Our lead development candidate, EDIT- 401. This webinar is being recorded and can be accessed in the future through this same link or through the Investors section of the company's website. After our prepared remarks, we will open the call to Q&A. To ask a question, please click the raise hand feature in the webinar portal. As a reminder, various remarks that we make during this presentation about the company's future expectations, plans, and prospects constitute forward-looking statements for purposes of the Safe Harbor Provision under the Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including those discussed in the Risk Factors section of our most recent annual report on Form 10-K, which is on file with the SEC as updated by our subsequent filing. In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. Except as required by law, we specifically disclaim any obligation to update or revise any forward-looking statements, even if our views change. I'd now like to turn the call over to our CEO, Gilmore O’Neill. Thank you, Dana, and good morning to you all. With me today are Linda Burkly, our Chief Scientific Officer, and Amy Parison, our Chief Financial Officer, who will join us for Q&A. Today, we are taking a critical step forward in our vision to be a leader in in vivo gene editing by developing CRISPR-based medicines that are best in class or first in class therapeutics. To date, we have made steady progress in advancing our liver and HSC programs, including presenting preclinical advances that we're incredibly proud of. With these advancements, we have been laser-focused on selecting a lead in vivo candidate that shows exceptional potential to be a transformative medicine that can advance towards human proof of concept data as quickly as possible within our current cash runway. Today, we are delighted to introduce our lead program, EDIT- 401. EDIT- 401 is a potential best in class, one-time in vivo CRISPR gene editing medicine designed to significantly reduce LDL cholesterol or LDL levels, demonstrating an unprecedented mean reduction of 90% in our preclinical studies and has the potential to transform the hyperlipidemia treatment paradigm by dramatically reducing the lifetime risk of cardiovascular events. With such exciting results, we have selected EDIT- 401 as our lead development candidate to lay the foundation for our future in vivo gene editing portfolio. We have selected EDIT-401 as our lead development program because our EDIT-401 preclinical studies in non-human primates and all other tested models have consistently demonstrated a 90% mean reduction of LDL, where the current standard of care, statins and PCSK9 inhibitors, have been shown to achieve only 40%- 60% mean reductions. EDIT-401 has the potential to be a one-time treatment, providing a lifetime reduction of LDL and durable lifetime cardiovascular risk reduction. EDIT-401 has a sizable market potential with favorable healthcare system economics. EDIT-401 also provides a very attractive business model that we expect to be aligned with typical biopharma margins, and EDIT-401's compelling preclinical data support rapid progression to human proof of concept studies. Accordingly, we are moving EDIT-401 towards the clinic with expected human proof of concept data by the end of 2026. Atherosclerotic cardiovascular disease, or ASCVD, is the leading cause of death worldwide and imposes a significant burden on the U.S. healthcare system, with national expenditures projected to reach over $300 billion in 2035. Elevated LDL, or so-called bad cholesterol, is a major causal factor in cardiovascular disease because it progressively and silently accumulates in arterial walls, leading to blockages and major cardiovascular events that include heart attack and stroke. It has been well documented that a 40 mg/dL reduction of LDL has been associated with a 20% reduced risk of cardiovascular events over five years. Indeed, very low levels of LDL maintained over a lifetime contribute to even greater risk reduction. The current standard of care fails to achieve desired reductions of LDL in up to 75% of patients with established cardiovascular disease and frequently requires multiple therapies and lifelong adherence. Elevated LDL, also known as hyperlipidemia, is a highly prevalent disease affecting over 70 million patients in the U.S. alone. Given EDIT-401's impressive reduction of LDL to date, we are confident in the potential of EDIT-401 to deliver meaningful benefits beyond the current standard of care across multiple segments of the hyperlipidemia population, which are highlighted in this slide. The current standard of care for hyperlipidemia has demonstrated mean reductions of LDL of 40%- 60%. As you can see in this figure, the 90% mean LDL reduction we have seen in our preclinical non-human primate studies of EDIT-401 supports our belief that EDIT-401 may provide reductions that go well beyond the reductions demonstrated by existing therapies. Intensively reducing LDL for as long as possible provides maximum benefit to at-risk patients. Key opinion leaders and experts to whom we have spoken confirm the LDL reduction potential of EDIT-401 will be transformative for the management of hyperlipidemia. I'd now like to pass the call over to Linda, who will walk you through our EDIT-401 program in more detail, including our differentiated approach with functional regulation and the very exciting data emerging. Linda. Thank you, Gilmore. Before I share more detail on EDIT-401, I want to take a moment to review our in vivo strategy to develop a pipeline of gene editing medicines for patients with serious diseases. Our in vivo strategy is based on our INDEL technology to edit non-coding elements to achieve functional upregulation of gene expression to address loss of function or deleterious mutations. To be clear, our strategy is not the knockdown strategy that others in gene editing are pursuing. Why does the difference between our functional upregulation strategy and the knockdown strategy used by other companies matter? First, with an upregulation strategy, we can go after targets that others cannot address with knockdown approaches. Second, our approach allows us to optimize gene upregulation and devise editing strategies with the potential to be differentiated best in class medicines, even where other approaches such as knockdown may apply. The results of our EDIT-401 strategy have yielded impressive efficacy data in non-human primates, supporting our belief that EDIT-401 may result in greater reductions in LDL than current treatment options, as well as other products in development. We believe our novel in vivo editing approach with EDIT-401 is de-risked by a naturally occurring variant in the LDLR 3' untranslated region, or UTR, that leads to significant LDLR upregulation and, consequently, robust reduction of LDL and offers a validated model for therapeutic gene editing. This natural variant was discovered in seven individuals within a single Icelandic family. It was associated with significantly lower LDL levels, as low as 13 mg/dL, when compared to Icelandic non-carriers shown in this slide on the panel on the left. Notably, there were no observed adverse health consequences among those individuals. De-risked by this naturally occurring proof of therapeutic strategy, EDIT-401 creates an optimized and proprietary deletion within the 3' UTR of the LDLR gene. EDIT-401 increases the liver's production of the LDLR protein, a protein that removes LDL cholesterol from the bloodstream. EDIT-401 deletion of regulatory elements in the LDLR 3' UTR increases the stability of the LDLR mRNA, thereby resulting in increased production of the LDLR protein. Our preclinical data have demonstrated at least a six-fold mean increase in LDLR protein levels following treatment with EDIT-401. The same level of increase has not been observed with targeting of PCSK9. Thus, EDIT-401's ability to increase LDLR protein levels in hepatocytes supports its ability to dramatically reduce LDL levels by facilitating increased clearance of LDL. The EDIT-401 program utilizes a proprietary CRISPR-Cas9 enzyme and dual guide RNAs to target the LDLR 3' UTR to upregulate LDLR protein expression. The LNP delivery strategy involves encapsulation of CRISPR-Cas9 mRNA and dual guide RNAs in a single GalNAc-targeted LNP for transient expression of gene editing cargo using validated LNP components accessed through a strategic partnership with Genevant. We have demonstrated impressive proof of concept data with a single dose of EDIT-401 in preclinical studies using healthy non-human primates. As shown on this slide, all four dose levels from 1.5 mg/kg- 4 mg/kg demonstrated a 90% mean reduction from baseline in LDL levels. A marked reduction was observed as early as 48 hours after dosing and was sustained for the one-month study duration. Importantly, there were no adverse effects observed. Transient increases in liver enzymes resolved within one week. It is worth noting that NHP data provides strong translational insight into LDL responses in clinical studies based on interventional studies in this therapeutic space. We believe the biomarker response and projected clinical efficacy position EDIT-401 to be a best in class medicine for reduction of LDL. What is the relevance of EDIT-401 in the presence of elevated baseline LDL? In this study, a single dose of EDIT-401 mirin surrogate was administered to wild type mice on both a regular and high-fat diet. LDL baseline was threefold higher in wild type mice on a high-fat diet compared to wild type mice on a regular diet. In this graph, we show that dosing with the EDIT-401 mirin surrogate achieved 90% mean reduction of LDL in the wild type mice on a high-fat diet as compared to the vehicle-treated wild type mice on a high-fat diet. What is the relevance of EDIT-401 in the presence of reduced LDLR function? In addition to studies in wild type mice, we have demonstrated proof of concept with the EDIT-401 mirin surrogate in the LDLR heterozygous mouse model, which harbors a loss of function mutation in one of their LDLR alleles, mimicking a genotype of HEFH. As expected, these mice have higher LDL levels than wild type mice. As shown on this slide, the EDIT-401 mirin surrogate achieved proof of concept with 90% mean reduction of LDL in the heterozygous LDLR mice. In summary, EDIT-401 has demonstrated a robust and consistently 90% mean reduction of LDL in non-human primates, mice with elevated baseline LDL, and mice heterozygous for LDL receptor loss of function. EDIT-401 has the potential to deliver meaningful benefits across multiple segments of the hyperlipidemia population. I'd now like to pass the call back to Gilmore. Thank you, Linda. EDIT-401, as Linda says, is uniquely positioned to be a potentially best-in-class treatment medicine for hyperlipidemia because our EDIT-401 preclinical studies in non-human primates and all other tested models have consistently demonstrated a 90% mean reduction of LDL. EDIT-401 has the potential to be a one-time treatment, providing lifetime reduction of LDL and durable lifetime cardiovascular risk reduction. EDIT-401 has a sizable market potential. EDIT-401's expected typical biopharma margins provide a very attractive business model. With these attributes, we envision that EDIT-401 will be a transformative medicine that will allow a patient to receive a one-time infusion at an outpatient clinic that delivers a lifelong reduction in LDL, far exceeding that provided by existing therapies. There will be no concerns for noncompliance and no need for mobilization or conditioning. EDIT-401 has the potential to not only benefit the patient by meaningfully reducing their risk of potential cardiovascular events, but also significantly reduce the overall costs for the healthcare system, payers, and the patient throughout their lifetime. Because EDIT-401's compelling preclinical data support rapid progression to human proof of concept studies, we are moving EDIT-401 towards the clinic with expected human POC data by the end of 2026. In closing, even as we have selected EDIT-401 as our lead clinical priority, we remain very excited by the very real preclinical progress that we've made across our portfolio, including with our hematopoietic stem cell program, as well as the meaningful success we've previously achieved in the clinic with our prior programs. We are confident our pipeline will follow that trajectory and remain committed to accelerating our other programs when additional resources become available. In that spirit, while our disciplined approach to capital allocation will keep the focus of our resources on the advancement of our lead 401 program in the clinic, we continue to work on optimizing candidates for our HSC program and exploring other tissue and cell types. We look forward to sharing more with you in the coming months. Thank you very much for your interest in Editas, and we are happy to answer questions. We will now take questions. Please use the raise hand feature to join the queue. Please limit your questions to one question plus one follow-up. We'll take our first question from Jack Allen with Baird. Please unmute your line and go ahead. Hi. Thank you so much for taking the questions and congratulations on the progress. Lots of interesting data as it relates to EDIT-401. I guess the first question I had on 401, and then I do have one quick follow-up, was on where you plan to start testing 401. Like what patient populations could you look at? I know hypercholesterolemia is a huge indication as you aptly lay out, but there are some familial components to the disease as well. Do you plan to go after general hypercholesterolemia, or could it be the heterozygous familial hypercholesterolemia that you pursue first? Thank you very much, Jack, for your question. We actually laid out a number of segments in the patient population, and obviously the heterozygous familial hypercholesterolemia and other refractory segments would be an obvious place to go. Heterozygous familial hypercholesterolemia is certainly a significant consideration. The final selection will obviously depend on discussions with the regulators, et cetera. I think you're absolutely right in highlighting the more refractory segments of the patient population. Got it. Very briefly, I wanted to ask about the ex-liver side of the business as well. Your last slide seemed to outline having proof of concept from an ex-liver tissue type in 2027. Keeping it broad and potentially not necessarily committing to the hematopoietic stem cell program, at least that's how I read it. Is it not clear that the hematopoietic stem cell program is second in line now, or are you still deciding on your follow-up? Oh, yeah, thank you. Thanks, Jack, for that clarifying question. Our commitment to the preclinical advancement and optimization of our HSC program and other extra-hepatic remains strong. The highlighting of the third tissue is actually related to sort of an additional commitment, our objective that we laid out at the beginning of this year. Our commitments across the preclinical portfolio remain strong. As I say, we are using the opportunity with our disciplined allotment or allocation of capital to 401 to allow us to do further optimization with our HSC program and look beyond. Thank you so much for all the questions. Our next question comes from Samantha Semenkow with Citi. Please go ahead. Samantha, we can't hear you, I'm afraid. Hi, good morning. Can you hear me now? Yes, yes, good to hear you. Perfect. How are you doing? Congratulations on the progress and the disclosure for EDIT-401. A couple of questions from me. First, is there evidence that reaching 90% LDL reduction would result in lower cardiovascular risk versus what we see currently with the current standard of care in the 40%- 60% range? I have a follow-up. Yeah, thanks, Sam. Thank you very much for the question. I think we can draw from the clinical interventional trials that have gathered data on this. We know that every 40 mg/dL lowering of LDL-C, there's a roughly 20% risk reduction for cardiovascular risk over five years. We also know from the interventional trials that the patients that achieved even lower levels of LDL experienced even greater risk reduction and notably no safety risks associated with them. In fact, the safety outcomes were similar across all the LDL-C ranges. I think the greater risk reductions with even lower LDL levels support the principle of the lower, the longer, the better. Also, you know, lifelong lowering of LDL-C is associated with even greater risk reduction of cardiovascular disease, and that's supported by genetic evidence with individuals who carry mutations that have loss of function that get very low LDL. I think we feel very confident in our strategy. Thank you very much for that question. I hope that answers your question. Yes, that's very helpful. I guess just maybe a theoretical one. How do you anticipate the LDL reduction you've seen thus far in the mice will translate to humans? Is the 90% reduction with a dose that is translatable to humans, first off? Is there a risk that you might see lower LDL reduction, or is the expectation based on the data we've seen across the gene editing landscape that what you see in mice is reasonably translatable to humans? Thanks very much. Yeah, Sam, thanks again for the question. We're seeing the 90% reduction in both the non-human primates and in the mice. In the non-human primate space, this has been very translatable, the LDL reductions from the non-human primates to the humans. The dose levels that we're seeing, you know, we have actually seen 90% reduction at all the dose levels that we tested. We haven't actually established our minimally efficacious dose, but we're projecting that a human dose will be below 1 mg/kg. We're viewing very favorably the translatability to humans because of the translatability of LDL lowering in this space and the observations in the non-human primates. That's very helpful. Thanks very much. Our next question comes from Alex Finnegan from Bank of America. Please unmute your line and go ahead. Hey, guys. Thanks for taking our questions and congrats on the progress here. Two questions. First, curious if you looked at modulating the upstream 5' region as well in your preclinical work. I just wonder if increasing promoter activity might lead to higher LDLR levels versus just stabilization of the transcript. Thinking about a competitive landscape and LDL-C potentially shifting from injectables to orals over the next couple of years, I guess how do you see a gene editing product like EDIT-401 fitting in? Would this be positioned for the most severe patients, or is maybe the one time in 90% lowering differentiating enough in your view? Thank you. Thanks, Alex. I'll have Linda answer the first question on different targeting strategies, and then I'll deal with your second question. Yeah, thanks for the first question. We really wanted to de-risk our strategy with human genetics, and we focused on trying to find natural human variants that would inform and de-risk our strategy. The information from the Icelandic variant and individuals carrying that was very important to us to use that information to de-risk both the efficacy and safety. We really focused on the 3' UTR. Thank you very much, Linda. With regard to your competitive landscape question and positioning of this, there are a number of points to make. First, EDIT-401 does have a really significant separation in the effect size that it gives to LDL reduction compared to existing therapies, and that in itself is very important. As you quite rightly pointed out, there are important segments of the patient population that we've identified, that experts identified, and even our discussions with payers have identified where they have recognized segments that would certainly benefit from such therapy. It is worth highlighting when you look beyond that, that 75%, an estimated 75% of patients treated with established liver disease or established cardiovascular disease or hyperlipidemia, do not achieve their targets for a number of reasons. If you combine Linda's point that lower, longer, better, and you combine that with the compliance, you can actually see the span of segments across who can actually deliver this therapy. OK, great. Thank you. Our next question comes from Joon Lee with Truist. Please go ahead and ask a question. Good morning, and thanks for taking our question. This is Mehdi for Joon. First question is, and I have a follow-up. How faithfully you mimic the mutation in the Icelandic population, is that the 2.5 kb deletion, or is it just you are removing the microRNA sites in that region? Thanks very much for the question, June. We are not sharing our exact proprietary optimized strategy for upregulating the 3' deletion in the LDLR 3' UTR. It is not exactly the 2.5 kb deletion because it is a proprietary deletion. We are obviously removing regulatory elements. Interesting. Thank you. It appears that unregulated upregulation of LDLR might induce some cellular toxicity and even might increase the risk of atherosclerosis in patients with APOE4 variant. Could you please elaborate on your long-term safety for your approach in contrast to other LDL-C lowering methods like PCSK9 inhibitors and SGLT3? Thank you. Let me just, you're asking a question about the potential for high levels of LDLR upregulation causing some cell toxicities and actually what are the long-term risks. What I would actually say is, before I pass over to Linda, at the very high level, we've actually been thinking about this carefully. I think there are a couple of things. First of all, we do have de-risking on the genetic side. The Icelandic cohort and heterogeneity, while small, is still really important in actually assuring us about the long-term safety of this approach. In addition, we also have some pharmacologic partial de-risking in that the way that PCSK9 knockdown or inhibition actually drives LDL reduction is by reducing the recycling or destruction of LDLR. You have some partial validation there. Linda, I don't know if you want to add to that. I think that, you know, part of the, we can draw upon the other current treatments that do increase LDLR expression, albeit through their own mechanisms and at lower levels, obviously, which is why they're not reducing LDL to the greater extent. In the interventional trials where there were patient cohorts who did achieve very low levels of LDL on the order of 10 mg/dL- 20 mg/dL, we can expect that in those cases, LDLR was increased to a greater extent. I think we can infer that without safety outcomes there, that there were that somewhat de-risked the question that you're posing. Thank you. Thank you. Our next question comes from Phil Nadeau with TD Cowen. Please go ahead and ask your question. Morning. Thanks for taking our questions. Just two from us. In terms of the reduction that you need to achieve in people, what do you think is the minimal effective level? 90% obviously would be a big improvement over standard of care. What's the minimum reduction you think you need to achieve in order to have a viable product? Second, based on your preclinical experiments, do you have a sense of what percent editing of the liver cells is necessary to achieve that level of reduction? Thanks. Thanks, Phil. I think I'll let Linda take the second question. With regard to the levels required to reduce, I think there are a couple of points. Obviously, we have seen long-term follow-up data over the years that demonstrate that mean reductions of 60% certainly could for benefit. I think it's very important to say that we're very confident about the transformational levels of reduction that we're seeing in our hands for a number of reasons. First of all, it is biologically plausible, driven by both the genetic validation in that Icelandic kindred, the fact that we're seeing significant upregulation of LDLR or increase of LDLR levels. Finally, that experience that Linda called out, that interventional studies of cholesterol lowering or LDL specifically lowering in non-human primates has demonstrated a high positive predictive value for translating from the preclinical state to the human. I think the final piece I just remind everyone is that in long-term follow-up studies, if you go from percentage to absolute reductions for every 40 mg/dL, or because much of that has been published using SI units, 1 mmol reduction LDL-C, you actually reduce the risk, the cumulative cardiovascular risk over five years by 20%. Actually, that lifetime risk is even further reduced. You can anticipate that with a higher percentage reduction, you're going to get a higher milligram per deciliter. Therefore, this is why we feel that you can see in the future a significant reduction in cardiovascular risk with this approach. Thank you, Gilmore. I can take the other part of your question, which is as to what percent editing we need in order to achieve the effect. Because we have this very nice dose response, we did various doses in the non-human primate, and all of them, as you saw, very remarkably lowered LDL by 90%. However, we were able to analyze in those animals the percent editing and the percen t of the level of LDLR protein upregulation. We have analyzed all of that data. We do have an evaluation of the level of editing that we need to achieve in order to get the 90% reduction. We do look forward to sharing all of that data. We're not disclosing that data in today's webinar, but we will be sharing that data at a future scientific venue. Fair enough. Thank you. Congrats on the progress. Thanks very much, Phil. Our next question comes from [Bill Mohan] with [Craigstreet]. Please go ahead and ask your question. Good morning, and thank you. My question is, how do you expect the prescribing and patient community to think about the trade-off here between a lifelong reduction in LDL-C versus other potential options that, for any reason, if a patient does want to withdraw a drug, they retain that option? Just for any theoretical concerns on that. Yeah, thanks very much, Bill. The way we are thinking about this is that one thing that is very clear is that a substantial proportion, you know, 75% of patients have great difficulty achieving targets. Even to achieve targets requires multiple interventions or, at the very minimum, a lifetime commitment to remember to take a medicine that is actually managing a risk factor that is silently accumulating but can actually create catastrophic consequences. The way we see it to start with is that you can actually see that within that patient population of hyperlipidemia, there are certain segments that are even more likely to be refractory and in higher risk. We could actually see that early embrace there. More importantly, if you don't just speculate on that, we have actually talked to KOLs. We've talked to treating physicians. By the way, it's also worth saying that payers have identified populations or segments or patient populations or segments within the hyperlipidemia population for whom this kind of high efficacy single infusion lifelong reduction would be beneficial. Thanks. As a follow-up, looking forward to the human proof of concept data. Obviously, we'll want to see LDL-C reduction and a clean safety profile. Are there any other observations or measures that you would expect to want to call out that you're looking forward to from that readout? I think there are a number of things we might look at, but I think you've called out the main ones, which will obviously be the LDL-C reduction, the dosing at the dose level at which we see that, and the safety profile. I think those are the key elements. Thank you. Thank you very much, Bill. Our next question comes from Jonathan Miller with Evercore ISI. Please go ahead and ask your question. Thanks so much for taking my question, guys, and congrats on picking your candidate here. I was going to ask, as a follow-up to some of the comments you've made about particular market segments, obviously different patient populations have different baseline levels of LDLR. Do you expect that you'd see differential efficacy in patients that already have robust LDLR expression and maybe their hypercholesterolemia or hyperlipidemia is coming from some other issue? Would you expect that you would put some sort of gate on inclusion criteria around baseline LDLR when you're thinking about the patient segments that you start with? Thank you very much. Before I pass it in, I just want to highlight one point. I think when we look at the consideration of baseline levels of LDL-C, the important thing to highlight is, one, that LDLR upregulation, in theory, in genetically defined human kindreds, that Icelandic population, and indeed in our non-human primate experiments has shown significant reductions. In addition, because you asked your question about baseline, we have seen these reductions at low baselines and high baseline levels of LDL-C. Hence, the experiments that Linda shared, including the LDLR heterozygous mouse model and then the mice with a high-fat diet that had high, significantly elevated baseline levels. Thank you, Gilmore. I can add a little bit to that. First of all, you can break it up into two parts, like delivery. Because we're using a GalNAc-targeted lipid nanoparticle, which is LDLR independent, we should have the ability to target segments regardless of their level of LDLR on the surface. We shouldn't have a difference between the patients who have more or less LDLR. Once you're in those different patients, because we're increasing, we're going after the root cause of the disease by increasing the production of LDLR. We should be able to address different segments of patients that have low or high LDLR by elevating their amount of LDLR. This is very different, obviously, than a PCSK9 inhibitor that acts to rescue, if you will, the existing pool of LDLR. That is very much dependent on how much LDLR is existing in the different patients, depending on their level. I think the answer to your question is our strategy should be agnostic, if you will, to the patient. Jon, you asked a question, would we anticipate restrictions, inclusion criteria, or label? Those are questions, obviously, that will be identified as we go forward. We don't anticipate necessarily a need for that as the development evolves. As I say, our data and, very importantly, discussing with regulators will inform that later in the program. Thanks, guys. Makes sense. Thanks very much. Our next question comes from Soumit Roy with Jones. Please go ahead and ask your question. Good morning, everyone. Congrats on the new target and the new asset. Not sure if I've missed it. Have you shown us the LDLR expression levels compared to pre-treatment? If not, what is your internal benchmark that you're going to use for the LDLR expression itself? Their PCSK9 or statins or cholesterol absorption inhibitors? Let me just resummarize the question by the way I think I understand you're asking, which is, do we have an understanding of the allelic effects or possibly another way, which is the level of editing that we're seeing at the liver? How are we measuring LDLR upregulation? Is that correct? Yeah. I have it correct? Yeah. I think from the point of view of the degree of allelic editing in the liver, we haven't actually shared that today. Yeah, we. was, you know, Linda pointe. Go ahead. Yeah, I think I pointed out that we've evaluated that. We're going to be sharing that at a future scientific venue. The other one is about LDLR upregulation is that we have actually been able to measure that in our non-clinical experiments. In fact, I think it's summarizing some of the data, in fact, all the data slides for both the non-human primates as well as the high-fat, low-fat diet mice and the LDLR heterozygous mice. You're looking obviously at expression in the liver. Right. They were looking at expression in the liver. We're looking at total liver lysate, and we're measuring total LDLR protein. As we stated, we were seeing at least a six-fold mean increase in the LDLR protein levels, which was able to give us this 90% reduction in the NHPs. I hope that answers your question. Sumit, you asked about benchmarking as well. We do cite some references there, but the experience looking at PCSK9 and its effects, which have demonstrated significantly lower levels of LDLR upregulation simply because instead of increasing the amount of protein produced, it essentially decreases the amount of protein that is being recycled or pulled down from the cell surface and destroyed in the lysosome or cleanup system of the cell. If you're doing that, you basically have a limit to the capacity that you can because there's only a set amount of protein being made. By our strategy, increase the amount of protein being made. That benchmarking, as I say, and that literature would support, has demonstrated is seeing substantially lower increases levels of LDLR. Does that help? Certainly helps, yeah. As I understand, the cholesterol metabolism is a complex process with multiple proteins and pathways. Do you know if there are any genetic data available, or will you be looking into long-term changes to the regulation of the LDLR gene itself, patients who are already on statins or other drugs? Essentially trying to understand if 3' UTR is the only regulatory unit for the expression level of the gene, or are there other compensatory mechanisms that can kick in? If I can, I'll address that. Linda, if you want to add to that, you're quite right. Cholesterol metabolism is highly complex. However, I think it's good to know that we have been looking at the biochemistry of this system for well over 60 years. The regulatory elements that regulate LDLR expression and other cholesterol metabolizing enzymes, both on the synthetic side, the biosynthesis side, and the catabolism or breakdown side, have been very well characterized. To date, we have been very pleased both in our preclinical experiments to see that the animals are tolerating this well. We'll follow up, very importantly, that we have also genetic validation. Obviously, LDLR, I should say, manipulation, even though at a more modest level, with PCSK9, has not demonstrated adverse events. This is also important to notify or acknowledge not just the PCSK9 inhibition pharmacologically, but even PCSK9, as I say, loss of function gene or genetic variants in humans. Overall, we actually feel that we are in a very good state here. Right. Obviously, we'll also be conducting a long-term durability study to demonstrate the durability of our editing approach. Congrats again on the data, and looking forward to the next round. Thank you very much. Next question comes from Eric Schmidt with Cantor. Please go ahead and ask your question. Yeah, my congrats as well. Fascinating data, fascinating biology as well. I wanted to ask Linda about this Icelandic family. It looks like the family members have maybe about a two-fold increase in LDL receptor expression, but you're getting more like a six-fold increase. What explains that? Is there some heterozygosity in the family members, Chad and Michael? Yeah, the family members are carriers of the 2.5 kD indel. They're not homozygous for it. They're carriers. Even though they have the roughly two to three-fold roughly increase, they have LDL levels that are as low as 13 mg/dL. They have a range, and the low end is 13. I can get ranges from 13 mg/dL- 70 mg/dL. We empirically have determined with our optimized strategy that we can achieve the 90% reduction with very tight error bars, instead of this range that's seen in the Icelandic family with our proprietary deletion, and that we need roughly to achieve this threshold of six-fold protein increase. We're trying to get a very consistent effect. OK, if anything, you'd expect more LDL receptor upregulation and even greater lowering than the family genetics. Yeah, exactly. Regarding the safety, I think the slides that you presented suggested that the LNP was accessed through the Genevant partnership and consists of clinically validated components. Can you talk about whether the LNP itself with the specific composition or makeup has been used in patients before? The various components have been used in clinic. The actual LNP itself has not been used in the clinic, but all of the different components have been used in the clinic. We've now progressed them into our LNPs into our NHP study. They were very well tolerated up to 4 mg/kg. There were no clinical adverse observations in our study. We're very pleased with the tolerability profile. Will this be essentially an Editas proprietary LNP formulation that you access through the partnership? I think that the strategic partnership, as you say, is with Genevant. We haven't gone in or disclosed how, you know, who owns what. Essentially, the key thing is that this is a great strategic partnership. We're very happy with how it's going. I would say it's a really good collaboration if you want to talk about, you know, infer beyond what we're not sharing. OK, thank you. Congrats again on some exciting data. Thanks very much, Eric. Thank you. Our next question comes from Yanan Zhu with Wells Fargo. Please go ahead and ask your question. Yanan, we can't hear you. Oh, can you hear me? Yeah, we can hear you now. Yanan, we have you now. Thank you. Congrats on the progress. This is Quan Ang on for Yanan. Can you talk? Sorry, forgive me. Yeah. Oh, can you talk about the safety profile of EDIT-401? Have you seen any off-target editing, and any other observations on liver enzyme elevations or thrombocytopenia in the NHP? Thank you. Thanks very much, Quan, for that question. Linda. I can speak to, you know, we are designing our, we design our cargo, our nuclease, our Cas9 nuclease, and our guide RNAs to be highly specific, you know, through our guide design. We do this design and testing through a specificity generation of a specificity package. We do this through basically a very comprehensive assessment using many orthogonal assays. These involve in silico assays, biochemical assays, and cell-based assays. This is the process that we've taken our guide RNAs through, and we're very pleased with where we are in terms of our specificity package. That's what I can share with you at the moment. Also, with respect to your other question of the LFTs, we saw very transient LFTs in the NHPs that resolved. We're back to normal within one week. We didn't see any thrombocytopenia. We saw no changes in any coagulation or any hematology parameters whatsoever. On both counts, the specificity package and the liver function tests, we're very pleased. Got it. Thanks, Quan. Yeah, that's a very helpful follow-up. Durability, you mentioned that you need more studies to evaluate durability. Sorry, Quan, to interrupt. You're very muffled. I'm having trouble. I can't make you out. Oh, sorry. Is it better now? That's better. Yes, that is better. Yes. All right. On durability, you mentioned that you need more studies to evaluate durability. Can you talk about whether redosing is possible if needed? Thank you. So far, we've shown, as you could see on one of the slides, that we have durability out to 12 weeks. You saw that on one of the slides where we studied mice that had been fed a high-fat diet, and we maintained our 90% reduction in LDL. We're very pleased with that study. Typically, one would do as part of their development package a longer durability study of at least one year. We are embarking on that study as part of our package. Your other question? Reducing. Yes, based on our analysis from our NHPs, we do believe we would have, if needed, room for reducing. Got it. We don't know that we would need that, but if so, we have room for that. Thanks very much. All right, thank you. Our next question comes from Gena Wang with Barclays. Please go ahead and ask your question. Gena, please go ahead and ask your question. Hi, Tony. Sorry, we're not hearing you. Sorry. Tony, we can hear you. Can you discuss any expectations on timelines downstream or pivotal development, like how many patients or follow-up would be needed for safety database requirements, and anything else in the package, like in silico assays, et cetera? Thanks very much, Tony, for that question. I think it's obviously very early days to be looking downstream. We actually believe that this medicine has a potential to treat multiple segments of patients' population. I think different segments may have different requirements, which obviously is determined by regulators. That's something that we will look forward to in the near future. I will tell you, however, that with regard to our human POC studies, we anticipate with the very large effect size that we're seeing and the positive predictive value of non-human primates in translating cholesterol-lowering medicines or LDL-lowering medicines into humans, that with that effect size, we would really require a small population in which to detect that biological effect size. Got it. Thank you so much. I guess on the next update, on that note, will you all be announcing, for clinical trial initiation, which segment that we'll be going into initially and then other details around that at the next update? At the next update, it's hard to say what we would do at the next update. The population that we will select or population segments that we will select for that human POC, first in human, will obviously be agreed with regulators and IRBs. I think that that would be the appropriate time to finalize it. As I said, I think in a previous answer, we are aware of a number of segments. It's likely that we would start with more refractory patients. An ATFH or high-risk arteriosclerotic cardiovascular patients who are not coming close to achieving target would be two obvious segments that we could start in. That will be a matter for discussion and agreement with regulators and institutional review boards/ethics committees. Got it. Thank you. Thank you very much. Our last question comes from Mitchell Kapoor with H.C. Wainwright. Please go ahead and ask your question. Good morning. This is Katie on for Mitchell. Very exciting data. I was curious if you have considered looking at plaque formation or other markers beyond just the LDL-C reduction. Katie, thanks very much for that question. That is something obviously that has been looked at in other studies. It usually takes larger patient populations and occurs later in the development of the program. Based on what we would in our early, first in human studies, we will be looking at LDL reduction and various safety parameters. Obviously, the evolution or maturation or reduction of plaque are elements that could be looked at later in the development program. Excellent. Thank you. Thank you very much. This concludes the Q&A portion of today's webinar. Thank you for joining. You may now disconnect.