we have for the time test, which isn't as extensive as North Star, what we're seeing is improvement beyond what we would expect for natural history with the time test as well. We're certainly doing all of these detailed analysis in preparation for our future studies.
Just to follow up on the CK, did at any point these patients go off steroids post gene therapy?
Steroids. Oh.
Go ahead, Louise.
I was going to say, they've all been tapered off. They went on daily steroids for the first 30 days, they go taper down to their standard of care dose. They're always on some level of steroids.
Okay. Thank you so much.
Thank you. Our next question comes from Christopher Marai from Nomura. Your line is open.
Hi, good morning. I have a question on patient two, specifically. Just noting that CK spike and then having the CK level come down, I guess it was the day 90 measure was quite high, 40,000 +, and came down to that 6,000 number. I was wondering if you could comment on how that might look for an untreated Duchenne patient. I suppose, relative to how we might expect the microdystrophin to impart mechanistically protective benefit to the muscle. I mean, is this something you would've expected, obviously, with the microdystrophin there? Then secondarily, on the safety front, have you looked at any immune responses against the microdystrophin construct? I didn't note any of that in the safety update. Thank you.
Yeah. Thanks a lot for that. A couple of things. Remember for that kid, these kids would never be in the 6,000 range. The question is, what would you expect to see in a Duchenne kid similar to this? You would never see a drop to 6,000. These kids are in the 20,000 and above range. As soon as they're told to rest, and they take a resting CK, in both of the two instances we've seen, they immediately drop down into the 6,000 range, below what we would see in a DMD patient. This is not what I'd see in a DMD patient, and I apologize. What the second part of your question was?
I guess any immune response against the microdystrophin construct, have you guys measured that or looked at that out to date 270?
Sure. Louise?
Sure. Part of our protocol is to look for immune responses to microdystrophin, and we have not seen any immune response to microdystrophin throughout the course of the trial.
Okay, great. Just lastly, maybe any rough timing on the potential subpart NSAA update? Obviously, that could be pretty interesting. Thank you. That's all.
On the first four patients. Our goal on the first four patients is not to continue to update. In fact, to be honest, because the data looks so good here, it's kind of what I was concerned about initially. We don't want to look like we're hiding the first four patients as we're in the middle of a placebo-controlled clinical trial. Our goal right now is to take what we see as very exciting results from the first four patients and to confirm them in our trial, which is a placebo-controlled blinded trial. We want to get started on a commercial supply trial as well, that if successful, we can hustle this therapy out to the community as fast as is reasonably possible. It is not our goal to continue to update.
Got it. Thank you.
Thank you. Our next question comes from Brian Skorney from Baird. Your line is open.
Hey, good morning, guys. Thanks for taking the question. Most of mine on the updated data have been answered already, I'm wondering, the other news last night was that Brammer Bio is getting acquired by Thermo, just wondering if you had looked at acquiring Brammer outright at all, given the importance of their manufacturing capability to this program, do you have any perspective yet on whether or not you expect an impact to your timelines from the Thermo Brammer deal?
Sure. First of all, there's nothing in the Thermo acquisition environment that puts any of my timelines at risk. There's no issue there at all. We are very pleased as it stands right now with the hybrid model that we have. We have a very good relationship with Brammer, working very closely with them. We're late in process development and yield optimization, we need to get that completed along with them getting all of our assays done so we can commence our commercial trial, our commercial process trial. We're working on that. Of course, we have a relationship with Paragon as well, both for our microdystrophin program the secondary supplier for our microdystrophin program, the primary supplier for our myotubular program. We feel very good about things. There's nothing about the Thermo acquisition or Brammer that puts anything at risk.
Great. Thanks.
Thank you. Our next question comes from Brian Abrahams from RBC Capital Markets. Your line is open.
Good morning. This is Bert on for Brian. Congratulations on the updated results. Thanks for taking our question. Can you give us a sense of what kind of deltas and functional measures you think you'll need to see in the 24-patient crossover study in order to show stat sig on some of the functional measures?
I think that the short answer based on the powering that we've done is if we see results like we're seeing in these first four patients, even over a longer period of time, frankly, we would hit stat sig on function. That's one of the reasons that we're so focused on moving as fast as possible to get our placebo-controlled trial enrolled. These results are giving us a lot of confidence that we're on the right track. It's also one of the reasons that we continue to use the same four to seven-year-old cohort in our placebo-controlled trial, although we'll be doing some additional work in our commercial process trial. Our powering analysis tells us that we would hit stat sig at this or even modestly less than these results.
It's easy to forget because this all becomes background, and we've seen some of these functional results before, not out to this level, but just so we're all on the same page, these kinds of functional results are completely unprecedented for any Duchenne trial. Again, we want to be careful about overanalyzing four patients' preliminary results, but it certainly gives us some confidence that we're on the right track.
Excellent. Thank you.
Thank you. Our next question comes from Ritu Baral from Cowen. Your line is open.
Good morning, guys. Thanks for taking the question. My first question is on the, I guess, the takeaways from the extended functional data, especially NSAA, on who you should enroll in the 102 study. Just given the improvements and the variable baseline NSAAs from 18 to about 26, I believe, what does this tell you about who you should enroll to show the maximum benefit and who you probably don't want to enroll to basically avoid any sort of ceiling effect?
We have some general guidelines around enrollment to ensure that we don't end up with any kind of ceiling effects with a patient that might be unusual for his age range. We're already sort of dealing with that issue. One of the things that it tells us that we're doing the right thing in enrolling four to seven-year-olds in our placebo-controlled trial. What we're seeing is a very consistent benefit against natural history across all of these ages. In the younger kids, because they are greatly outperforming any functional benefit that you would see in natural history for that age matched group. In the older kid, he's gaining function when he should be losing function, at least based on the natural history we have at a patient-level natural history. It's about the same.
We are seeing in these four to seven-year-olds, again, I'll give you a cautious note that these are early days, only four patients, but with that cautious note in place, we are seeing a pretty consistent and significant benefit functionally versus natural history that tells us we're on the right track for our placebo trial.
Do you think you have more confidence in the natural history on the increase in the older patients or in the decline. I'm sorry, the increase in the younger patients, or more confidence in the decline of the older patients in that range? Where is the natural history more robust?
It is consistently robust across all of it. It's an interesting question to ask which of those two subgroups we think is we have more confidence about showing differences. The truth is it's about balance. On the latter, the six and seven-year-olds, if they show function while others decline, you're going to see a big gap. You'd say, "Well, what about the earlier kid? They could actually gain some in natural history." Remember, they have a lot more headroom to ever into a ceiling effect as well. Our goal is not to simply. We're seeing at least, this does not just moderate the decline in the disease. It appears in these early days to be getting significant gains in function. NSAA are actual discrete gains in function.
There is a lot of headroom in the older kids to gain a gap away from DMD toward more non-DMD NSAA scores. If you sort of think of that mechanically, results, we feel pretty comfortable right now in the entire four to seven-year-old range, both from a natural history perspective, we've looked at patient level data across that. I think we have more information about that than just about anybody would on Duchenne muscular dystrophy. We feel very good about the results across these age ranges for this.
Got it. My last quick question was just on the protocol violation that you mentioned on patient two, the increase in CKs. I was noticing that patient two also was the patient that had, while a good increase in NSAA, also an increase in time to rise. Can you give any more detail on what the protocol violation was or how that might impact this patient's functional measures?
The protocol violation is straightforward. Look, again, it's not that surprising. These kids are very active in ways that are, at least anecdotally, thicker than you see in DMD patients. The kids are often, I think maybe consistently in the first four kids, were having their CKs taken on a Monday. It's the most convenient time for them. It's also a problem because it's right after a weekend. There's a real probability the kid can do something on the weekend that's inconsistent with the protocol. They're supposed to be resting for the two days beforehand. On this particular kid, I think he was at a park, if I'm not mistaken. Anecdotally, I can tell you he's very active on input.
When he came in for the CK, his parents admitted that he had been at a park and been very active the day before, I think literally been doing handstands and cartwheels and the like. He had a higher CK. His parents were reminded to come back in and do a resting CK, and as you can see, when they did that, it immediately dropped down to 6,000. That's what happened there. I think the other kid that had a spike was at the zoo. The Ohio zoo is a big zoo, so it's very active at the zoo. It's very simple. The struggle is, I can tell you, my semi-comic chief had seen the father of patient two at a conference right around the same time that this CK was being taken.
the father was talking to me about how active this child was, I actually tried to convince him that maybe we could convince him to be less active while we're in the middle of trial. He respectfully told me that that wasn't going to change, it is very difficult to get these kids to not act like children.
Thank you. Our next question comes from Salveen Richter from Goldman Sachs. Your line is open.
Hi, this is Andrea on for Salveen. Thanks for taking our question. As a follow-up to one of the initial questions, you mentioned that the preclinical data showed durability lasting years in a number of different animal models. How should we be thinking about trends over time? Can we expect the functional improvement in the CK levels to continue as we've seen in the initial nine months, or is it more likely that we'll see some leveling off? Thanks.
Louise, do you have some thoughts on that?
In the mouse, we've looked in primates as well. We can look at expression there, but in the mouse it's the best we can do as far as function. Over the time points that we've looked at, we've seen a continued improvement in function over the lifespan of the mouse. I also know some other work in the golden retriever. They have durability out to, I think almost eight years now, showing still sustained functional improvement. Those are the collective data that we have to rely on that basically shows that there's durability of functional benefit over that time point.
Thank you. Our next question comes from Joseph Schwartz from SVB Leerink. Your line is open.
Hi, good morning. Thanks for taking the question. This is [Dagan] dialing in for Joe, and congrats on the update. I understand that it's still early days, but great progress so far. Doug, two questions for you. First one with regards to, I guess, your prepared remarks, you were talking about discussions with the payers and how they want to look for some durability measures. Just wanted to get your take on, since you mentioned functional measurements on one aspect as an indicator of long-term durability, and on the other hand, potentially looking at CK, I guess there were a lot of questions during the Q&A talking about the variability aspect and protocol violation. Which of those two aspects do you think is gaining a little more traction in terms of progressing on the dialogue?
I guess the second question is, when we look at the improvements here, is it safe to assume that these treated patients should, at some point, reach normalcy? Given that, in the four to seven-year-olds, you're seeing such dramatic effect, if you were to take these patients out for a longer period of time, that it's no longer the natural history that you should compare it to, but the normal boy.
On the last question, we don't know how well they'll do over the long term. We certainly have as our goal, and we have as our belief that this therapy is going to be truly transformative for these children. That's our goal. The children have had Duchenne muscular dystrophy since they were born, so they've had the effects of Duchenne muscular dystrophy from birth, and so that may be some sort of limiter, and I don't want to overpromise. It is our goal, and certainly it is our subjective belief now based on everything we've seen, that we have a therapy that could truly transform the lives, extend the lives, improve the quality of the lives of these children in a way that has never been seen before in Duchenne. If we look to the discussions with payers, I'll say a couple of things.
One, there's no way payers would ever take CK as a measure of durability. To us, it's really two issues there. A couple issues. One is I think the gold standard for payers is function. They all want to see function durability versus natural history over time, and so long as we can come up with objective standards for natural history and the like, that might very well be the thing we end up with. There's another alternative, but you can see the issues associated with it. The other one would be just the expression level. The issue with looking at expression levels is that they require invasive biopsies over the long term, and there probably are significant practical and ethical issues associated with asking children to come in for regular biopsies, or post-therapy follow-up once the therapy is on the market.
We're looking at other things as well. One of the things we're looking at right now is are there other biomarkers that we could find that are less invasive but that would be directly correlated with expression levels? We don't have an answer to that yet, but we'll be working that through. We are in ongoing dialogue with payers even as we speak. I think we'll have a better understanding about what those measures would look like as we track into the first quarter of 2020.
Thank you. Our next question comes from Gena Wang from Barclays. Your line is open.
Thank you for taking my questions. Maybe first question also a follow-up with two questions regarding the CK. I remember back at the World Muscle Society, also there is variability on CK, and then there is a discussion on closely monitoring a patient's activity. You also mentioned patient two with some violation of protocol. What about patient three, and what kind of control you have to avoid the influence from activity in terms of pre-testing monitoring? After test, if you see the high score, do you have a follow-up score, and can you share that score with us?
The answer, patient three's high score appears to also relate to activity. Every time we've seen spikes, they've been consistent in a clear pattern associated with it. When they, so far, because patient three doesn't have a follow-up yet. So far, when they've been reminded to do a resting CK, at least two of the three now, as soon as they've done that, they've dropped below what would be DMD-like CK levels.
Thank you. Our next question comes from Joel Beatty from Citi. Your line is open.
Good morning. This is [Shawnee], again, for Joel. Thank you for the update this morning. My question's also on CK. Could you remind us at what point patients were tapered back from the daily steroid regimen back to standard of care steroids? What trial design protocols are built into your studies to kind of control for this? As a brief follow-up, are you looking at any other muscle damage biomarkers besides CK, such as lactate dehydrogenase or alanine aminotransferase?
I'll leave the second question to Louise. The first question is the children in the first four patient cohort were on 30 days of steroid. 30 days of increased steroid, tapered back. If there was a signal of an increase in liver enzymes, they were tapered back. They were put back on the steroids for an additional 30 days, then tapered back down to normal steroids. I will say, just so we're absolutely clear on this point, there is no correlate between the use of steroids and any drop in CK. We've shown that repeatedly. Recently, you may recall that we had some results on our limb-girdle 2E, and there are only two times that we're aware of in studies where there's been any correlate between significant drops in CK and therapy, and the one is our micro-dystrophin program, and the second is our 2E program with limb-girdle.
In connection with that, we showed, we actually had an interesting, in addition to all of the literature that shows that steroid use does not correlate with drops in CK, we also showed in that study that using the same protocol for a different of our limb-girdles, 2D, but at a much lower level of non-systemic gene therapy. It was isolated limb at a much lower dose. We did systemic steroid use with the same protocol that we're talking about, both in that program as well as in our micro-dystrophin program. What we showed there was zero impact on CK. Even with isolated limb gene therapy, but at low doses, the systemic CK did not have any impact at all. In fact, CK went up over the course of the study, not down.
The current protocol for these kids was 30 days of increased steroids, tapered back down to baseline steroids unless they saw an elevated liver enzyme, in which case they would be put back on steroids and allow that liver enzymes to go back to baseline, which they always did in all those kids. It was the same thing with limb-girdle, except with limb-girdle, because standard of care is not steroids, they were tapered all the way off, no steroids at all for limb-girdle. That's the protocol. For the avoidance of any doubt, there's no evidence whatsoever that CK level drops correlate in any way with the steroid use. It seems pretty clearly related to the use of that gene therapy itself.
Thank you. Our next question comes from Yun Zhong from Janney. Your line is open.
Hi. Excuse me. Thank you for taking the questions. The first question is, sorry, also on CK. Just noticed that all the variability happened after day 60. I wonder, is physical activity the only reason that affects CK level, or can potentially anything else affect it? Any reason why nothing happened before day 60?
Well, we might be speculating to suggest that it might be just coincidence they didn't follow the resting protocol a little bit later and they assiduously followed it immediately after the therapy. Beyond that, Louise, do you have any other speculation about why there would've been these protocol violations later, but not earlier?
No, just it would be anecdotal or speculation that as they're feeling better and getting more comfortable with the way they feel, that they had an increase in activity later on versus early on in the trial. We don't have any specifics.
Thank you. Our next question comes from Tim Lugo from William Blair. Your line is open.
Hi. This is Martin Jones for Tim. Thanks for taking the questions. Mine just revolves around patients one, two, and four . The improvement in the NSAA is pretty similar amongst those patients, yet I know patient four has considerably high microdystrophin expression at the three-month biopsy. My question is there a rooting effect on microdystrophin expression that could confer functional benefit, or is there milestones that are acquired by patient four in those nine months that we're not seeing reflected in those numbers that are only in patient one and two ? The second, just an enrollment update, if you could, on the placebo-controlled trial, that'd be great. Thank you.
Yeah. I don't think we can take from this data that there's a ceiling effect on the functional benefits, but we can take from this data potentially that there is a ceiling effect on the NSAA. These kids at 27, 26, these numbers are getting close to the top end of NSAA. We can't do better than the top of the NSAA, and we can't do better than an aged matched non-DMD child at this age. That's the ceiling effect. These kids have had such a profound impact. If you look at these kids, they were baselined, as one would expect, of 18 and 19 and 19, and now they're getting up to nearly 30 points on what is a theoretical 34-point scale.
There's that potential ceiling effect that occurs, where they're getting very close to what an aged matched non-DMD child would perform on this therapy. Then I think you asked about enrollment, if I'm not mistaken, on the current placebo-controlled trial. Things are going very well. Our goal is to complete the. Let me make sure we're clear about this, because people have asked, "How is enrollment going?" In one sense, I'm going to be very clear. We don't have any issues with enrollment. There is a significant inventory of patients available for our 24-patient trial. It's not really about enrollment like you would expect to see in some rare diseases. What it's about is just simply workload. We have a single site, single principal investigator. Dr. Mendell is our principal investigator.
He's required to do much of all of the work, including all the initial analyses, the infusions, follow-ups, and the like. As productive as Dr. Mendell is and as committed as he is, and I think nobody who knows him wouldn't expect him to be unbelievably committed, there's just a certain limit to his ability to do that. As we stand right now, we are dosing just about one patient a week. We would love to improve that to two, but frankly, our current timeline would suggest that we'll be completed before the end of the second quarter, certainly only requiring us to dose once a week. Things are going great. I think we are, I'm not sure of the exact number, maybe 13 patients or so by now. They're going very, very well.
Thank you. Our next question comes from Nirav Shelat from Piper Jaffray. Your line is open.
Hi, this is Nirav Shelat on for Danielle Brill. Most of my questions have been asked. The only question that I had was, I know the subcomponent analysis hasn't been done yet on the North Star, are there any expectations into which subcomponents will show greater or lower effects down the road as these patients get older?
Louise, do you have some thoughts on that?
Yeah, I can't speculate now until we do that analysis on the different subparts in terms of which would respond. I don't want to speak too soon on that right now, we're certainly evaluating it.
Thank you. Our next question comes from Vincent Chen from Bernstein. Your line is open.
Yes. Hello, Louise. Thanks for taking the questions. A couple just to help us better understand the bumpiness in the CK levels. Could you help us dimensionalize the degree of variability in CK levels that one might see in untreated DMD or Becker patients with variation in activity? How much impact, if any, would you expect that the temporary increase in steroid dosing might have on CK levels? Finally, just to follow up quickly on Gena's question, when there is a protocol violation related to activity, are patients simply told to rest before the next scheduled test 90 days or so later, or are they actually receiving additional tests in the interim period after resting appropriately, whether it's part of the protocol or just other clinical care?
Going to the first one there, Louise might have more detailed data on the fluctuations. Just to know, there are normal fluctuations. They're all above 20,000, but there are significant fluctuations in DMD children even in one day. In fact, it's not uncommon for DMD children to have instances of rhabdo if they over-exercise. On the protocol violation, the answer is yes. The parents are reminded to have the kids rest in the two days preceding it, they come back in. At least so far, that's worked. I apologize for that. Can you repeat the second question for me?
Pardon me, could you please press star one to get back in the queue? Mr. Chen, your line is back open.
Sorry about that. The second question is, how much impact, if any, would you expect that the temporary increase in steroid dosing might have on CK levels?
Oh, great. Thank you. The answer is none. None. This is going back all the way to the '80s. There was literature where there was early attempts in the hope that steroid use could be correlated with drops in CK. Notwithstanding the fact that steroid use has been shown, at least temporarily, to slow down the progress of the degenerative disease, there's never been a correlate between the use of steroids and any drop in CK. In our studies, at least with [evomeldro], I can tell you in the durable studies, we actually had secondarily kind of an interesting experiment on this where on the one hand, we did 2E full infusion at 5 x 10^13. Then we used the same protocol we're using here. We did 30 days, and then tapered unless we saw an elevated liver enzyme.
We did the same thing in the limb-girdle program, 2E. In 2E, you see these profound drops in CK. We also, in the limb-girdle program did for our 2D program. We did a low dose lower limb perfusion study, and we did the same exact steroid protocol. Where you saw real low dose and non-systemic gene therapy, so obviously less effective than the higher dose. When we looked at the actual steroid use and we looked at the CK, in that instance, because you didn't have systemic gene therapy, you didn't have gene therapy at more robust doses. We saw no impact on CK. Clearly, there was no CK-related impact of the steroid use. In fact, in the 2E study, we showed this in connection with our webinar for the 2E. The CK actually went up over time.
It seems pretty straightforward that once you've seen this kind of profound CK drop, it is associated with the protective nature of the therapy itself. In this instance, with the microdystrophin, and on prior instance, the use of the 51% protein positive fibers on the gene that chose for a big sort of blanket in that case, 2E program.
Thank you. Our next question comes from Christopher Marai from Nomura. Your line is open.
Thanks for the follow-up. I was wondering if you could further clarify perhaps some of the increases in things like time to rise on patient two. Perhaps could you, number one, help us understand some of these are effort-based outcome measures and how you are trying to control for that. Are there multiple measures in this study? Secondarily, where should a patient like this, patient two, and the others sort of be on the time to rise in general? Finally, is there a cutoff level on measures like that that you might think about with respect to, I guess, past the point of no return in a patient like Duchenne? Just specifically on that time to rise, since there was a question on it earlier. Thank you.
Sure. Louise might have some more specific information.
Actually, hi. This is [Dilawa] I'm here. Let me address some of those questions. I think first of all, the most important thing to understand is that we took out the functional data. It's all moving in a very positive direction. If you actually take individual data points patient by patient, you will actually see where variability can play a role. Certainly, we know from our analyses of time function tests and from our experience in the published literature that you can get some more variability on some of the time function tests. I think the other thing you asked about is the normal data, like what a normal boy would be doing at those different ages with those time function tests. We actually are collecting that information. We actually are working with a number of collaborators.
I think it will be published soon by some of our academic collaborators. We recently started doing that. What I can tell you is that what we are seeing is these boys achieving outcomes that are in excess of what we expected of their age group with their disease and do approach or move them towards a more normal range. I think the final thing you asked is about exceeding effects. You can certainly obviously anticipate exceeding effects even in normal boys for certain functions like going from supine to standing. In terms of the order of, I just quoted one to one and a half seconds. We obviously are doing those analyses and building the publications you mentioned at the beginning, probably coming out based on scheduling of some of our academic collaborators. For other things like running
You're very well aware of the limits to it, because even Olympic athletes cannot exceed certain caps for running or 100-meter walk. I think the optimal Olympic athlete cap is about nine seconds for 100 meters. You are right that there are caps there and ceiling effects. However, they are much less restrictive, if you will, than something like an NSAA, which is a functional modality at scale or no scale. Does that make sense the way I've answered that?
Thank you. Our next question will come from Yun Zhong from Janney. Your line is open.
Hi, thank you for taking the follow-up question. Can you remind us if you have had any discussions with the FDA on the length of follow-up on FVC analysis and safety analysis for potential approval, please?
We haven't had detailed discussions yet. Certainly, we're in continuing dialogue with the agency as we complete our placebo-controlled trial and we plan our commercial supply trial.
Thank you. Our next question comes from Edward Nash from SunTrust Robinson Humphrey. Your line is open.
Hey, good morning. Thank you for taking our questions. This is Fang-Ke Huang for Edward. Could you remind us what's the rationale to conduct a 24-patient trial at a single site? Thank you.
First of all, remember, this is very consistent with what AveXis, Novartis did as well. It started with a single site study. With Dr. Mendell as well, ironically. Very similar program to ours. We will be moving to a multi-center trial for our commercial supply trial, which our goal is to start that before the end of 2019. We're in a single site right now for a couple of reasons. One, because of the expertise of Dr. Mendell himself, and the consistency associated with the infusions and the like from Dr. Mendell. And second, for speed. That to get going with this study and to get the functional data confirmed in a well-controlled, placebo-controlled trial at the fastest possible pace required us to go with Dr. Mendell, who had a site that was up and running and able to dose these kids.
It would have probably delayed us by at least five to six months if we had attempted to get additional sites up and running before we commenced this first placebo-controlled trial. With that said, we have the time over the course of this year to get other sites up and running. It is our goal to get at least 10 or more sites up and running in the U.S. and very likely ex-U.S. for our next trial, which is our commercial supply trial.
Got it. That's very helpful. Thank you.
Thank you.
Thank you. Our next question comes from Tim Chiang from BTIG. Your line is open.
Thanks, Doug. Do you guys have data with patient one all the way above and beyond one year at this point? If you do, when do you think you'd be able to release that data?
I'm not sure if we have additional data to be honest with you. Might wi th patient one, I don't have it in front of me. We were updating because Dr. Mendell had updated. Again, I will say I am very concerned about continuing to update on the first four patients as we're literally in a placebo-controlled trial right now. I think there would be a real risk that it inadvertently looks like we're overly promoting the first four patients while we're trying to confirm the results in a placebo-controlled trial. I want to the extent possible, avoid additional updates to just really get this placebo trial completely dosed and get the functional results confirmed. Hopefully, if those functional results are consistent with what we're seeing so far, we'll have success in the trial.
That's our goal, certainly, and then to get our commercial supply ready to go and to get into our commercial supply trial and then get the commercial supply available so that as early as the end of 2020, we would have commercial supplies ready to go. I think if we get an approval, start serving this community that is so desperately in need of a transformative therapy for Duchenne muscular dystrophy.
Thank you. That does conclude our question and answer session for today's conference. I'd now like to turn the conference back over to Doug Ingram for any closing remarks.
Thank you very much. Well, presumably, you will understand based on this data why we are moving with such speed to confirm these results in our placebo-controlled trial and get this therapy, if successful, to the community as quickly as is possible. While preliminary, these functional results are better than anything that has ever been seen in Duchenne before, and better even than we would have anticipated at the outset. The CK drops are unprecedented, while we see occasional spikes due in part to the variable nature of CK, and in part to the non-DMD-like activity of some of these children, and from the occasional inconsistency with the resting CK protocol, we also see that whenever they spike, they drop back down to below DMD-like levels whenever that protocol is followed.
Of course, safety is extraordinarily important in these gene therapy trials, and we are very encouraged by the safety profile that has been observed to date. With all of that said, we are moving as fast as is reasonably possible to complete our placebo trial and to get our commercial material trial initiated, which we intend to do in 2019. This will be the focus for the rest of 2019 for us as we feel an obligation to the families living with Duchenne to move at the pace that this degenerative disease demands. With that, I thank you all for joining us this morning.
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.