Good day, and thank you for standing by. Welcome to REGENXBIO's data update from phase 2 ALTITUDE trial of ABBV-RGX-314 for the treatment of diabetic retinopathy using suprachoroidal delivery from AAO 2023. At this time, all participants are in a listen-only mode. After the speaker's presentation, there will be a question-and-answer session. To ask a question during the session, you will need to press star one one on your telephone. You will then hear an automated message advising your hand is raised. To withdraw your question, please press star one one again. Please be advised today's conference is being recorded. I would now like to hand the conference over to your speaker today, Ken Mills, Chief Executive Officer. Please go ahead.
Welcome, everyone, to our American Academy of Ophthalmology, or AAO, event update. I'm Ken Mills, CEO of REGENXBIO, and I'm pleased to introduce our agenda and make some opening remarks. This event is designed to review and discuss some new interim data from our ALTITUDE clinical trial of ABBV-RGX-314, henceforth referred to as three one four, for diabetic retinopathy, or DR, using one-time in-office suprachoroidal delivery. The slides for this presentation are available in the webcast and on our website on the Publications page at regenxbio.com. On the second slide of our presentation, you will see that today's event will include forward-looking statements. Please see here our full slide with our forward-looking statements, which can be reviewed at any time. Please be advised that today's call is being recorded and webcast.
On slide 3 is our agenda, and today we're joined by REGENXBIO Chief Medical Officer, Steve Pakola, and Dr. Mark Barakat, Director of Retina Research Institute, Retina Consultants of Arizona, Clinical Assistant Professor of Ophthalmology at the University of Arizona College of Medicine, as well as Dr. Peter Kaiser from the Cleveland Clinic. At the AAO meeting on Friday, Dr. Barakat presented encouraging one-year data from our phase 2 ALTITUDE trial for 314 for diabetic retinopathy. Again, using one-time in-office suprachoroidal delivery. Steve will provide a quick review of the update and then lead a discussion about the data with these retinal specialists that we have on the call today. At the end, we'll have some time for questions and answer session.
Before I hand it over to Steve, I want to remind everyone that 314 is part of our 5 by 25 strategy to progress five AAV therapeutics from our internal pipeline and licensed programs into pivotal stage or commercial products by 2025. Moving to slide 4, we believe that there is a multi-billion-dollar potential for 314 as a one-time in-office injection to become a new standard of care to treat and prevent progression of diabetic retinopathy in what amounts to over 10 million patients worldwide potential. While frequent intravitreal anti-VEGF treatment has shown to reduce the risk of blindness in randomized controlled trials, real-world evidence shows that less than 1% of patients with early DR are treated due to the unsustainable nature and burden of repeated anti-VEGF injections.
This means that over 99% of patients remain at risk of potential irreversible vision loss over time. And on slide five, we emphasize that treatment strategies that mitigate the disease burden and prevent vision loss are urgently needed, that early one-time treatment that's long-lasting can potentially modify and prevent disease progression. So now I'll turn the call over to Steve to take us through the data and lead our discussion.
Thank you, Ken. I'll start on slide 7, showing the design of the ALTITUDE study, which is evaluating one-time in-office 314 suprachoroidal injection for the treatment of diabetic retinopathy. The study has enrolled patients with moderately severe and severe NPDR and mild PDR without active center-involved DME in cohorts across 3 ascending doses with embedded observation control. Enrollment has completed, and we now have available the 1-year results for the dose level 1 and 2 cohorts, which were presented by Dr. Mark Barakat for the first time at AAO this past Friday. It's my pleasure to review these results with you this morning. Slide 8 shows the baseline characteristics, which were generally well-balanced across cohorts and dose level.
Moving to safety on slide 9, three fourteen has been well tolerated in the 50 patients treated with dose levels 1 and 2, with no SAEs considered drug-related. As a reminder, patients in dose level 1 and 2 cohorts received no prophylactic steroids. Less than 10% of patients had IOI in dose level 2, and these cases were all mild and easily managed with short-course topical steroids. Similarly, patients with episcleritis were easily managed with short-course topical steroids. Additionally, patients at both dose levels have shown stable vision through 1 year. Now on slide 10, we see the 1-year DRSS results.
To orient you to the color scheme, gray represents proportion of patients with no DRSS change, while progressively darker red bars represent proportion of patients with DRSS worsening, and progressively darker green bars represent proportion of patients with DRSS improvement. So red is bad, and gray and green are good. And you can see that in the observation control patients, as expected, there's more red than green, meaning on average, these patients are getting worse. Meanwhile, in patients treated with 314, overall, we see stable to improved diabetic retinopathy, in particular in dose level two. Of note, looking at NPDR patients treated with dose level two, 100% of these patients, 24 out of 24, had stable to improved DRSS score. On slide 11, you see the same data for NPDR patients represented in bar graph form, with the binary cuts highlighted that are accepted as pivotal primary endpoints.
We see that in patients treated with 314, there is a reduction compared to control in percent of patients with at least two-step worsening and an increase compared to control in percent of patients with at least two-step improvement. And also, as shown in slide 12, for proportion of patients with any improvement, we see better results for 314 treated patients, with 71% of NPDR patients treated with dose level 2 having improvement. Importantly, these standardized, validated imaging results are translating into benefit in terms of decreased risk of vision-threatening events, as shown on slide 13. 37.5% of control NPDR patients developed a vision-threatening event during the year, while 314-treated NPDR patients had a dose-dependent reduction in VTEs, with patients who received dose level 2 having an 89% reduction in vision-threatening events.
We'll finish with one case of a patient who received dose level 2. This is shown on slide 14. This patient had a baseline DRSS score of 47, in other words, moderately severe NPDR, and at 1 year had a 1-step DRSS improvement. Retinal thickness, as measured by CRT, was decreased slightly, and the BCVA remained stable. Slide 15 shows the fundus photographs for this patient that are used by the central reading center to grade DRSS. Of note, even though this patient had a 1-step DRSS improvement, the decreased signs of diabetic retinopathy compared to baseline are still clearly visible, with fewer hemorrhages present at 1 year. In conclusion, the 1-year results show 314 to be well-tolerated. Additionally, one-time in-office 314 injections demonstrated clinically meaningful improvements in disease severity with reduction in vision-threatening events.
Importantly, 100% of the patients with baseline NPDR treated with dose level 2 achieved stable to improved disease severity. Moreover, dose level 2 in these patients reduced the risk of developing vision-threatening events by 89%. Now, as Ken mentioned, we have the pleasure of having investigator and presenter, Mark Barakat, and also Dr. Peter Kaiser here with us today to answer questions from the audience. Before turning it over to the operator, let me start, though, by asking you both, what are your key takeaways from these 1-year results? Mark, you presented the data for the first time, so why don't you kick us off?
Thanks, Steve. From my perspective, this is highly encouraging data. You have a one-time treatment. We all care about safety. Safety signal looks good. This is a little bit for everybody. For the FDA, ultimately, the signal looks nice in terms of approvable endpoint, in terms of diabetic retinopathy severity score, both, you know, prevention of worsening and also improvement. But frankly, from a clinician perspective, you also have reduction in terms of vision-threatening events. It's encouraging all the way around.
Great. Thanks, Mark. How about you, Peter?
You know, I agree with Mark. To me, when I'm looking at a treatment for my patients with diabetic retinopathy, I'm looking at two things. One is durability of effect, and number two, reducing the problems that we worry about. And the problems we worry about, number one, would be either progressing, but more importantly, worsening of their diabetic retinopathy. So in general, over 1 year, most of the diabetics I see in Cleveland will worsen without treatment unless they, you know, somehow are improving their sugars by actually taking care of themselves, which again, in Cleveland, is rare. But the other thing that really struck me about the results of the 1-year cohort was that the vision-threatening complications that we really worry about were dramatically reduced, especially in dose level 2.
To me, that's really what was impressive. You know, I think showing the patient who improved their diabetic retinopathy score only one level according to the reading center, but if you look at that as a clinician, at one year, that patient has really improved dramatically and is doing really well, which is what the goal is for treating patients with diabetic retinopathy.
Thanks, Peter. I think it's interesting that you both highlighted in your own clinical perspective the particular importance of preventing worsening and real focus on what matters is decreasing the bad outcomes, such as vision-threatening events. So I think it would be helpful for our audience to hear how does that fit within your day-to-day practice, and how a one-time in-office injection might impact how you think about treating your patients? So again, let's start with you, Mark.
So, you know, we have excellent data to know that if we were to treat patients with diabetic retinopathy with some frequency of anti-VEGF injections, whether it be every 3 months, every 4 months, what have you, then we can drastically reduce the number of vision-threatening events. Yet, as a community, we hardly do that. A large part of that is the treatment burden and patient adherence, especially in a diabetic population. On the one hand, we have good data for something that will be helpful to our patients, on the other hand, no one does it. If you have potentially a one-time in-office treatment, that could be a game changer in terms of you treat the patient once, and then you can always monitor them, but you have that inbuilt safety in the background.
Peter, anything to add to Mark's comments?
Yeah, I think it's important to understand, right? These are patients who are working-aged. You know, we have FDA-approved products to treat diabetic retinopathy without diabetic macular edema in, in the form of our anti-VEGF agents, but the use in clinical practice is essentially nil. It's not because we don't think anti-VEGF works, it's because our patients simply don't want to return for the frequent injections that will be required to maintain the improvements in diabetic retinopathy scores and, and prevention of worsening. In contrast, 314 offers the ability to do an in-office treatment, and then we have a pretty good feeling that in one year, as shown in your data, they won't get worse. And if we look at vision-threatening complications, which probably would bring them into my clinic, those are also reduced.
To me, for my patients, these working-age patients with diabetes, this is a treatment that would be very useful.
So, given that, Peter, and I'll switch it up, I'll start with you on my last question. You know, you've highlighted some of the one-year results and how you see this may fit in, in terms of considering treatment for your patients. But, of course, one broader aspect is the overall risk-benefit equation that could exist for a one-time treatment. I think it would be helpful for both of you, first you, Peter, to say what risk-benefit characteristics you'd be looking for and how our one-year results are stacking up against that.
Sure. Yeah, to me, whenever I evaluate a new treatment, I'm going to look at the safety of the treatment. Delivering drugs into the suprachoroidal space, we have a lot of experience in doing that now. We have FDA products that are approved using delivery using a similar needle into the suprachoroidal space. So in the past, where it may have been a little bit difficult, now we're actually very used to delivering into this space. We're also used to some of the issues that are around that space, and I was very pleased to see in the interim safety analysis through year one that was presented by Mark this past week that the, you know, side effects or adverse events were minimal and ones I would expect, delivering something into the suprachoroidal space.
With gene therapy, we look very closely at intraocular inflammation, in particular, intraocular inflammation that persists. And I was pleased to see that it without prophylactic steroids, that the IOI was actually very minimal and basically resolved quickly with topical steroids. This is very, very encouraging. Then finally, if you look at the safety of the actual treatment, you know, the goal of our therapy is to prevent worsening. And in the NPDR group, the prevention of worsening was essentially seen in all the patients in dose level 2. So very exciting, very exciting data, and the safety to date over the past year or over a year appears good.
So, you know, basically, I agree with everything that Peter said. Data looks good in terms of safety. Intraocular inflammation, which is always the one thing you worry about, actually looks mild and was easily treatable with topical therapy. There was no additional interventions that were needed. And ultimately, whenever you're having a conversation with a patient about the risk-benefit ratio, the biggest risk is not treating the disease and watching disease progression, and yet we don't do it. So if you have a procedure that's possibly one time in the office, where the risk profile is small and easily treatable if they were to occur, that's potentially paradigm shifting.
Great. So, I want to thank you both for joining, bright and early on a Monday and for your insights on the one-year data from ALTITUDE. So before we wrap up, we have time for a few questions. So for that, I'll hand it over to the operator.
As a reminder, to ask a question, please press star one one on your touchtone telephone and wait for your name to be announced. To withdraw your question, please press star one one again. In the interest of time, we ask that you limit yourself to one question and rejoin the queue for any additional questions. Our first question comes from the line of Dane Leone with Raymond James.
Hi, thank you for taking the questions, and congratulations on the data and presentation. Maybe two related questions from me. How, how is the, how are the investigators and, and team at REGENXBIO thinking about dose response, when you kind of cut up the data and, and even looking for maybe an imbalance in dose level one for more, mild PDR patients? There seems to be a good dose response to dose level two relative to control and dose level one. What, what do we think is a clinical endpoint that's going to be, you know, usable from a regulatory perspective, on the DRSS change from baseline? Are, are we looking at, really stringently three-step improvers or, or percentage of patients that had a three-step worsening, or is it overall improvement versus worsened?
And any thoughts of what kind of scale of trial that would take to power effectively? But then on a related note, what we've seen from Panorama and some of the traditional studies that have preceded RGX-314, looking at diabetic retinopathy, there is always kind of a golden rule of looking at the percentage of patients that go on to have diabetic macular edema over time. I was wondering, do you guys know the breakdown of actual DME events within the cohorts and kind of across the different dose levels, and how different that looked? Or would you need more data maturity or perhaps a larger cohort to really assess that as a specific endpoint? Thank you.
Hey, Dane. Thanks for the good question. Steve, do you want to go into the observations about dose response, regulatory, and some of the sort of golden rule perspective?
Sure. Thanks, Dane, for the, for the questions. So I, I think one aspect we know that's pretty clear is what would be acceptable as, as a pivotal endpoint. We, we know at least two, which are based on DRSS, and it's one of the reasons we're excited about the data we have and that we've shown, because it's one year DRSS two-step improvement or one year DRSS worsening. So either of those are acceptable, and based on that, that's why we, we actually showed the, the one slide that showed a signal clearly on both of, of those endpoints.
As far as historical data like Panorama, where we see in a control group, about 40% of patients who have vision-threatening events at one year, we do know that the majority of those are PDR, progression to PDR, compared to the other vision-threatening event of center-involved DME. And actually, our data breaks down similarly. So most of the VTEs that we saw were PDR, progression to PDR, as opposed to DME, though we had one case of center-involved DME. So the breakdown is actually pretty consistent with what's been seen before. And the fact that these patients, mainly these VTEs, are a progression to PDR, also is supportive to the concept of the potential to look at worsening and also, in addition, to look at the potential for improvement.
To the question of what we would do, certainly we have the flexibility to look at either, and that's the kind of thing that we and our global partner, AbbVie, will be assessing. You know, we also have dose level three, where we'll have the opportunity to look at longer-term follow-up results. We'll have to see those results to, you know, have a better sense of dose response across these. I think it's fair to say that both these dose levels have signs of efficacy, but also our belief is on the most important endpoints, like what Mark and Peter both independently focused on. What matters the most is preventing these vision-threatening events.
You know, I think dose level 2, with an 89% reduction in that, for us, I think that's a very important finding and what our investigators and thought leaders have been very excited about.
Thank you.
Our next question comes from the line of Gena Wang with Barclays.
Thank you for taking my questions. I would just ask one safety question. So, we did see there are two more cases for dose level two and one more cases for dose level two regarding the conjunctival hyperemia and also conjunctival hemorrhage at the one-year follow-up compared to six months follow-up. So maybe if you can give a little bit more color there. And also wanted to ask both doctors, you know, any thoughts there?
Steve and doctors?
... Yeah, maybe I'll start in terms of the characterization of these. So these are mild, and over the course of the year, any findings are documented by investigators. So even things that frankly are not concerning, such as mild conjunctival hyperemia or hemorrhage, that can come from various sources that are not something that requires intervention or other aspects in that resolve. So these were not an issue. But, you know, Mark, maybe you can comment on how you think of mild transient hyperemia or hemorrhage that can occur during a trial.
No, absolutely. I mean, you always want to be vigilant. You want to record everything you possibly see on examination to be thorough. But frankly, in terms of conjunctival hyperemia and hemorrhage, in my mind, these are, these are non-issues. They, they can be easily seen in, in clinic on a regular basis, even from, from simple things like dry eye. So, and they, they tend to resolve spontaneously on, on, on their own. So to me, the most important thing that I focus on in looking at a safety profile of any investigational product is more the intraocular inflammation and episcleritis, for example.
Thanks, Gina.
Thank you.
Our next question comes from the line of Alec Stranahan with Bank of America.
Hey, hey, guys. Thanks for taking my question. This is John. I'm on for Alex. Yeah, just a quick one from me. Have the investigators collected maybe some quality of life metrics? Because I'm seeing here, you know, a lot of improvements are, you know, one step for dose level two. I'm just trying to gauge, you know, how significant that is in terms of, you know, symptom improvement, lifestyle improvements from the perspective of patients. If you could shed some light on that, be great. Thanks.
Thanks, John. Anyone want to step up and-
Yeah, I can do that.
Give a perspective about... Thanks.
This is Dr. Kaiser. When you're talking about diabetic retinopathy in the absence of macular edema, many of these patients are actually 20/20 and have absolutely no visual problems whatsoever. That's our big issue in ophthalmology is these patients oftentimes don't show up until they develop vision-threatening complications. So a change in diabetic retinopathy score, up or down, may not lead to any visual acuity changes in the short term. Now, long term, we do know that obviously as the retinopathy worsens, there's a corresponding rise in the vision-threatening complications, which you can see even just in the control group in this study.
But we also know that from control groups of many, many other studies, that over time, it's just simply going to get worse, which is why the FDA allows us to use the DRSS as a surrogate to prevention of that future vision loss. So a one-step improvement is actually really good. In my mind, prevention of worsening is the goal. Any improvement is sort of like gravy.
Yeah, and this is Mark Barakat. I want to tack on to that. I totally agree. In terms of quality of life, it's all about preventing the vision-threatening complications and events. That's number one. And number two, it's a question about the frequency of treatment. So as I mentioned before, we know we can achieve a drastic reduction in these events with frequent injections, but that impacts quality of life. These are working age patients. These are patients that have other doctor's appointments, possibly other complications that would preclude them from coming in. And then at the same time, they might have a problem with their vision, and that's a big problem. Whereas if you treat them one time and you have that on board, that would be - could be a game changer.
Thanks, John.
Thanks.
Thanks.
Our next question comes from the line of Ellie Merle with UBS.
Hi, this is Jasmine on for Ellie. Thanks so much for taking our questions. We just have one on safety. Could you give some more detail on the episcleritis and the IOI cases? So, you know, how long it took for patients to resolve, how long they were on steroids, and how many had moderate versus mild? Thanks.
Sure. You may have that one.
Yeah. Thanks for the question. So fortunately, this is short and sweet in that these resolve very quickly. So in a matter of days to weeks, and sometimes the weeks part is just because of the cadence of visits with the steroids. And all of the episcleritis, oh, excuse me, all of the IOI are mild, and that's really the most critical detail or event that Mark and Peter and the other investigators and clinicians care about. On the episcleritis, the vast majority of these are also mild with, you know, I don't have the exact number of how many are moderate, but either way, these also resolve within days to weeks of topical steroids.
Thank you.
Thanks, Jasmine.
Our next question comes from the line of Luca Issi with RBC Capital Markets.
... Oh, great! Thanks so much for taking my question. Just maybe a quick one. Bigger picture, what do you on cohort 4 and 5, what do you and AbbVie really need to see from cohort 4 and 5 at higher doses to actually start a phase 3? Do you need to see both better efficacy and safety from those cohorts, or just better safety would be sufficient? Thanks so much.
Thanks, Luca. Steve, want to share a perspective?
Sure. So we don't actually need to show both the improvement or the worsening, you know, as long as neither is actually worse than than placebo. But we do need to see on one of those enough of a signal to believe that, A, we're hitting our target and also that we can power a pivotal. So those are the aspects that we and AbbVie would look at. From a safety standpoint, we believe we're there, frankly, given the answer I gave to the last question and the fact that there's no other concerning safety issues. So we can't, you know, give any more definitive answer since, of course, this requires collaboration and review of the ongoing data with AbbVie. But certainly with the data we've seen, you know, we're very encouraged.
Great. Thanks so much.
Luca, I would just add to Steve's point. I mean, I think that the new evidence here that's being talked about of the reduction in vision-threatening events has certainly had a profound impact on, I think, the views both from the clinical and, and commercial teams that are part of the AbbVie-REGENXBIO partnership. And I think you're, you're hearing from us that, you know, we're seeing the shape of a regulatory endpoint coming forward with safety that I think gives us a lot of enthusiasm, and that the, you know, physicians are here representing what they know, but also what they need in the clinic to really, you know, put product into use.
I think, you know, this longer data from dose level 1 and dose level 2 is really something that we're reflecting on right now in terms of how to think about immediate next steps with respect to clinical development.
Super helpful. Thanks so much, guys.
Yep.
Our next question comes from the line of Brian Skorney with Baird.
Hi, good morning, everyone. Thanks for taking my question. I guess it's kind of a question for both the REGENXBIO management team and Doctors Barakat and Kaiser. In the same way, when you think about sort of a pivotal trial design, I guess what would you need to see in terms of the benefit relative to other options out there to really utilize this as a therapy in practice? You know, what is sort of the regulatory position right now and sort of what is required? Do you need to go against EYLEA and show non-inferiority to EYLEA? Can you do sham-controlled studies still, given that it doesn't have a lot of uptake, or is there some sort of median to look at as a control? Thanks.
Yeah, I can start on that one. Hi, Brian. So as far as the pivotal and what would be needed from a clinical standpoint, our view is really any benefit, particularly when you think of the vision-threatening events. And the reason for that is the in-office one-time treatment. So the problem with the existing therapies, as both of our guests have highlighted, is while they work, the repeated injections are simply not sustainable. And when you stop treatment, the DRSS gets worse, and the patients still then are going to have the vision-threatening events. So that's the reality from a clinical standpoint. From a clinical design standpoint, we, of course, still have to consider powering for the acceptable endpoint that we could get.
As I mentioned earlier, we have flexibility based on the good outcomes that we're seeing. As far as a control, because the real-world standard of care right now, because of that treatment burden with available repeated injections, is still observation in 99% of the patients. So we still have that opportunity and would use the opportunity to have a negative control, which makes it a lot easier in terms of being able to demonstrate benefit. Mark or Peter, any addition there?
Yeah. So I mean, from a clinical perspective, again, really what I'm looking for is reduction in vision-threatening events, because that's what matters to patients, that matters to the quality of life, as I've mentioned before. And so, I mean, right now, looking at dose level two, it's almost a 90% reduction in these events at, like, one year. And that. If you gave that to me in clinic, that would be a home run. So especially considering it's a one-time treatment. Frankly, even if you didn't, if you gave me a slightly lesser response than this, I would still be happy because I don't have to treat this patient over and over and over to get this response.
Yeah, I agree. You know, and specifically from the question about whether you need to do a clinical study in diabetic retinopathy against EYLEA or Lucentis in, say, a non-inferiority design, that's not required. So the FDA does not require you to go up against-
... anything. It's whether you can enroll the study in our current environment, as Dr. Barakat has mentioned, our normal treatment for someone with non-proliferative diabetic retinopathy is watchful waiting. We wait for vision-threatening complications. So because of that, in a diabetic retinopathy study, an observational control is absolutely not only acceptable, but it's the way almost all DR studies are done. There's no reason to do it against an active control.
All right, thank you.
Thanks, Mike.
Our next question comes from the line of Annabel Samimy with Stifel.
Hi, thanks for taking my questions. I had a big picture question for Doctors Barakat and Kaiser. Do you see a specific patient type here that you believe gene therapy would be more appropriate for? Obviously, this is a very big market, and we see more activity in NPDR patients, but is there a certain type of patient that you think would be suitable for gene therapy, or you think it would be appropriate for anyone who has moderate severe NPDR?
Peter, Mark?
I can take that. Hi, Annabel. This is Dr. Kaiser. You know, to me, the results to date, if they're mirrored in phase III, you would probably use this in almost everybody. You know, in Cleveland, our big problem is the patients don't return for follow-up. With this treatment, after we do the treatment, we could feel pretty comfortable that they're not going to worsen, and if they happen to miss their visits. And as you know, diabetic retinopathy is a function of sugar control as well as time of diabetes. And so for you to have developed diabetic retinopathy in the first place means you probably haven't been taking good care of yourself at all. This is really an insurance policy.
It's one of the reasons why we don't use anti-VEGF injections is because we know they're not going to come back. We're much more likely, especially in a patient who we really are worried about, just to do some laser, because they just aren't going to come back. But laser is destructive, causes all sorts of side effects, decreased peripheral vision, decreased night vision, et cetera. In contrast, this allows us to basically do the same thing, which is prevent worsening, but in a way that doesn't cause the side effects of our destructive laser.
Yeah, I mean, I agree. I want to add a little bit more color to it as well. I mean, it with this watchful waiting paradigm that we have right now, I mean, if you were to take the analog of that, if these diabetic patients were to see the primary care doc, and they would say, "Well, we'll just keep watching you until your sugar is under 400s and 500s, and only then when you have a complication, we treat you," that wouldn't be acceptable, right? And so the reason why we haven't been doing it is the treatment burden and the lack of follow-up, and a one-time treatment can change all this. That said, I definitely think moderate severity or severe NPDR is a sweet spot.
I think the adoption for that will be really easy and will be early. In mild cases, I think it might be case by case.
Just as a follow-up, do you not think it's appropriate for PDR patients at all, or are those the ones that are going to anti-VEGF treatment?
So I think PDR cases are reasonable. I think it depends how far advanced they are, right? And so if it's someone that has a vitreous hemorrhage or tractional retinal detachment, I mean, at that point, that ship has sailed. But earlier on, if it's a low-risk PDR patient, I think it's reasonable as well.
Okay, great. Thank you.
Thanks, Annabel. Welcome to the REGENXBIO coverage universe. Appreciate it.
Our next question comes from the line of Daniil Gataulin with Chardan.
Yes, hello, can you hear me?
Yes. Hey.
Yes, great, great. Thank you for taking the question. Yeah, I have a quick one on, durability that you guys see to this point. For example, for patients who showed 1 or 2-step improvement at 6 months, what proportion has maintained that improvement to 1 year? And conversely, for those who, what proportion of patients show a deepening response from 6 to 12 months? And I know you showed a case study of a single patient improving from 6 to 12, but, what is the big picture?
Steve, do you want to take that?
Yeah, thanks for the question. So the good news is that we previously presented six-month data. So what we're particularly excited about is not only the one year is the pivotal time point that we know of, but also the durability that we've seen. For DRSS, I think it's important to note that there's some variability in this, where you can have DRSS move one step in either direction in a small proportion of patients on repeat measure. So that's really what we've seen just in a minority of patients. So in the totality, we've had the majority of patients who were two-step maintain, but some who were two-step better might have gone down to one step, and others that were one step at six months might have gone to two steps.
But in total, we've seen, on average, a greater number of two-step or greater improvement and good stability across both dose levels.
Okay. Thank you.
Thanks, Daniil.
That concludes today's question and answer session. I'd like to turn the call back to Ken Mills for closing remarks.
Thank you all for joining us today. I really want to thank, Mark and Peter for making time this morning to share their thoughts with us and all of you about this update. We're excited about this data and what it means for the path to new treatments for patients, the value of the RGX-314 program overall, and for our eye care partnership with AbbVie. In just a few days, we also look forward to sharing more updates with all of you during our earnings call on Wednesday. Have a great rest of your week.
This concludes today's conference call. Thank you for participating. You may now disconnect.