Good morning. If you are a covering analyst, please join the link that was emailed to you by Laura McCormick instead of the public link so that you can be a part of the Q&A session. With that, I will now turn the call over to Ken Mills, CEO of REGENXBIO. Good morning, everyone, and thanks for joining us. Today we're excited to share new positive efficacy data from the AFFINITY DUCHENNE trial of RGX-202 for the treatment of Duchenne. Since our last update on February 7th, we continue to be very encouraged by the data we observe in this trial. A couple of housekeeping items before I kick us off. For our covering analysts participating in the live Q&A today, you'll be muted throughout this presentation. Once we begin the Q&A section, please raise your hand if you have any questions. Our moderators will address you by name within Zoom and prompt you to unmute. Once your question is complete, please then mute yourself again. Turning to the second slide of this presentation, you will see that today's event will include forward-looking statements. Here is our forward-looking statements disclosure. Please be advised that today's call is being recorded and webcast. Okay, let's move to slide three, and here's our agenda. I will give an overview of today's positive updates. Then Dr. Steve Pakola, our Chief Medical Officer, will review the data from the AFFINITY DUCHENNE trial. Importantly, we're pleased to have Dr. Aravindhan Veerapandiyan, principal trial investigator on today's call, and to engage in a discussion with him about the trial data and what he's seeing in the clinic. Dr. Panda, as he's known among his patients and families, is joining us from the Muscular Dystrophy Association Clinical and Scientific Conference in Orlando and will also be sharing these positive interim results on podium at the conference tomorrow. As part of his MDA presentation, Dr. Panda has a video featuring an early look at clinical videos from a couple of dose level one patients and home videos provided by the family of the first dose level two patient. Before I turn it over to Steve and Dr. Panda, let me share a few important reminders about RGX-202, our potential one-time therapy for the treatment of Duchenne in this new data we have today. On slide four, we highlight a few things that make RGX-202 special, including among AAV-mediated microdystrophin treatments. First, it expresses a new differentiated microdystrophin with important biology that is most similar to a natural shortened dystrophin found in boys and men that protects muscles from degenerating. RGX-202 has the only microdystrophin designed to deliver a transgene that includes the functional elements of the C-terminal domain found in naturally occurring dystrophin. All this really means is that it's designed to be the closest thing to recreating healthy muscle throughout the body. Also, RGX-202 is designed to be great for targeting muscle, and it represents an important potential alternative for many boys who may not be eligible for other therapies. Now, slide 5 presents our outline of our trial design for RGX-202 and its enrollment and safety status. We are enrolling boys who are generally confirmed genetically with Duchenne between the ages of 4 and 11, who are ambulatory. The primary endpoints of this study are safety and tolerability at 12 months, but across the 12-month period, we will complete a number of assessments, including of strength and function of all the boys. At three months, we take our important measure of microdystrophin expression, which gives us the evidence that our gene therapy is expressing in muscle and exists as one of the strongest and most validated biomarker predictors for the likelihood of clinical benefit. We've announced that we've enrolled five boys in this study to date, three at the first dose and two at the second dose. We will have an opportunity to enroll additional boys in this study. Overall, the data shows that RGX-202 has been well tolerated in all five patients treated. This morning, we announced the first microdystrophin data from dose level two. This was from a patient who was 12 years old at dosing, and we're thrilled to share that this microdystrophin levels are robust. Notably, this level of Microdystrophin was significantly higher than that of a dose level two patient in a similar age range among, say, eight-11-year-olds. With that, I'm going to turn the call over to Steve now to share more details about this data and the interim results to date. Thank you, Ken. I'm pleased to present today new positive interim results from the AFFINITY DUCHENNE trial. We'll start with the dose level one interim efficacy results on slide 7, which have previously been presented. Microdystrophin expression was calculated via the Western blot Jess method, and percentages listed are percent of normal control. Of note, all three patients showed robust microdystrophin expression and reduction from baseline in serum creatine kinase, or CK, levels, supporting evidence of clinical improvement. This RGX-202 activity was observed across the broad age range. Now on slide 8, for the first time, we present the interim efficacy results for the first patient treated with RGX-202, dose level two. RGX-202 microdystrophin expression level at three months following RGX-202 administration was 75.7% of normal control. Additionally, there was a reduction from baseline in CK levels of 77%. Moving to slide nine, these results in the dose level two treated patient are particularly striking when considering the age of this patient, 12 years of age at the time of dosing. We were already excited to see in dose level one not only robust microdystrophin expression in all patients, but greater than 10% expression even in the over 10-year-old boy with this lower dose. To now see at dose level two in an even older patient an expression level of 75.7% is quite remarkable. On slide 10, we see that not only is there robust microdystrophin expression, this microdystrophin is appropriately localized to the muscle cell membrane, as shown on immunofluorescent staining. To recap, RGX-202 has been well tolerated with robust microdystrophin expression at both dose levels in all ages. We are encouraged by the observations of early improvement seen in the videos that Dr. Panda will share. We remain on track to initiate a pivotal trial in the second half of this year. We continue to be excited about the microdystrophin expression data to date, and we are also pleased with what investigators are sharing about their patients. While we plan to present strength and functional assessment data for both dose levels from the trial later this year, today Dr. Panda will show us a first look of three AFFINITY DUCHENNE boys. This is a glimpse of how these boys are gaining functional skills since dosing. Dr. Panda will also show videos provided to him by an AFFINITY DUCHENNE family. The first two videos are of a four-year-old boy who was treated with RGX-202. At baseline, he's working on balance to stand on one foot, whereas at nine months, you can see him hopping on one foot. This same patient shows an improvement in the quality and speed of his 10-meter walk run at nine months compared to baseline. This next video shows a 10-year-old boy who was treated with RGX-202 at six months after treatment, showing increased confidence and velocity in climbing four stairs compared to baseline. You could also notice his improvement in standing from supine position, suggesting greater motor stability. This set of home videos was provided to me by the family of our first dose level two patient who received RGX-202 at 12 years of age. Their enthusiasm was contagious, and I wanted to share these moments to provide some insight into what I'm hearing and seeing from families. Though we blurred out his face for confidentiality, I do wish you could see the smile and pride he takes in being able to perform these activities, which can be quite difficult for boys with Duchenne. Finally, I would like to share a quote from this mom regarding her own informal but important observation after being treated with RGX-202. Now we will transition to the Q&A session. So, Dr. Panda, good afternoon. And first, of course, thank you for joining us. We know you're on the ground there in Orlando at the MDA conference, and we know you're busy, of course. So I think to kick things off, why don't we hear what your thoughts are on this data, and I think particularly how you're feeling about the data that you're going to be presenting tomorrow. Good morning, Steve. Good morning, everyone. No, I think it's like I showed. I think it's I'm very pleased to see the robust microdystrophin expression to begin with and consistent with the dose level one, also in the dose level two boy. And also, regardless of the age, he's an older one. He was 12 years old, and this microdystrophin expression was robust, which I'm very excited to see that. And also the videos that I've shared from this mom are quite telling. These are the day-to-day activities that these boys would not be able to do without treatment, and now they're doing that. And the stories that the mom and the kid are sharing with me, it's quite telling. So I'm very pleased with these preliminary results that I'm seeing with microdystrophin expression as well as the functional improvements, early functional improvements that we are seeing. From a safety perspective, like you said, I think we haven't seen any serious adverse effects in any of the spots we've dosed so far. I think that's also encouraging, and I'm very excited to share these results with our colleagues here and the Muscular Dystrophy Association conference and spread these positive results here. So you mentioned being pleased with the microdystrophin expression levels as we moved up to dose level two. Do you have any perspective when you think of the differentiation of 202 that Ken discussed, the facts or the actual results that we're seeing where at this age group, this much older age group where there really hasn't been other data presented outside of what we presented when you get up to this age group? As far as now having this data when you consider the dose level one patient that was above 10 years old and now seeing this increase at dose level two with the 12-year-old patient, any perspective on those findings? No, I think it is encouraging, but of course, you're talking with NF1. There's a lot of, there could be some factors that could play a role in terms of the sampling and the muscle you choose and all of that. But regardless, I think in this age group, having this robust dystrophin expression is exciting to see, and we hope that this predicts the clinical benefit, and we continue to see the more outcomes, the continued more improvements. My expectation, I think at least, was from a microdystrophin expression perspective, there is going to be a variability regardless of the age and I think we don't still completely understand why that variability is happening, but with NF1, with the older boy, with 12-year-old showing the 75% of normal dystrophin expression, I think it's very encouraging to see. Thanks, Dr. Panda. So I think for the audience, it would be helpful as well to step back and, given this data, just to hear, how do you talk to your patients when you're considering potential participation in a gene therapy clinical trial in the context of the landscape that exists for treatment of Duchenne? I think that's a good question with the therapies in pipeline, the approved therapies and the clinical trials. If I'm seeing a newly diagnosed Duchenne or I'm seeing them for the first time or no matter if I'm seeing them for the first time or I'm seeing them, I think we're obligated to present the options to them, right? So what are the approved therapies that's available versus what's in the clinical trial pipeline? And you discuss what you have in hand from a data perspective and the risk benefits and commercial dosing versus dosing the research setting and make an informed decision based on all of this. And I think if I'm discussing the REGENXBIO RGX-202 clinical AFFINITY DUCHENNE trial, obviously, I will be showing the data that's publicly available to them and to show they're making an informed decision based on what we have. And then I think also the therapies that are approved, there are some restrictions too, right? From an age perspective, and if you're looking at exon skipping agents, then that's also restricted to patients who have specific genetic change with amenable exon skipping agents. And then so I think those things would need to be taken into consideration when you discuss these options of treatments and participation in clinical trials, and we just choose the best that's best for that particular boy with Duchenne and make an informed decision. Great. So since we're appropriately talking about the patient and the family perspective here, for my last question before we turn it over for the group Q&A, let's go back to those videos you showed. I wonder if you could give any additional perspective when you see these findings in the clinic and also the patient videos and even what you're hearing from the families when they are seeing these kind of findings. Sure. I think I've said this to some of our colleagues as well, I think. To me, yes, the assessments that we do in the clinics are important, like North Star or Time to Stand, but what's more important to me is how is it impacting the quality of life in this kid? I think that's more impactful for me, and I think that's what made me share these videos when the families are showing me this. If they're telling me if my son wasn't able to play with his siblings, but now there's a chaos in the household, always there's arguments between brothers because the brother who has Duchenne is not able to play with the younger brother who doesn't have Duchenne. But now it's better. Now they're playing. Now it so that is a significant change or impactful change in the quality of life. The riding bike video, I think that's the first time that he's doing ever in his life. I think that's more impactful to me to get this real-world quality of life data. How is that being changed or impacted? I think that's more important for me. Great. So thanks again, Dr. Panda, for joining us and as well, of course, for your expert insights. So before we wrap up, we have time for a few questions. As a reminder for our covering analysts participating in the live Q&A today, please raise your hand if you have any questions. Our moderators will address you by your name within Zoom and prompt you to unmute. Once your question is complete, please then mute yourself again. Actually, it's going to be me who's going to identify people for questions. This is Ken. So I'm seeing people queued up with hands raised. We're going to start with the Barclays team. And Gina, could you unmute yourself if you have a question? Yes. First, wanted to say congrats on the great data. So I have two quick questions. One is for Dr. Panda, and one is for the company. For Dr., so how soon do you start to see patients show the functional improvement if we look at the protein level? So second question for the company, it seems like a dose level two is the path forward. Given this data, what would be the age group for your pivotal study? And also, did you get a confirmation from the FDA that single-arm study with protein level will be sufficient for approval? All right. Thanks, Gina. Good question. Dr. Panda, yeah, do you mind answering her? Sure. I'll take the first question. I think for the experience with RGX-202, the improvement that we're seeing is actually pretty early within a week to 2 after dosing, I think. The videos that have been sent to me were also around the same time frame. So I think we started seeing these changes within a week to two after infusion. In terms of plans moving forward, Gina, we obviously continue to be on track for initiation of a pivotal in the second half of the year. Yes, we have very dynamic and regular conversations with the agency about the data that's coming off. We're just so it's pretty amazing, pretty emotional the past week running up to this data and the share for some of the improvements we're seeing from Dr. Panda and what he's describing. So we've been able to even insert that into our conversations with the agency. We continue to feel strongly that there's really a broad application here age-wise for boys. We'll be on track for making that pivotal dose selection and completing the idea behind the design of what we think will be an efficient and important pivotal trial. Absolutely, we continue to view that for pivotal microdystrophin as a surrogate that's reasonably likely to predict clinical benefit. We'll support that. Again, we want to stay in a broad age range. Seeing the types of results we're seeing in 10-year-old, an 11-year-old who turned 12 just before they were dosed is really encouraging because I think that there's been a paucity of data to support microdystrophin, but also evidence of potential clinical benefit there. So we're moving forward with that in mind, and more to come from us. But I think today, I can signal to you, we continue to have those discussions, have had those discussions, and have been able to share the data even that we're looking at today with you, also with the agency. Thanks for the question. Let's go back into the queue here. How about maybe the Morgan Stanley team, Vikram or Gospel, are you on? You can unmute. Yeah. Can you hear me? Yep. Good. Hi, everyone. This is Gospel on from Vikram. We have two questions from our end. The first one is, Will the MDA presentation contain updated data versus what was presented this morning? The second one is, How does this data impact your thoughts on the trial size and design? Thank you. Yeah, thanks. So I can take both of those at this point. No, Arvind is going to present the same data that we looked at this morning with all of you to his colleagues, clinical and scientific, at the conference in Orlando tomorrow. So what you've seen from us today is going to be, I think, a powerful encore presentation tomorrow midday. And sort of similar answer to Gina here, Gospel, in terms of the direction of things that are going. We have a goal to initiate pivotal by the end of the year. I think we're looking to do something that is efficient, something that's responsive to, I think, what the community needs in terms of unmet need for kids maybe in areas. I think Dr. Panda was talking a little bit about the experience in the clinic today with obviously already some options, including an accelerated approved product in certain age range. I think what we've been seeing and what we've seen today has created, I mean, a renewed sense of urgency for us to be able to program in a trial that is efficient, that we can execute on efficiently. And as Gina sort of alluded to, I think for us, the safety and the early evidence here of both microdystrophin expression and the beginnings of seeing a series of early observations about strength and function at dose level one at nine months and six months and early emerging data from dose level two, we think we can put something in place. It reminds me too, Gina and Gospel, I didn't answer the question about placebo control. And I think that we've heard loud and clear from the community, and I'm sure the physicians and the clinical trialist agree with this. There's just not really something that is acceptable for the Duchenne community at this stage in terms of installation of long-term but even short-term placebo control arms in trials. There's too much unmet need. There's too much serious consequence for that. And we're getting a real sense that that understanding has landed into the FDA, and they're supportive of using ideas like natural history and sort of other types of control arm benefit assessments based on what's known. So I think that also will contribute to our ability to enroll and execute efficiently in pivotal. Thanks for the question. Let's see. Maybe we can go to Bank of America and Alec. Yeah. Hey, guys. Thanks for the questions. Just two quick ones from us as well. Maybe first for Ken, what should we expect from the next NSAA functional data? I guess what would be a good bar for the new data later this year? And then one for Dr. Panda, if he's still on. Given the data today in the 12-year-old, do you now see 202 as maybe the de facto study you'd recommend to new patients, especially if an older boy comes into your clinic given there's currently limited options for these children? Thanks. Aravindhan, did you have a comment there? And we'll go in reverse order. Sure. Can you repeat that first question? Sorry. Yeah. It was a question from Alec about your thoughts on recommending patients for trials and whether or not AFFINITY DUCHENNE and 202 stand out for you in general or for certain types of patients at this stage maybe? No, yes. I think definitely for the with the current trial setup, with the inclusion/exclusion criteria in mind, definitely this is something that we would discuss as an option. Again, like I was alluding before, the options for those older boys is very limited at this point of time. And I think this opens up a door and is encouraging for them to have a clinical trial that actually addresses that age group. And I think that is definitely something that we would discuss with our patients. Yeah. No, thank you. Alec, your first question, I mean, obviously, we remarked today that several of the items in the clinical readouts are part of the timed tasks, are things that are also measured in North Star. And I think Dr. Panda has also emphasized that obviously, from his perspective, I think some of the quality of life, heard him say, and kind of evidence that comes in from sort of day-to-day activities is also important. I think as we have guided in the second half of the year about functional results, that it would include strength and functional assessments for both doses. We're going to be continuing to play out the trial assessments from AFFINITY DUCHENNE, including North Star and the subdomains thereof, and have a more complete dataset for patients that have been dosed at dose level one and dose level two with respect to those assessments in the second half of the year, obviously, just given the passage of time and how the trial is designed. So we're excited to bring that forward in more full form. But when we had the opportunity to get the microdystrophin result this week and Dr. Panda contacted us about some of the existing 9-month and 6-month evidence at dose level one and the emerging things he was seeing even with the first patient at dose level two, we felt it was important to insert this into our regulatory discussions and therefore publicly as well. Definitely more of the full domain assessments in the second half of the year is what we would target as we continue to share data about this study and make final decisions about the pivotal. Great. Thanks, Ken. Maybe we can go to Annabel at Stifel. Hi. Can you hear me? Yep. Hey, Annabel. Great. So this is for Dr. Panda. So I was just curious if you saw any correlation between the Microdystrophin expression in these patients of whom you had videos and the improvement that they experienced? And just separately on the 12-year-old, which I realized he was 11 when he got into the study, but was there anything about this boy that suggested he would have a higher expression than what we saw, say, in some of the younger boys? And even seeing the level of functional improvement and strength, I assume this age group would have been already too far deteriorated. So maybe you can provide some color there. No, I think kind of talk about the sort of correlation between the function and dystrophin expression. I think it's kind of too soon to comment on the NSAA scores and stuff. We still don't have that functional assessment data. But definitely, we know dystrophin expression, they have no dystrophin and dystrophin expression correlates with more improvements. From how he, as an older boy, having higher dystrophin expression, I think I don't know if we have a clear answer for that. One would expect that they have more muscle damage. The dystrophin expression could be lower. But I don't think there's a lot of factors that come into play there. Is it a sampling part in the muscle that you choose? But having said that, all of these patients had exact same biopsies from the exact same muscle. I think that variability in the Dystrophin expression is something we need to look into more and why is that happening. This is something we have seen across other programs as well. Does that make sense? Yeah. If I could possibly get a follow-up here, is there any clarity at this point on—I mean, you all referred to the NSAA score for the functional test, but we see that scoring has tripped up some other companies. Is there any further clarity on what type of functional and strength measurements the FDA may accept further on down the line when you're looking for not just the accelerated approval here but for full approval? Maybe you can comment on that, Ken or Steve. I mean, sorry. Yeah, again, I mean, yeah, Dr. Panda, please. Anyone, actually. No, that's fine. I can throw my two cents. I'm glad that he brought up the NSAA. I think the disease that we're dealing with here is so heterogeneous, and it slowly progresses. I think to see a meaningful difference or that is statistically significant with NSAA, it needs longer follow-up, more than a year or even two years and years. I think practically, in the stage we're with this disease and unmet need, I don't think it's fair to keep these patients that long on a placebo or to see the treatment effects or difference, right? I think some of the other endpoints that we could possibly use would be those which the FDA had considered in some of the other trials would be the time to stand or four-stair climb. The vamorolone that was just approved, they used the time to stand velocity as a primary endpoint and got the approval. One of the other products that's being reviewed right now with the PDUFA for it coming up soon is, I think, with givinostat, I think they have used four-stair climb as a primary endpoint. So some of those things could be considered as well. Sorry, Ken. Yeah, Annabel, I mean, those are great insights from I think the source of people like Dr. Panda who see these patients and can provide a level of perspective for the agency and for us as sponsors into what we can rely on to show evidence of clinical benefit. And all I can add on top of that is that we absolutely see the receptivity of the agency in listening and understanding and not applying some strict set of rules about something like North Star for sure. I think, look, we're talking about RGX-202 as something that's new and innovative in the class of microdystrophins, and we're starting to show data now for the first time in terms of strength and functional assessments that are emerging that we don't rule out being able to incorporate North Star in a meaningful way into the evidence about performance of RGX-202 both clinically and as we aim to bring it to patients and families on a basis where people like Dr. Panda can think about prescribing it. Again, we can't forget RGX-202 with the C terminus has biology that we've been emphasizing for a while is more representative of naturally occurring dystrophin than anything else that has been brought forward at this stage and this far along clinically. So we think we can tackle things in principle that could be demonstrations that haven't been shown before. While we're working through this, we're seeing really good progress on, I think, some of these early areas. Great. Thank you so much. I think another important point is that microdystrophin is reasonably likely to predict clinical benefits. So these findings that Dr. Panda is showing as well as any additional functional benefits that we see are really a bonus from a regulatory standpoint because these functional questions of which endpoints will have more sensitivity and more power really relate to, from a regulatory standpoint, a confirmatory study. Yeah. Good point. Thanks, Annabel. Maybe we'll move to the UBS team. And Ellie, are you on? Hey, guys. Congrats on the data. Maybe just as you're thinking about dose selection and what would give you confidence to move forward into Pivotal, I guess, how many patients and at what ages would you want to dose with dose level two before making that Pivotal dose selection? Just any more color on when in the second half you expect to start the Pivotal trial. Thanks. Yeah. Look, the trial design, which started at sort of 3+3 and now with early evidence of safety demonstrated, we were able to amend with the FDA to the 3+2 design, I think, is a bolus of data that provides us the foundation to make a decision about safety, about some evidence of dose response. I've said for a while, look, scientifically, and we're led very much here by the science and being transparent about the science, we've rerun these 2 doses in our preclinical models, and we've continued to show separation between dose level two and dose level one. Now we're seeing some early emerging evidence of 2 different boys but in the same age range, kind of that 8-11 range of kind of some increase in expression from dose level one to dose level two at microdystrophin. And we're seeing good safety. I mean, all of this very much this is what we need. So I don't think that there's going to be some more passage of time. There's going to be a bit more inventorying. We, of course, have another patient at dose level two that we expect to be able to collect data on now in the we just announced we completed that cohort about 3 weeks ago. So sometime in the second quarter, we would have additional results. And I think we'll be in a position, as expected, to make that Pivotal dose decision by mid-year. But we've got a little bit of wind at our back now, in my view. And the feedback from Dr. Panda and investigators is giving us new resolve to move as quickly as possible into that initiation of Pivotal phase. I can't say sitting here right now, Ellie, how much time we can gain on kind of our base plan. But this is the type of data that I see today that we're going to be redoubling our efforts to make sure that as soon as we have all the data that we need, we can get to the FDA, complete a Pivotal design, and move forward as quickly as possible. And it's a great time to be talking with the agency on these topics because they've got a number of decisions and contemplations that are happening around Duchenne and around microdystrophin expression with Duchenne in other cases as well as ours. So it actually, in our view, sets up as a very good time to have that dialogue and move quickly. Great. Thanks. Thank you. Looking at the hands raised still. Maybe Brian and Baird? Hey, yeah. Good morning. Thanks for taking the question. And really impressive dose level two data here. I guess as we're kind of thinking about the whole pathway, one of the things that really hasn't come up, but I'd be interested in hearing your opinion on, is sort of the non-ambulatory patient setting where it seems to me like there's just the biggest delta in what is potentially available, approvable, the data that we have from Elevidys or even from the PMOs and the unmet medical need here. And given your great expression in older patients, how are you thinking about looking at non-ambulatory patients? Can you look at those patients in this current study? And it just seems to me like maybe there's a very quick path to approval, perhaps even quicker than in the ambulatory setting given Elevidys's presence. And I guess for Dr. Panda, do you think sort of dystrophin expression in muscle biopsies is enough to have confidence in a non-ambulatory patient's efficacy at this point? Go first. I can, yeah. I think my opinion about non-ambulatory is not just the dystrophin expression, or it's not just the age or ambulatory status. It's more about the weight and the cardiac reserve, at least from the learnings that we have had from the other programs. I think, personally, I would be comfortable with those limitations, with those caveats, keeping in mind we're dosing them safely to move on to a non-ambulatory patient's dosing. But of course, it's not my decision. It's always going to be hard for us to argue with the people that are expert in the disease, Brian, about the pathway for moving forward. And again, the influence that Dr. Panda and his colleagues would have on FDA's thinking about that will be important. Look, where we are is we've obviously focused early on in the differentiated benefits of 202 in 4-11 ambulatory. And the fact that we're, I think, seeing the type of results in this older age range, in the 8-11, is giving us some conviction and is allowing us to have conversations and discussions and thoughts specifically with Dr. Panda and other investigators about whether there are other types of cohorts, if you will, opportunities for expanding and sort of also accelerating the development. That includes the notion of non-ambulatory, the notion of age ranges that haven't been studied as deeply or as transparently have been limited in terms of data that's been shared, and even concepts around mutation status and things that have been excluded previously. But I think Dr. Panda's point is an important one. Safety is paramount here. So far, we have, not just in an age range, but in a weight range, been able to show a well-tolerated safety profile. Again, our goal here is about efficiency, transparency with data, and finding new areas to contribute something to the community, both the physicians, the families, FDA, and for ourselves. Knowledge that doesn't exist, we think that is the recipe for success in terms of how we can benefit everyone that's a stakeholder here and accelerate things as quickly as possible. So I love that you're taking that away, Brian, because I think it's telling us, and I think it's reinforcing for us, people that think on these topics, that this is opening up a spectrum of things for us to look at, not just to accelerate, but to grow value for patients. Thanks. Let's see. We'll go back into the queue. I think Danielle and Raymond James, are you able to unmute? Yes. Good morning. Thanks so much for the question and congrats on the promising data. So I have two, one for the company and one for Dr. Panda. For the company, trying to better understand the contributing factors other than dose that might explain the striking difference between the two older patients that were enrolled. And were there any notable differences in baseline characteristics such as baseline NSAA, dystrophin expression, or mutation status? And then for Dr. Panda, I know the data are early, but curious, based on the results to date, where do you see 202 fitting into the landscape with Elevidys on the market? Thank you. So I can address my question first. I think with the commercially available delandistrogene, as we all know right now, it's only approved for age 4 and 5. But the clinical trial here, it's broader range for the age like 4-11. And so I think definitely that's there. And even if I'm seeing a 4-5-year-old in the clinic, I think in my clinical practice, I'm presenting all the possible options that's available for them, right? That is commercially available product versus the clinical trials as well. So I think we discuss that. And definitely, this is an option that comes up, and we discuss that as well and make a decision from that. And also, again, kind of there's still unmet need in terms of, like Ken was pointing out before, from a mutations perspective, and also the antibody status would come into play as well. There are several other factors that come into play. Definitely, this is something that we would discuss in the clinics to consider. Yeah. Danielle, on the correlations in terms of difference, I mean, really, the strongest correlation has been the dose level. I mean, the inclusion criteria in this study is I mean, obviously, we repeated the age range. I mean, genetic confirmation of Duchenne and mutations and their baseline status in terms of meeting the tests for ambulation and kind of how these patients are coming in. We've seen, obviously, some variability because we have, and even Dr. Panda was just emphasizing, we've enrolled a 4-year-old. One of the videos from clinic today was looking at the observational evidence in that patient as well as the 6-year-old. We've been emphasizing that right now, we have that increase from the 10-year-old to the 11-year-old in terms of dose level one and dose level two because that's the evidence that we have in this moment. But that's the strongest correlation. The medical team and, I think, with investigators have been through, and there's no other correlation that's popping out right now, which is, again, consistent with our science in the preclinical dataset that we saw higher levels of expression with dose level two, which is why we recommended it to FDA as part of our dose escalation. And we also saw separation between dose level one and dose level two in terms of function and strength in the animal models. And I think we're really encouraged and enthusiastic that that will reproduce itself, so. Thanks for the question, Danielle. Thank you. Let's see. RBC, Luca, are you on? Or Lisa, you need to unmute yourself. Yeah. Yep. Can you guys hear me okay? Yeah, we can hear you now. Thanks. Great. Great. Thanks so much. Two quick questions. Maybe one on prophylaxis here. Can you just remind us about the difference in prophy regimen versus Sarepta? I believe they're using just steroids versus you're using also Soliris and sirolimus. So just two questions. One, is that correct? Two, if that is the case, is there a vision for the future here where you may be going to align with them and just use steroids? Again, any thoughts there? Much appreciated. And then maybe on the eligibility, can you just remind us what percentage of patients are not eligible for Sarepta just because of neutralizing antibody status? I remember you guys mentioned 15%-30% in the past. I'm just wondering if that's the latest thinking. Thanks so much. Sure. Yeah. Dr. Panda, do you want to talk anything about kind of the protocols that we're using in terms of run-in for safety and your experience with it in terms of its manageability? Sure. I think, like you rightly pointed out, we use here eculizumab, sirolimus, and corticosteroids. And so far, it's been well-tolerated. We haven't seen any adverse events even to that protocol per se. And from a practical logistical standpoint, from this kid's taking that, also, we haven't seen much of a challenge. And I think that's good. And even when you talk about this unmet need and some of those low exons, high-risk genetic change, having this proactive immunosuppressive regimen, in my opinion, is probably the way to go. And I think that's how the future holds. And I think with that immunosuppressive regimen, that actually gives me more comfort level to treat those patients with high unmet needs, especially the high-risk mutations. Yeah, we haven't seen any challenges with this immunosuppressive regimen in the trial. Yeah. No, thanks for bringing up that point because I know it's been a specific discussion with you and for the community about how the application of an immune suppression protocol may open up opportunities for treating boys where maybe other trials or other instances have presented themselves vis-à-vis concern. And I think that some of the mutations on the N-terminal end of dystrophin naturally have been things that have been part of that discussion. So I do think that gets back to the kind of theme here of not just the difference in biology, but I think a broad-spectrum approach to safety for as many boys as possible, different mutations, different age ranges, different weights, and sort of has been an approach for this trial design from the beginning. So I think continuing to open up options not just for acceleration and efficient implementation of pivotals, but for exploring new areas that may be untouched right now by some of the previous microdystrophin products, which does get to the neutralizing antibody status question, Luca. And yeah, I mean, so we generally have seen and we talk about the fact that AAVs have a kind of standard serological preexisting prevalence in communities, especially children of these ages that we're talking about of, I mean, it can be 30%-40% of boys who may be ineligible for treatment. That can have variability. When we've talked about a conservative insertion point for RGX-202, we've layered in the fact that we're aware that, of course, Elevidys has entered the market with a certain AAV serotype, that Pfizer is running a trial that has reported enrollment and we expect can report data at some point. So we're kind of giving guidance to the market that in a scenario where there are two other AAV products - and this would be true not just for us, but it would be true for the corollaries of those other sponsors - that then the Venn diagram may look more like 15% of boys that would be just unique and sort of indiscriminately available just to the AAV8-based capsid that we use in RGX-202. So that's, I think, how we think about the AAV immunology. But then again, as you start to layer in changes in what we're seeing today and the impact of that, if you go to a population of boys either on an age basis or on a mutation basis that isn't accessed by those other treatments, then again, I think you would see 70% of those boys being eligible for something like RGX-202. So I think this is becoming a very important and dynamic conversation and one that we're just happy that our science and data is contributing to because we know there's still significant unmet need here for patients and families with Duchenne. Got it. Thanks so much. Thanks, Luca. Heading down here to near the end, Mani and Leerink team, are you on and able to ask your question? Hey, guys. Thanks for taking the question. Congrats on very impressive data. A quick question around that Venn diagram dynamic that you brought up. Obviously, there's going to be patients who fall in the eligibility criteria for one or another AAV and a relatively modest number who are broadly available in sort of more of a competitive sort of free-for-all. For Dr. Panda, how do the parents think about choosing between these agents? Are there specific data points they're looking at? Do they see the safety as different? How does that decision get made in the conversation that you're having with the family? So I think that's a great question. There's a lot of factors, again, come into play. Like I was saying, we are discussing the options, right? The commercially available, what data that they have, and also the other options. It's quite variable. That depends on the family. That depends on how sophisticated, educated they are and how I have had families who come up to me and said, "Hey," they look into the C-terminals, and then I want to be in the study because of that specific reason. And also, they have good knowledge of the preclinical data on this and that it's commercially available. I mean, that's publicly available on RGX-202 with the same age group, the 4-5. But on the other hand, I also have families who would come and say that this is approved by FDA, but I don't want to be in a trial. So it's in a research. So it's quite variable depending on the families. But as long as we are putting out the options that we have and talk about the pros and cons, and I think that's important. And there are also in the clinical practice, sometimes they would say, "Yeah, this is all good, but what would you do if this was your kid?" I think that also comes into play. So I think there's a lot of factors, and it's very individualized based on the patient and the families that you're working with. Thanks, Mani, for your question. I think we're down to—I see—one more, Daniil and Chardan team. Hey, good morning, guys. Congrats on the data, and thank you for taking the question. One on safety, I was wondering if you could provide any additional color in terms of any adverse events. I know there's no serious adverse events, but maybe any other signals that you're seeing, liver enzymes. Do you see any correlation with age? And have you used any or have you had to use any interventions outside of a prophylactic regimen? Hey, Daniil. No, thanks for the questions. I think we haven't reported anything drug-related and certainly no serious adverse events today. We have evidence of this being well-tolerated across all five boys. And I think very, look, obviously, we've run a lot of trials as REGENXBIO, and people have used a lot of our vectors. So I think that our context here for well-tolerated in an important disease like Duchenne is an important one for us. And I think that we see what we want to see for being able to make the types of guidance statements about being able to move assertively and efficiently into pivotal phase. So good news from my perspective. I think that is it for the Q&A. I don't see any hands up. I appreciate the analysts. This is a little bit of a different format for us today with the Zoom. You're all really good at it, and I want to compliment you all. Dr. Panda, I'm just really grateful. I'm sure you're feeling some excitement and energy down there with a lot of things happening at MDA, and we're just so grateful for you to be presenting on behalf of REGENXBIO and to the community on these updates. Good luck tomorrow, and thanks for your overview for everyone today. Look, our initial efficacy with the first patients with RGX-202 is truly enabling us to accelerate this program. This is a market in Duchenne that there still our view is a large unmet need for new therapies. It's capable of supporting multiple gene therapies, and we think that RGX-202 is unique. It has differentiated features that support its potential to be a best-in-class product. Plans are for the remainder of this year, I think, clear. We are intending to focus on accelerating and creating significant value for patients and our shareholders. The resources, I think, are focused in the right areas. The milestones today reinforce for me that this year, we're well-positioned for success. So thanks, everyone, for the questions, the conversations. Thank you again, Dr. Panda. Thanks, Steve. And everyone, have a great day. We'll connect with you all, I'm sure, again soon.