Good afternoon, everyone, and thank you for joining us today for today's episode of Genetic Medicine for Generalists with Regulus Therapeutics. As we like to say, genetic medicines are complicated, but the conversation around them doesn't have to be. And so the goal of the call today and throughout the series is to dive into exciting new therapeutics and technologies, but in a way that is accessible to all and useful to all as well, including any specialists who might be listening in. A reminder, though, to the audience on questions, the more the merrier, and there's no such thing as a stupid question, so ask away, please. But do so via the webcast interface, because I will not be keeping an eye on my email during this call. So with that, I'm very pleased to be joined today by the Regulus team, CEO Jay Hagan, Preston Klassen, President and Head of R&D, as well as Rekha Garg, SVP of Clinical Development and Regulatory. Thank you all for joining today. Thanks for having us. Jay, I'm gonna turn it over to you for some brief intro remarks before we get into the questions. Sure. First, I would just wanna thank you, Whitney, and the team at Canaccord for hosting this opportunity to provide an update on our program in ADPKD. Regulus is a company focused on developing antisense oligos directed against microRNA, short non-coding RNA implicated in disease. We had a exciting update last March from the second cohort of our ongoing phase Ib study in patients with ADPKD, and looking forward to further updates throughout the year. I know we've got lots of questions planned. Why don't we jump into it, Whitney? Sounds great. So, let's start with kind of setting the stage, level setting the conversation around ADPKD, and its origins. 'Cause it's not... it's a monogenic disease, but maybe not as straightforward as some other monogenic, monogenic diseases that we're used to thinking about. Took me a while on that one. So, so what do we know, and what do we still not know about what causes this disease? Sure. I'll get started with that, and thanks again for the opportunity. And you phrase it, you know, absolutely the right way. It is, it's a monogenic disease, and so you might think the story is straightforward, a gene's not working as well, and so whatever that gene was supposed to do, you know, has some problems. But as it turns out, you know, there's a much about the pathogenesis of ADPKD that's still being researched, even though it is, you know, one of the most common monogenic diseases out there. So I'll start with what we know, and about the gene and the gene product, the PKD gene, the PKD gene product, which is polycystin, and then what we are still kind of uncovering, even as of recently in your... You know, you had a recent note that highlighted a very cool publication in this space that talks about the complexity of it. So at the bottom line, ADPKD is a disease of abnormal cell proliferation and cell transformation, where the epithelial cells that make up the tubular structures in the kidney hyperproliferate, and they transform to cystic epithelial cells. And so that causes abnormal fluid-filled cysts in the kidney. Those cysts progressively grow, and not only is the renal tubular function that those cells used to be renal tubular cells, you know, so those cells aren't functioning properly. But in addition, as the cysts grow, they exert pressure 'cause the kidney's encapsulated, pressure on adjacent normal tissue, and that eventually destroys it as well. So you get a gradual decline in kidney function. And in terms of the more severe form, PKD1, 50% of those patients reach dialysis by the age of 55. So it's a very significant impact in terms of life quality and longevity. So there's two genes that we're talking about in terms of PKD: PKD1 and PKD2. And a germline mutation in either gene, meaning it's a mutation that's inherited from one parent, will cause the PKD phenotype. As I mentioned a second ago, the PKD1 mutation in that disease is more severe, but it also represents almost all of the disease. It's 85% of ADPKD is PKD1. Both genes, PKD1 and PKD2, encode for a protein called polycystin, and so each gene that makes polycystin one or polycystin two, and these two proteins are transmembrane proteins that together form a receptor ion channel. That's a channel complex in the membrane of renal tubular epithelial cells, and under normal functioning, that helps control a cascade of chemical reactions inside the cell. It helps regulate cell growth and proliferation and differentiation, cell position, and communication with other cells. So what has been shown is that a lack of that polycystin does promote abnormal proliferation and cyst growth or cystogenesis in kidneys. And so a germline mutation in that PKD gene will knock out, 'cause each gene has two alleles, it'll knock out or reduce the production of one of those alleles, and you still have a wild type that can make protein, but over time, you can get the accumulation of additional mutations, those are called somatic mutations, and that may further reduce, over time, the kidney's ability to produce polycystin. Maybe the last thing I'll say about polycystin is that we also know that if you transgenically in a mouse, give a background of PKD, but then restore polycystin production, after disease has been initiated, you can actually reduce the proliferation. So you're now kind of forcing more polycystin to be made. You can reduce proliferation, you can reduce cyst growth, and perhaps even start to return the kidney towards normal tissue. So reduced polycystin is clearly an important, you know, part of the disease pathogenesis and progression, and a therapy that can increase polycystin should help address abnormal proliferation and cyst growth. So that's what we know. What we're also learning a lot more about is that linear story of the PKD gene is, you know, mutated; it doesn't make as much polycystin or as much functional polycystin. It's actually much more complicated than that, because we know that the PKD mutation, that gene mutation, also triggers widespread dysregulated gene expression across hundreds of genes. Many genes are impacted, not just the PKD gene. This involves a variety of transcription factor signal pathways that are essentially proto-oncogenes: c-Myc, c-Fos, c-Jun. As proto-oncogenes, you know, you'd expect they're involved in cancer biology, and this is really interesting because PKD is not cancer, but it is a hyperproliferative cell-transforming disease that has some similarities to cancer biology. Mm-hmm. So you see that beyond just that PKD gene expression and the ability to make polycystin, there's many genes that are impacted. So, if you look at the genes that are most impacted, they tend to be genes that are focused on proliferation, either pro-proliferation or anti-proliferation, and also inflammation. So some of the genes that promote proliferation, including mTOR, RICTOR, and others, have increased expression when you have PKD. Genes that promote inflammation also have increased expression. Some of those include TNF-alpha, IL-6, JAK/STAT, even interferon gamma. And then genes that control or reduce proliferation, including the PKD gene itself, 'cause that's what polycystin helps to do, but also PPAR-alpha and PPAR-gamma, which impact, oxidative phosphorylation in the mitochondria, those are all reduced. From a transcriptomics perspective, you see this wide gene dysregulation that basically favors proliferation, cyst growth, and inflammation. That story is much more than just about, you know, polycystin, you know, coming from the PKD gene itself. We think that a therapeutic intervention that can help rebalance that, that widespread gene expression dysregulation, bring that back all towards normal, could be a really, you know, potentially powerful disease-modifying therapy. That's how we think RGLS8429 works, and so we think there's a nice opportunity here. Mm-hmm. Okay. That is helpful, but a lot... I'm gonna summarize and make sure I understood, I think everything, so bear with me here. I think, so basically what you... You know, there's tubes in the kidney that fluid flows through that are lined with epithelial cells. You're saying in ADPKD, the growth of those cells gets out of whack, basically, and they're growing and kind of dividing and, you know. Expanding. Copying themselves, whatever. They're expanding. There's more of those cells, and they're growing more rapidly than they should be, so that's kind of what creates these cysts and causes the problems. Correct. This imbalanced growth, wacky growth profile is caused by decreased levels of PC1 and PC2? So what I would say- That's probably an oversimplification. Decreased levels of PC1 and PC2 are a part of it. A part of it, right. Really, you phrase it quite well. It's kind of like a tube like a straw, but- Yeah ... instead of staying in that straw formation, they abnormally grow and just begin to form a balloon, essentially, right? Like a sphere. And, and that does involve a reduction in PC1 and PC2, but it also involves an upregulation in other genes that promote proliferation, like mTOR and RICTOR. Mm-hmm. It involves a decrease in expression of other genes that help prevent that proliferation, PPAR-alpha, PPAR-gamma, and the mitochondria, et cetera. Mm-hmm. And so, and then the inflammation markers are also, or genes, are also increased as well in the disease. Right. So it's kind of a... It is. It's a wide—even though it's one gene that's mutated— Mm-hmm ... it initiates- Right ... a variety of dysregulation across hundreds of other genes. Right. Right. That's all important in creating essentially a very proliferative, inflammatory, condition in the kidney. Mm-hmm. Okay, that, that's helpful. And then something we've read about, we've heard about is the PKD1 dosage effect. So at high level, what is that? Yeah, I guess I'd say, 'cause people talk about the dosage effect, and they talk about the Two-Hit Hypothesis. So the dosage effect basically says, you know, the severity of disease, it can be linked with the severity of the mutation in the gene, and that does lead to the severity of impact on polycystin, but also, you know, likely the severity of impact on that widespread gene dysregulation. That's kind of how we think about it as well. Mm-hmm. And it is clear you can have a truncating mutation, at least epidemiologically and clearly, from an in vitro perspective, if you look at animal models, the more severe the mutation, the more severe the disease. And we see that that tracks across when you look at Mayo imaging class 1A through 1E, 1E being more severe, most severe. The severity of that, of the mutation does, you know, tend to go across those degrees of severity. I think some people focus on something called the two-hit hypothesis, which takes it a bit of a step further, saying, "Sure, so the gene mutation is one... One allele is either completely knocked out or mostly knocked out in terms of its ability to make polycystin, and in order to have the disease kind of initiate and really propagate, you need to have the other remaining wild-type allele also have a number of somatic mutation hits or somatic mutation hits that basically take out its ability to make polycystin as well. So it's kind of a story of you really take out all of your ability to make polycystin as a disease propagator. We don't think that's quite correct. We think the evidence for that is that... Well, the evidence that supports the two-hit hypothesis came from kidneys that were very much end-stage. They were being surgically removed from a person. Mm-hmm. And they were the oldest or largest cysts that they could get a sample from. And so, we think at end stage, it, you know, might be more likely that you have a lot of somatic mutations. But we know the disease starts, you know, at an early age, even in utero, in terms of cystogenesis. We think before you'd have that level of somatic mutation. Probably more importantly, if you believe that you're, you know, genetically you didn't have any more ability to make polycystin, then by initiating an upstream change, which is what our drug does, RGLS8429 works upstream of that. You shouldn't be able to necessarily create more, you know, full-length functional polycystin. And we've clearly demonstrated we can do that. Mm-hmm. We measure full-length polycystin in the urine as one of our measures, key measures of mechanistic activity, and we've shown with our recent, 2 mg/kg cohort in our ascending-dose, phase Ib study, that we're getting much more, you know, incremental increases in polycystin, even to the level where some patients are getting up kind of into the normal range for healthy volunteers in terms of the urinary polycystin levels. So we think, generally speaking, it's we, we favor the, the PKD dosage hypothesis, if you wanna call it that- Mm-hmm ... as opposed to the two-hit. But maybe the final thing to say about all of this is RGLS8429, because it works upstream to control that or, or, normalize that widespread gene dysregulation I was talking about- Mm-hmm ... including impact on PKD and polycystin, but many other genes. We actually see that in animal models that are renal cystic diseases that don't require PKD mutations. They don't require polycystin changes. We see effects there as well. So it's just broadly speaking, an anti-proliferative, anti-cystogenic way of impacting the kidney, and we think that's spot on for this disease. Interesting. Interesting. Okay, I think I'm gonna try to come back to that 'cause that's, like, an interesting tangent we could probably go down. But, sticking with ADPKD for the moment, so, we kind of, you just talked us through the kind of the genetics and sort of, what we know and what we don't know. What does that mean clinically? Like, how - what do these patients end up looking like in the clinic? What happens to their kidneys over time? Kind of on a- Yeah. Yeah, it's a great question. So clearly, they've got the disease from birth, right? Mm. But we don't screen for it at birth in terms of genetic testing, and so people don't know that they have it. Now, it's because it's autosomal dominant. You can certainly see that it runs in families, but again, if you don't have the right diagnosis. We often, you know, have it be the case that a patient will say, "You know, my grandfather, I was told my grandfather passed from you know kidney disease, or... And then my uncle," and that kind of thing. Because as their cysts are growing in the kidney and eventually starting to destroy renal function itself, you don't really notice it until a couple of things happen. The first thing that can happen is the kidneys actually just get big enough that they start to cause flank pain, so you actually notice and feel it. "Oh, something's, something's, you know, hurting." You have a scan, you say, "Well, that's a pretty big kidney. Something's going on here. Mm. Another way is you have a scan for some other reason. In fact, females who are getting ultrasound for pregnancies, you can often pick it up that way. So obviously, that's you know, totally an ancillary finding, but super important finding. Mm. And then the other way is, as you're getting, you know, labs checked, you start to see an actual decline in renal function. So that would be late in the game- Mm-hmm ... really on the path towards the decline in GFR. We see that probably doesn't happen until your fourth or maybe even fifth decade in life, but then it can be, depending on your severity of your disease, and somewhat related to the severity of the mutation- Mm-hmm ... it can be a very rapid path down towards dialysis. And as I mentioned, with PKD1, the more severe type and the more common type, the median time to dialysis or age of dialysis is 55 years. So it's, it's very significant. Mm-hmm. Mm-hmm. Okay, that's helpful. And then kind of going back to the cy- or I guess a higher level question, what makes the kidney big over time? Is it the cyst cells- It is simply the growth- ... Is... Is it other stuff that happens? Yeah. Okay. It's simply non-real kidney tissue, you know. It's cysts increasing in size. The cyst cells, the epithelial cells- Mm-hmm ... secrete kind of a water-like fluid, and so that's what's mostly water inside the cysts. So it's non-functional, non-communicating with the urinary system. Mm-hmm. They just kind of grow over time. You can have up to 800-1,000 cysts- Yeah ... in the kidney. Mm-hmm. As all of those grow, you can get kidneys that are, you know, massive in size. Yeah, these are just, just to put a finer point on that, Whitney, you know, in the ongoing study, we have looking at patients with ADPKD and using those novel imaging markers, you know, you can see this on MRI, up to 1,000 cysts in a kidney, and it's bilateral. Mm-hmm. So it's quite pronounced, and the kidneys, as a consequence, will grow to the size of, like, an American football, where a normal, healthy kidney should be about the size of a closed fist. Okay. Okay, and it's really just- Like 10 times the size of a normal kidney. Okay. All right, that's and it's just, it's like the fluid, the fluid-filled balloons. I like this balloon analogy. Yeah. That's what's doing it. We've heard about, like, fibrosis and some of the downstream things that happen. That's because of the cysts, then cause things to go awry, and then there's things that happen there, or what's that about? It's a bit of both. As you have that physical disruption of the cysts, that can lead to some inflammatory cascade. But I'd say equally, if not even more important, is that initial, as I mentioned, widespread gene network dysregulation. Mm-hmm. The genes that are involved in the overproduction of inflammatory, mediators, TNF-alpha, IL-6, JAK/STAT pathway, et cetera, are increased, and we've shown that. We, we've got a nice transcriptomic slide on our corporate, presentation, that, that outlines, how we can, you know, isolate those specific genes and show that they're increased in the disease, and then that increased expression is reduced in a dose-dependent fashion when you add our compound, RGLS8429, into the mix. Mm-hmm. Okay, got it, got it. All right, and then a quick side question on epidemiology, actually, 'cause I think it's relevant to talk about here: What is the current thinking around how many of these patients are out there, and could that change, to your point, once there's people are looking more for this disease? Yep. Yeah, no, it is actually- And others ... very, very important from a practical perspective- Mm ... because, the current, you know, kind of documented prevalence is about 160,000, so technically, that makes it an orphan condition. So we have orphan drug designation. Mm-hmm. That, of course, affords some regulatory streamlining in terms of the path forward. So for ADPKD, a medicine can get approved on the basis of a phase II kidney volume study. Then you need to do some additional work over time in the post-approval setting, but it's a bit of a more streamlined path because it's an orphan condition that has a significant unmet need that we can also talk about later. But in terms of the, you know, prevalence, as I mentioned, it's, you know, it's not screened for genetically, and so there are many cases that are undiagnosed. We think likely there are more than 160,000 patients out there from a prevalent perspective. But, you know, people would need to do more screening to really know that for sure. ... Yep, okay, understood. All right, last question before we dive into your therapy is just what, how are these patients treated currently, I guess? Right. Once they find out they have the disease, and they know they're on this steady decline, what's out there for them? Yeah. So, you know, the first thing generally is that you try to just do all the good things that you do, you know, for the kidney. Control blood pressure. Right ... and, you know, typically, you know, use angiotensin and, you know, there are other kind of proteinuria-reducing kind of compounds, but like you would for diabetic nephropathy, et cetera. The reality is that those measures don't actually impact much because it's not a blood pressure disease. It's not, you know, diabetic nephropathy. It's different. So you try to do all those things, but that's not - that doesn't really do a lot of impact. Mm-hmm. The one therapy that has been approved specifically for ADPKD is tolvaptan, and it's a vasopressin receptor antagonist, which means it one of the key ways it works is by reducing the kidney's ability to reabsorb free water. And so you basically pee out all of your free water. And as I mentioned earlier, in the cysts, you know, the fluid in the cysts is mostly water, and so you can reduce kidney volume by peeing out all of your free water. I think that also, it's very clear that that leads to significant tolerability issues because you are urinating all the time. It's a twice-daily drug, so urinating all morning, and then you're urinating all night. And that brings with it what patients describe as unquenchable thirst. Mm-hmm. And the label, you know, suggests you need to drink up to 8-10 L a day just to kind of keep up. So that's, that makes a significant tolerability issue. And it also has a black box warning for liver toxicity, including fatal, you might say, liver disease. And so, you know, it has some challenges, and as a result, it doesn't get used nearly, you know, by nearly as many patients as need to have a therapy. Mm-hmm. But it has been shown to both reduce the growth of the kidney. It doesn't shrink the kidney, but it reduces the growth from about 6% per year to 3% per year, 50% reduction in the rate of growth of the kidney. And that has translated into about a 30% improvement in the decline of renal function. So kidney function is still gonna decline- Mm-hmm ... but it will do so at about a 30% slower, growth rate or, or decline rate compared to placebo. So it is a therapy. It's just kind of hard to take, and so it's very clear that, you know, that more is needed in this space. Mm-hmm. Mm-hmm. Definitely. To add on top of that- Please ... we need to, you know, the consequence of that delaying, you know, that decline in GFR means delaying the onset of the need for dialysis or transplant. So, you know- Just- ... the estimates are that you can delay the onset, you know, with tolvaptan use. They estimate you could delay it, I think, five to eight years, which is a very significant impact on the quality of life for- Mm-hmm ... for those who can tolerate it. Got it. Got it, yeah. Okay, so it does something. It's hard to take, though, but even whatever it does is kind of dealing with the contents of the balloon, not the problems that created the balloon themselves, I guess. Is that a fair way to very much oversimplify the mechanism of tolvaptan? Excellent. All right, so taking a step back then, where does miR-17 come in? Or maybe let's start with what is miR-17, and then where does that come into what's known about the mechanism of this disease? Sure. miR-17 is a microRNA. It's a great example of a microRNA, right? So microRNAs are short, non-coding RNA segments that essentially are created in the body to help regulate other genes. And so a microRNA will bind to not a gene, but a message RNA, you know, mRNA from a gene, and essentially block the production of whatever that protein is that message RNA is that the microRNA is targeted to hit. And microRNA is a pleiotropic, so unlike you may have heard of siRNA, which is very specific just for one very specific, you know, mRNA segment. But microRNAs tend to bind to message RNA from many genes, so again, pleiotropic in nature. And it turns out that I talked about that widespread gene dysregulation, right? So some gene expression goes up, some gene expression goes down across many genes that are involved in proliferation and inflammation. And it turns out that what is happening in the disease is that as those proto-oncogenes, I noted c-Myc in particular, but also, c-fos, c-jun, as those go up, those actually drive, in the kidney, drive an increase in the miR-17 family of microRNAs. And it turns out if you take a normal mouse that does not have a PKD gene mutation, right, normal mouse, and all you do is you transgenically overexpress miR-17. So now what they're doing is they're making a lot of miR-17. It results in kidney cell renal tubular cell proliferation and inflammation and cyst creation. Mm-hmm. It's very, very clear that an increase in miR-17 is part of the pathogenesis of the disease. You can also give a kidney the PKD gene mutation, but knock out that mouse's ability to make miR-17, and you have a vastly reduced impact in terms of a disease, cyst growth, cystogenesis, and decline in renal function. We know that miR-17 is kind of the way I view it as an important control point or gatekeeper- Mm-hmm ... to that widespread gene dysregulation. A lot of how the gene expression that goes up or down is because miR-17 is doing what it's doing. And so our therapy is a short oligonucleotide that binds to the family of miR-17s and simply blocks their ability to bind to messenger RNA. Mm-hmm. So miR-17 is not able to do the job that it was intended to do. And so, we see that, again, using transcriptomics, the gene networks that are dysregulated, some genes go up, and some genes go down in disease. Then that begins to be reversed when you block miR-17 with RGLS8429. Mm-hmm. The genes that went up, go down, the genes that were down, go up. ... Gotcha. Okay, very interesting stuff. And I guess just on that note, how should, you know, the, so the benefits of miR-17 in that it kind of hits a bunch of different genes is good. Is there, are there any off-target or safety concerns, I guess, around that? Yeah, it's a really important question. So maybe the easiest way of answering it is noting that miR-17 is really important from an embryologic perspective when proliferate, right? 'Cause it promotes proliferation, and when you need growth the most, you know, time you need growth is when you're actually growing from an embryo, you know, beyond that. Mm-hmm. But actually, in an adult mouse, you can then knock out miR-17 completely, and you have no detectable impact on an overall, phenotype, morphology, et cetera. Okay. And so we don't see anything negative in terms of the consequences of just simply having zero miR-17 around. I'll also point out that the actions of our therapy are predominantly localized to the kidney, because as it turns out, when you have a short oligonucleotide, and ours is a very short segment, and it's not conjugated, that tends to traffic just from a normal, you know, PK perspective, it tends to traffic most importantly to the kidney, and most with highest, you know, frequency and concentration. So when you give a dose, most of it goes to the kidney. Tenfold less goes to the liver, which actually is important 'cause the liver can develop some cysts as well. Mm-hmm. But it's at a much lower level, and then vanishingly small in the plasma and vanishingly small in other tissues. And so we have a therapy that is impacting, you know, microRNA that is overexpressed, ends up being negative in the setting of disease. We can block that and do so pretty much at the site of action where you're concerned about it in the kidney. Mm-hmm. Okay, got it. Excellent. All right, so I think you've kind of touched on, on some of the preclinical results, but just kind of, can you review at a high level, I guess, what are the key things that you've been able to show preclinically? Yep ... both from an efficacy and a safety perspective? Yeah, sure. I'll start with efficacy. We've definitely shown this is spread across our corporate deck, efficacy in models of PKD1 disease, as well as PKD2 disease, and importantly, and I mentioned this earlier, other renal cystic disease models that have nothing to do with PKD gene or polycystin, and that's in particular the Pcy CD1 model. Mm-hmm. The clinical correlate for that is a disease in people called nephronophthisis. But again, just the point of that is that RGLS8429 is essentially anti-proliferative, anti-cystogenic, across, you know, any model where you see abnormal proliferation and cyst growth in the kidney. So that's from an efficacy perspective. And then from a safety perspective, you know, really the main results are our tox program, right? And so, we've seen absolutely nothing in our IND-enabling tox, and we've completed the chronic tox in mouse, which is the most sensitive species. Mm-hmm. The highest dose was the N OAEL because we didn't see anything. So we haven't come across anything from a preclinical perspective, that it- Mm-hmm ... you know, is a concern from a safety perspective. We are underway with our second species, and the dosing for that will wrap up in the next couple of months. That's in the monkey, and again, haven't seen anything, and we were very aggressive with our IND-enabling tox in the monkey. Didn't see anything. NOAEL was the highest dose. And so, we're very confident that we're gonna be clean from a tox perspective. Mm-hmm. Okay, excellent. All right, so moving to the clinical data, and starting with the impact on PC1 and PC2, I know you've talked about miR-17 as having all these different effects, but the biomarker, I guess, that we're focused on, and I guess maybe we could come back to whether we should be, but the biomarker that we're focused on, biomarkers, plural, are PC1 and PC2. And you saw increases in both, and, and I guess for the duration of this conversation, I think we'll focus most on the second cohort data, but- Mm-hmm ... but yeah, I'll share my screen, which has them both. So, in any case, can you talk about kind of what you've seen in that regard, and in particular, on the kind of kinetics of once patients take the therapy, how long does it take for PC1, PC2 to kind of start getting made in cells? And how do you think about that relative to the data that you've shown, which I will share momentarily? Yeah, it's a really great question, and the short answer is we are still learning about the temporal kinetics of giving RGLS8429 and seeing at the end, in a human, you know, the excretion of polycystin in exosomes. And so it ends up being, you know, a little complicated because obviously excretion in an exosome in the urine is far away, far removed from where the action is happening, at the kidney. So there's a time lag. What has to happen is RGLS8429 has to get into the kidney, and then it needs to block miR-17. That then allows message RNA to make protein, and in this case, PKD message RNA makes polycystin. And then that protein polycystin works in the kidney and then is eventually packaged up in exosomes and then gets excreted. There's some time lag there. Mm-hmm. One of the challenges is that we aren't able to sample the same tissues in a mouse, where we have really great detail in the kidney, for example, of how the drug works, you know, what its actual impact on gene expression is, et cetera, in the kidney. 'Cause we can take out the kidney and, you know, look at the tissue. You don't get to do that in a human. You can't even do really renal biopsies because the high number of cysts make it a bleeding, you know, a significant bleeding risk, and so we don't get kidney tissue from people. Mm-hmm. We get the urine excretion from people, but we don't get to do that same urine excretion in a mouse. We're still working on the assay. They don't make enough urine- Right ... to actually enable us to collect enough exosomes to really do the test. So we're working on that. It would be great if we could know tissue temporal kinetics into urine in a mouse, and then at least kind of be able to back-calculate that from a person. Mm-hmm. So what we do instead is we just make sure that we continue to collect samples up to a month after dosing, and that's what you see here on the slide. So in this, this shows placebo in the open circles, 1 mg/kg in the black circles, and then 2 mg/kg in the red circles from our ongoing first two cohorts, or the first two cohorts from our ongoing study, phase 1B. And maybe just for reference, that day 57 there, that's a the fifth dose when you start to reach steady state. Mm-hmm. And you see, at least based on our Wilcoxon signed-rank test, that's when you start to see statistical significance, the 2 mg/kg group, and most of the time points are significant. But you see that our final dose, it's a three-month dosing every other week, so 7 doses total. The seventh dose is given on day 85, and so we measure pre-dose, day 85, post-dose, day 86, and then three more time points across the month, just to start to understand temporal kinetic profile, and so 92, 99, and 113. And so and you see that the, for the most part, it still goes up. It actually was pretty high at 113. You can tell by the wider confidence intervals, that was driven in particular by one patient who had actually had very high levels and had a very good response in terms of kidney volume. Mm-hmm. But the results that we see are the same, whether you include that patient, which is shown here, or remove that patient because they're kind of an outlier. We still see the same pattern overall. Got it. And so we are seeing 2 mg/kg, you know, some continued increase in at least evidence of urinary exosome polycystin, likely because of that temporal lag, but we still haven't been able to nail down in terms of the specific timing. Got it. Got it. Okay, so the follow-up question would be, do you think you are getting to a steady state level by day 113, but maybe don't know because still don't know the- Yeah. For sure, in terms of what we know based on our non-clinical work, in terms of the steady state for the drug concentration in the kidney- Mm-hmm ... you reach that by day, around day 57, 5 half-lives. Okay. It's about a 12-14-day half-life in the kidney tissue itself. Got it. So, yeah, we're definitely steady state. But I think, you know, what you're seeing is with the continued increase over the next 30 days is, you know, at some point we will reach that steady state. We just haven't, you know. We'll be dosing longer as we get into phase II, and possibly even doing longer follow-up to understand that, you know, how that time lag really works and when you actually start to see the drug effect go away off therapy. Mm-hmm. Mm-hmm. Got it. Okay. And then a follow-up investor question we get often is, you know, well, can you talk about, I guess, the relative increases you're seeing in PC1 versus PC2, and do you need both? Do you want both? Yep. Whether or not one or the other increases, does that depend on the patient's mutations? The short answer is you want both. Mm-hmm. Actually, if you want, probably the next slide also in this deck is a really good view of both PC1 and PC2 on an absolute and percent change basis. This really is how I look at the data in the end. You gotta kinda slice and dice it a couple of different ways, but I think this is most representative of what we're trying to look at, which is, relatively speaking, we wanna see increases in PC1 and PC2. So if you think about, you know, how our RGLS8429 is working, it's blocking miR-17. miR-17 is no longer then able to exert its negative pressure on gene expression, i.e., polycystin production. So even if it's a PKD1 mutation, you should see increases in PC2, and other way around. If it's PKD2 mutation, you should see increases in PC1. We know that both of these transmembrane proteins work together to form a receptor ion complex, a channel, essentially, complex. Mm-hmm. Having more of one seems to help the other, even though that's not necessarily the genetic mutation. We do wanna increase both. It's interesting, a question we get a lot from investors is, "Okay, I see what you're showing here. How much do you need? Mm-hmm. That's not exactly the right question, because that would be assuming we're looking at exactly what's happening inside the kidney, and this is not the case. This is excretory, you know, exosomal excretory polycystin. Mm-hmm. But I think more importantly, the real question is, how much miR-17 can you block? And unfortunately, we can't measure that in a person. We can measure that very well in a mouse, and so we translate over. Because the entire mechanism here is to block miR-17, so it's no longer able to exert its pressure on a variety of genes, one of which is the PKD gene itself, and polycystin. And so there's no... You know, we're doing so much more than just polycystin. Mm-hmm. It's not exactly how we look at it. You've got to get to a certain threshold. We use this as a rough measure of mechanistic activity. Mm-hmm. Are we seeing a dose response? Very clearly, we are at this point. The impact on polycystin, as measured in urinary exosomes, at 2 mg/kg is far greater than you see at 1 mg/kg. We also know that based on full miR-17 target engagement in a mouse- Mm-hmm ... you get that at a level that translates to a human at around 2.4 mg/kg. Mm-hmm. And so here in red is the 2 mg/kg. We'll also be testing in the ongoing third cohort, 3 mg/kg, and those were picked in particular to bridge over that kind of 2.4 mg/kg level. Mm-hmm. We feel that most likely you wanna get beyond 2.4 mg/kg. We don't exactly know how much, but as long as it's safe and well-tolerated, and we have very large tox margins, we essentially wanna just make sure in everybody we're getting kind of as much as you can get in there. And we think it's just over 2.4 mg/kg to then have that full miR-17 blocking ability. Mm-hmm. Got it. Okay, that's helpful. And, and maybe just to summarize, a bit of this discussion here, which I think was worth reiterating, just given the sort of monogenic disease discussion, that, you know, unlike other diseases where maybe we say, "Okay, patients have 10% of normal, and they get disease. If you can get them to 30% of normal, they won't have disease." There's not, there's not similar lines in the sand here because of the nature of this disease, and it's being complex, et cetera. So, is that fair? And that also, that's definitely fair. I'd also say, because this is urinary exosomal polycystin, you know, no one's really... We actually helped develop this assay. Right. You know, it's relatively new in the grand scheme of things, and so I don't, I don't— You know, no one's done that direct correlation back to urinary polycystin. Mm-hmm. Okay, fair enough. And then on the assay itself, and we have gotten this question as well, what type of PC1 and PC2 are you measuring? Is it normal? It is- Is it functional? It is full length. Okay. It is full length, a polycystin, so it's not, not a truncated mutation. We wouldn't be measuring that. Okay, got it. Got it. Okay. And I guess, do we know for sure that full-length PC1 and PC2 are functional? Yeah, for the most part, we believe that is. There may be some missense mutation in there that may make it a little less effective, but we believe that's functional. Got it. I think, you know, we're starting to see some, some what we think is evidence of, of mechanistic activity in... with respect to what we're really trying to impact, which is kidney volume. Mm-hmm. And then down the line, eventually, in a post-approval setting, as a PMR, we'll need to show benefit on GFR. Yep. Yep. Okay. We measure full-length, you know, polycystin in the animal models as well in the tissue level, and that's associated with the efficacy that we've published on there, too. Mm-hmm. Yep, got it, got it. Okay, excellent. All right, so moving over to kidney volume, 'cause as you've said, you know, measuring the protein is good. Measuring the downstream effects in terms of, like, the structure and function of the kidney is actually what matters. So, and that's where I think there was upside surprise in the data, that you did. You were able to show, impact on total kidney volume. So can you kind of talk us through, what this measure is, height-adjusted total kidney volume, and kind of walk us through a little bit of what we're seeing on these charts? Yeah. So, height-adjusted total kidney volume is essentially the MRIs, just measuring the overall size of the organ itself. Mm-hmm. It's a computer-driven algorithm, and that is the endpoint that the FDA cares about. Because that is, you know, total kidney volume has been shown both in interventional studies, most importantly, the tolvaptan program itself, but also observational studies like the CRISP and HALT datasets, to be related to GFR and decline in GFR over time. So that's what the FDA cares about, and that's in this slide shown on the far left. Mm-hmm. In the middle, we're helping to kind of advance the knowledge around more cystic architecture-specific endpoints. In this case, it's total kidney cyst volume. So as we mentioned, you know, 800-1,000 cysts. The MRI is actually to localize those and, and total up the volume just inside those cysts, which is interesting. The FDA doesn't use that. That's not part of the regulatory endpoint. But this study is the first time in a prospective interventional trial these two measures have actually been measured together, and so we elected to do a regression analysis, and that's what you see on the far right. As you can see, it's a very tight correlation. Literally, the slope is 1, and so that just helps you understand that when you're seeing changes in kidney volume, those changes are being driven by changes in cyst volume, which is what you're, you know, looking to impact. But the main variable or endpoint that the FDA will be looking at is on that far left, the total kidney volume. And I'll just talk about this for just a second. You know, overall. So maybe a step back. We never expected to see, you know, clear changes in this kind of small data set. It's 11 patients in 2 mg/kg, 9 in 1 mg/kg, and 6 overall in placebo. Those are very small numbers. And it's a 12-week dosing period, 3-month dosing period, right? And that's pretty short as well. So we didn't necessarily expect to see anything. However, I do think that we are... Sorry, and because of the small numbers, and as you can see in the table in the bottom, the standard deviation is pretty big compared to the mean changes. You wouldn't use this to say, "Hey, one group is better than another group. Mm-hmm. Not at this point. The numbers are too small. However, if you kind of treat this a bit more like an oncology phase Ib or phase II study, and you say, "Hey, are there responders in here? And what's happening mechanistically with them? Mm-hmm. That's where things get a little more interesting because you do see, in the, in the far left, the 2 mg/kg, the red, squares, those four patients that have, looks like greater than 2.5% reduction in kidney volume. We know the kidney grows about 5%-6% per year, so over... This is actually over a 4-month, window because the, the final MRI is taken a month after dosing at the day 113 time point. Mm-hmm. So four months, you'd expect the kidney to grow about 2%. So in this case, these four patients are reducing by that amount or more, right? Greater than 2.5%, all four of these. And then you say, "Okay, could that just be variability?" Yes, there's variability in an MRI measurement. The variability itself of just the MRI measurement is upwards of 2%, and there's other ways that additional variability can come into there. So you'd never look at that and say, "Hey, you know, that, that's a lock." But the question is, what's happening mechanistically with those individuals specifically? And so we went back and looked, and each of those four patients had very strong increases in both polycystin 1 and polycystin 2. But what's more important is when you kind of turn the question on its head, and you say, "Which patients had the highest increases in polycystin-1 or the highest increases in polycystin-2?" The one patient that had the highest in PC1 also had the highest in PC2, and then the second highest increase in PC1 and second highest increase in PC2. So those three patients are the three highest volume responders there, where each one of those three was greater than 4% in terms of their reduction in kidney volume. And so you can definitely talk about variability in the MRI measure itself and variability in the polycystin measure itself... but I think it's rather unlikely that the top three responders in terms of polycystin increases- Mm-hmm. would also be the top three responders, if you will, in terms of reductions in kidney volume. I think that's very interesting. It's not a lock. It's, you know, it was never meant to be. Mm-hmm. But, it makes us more excited to get to the phase, sorry, to get to the third cohort at 3 mg/kg. And then even more so, and I'm sure we'll talk about it more, the fourth cohort at a fixed dose of 300 mg We've decided, on the basis of these data, to actually increase the sample size and go up to 30 subjects, open label. Mm. To see if we can get a bigger read on a potential, you know, volume signal. But as a final point, I just wanna mention, because we never expected to see anything here, seeing something on volume is not, you know, is not the threshold we need to go into our pivotal phase 2 study. Uh-huh. We had always intended to simply use urinary polycystin as our, you know, kind of rough measure of mechanistic activity to pick a dose, and then go into that pivotal, phase II study. Mm-hmm. Fair enough. Okay, that's all- Just my thought, I would- Oh, yeah. The reason we adjust it for the height is because that ties to disease severity. So you could imagine if you happen to be a shorter individual with the disease, with really large kidneys, it's gonna be more profound than somebody really tall. Yeah. And so you normalize this to your height level, because that's what's been correlated with overall disease severity in the Mayo Classification system, is to adjust for height. The other thing I'll mention here on this chart is, you know, you do see that one individual at the 1 mg/kg dose level, it had a pretty dramatic in terms of numeric reduction. We went back to dig into that because, you know, some investors were curious about, you know, how to interpret that. And it turns out that was the one individual that was noted by the central reader who had significant motion artifact, meaning that they were moving around in the MRI. Uh-huh. And so, that's gonna happen. Some people get anxious in an MRI machine. Mm-hmm. But it turns out that that was the one that was noted, clearly. Sure And so it's understandable you'd have trouble getting a reading on that. Yeah. Okay, that is very helpful, and one thing I was gonna follow up on, so thank you for that. All right, and just going back to the point of variability, 'cause I think it's worth reiterating that too. You know, a question we get is, "Yeah, what's the variability of the MRI measure itself?" So I think you said it's around 2%, you know, in terms of kind of the measurement itself might vary by 2% just based on inherent errors. And then, there might also be, though, some variability, or maybe not, I don't know. That's a question in terms of what kidneys are actually doing, or do we know that? Like, is there? On average, do kidneys grow, but maybe there's some variability. No, it wouldn't, it wouldn't be that. It'd be more about- Yeah like hydration status and things like that. Okay. Hydration status. So- Fair. You know, it's about, you know, 2%, give or take. Could be a little higher than that. I think all of that means- Mm-hmm ... you shouldn't take 11 patients- Yeah versus 9 patients, versus 6 patients Right and say, "Look at the average. This is a win or not." That, this is not meant for that at all. Mm. Right. Right. We calculate our estimates. If you just assumed that you needed to show a benefit similar to what tolvaptan showed, and again, that didn't show a regression in kidney volume- Right ... it showed a slowing of the growth, so- Mm 3% per year instead of 6% per year. Mm-hmm. We calculate that would take about 300 patients in a 2-to-1 randomization dosed over a year. And so those are the kinds of numbers- Yeah to really have significant power to, you know, see a significant difference between groups. Mm-hmm. These numbers were not meant to do that. I think we look at it more, this is a mechanistic study. We look at it more from a mechanistic perspective. "Hey, those folks who are looking like they're actually really having some nice response in volume are, in fact, the folks that are having the highest evidence of mechanistic activity." That's a nice message as you're moving forward in your studies. Mm-hmm. Yeah, and de-risking that, you know, that endpoint for phase II, we can tie, you know, evidence of target engagement through polycystin to evidence of potential reductions in cyst volume, that then tie to reductions in, or just even stabilization of height-adjusted total kidney volume, de-risks that phase II endpoint. Yep, absolutely. Okay, that's all, that's all really helpful. And then, I guess just going back to something you said around not expecting to see changes in total kidney volume in the current study, because we didn't either. And so as we were like: "Oh, wow, this is really interesting," one of the questions we had, and we were getting at, is like, "All right, at this early time point, what would even be causing that?" And I think now that we've set up kind of what cysts are, it's a little bit more straightforward, but yeah, what would be the mechanism of that rapid of a decline in kidney volume at a relatively early time point? Well, I mean, I think, you know, what I've tried to lay out is that the disease creates a constant genetic push, gene expression push towards proliferation, cyst growth, and inflammation. And if you are restoring that gene expression back towards normal, all of those genes, their normal job would be, you know, in terms of having normal expression, to control growth and ensure that renal tubular cells are functioning appropriately. That's what polycystin helps to do. Mm. Communicating with other cells appropriately. This likely involves apoptosis of cystic epithelial cells themselves, so those cyst cells, you know, may die off and help shrink, shrink, if not obliterate, some of the cysts. And so, you know, some of this is speculative in terms of what's really happening. As I mentioned, you know, it's just that this whole understanding of widespread gene dysregulation is actually kind of relatively recent- Mm ... in terms of our overall understanding of the disease. But, it's not too much of a leap to think—you know, when you have normal gene expression, it's about control of proliferation and not allowing cyst growth. It's when that gets out of whack that you have the proliferation and cyst growth. We're just bringing back the, you know, the genetic metabolic milieu- Mm-hmm - towards a more normal picture. Mm-hmm. Okay, that's helpful. And then, I guess, going back to what makes the kidney big question, another line of questioning I think we got around the data was, you know, if, if, if all that's making the kidney big are these fluid-filled sacs, that feels fairly straightforward. But if there's fibrosis and other kind of broader tissue remodeling changes that are presumably more permanent or would be harder to reverse, could that be expected at this early time point? But I think we laid out earlier that that's not really what's driving kidney- Yeah, well- - Volume increases. It's a really good question, and there is no question there's inflammation and some fibrosis that's involved as well. Mm-hmm. Again, RGLS8429 should and does, you know, impact that, that inflammatory, you know, pro-fibrotic genetic profile- Mm-hmm because it kind of reverts back towards normal in terms of gene expression across this dysregulated gene network. But I'd also maybe point out that tolvaptan did demonstrate, I mean, it has been demonstrated, that reductions in kidney volume can translate, do translate into reductions in the decline of renal function. So you get better renal function. GFR didn't improve. It still continued to go down, but it went down at 30% less, you know, rapidity- Mm-hmm ... compared to placebo. We believe that blocking microRNA miR-17 and its families is a more powerful mechanism, and so we'll see where we can get. But we fundamentally believe we have a great opportunity for disease modification here, and if nothing else, having very significant decline in the time towards end-stage renal disease, which is huge for this population. Mm-hmm. Yes. Yeah, I would just chime in further. You used the word "reverse," there, and, you know, our benchmark here is to have a product with, you know, at a minimum, tolvaptan-like efficacy. So it's not reversal. Mm-hmm. It's not even stabilization. It's a slowing of the disease progression. Stabilization, which, you know, maybe that's the phenomenon we're seeing, that would be a home run scenario. If we could just halt that cystic expansion- Mm-hmm ... and the inflammatory cascade that drives, you know, the kidney ultimately to end-stage renal disease would be a real significant step forward for patients. So, I just want to caution the word "reversal. Yeah. You know, I know we did see, you know, numerically, reductions in cyst volume, but our goal here is to have a therapy that's gonna have, you know... an effect that's tolvaptan-like or potentially better. And as Preston said, in all the animal models of the disease, certainly our molecule looks to be more potent. And it's, you know, it's working at the genetic level of the disease. And if it's better tolerated, it'll be a big step forward for patients. Yeah, absolutely. Okay, that makes sense, and you... Yes, sometimes we get carried away with thinking through the possibilities, but... Yeah ... but very fair point. Okay. And then, looking ahead to cohort 3, I guess, can you help set expectations there? I guess, first of all, have you said anything around patient baseline characteristics or anything of the patients that are enrolled in that cohort relative to previous cohorts? No, we haven't, we haven't said anything, with respect to that. We'll, we'll, we'll take a look at it as it comes out. You know, I think the most important inclusion criteria is the Mayo Imaging Class 1C, 1D, or 1E- Mm-hmm ... which, as it basically, you know, defines moderate to severe disease. Mm-hmm. Everything, you know, kind of falls out from that. We've seen across the, you know, cohorts 1 and 2, that we're getting the kind of patients we wanna get. Yeah. We expect to see the same thing in terms of the third cohort. Okay. I think, in terms of our expectations, you know, for the cohort, most important, of course, in a phase IIb is safety and tolerability, and everything's looked good in cohorts 1 and 2. We, you know, review safety in a blinded fashion, with our ongoing cohorts, and so everything's looked good so far, but we'll need to, you know, get to the unblinding. And then beyond safety, the primary focus, as I've, you know, mentioned, is on urinary exosomal polycystin, right? Mm-hmm. As our kind of rough measure of mechanistic activity. We'd like to see some incremental increase at this 3 mg/kg level over 2 mg/kg. I can't tell you exactly how much. And again, with these kind of numbers, you know, I mostly just wanna see that it's present. Mm-hmm. And, and again, because now we do think we've seen a bit of a signal, at 2 mg/kg in terms of some key kidney volume responders, you know, that's not, that's not necessarily expectation. We had never expected to see that before. It'd be great if we did see it, as well, and one of the reasons why we're increasing the cohort size in the fourth cohort, kind of double it up to get more patients, to see if we can bring greater clarity to that potential signal, but that's, that's kind of a bonus territory. The main thing is urinary polycystin and helping us pick the dose. Mm-hmm. Okay, got it. And is the goal really to see more increase in PC1, PC2, or is it to bring... to decrease the variability in response, I guess, on levels of increase? No, it's not decrease the variability. It's the same, you know, gonna be roughly the same numbers. I'd expect to see- Okay ... the same variability, and even more to see, you know, what are we seeing compared to the 1 mg and 2 mg/kg groups? Okay, very fair. All right, and that data is on track for mid-year, I believe? Mid-year, right. Mid-year, okay. Exciting, we look forward to that. Mid-year is right around the corner. But thereafter, you've mentioned cohort four, where you're moving to a fixed dose, and you've increased enrollment. So can you, first of all, remind us the rationale behind- Yeah ... those choices of the fixed dose and increasing enrollment, and talk about timelines there as well? Yeah, great question. So, we obviously want a fixed dose and a pre-filled syringe for our phase II trial because that's also because this is a pivotal study we can get approved on that study, and so then you need to have, you know, your commercial presentation. Eventually, we'd move to an auto-injector, but to start off with it'd be pre-filled syringe with a fixed dose. So that's the plan. And so we'd always intended to do, after the weight-based cohorts that we think predominantly help us, you know, pick the dose range, another cohort of a fixed dose, just to kind of make sure, sense-check, you know, that a fixed dose is performing the way we expect as we go into the phase II study. And so that's the kind of rationale for why you would test a fixed dose here. It's just kind of a bridge. It's not required, but it, we think it's helpful to us. And then in terms of the dose, at 300 mg, based on the average weight of the folks we've enrolled so far, we believe that it'll be a little bit higher than the 3 mg/kg the highest weight-based cohort. So on average, it'll be around 3.5 mg/kg, which again, we think is nice. We're trying to... As long as it's safe and well-tolerated, and we have large tox margins, which we do, we wanna absolutely make sure we've got enough in there to cover, you know, the available miR-17 to block it. Mm-hmm. and so that's that covers the dose. And then in terms of the size, we had always intended this fixed-dose cohort to be open label, polycystin as objective, so was measuring kidney volume, et cetera. And it wasn't part of the weight-based, you know, the kind of the key weight-based cohorts, which are placebo-controlled. And so we were planning to do around 15 or 16, 'cause each cohort can enroll up to 16 subjects- Mm. - in that randomized space. So we're gonna do 15 or 16 in the open label with this fixed dose. Because of what we think is a potential signal, we wanted to have a shot at increasing the clarity of that signal. And so, we've amended the protocol to go up to 30 patients- Mm. Open label on, you know, everybody's on drug, at that 300 mg fixed dose. And so, from a just... It's important from a timeline perspective. While that does extend out when you're gonna end that phase Ib study, it in no way, shape, or form is a deviation from our overall, you know, plan to, to get our weight-based cohorts and get to the FDA. Mm-hmm. So we have mentioned publicly that we intend to get to an interaction with the FDA in Q4 of this year to go over study design for phase II, you know, confirm again that it's pivotal, although we've already, back in December, had a great interaction with the FDA to confirm that PKD is approvable through an accelerated pathway on the basis of kidney volume. We've gotta take the protocol to them, make sure everybody's in agreement with what we're planning to do, show our, you know, tox data, et cetera, and cover everything that enables us to move forward into that phase II. So the overall plan has been to get to the FDA to do that in Q4 of this year, and that sets you up for a mid-2025, mid-next year- Mm-hmm ... start of enrollment for that pivotal phase II study. So none of those timelines have changed. Okay, that is super helpful. And as you said, it's an open-label study, so in terms of what you're seeing and what you might communicate, there's no delay because of the larger size as well? Absolutely not. No, we'll probably, yeah, we'll probably report out, you know, a cohort of patients in the fourth quarter. We'll have that available for us as we talk to FDA and then the remaining group or groups early next year. Mm-hmm. Yeah, it doesn't affect our ability to start phase II. Got it. Okay, super helpful. We have a lot of good audience questions, and I think we've touched on a lot of them, so... But apologize if I missed it. I'm gonna ask one here that I think is relevant, as we think about kind of total addressable market, patient populations, enrollment, et cetera. "Do you expect efficacy to be limited to patients with germline missense mutations?" This person says: "Given the 90% rate of second hit truncation mutations? Absolutely not. Okay. Again, I kind of went through our view of the two-hit. Mm-hmm. Even if you believed that in most of disease you had zero ability to create, you know, new functional polycystin, RGLS8429 ought to work because it works in renal cystic disease models that have nothing to do with PKD or- Yeah ... or, polycystin. However, we have already demonstrated the ability in, you know, non-selected patients, they just had PKD, they were with moderate to severe disease through, you know, 1C through 1E in terms of Mayo Imaging Class. We've already demonstrated that those individuals can produce, after dosing with the RGLS8429, more full-length polycystin. And, in fact, that starts to push up, in some patients, up into the range of healthy individuals. Mm-hmm. And again, it's not a lock on that answer, and it was never intended to be, but we think we're seeing some real evidence of miR-high mechanistic activity translating to impact on kidney volume at this early stage, which is great. So I'd say that we're not concerned about that kind of two-hit hypothesis at all. Awesome. Excellent. All right. I think it was worth it covering that, even though we went a little bit over time. Thank you both very much for your time today, and thank you to everyone for joining. There's probably more we could talk about, so we'll have to have you back. Well, thank you for the great questions. Thanks. It's a great conversation. Thanks.