ProQR Therapeutics N.V. (PRQR) Earnings Call Transcript & Summary

Good morning, and welcome to the ProQR Therapeutics Virtual Investor and Analyst Event. [Operator Instructions] As a reminder, this webinar is being recorded, and a replay will be made available on the ProQR website following the conclusion of the event. I'd now like to turn the call over to Sarah Kiely, Vice President of Investor Relations and Corporate Affairs at ProQR Therapeutics. Please go ahead, Sarah.

Good day, everyone, and thank you for joining us. I'm Sarah Kiely, Vice President of Investor Relations and Corporate Affairs at ProQR. To begin, let's briefly review today's agenda and introduce our speakers, which you'll find on Slide 2. First, Daniel de Boer, our Founder and CEO, will provide a brief strategic overview of the business. Following that, Dr. Cristina Lopez Lopez, our Chief Medical Officer, will welcome Professor Henkjan Verkade from the Beatrix Children's Hospital and University Medical Center of Groningen. He will share insights into unmet medical needs, disease pathophysiology and key biomarkers for assessing NTCP modulation in cholestatic diseases. Then Cristina will provide an in-depth review of the design of our Phase I trial of AX-0810 in healthy volunteers to assess safety, tolerability and PK of this first editing oligonucleotide to enter the clinic from our Axiomer platform and expectations for biomarkers and proof-of-target engagement. Finally, Dennis Hom, our Chief Financial Officer, will provide a corporate outlook update. We're looking forward to sharing these updates with you today. Following the presentations, our management team, Daniel, Cristina, Dennis and Chief Scientific Officer, Gerard Platenburg, will host a Q&A session with covering analysts. Today's event is being recorded, and both the replay and the presentation slides will be available on our website afterward. Before we get into the program, I ask that you note Slide 3, which includes our forward-looking statement. During the presentations today, we will make forward-looking statements. There are risks and uncertainties associated with an investment in ProQR, which are described in detail in our SEC filings. I will now turn the program over to Daniel de Boer. Daniel?

Thank you, Sarah, and good morning, everyone, and thank you for joining us today. We stand at the threshold of a major milestone for ProQR. With our CTA authorized in Europe, our Phase I trial in healthy volunteers beginning and initial data towards the end of the year, this is the moment where our science begins to translate into the clinic on the path to help patients. At the core of ProQR is Axiomer, our proprietary RNA editing platform. Axiomer harnesses the body's own editing enzyme, ADAR, and uses short chemically modified oligonucleotides to direct it precisely where we wanted to edit the RNA. Editing an adenosine into an inosine, which is translated as if it was a guanosine. What this means in practice is that we can repair mutations, restore or fine-tune protein function and even modulate protein activities in ways that opens up entirely new therapeutic possibilities. In short, Axiomer's versatility allows us to fix, fine-tune and reprogram proteins at the RNA level without altering the DNA. That's the power of the platform that we've been incubating for over 10 years. Our strategy with Axiomer is grounded in 2 pillars: our pipeline, where we're advancing multiple proprietary programs, which are rooted in human genetics and our partnerships, most notably our $3.9 billion collaboration with Eli Lilly, which is exclusively focused on Axiomer RNA editing. Together, these pillars underpin how we create value through our science, our pipeline to bring these new medicines to patients, our partnerships, our team and our financial strength. And today, I want to highlight how all those drivers are converging at this important stage for ProQR. First, scientific innovation. Our Axiomer platform is built on our proprietary editing oligonucleotide science invented here at ProQR. With a leading IP estate and robust editing efficiency demonstrated in liver and across CNS, Axiomer is poised to enable transformative impact for patients. Second, our pipeline. AX-0810, now with an authorized CTA is starting human trials to generate target engagement data. We're also building a leading capability in RNA editing in CNS and have demonstrated durable and efficient editing across regions of the CNS. AX-2402, our first wholly owned CNS program, targets the MECP2 protein for Rett syndrome. And beyond Rett, we see CNS as a major area of opportunity where our platform can deliver transformative therapies. Behind these, earlier programs such as AX-1412 for cardiovascular disease and AX-2911 for MASH broaden the scope into larger common diseases. Third, our partnerships. Our strategic collaborations with Eli Lilly and the Rett Syndrome Research Trust validate the strength of our science and accelerate development with important financial and other resources and expertise. Fourth, our team. We've built deep in-house expertise in RNA science, drug development and clinical execution. This year, we further strengthened the management team with the appointment of Dennis Hom as our Chief Financial Officer; and Dr. Cristina Lopez Lopez as our Chief Medical Officer, positioning us to execute on this next stage of growth. You'll hear more from both of them today. And finally, our financial strength. We're funded into mid-2027 with a runway to achieve multiple clinical and platform milestones. So how does this translate in what we'll be sharing today? We look at 3 horizons in our pipeline, the near term, where today, we will zoom in on AX-0810, our lead program targeting NTCP for the treatment of cholestatic diseases. Now that the CTA is approved, we are starting a target engagement first-in-human trial. And today, in this event, we'll walk in detail through the trial design, the endpoints and the expectations for the data. Next, our CNS capability and first pipeline program, AX-2402 for Rett syndrome, advancing rapidly towards candidate selection, uniquely positioning ProQR as a leader in neurological RNA editing medicines. And beyond, we have several other pipeline programs, including AX-1412 for cardiovascular disease and AX-2911 for MASH, which leverage and advance our platform, strengthening the portfolio and opening the door to previously unaddressable targets. These 3 horizons position ProQR strongly and make clear that we are poised for value creation at every stage. Today, Cristina will walk us through AX-0810 and the trial in more detail. The centralized review process of our CTA submission in Europe took longer than we had expected, reflecting the relative newness of the process and variability in review timelines. Now that the CTA is open, we look forward to walk you through the specifics of the trial in more detail. For that, I will hand over the call to our Chief Medical Officer, Dr. Cristina Lopez Lopez, to take you through AX-0810, our lead program and the first clinical trial for this program. Cristina?

Thank you, Daniel. I'm excited to present today on our most advanced program, AX-0810, which has just received CTA approval and will now begin its first in-human clinical trial. We're also delighted to be joined by Professor Verkade from Beatrix Children's Hospital of the University Medical Center of Groningen, a world-renowned expert in pediatric liver disease, who will share insights into NTCP and the biomarkers selected for this trial. Before we dive into the details of the trial, I would like to briefly remind you of our strategic rationale for targeting NTCP in cholestatic diseases and why we are so enthusiastic about this compound. We believe AX-0810 has the potential to become a first-in-class therapy targeting NTCP by acid reuptake to address one of the core drivers for cholestatic diseases. The fact that we are modulating a protein through RNA editing is a major milestone for the field and a step toward transformational therapies for patients with severe unmet needs. Let me provide you with some additional details about cholestatic diseases. Cholestatic diseases include a wide range of conditions affecting individuals from childhood to adulthood. They progress from inflammation to fibrosis, leading to chronic liver injury. Despite their diversity, they share a common biological denominator, toxic accumulation of bile acids in the liver that contributes to inflammation, cell damage and fibrosis. This all converges to create a powerful therapeutic opportunity to target bile acid toxicity as a shared disease mechanism. Bile acids are released in the intestine from the liver and are mainly used by the body to digest fat. Bile acids are costly for the body to produce. To conserve energy, the body relies on an efficient recycling system that transports bile acids from the bloodstream back into the liver. One of the key factors in this process is called sodium tau correlate co-transporting polypeptide or NTCP. As Daniel mentioned, one of the most striking aspects of our Axiomer platform is its versatility, particularly its potential to enable entirely new therapeutic approaches, including precise protein modulation. AX-0810 is the first other RNA editing oligonucleotide designed to modulate wild-type protein to enter the clinic. Through a specific A-to-I RNA edit, AX-0810 fine-tunes NTCP protein to limit bile acid reuptake from the bloodstream into the liver, directly reducing the toxic bile acid accumulation inside the hepatocytes that drives cholestatic diseases. With this novel mechanism, this program is positioned as a disease-modifying therapy with the potential to alleviate symptoms, encourage static diseases and most importantly, prevent or delay disease progression, ultimately reducing health care resource utilization and the risk of fatal outcomes. Our conviction comes from the converging evidence, biological rationale, human genetics and preclinical data all reinforcing AX-0810's potential as a transformative approach. Let me walk you through the scientific rationale and the supportive evidence. First, a strong biological rationale. As I mentioned, NTCP is the main transporter for bile acid reuptake. Elevated intrahepatic bile acid levels are directly linked to cholestasis, inflammation and fibrosis. Second, NTCP as a target is validated in human genetics. Healthy individuals with NTCP variants have reduced bile acid uptake but no adverse effects, demonstrating both safety and efficacy potential. Third, we see clear target engagement with Axiomer editing in preclinical models. Axiomer editing reduces bile acid uptake and increases plasma bile acid levels. Fourth, we have functional relevance confirmed both preclinically and clinically. In vitro and in vivo studies show that modulating NTCP decreases bile acid uptake, increases serum bile acids and improves biomarkers of liver health. Furthermore, clinical proof of concept in hepatitis D demonstrated that NTCP modulation improves liver health. And finally, AX-0810 is highly selective and specific. Our approach precisely modulates the sodium binding pocket of NTCP without affecting expression or membrane localization, demonstrating its potential to modulate the target without significant off-target effects or impacting other functions. Taken together, this body of evidence builds a robust derisk case for AX-0810 as a first-in-class disease-modifying therapy for cholestatic diseases. Within the broad spectrum of cholestatic diseases, we have the potential to target multiple indications. Among these, 2 stand out for the significant unmet medical need. The first is primary sclerosing cholangitis or PSC, which affects more than 80,000 adults across the U.S. and Europe. The second is congenital biliary atresia or BA, a devastating pediatric disease that impacts approximately 20,000 children worldwide. Both conditions are severe, progressive, life-threatening and may require liver transplantation, and option associated with significant clinical and economic burden. Importantly, there are no approved disease-modifying therapies available today, highlighting the need for truly transformational treatment options. This is exactly where AX-0810 has the potential to make a profound impact. And we are very pleased to be joined today by Professor Verkade, one of the world's foremost experts in pediatric liver disease, who will give you more information regarding these cholestatic diseases and the unmet need. His groundbreaking research has shaped the field's understanding of hepatic lipid metabolism, bile acid transport, metabolism and signaling in health and pediatric liver disease. Importantly, his work has direct relevance to the development of NTCP modulating therapies such as AX-0810. It's a true privilege to have Professor Verkade with us today to share his expertise and perspective on NTCP biology and biomarkers in our upcoming first-in-human trial. Professor Verkade, over to you.

Thank you, Cristina. It's my pleasure to illustrate a little bit the findings and the problems of cholestatic liver diseases. It will be a short presentation of which title will be therapeutic targeting of bile acid circulation in cholestatic liver diseases to disclose other interests are that I have a consultancy, advisory board appointments with different companies and have some funded research, both the fees for this are actually paid to the institution. There is a high unmet medical need in different cholestatic diseases. And one of them is, for example, primary sclerosis cholangitis or PSC. This is a disease that this table shows the main characteristics that's actually occurring both in children and in adults, in children, mostly in the second decade between 10 and 20 years of age starting, but also in adults between 30 and 50 years of age. The disease is so severe because we -- at this very moment, we don't have very effective drugs that prevent the cause of progression of disease and frequently, it goes into the need for transplantation. Annual transplant rate in children is between 17% to 30% and lifelong, probably closer to 50% as we know now. In adults, it actually is worse in the sense that it even adds up to 1% to 2% per year of the patients, and that's not only everything. The problem is also that after transplant, between 20% and 40% of the patients experience a recurrence of the disease, which may actually necessitate another transplantation or even a third transplant. And certainly has been associated with a shortened expected lifespan of these patients. Another disease I would like to have your attention to is biliary atresia. Also, biliary atresia has high unmet medical needs, as an example of the cholestatic diseases. Biliary atresia is purely a pediatric disease. It becomes apparent in the first weeks of life, mostly by exaggerated or remaining jaundice and at some point in pale stools. The population incidence is low. Only 1 in the 10,000 to 20,000 birth neonatal jaundice appears. The progression, however, is rapid and without surgical treatment, the survival does not extend the second birth [Technical Difficulty]. In the '60s, there was a surgery development successful, which is called the Kasai procedure. Nevertheless, however, even with the Kasai procedure, about 70% to 80% of these children with biliary atresia do need a liver transplantation before they reach adulthood at age 18. This major cause of disease going to transplantation can actually be also derived from these data on the 16,000 present liver transplantations, which have been performed in Europe since the '70s, divided into 3 -- approx, 3 eras before 2000 to 2009 and the recent area since 2010. It shows that the blue part of the graph, which is biliary atresia, has been consistently about 40% to 50% of all pediatric transplantations. So biliary atresia is responsible for almost half of the liver transplant at pediatric age. To discuss biliary atresia and PSC or in general cholestatic diseases, it's very helpful and I think understanding that we delineate what is the enterohepatic circulation of bile acids. This scheme shows the liver and as a central organ in the enterohepatic circulation of bile acids. The liver is the place in which bile acids are synthesized, depicted here by the green balls and are secreted into the bile duct, gallbladder here and to the intestine. At the end of the small intestine, they are taken up for the majority, 95%, reabsorbed and transported through the portal vein towards the liver to undergo again, cycling a secretion into bowel and thereby filling the cycle, the enterohepatic cycle, enter from the intestines to the hepatic, the liver, and this goes on. This is very efficient and in humans with normal physiology, this cycle takes place about 4 to 6 times per day. Cholestatic disease is, in general, the process in which the bile acids do not sufficiently get out of the liver into the intestine. This can be by hard block at the bile duct level, but it can be also by genetic diseases or immunological diseases like PSC or biliary atresia that the bile ducts are actually disappearing through a damaging process, a fibrotic process before and after birth. And this leads to the accumulation of bile acids in the liver where they have toxic effects. And secondarily, the bile acids are also spilling over into the systemic circulation. And that's why cholestatic liver disease is frequently also defined by an increase of bile acids in the systemic circulation measured by elevated serum bile acid levels. The mechanisms by which bile acids actually damaging are damaging the liver and thereby the whole system is, for example, occurring here through the bile acids generating cell stress and cell death. And you can see it on the left of this graph, either by genetic factors or environmental factors, you get this cholestatic liver disease, you get these immunological processes that may actually be the origin or contribute to the propagation of the disease and actually provide actually damaging patterns into the hepatocytes as well as sometimes in the bile duct. And the NTCP modulation as a therapeutic strategy that this company now is propagating in their approach is to prevent bile acids to enter the liver where they are mostly toxic. And if the bile acids are not entering the liver, you are expected to reduce the hepatocyte bile acid concentration, the [ intrahepatic ]bile acid concentration and thereby hepatocyte stress and cell death and secondarily, to reduce liver inflammation and fibrosis. This paper published this year is on the second disease I was creating biliary atresia. Biliary atresia, as I tried to explain, has been greatly helped by the development of Kasai portoenterostomy. However, a major fraction of the patients still need at some point in their pediatric life, childhood life, liver transplantation. And this study published in JHEP this year illustrates that is strongly associated with the amount of total bile acids in serum after Kasai surgery from -- to come back to the problem of enterohepatic circulation, cholestasis, as I explained, is that bile acids are remaining in the liver and are not being excreted as was suggested here into the blood, but largely remain in the liver to prevent to prevent the [ enterohepatic ] circulation, there are several strategies. One strategy is to prevent, if you have still some bile acid secretion into bile to prevent the reabsorption of bile acids. The reabsorption of bile acids is an effective way to drain the enterohepatic circulation and thereby, the amount of bile acids that needs to be secreted into bile is actually decreasing because the liver new synthesis of bile acids cannot compensate for the complete loss of bile acids by the tools. So this way will actually decrease the amount of bile acids that need to be secreted into bile. Accordingly, the bile acid levels in the spillover of bile acids into the systemic circulation usually decrease as well. And this is a good example for the so-called progressive familial intrahepatic cholestatic liver diseases or BSEP deficiency in which there is this IBAT inhibitors, the inhibitors that have recently been approved by EMA and FDA that inhibit the secretion -- the reabsorption of bile acids from the intestine and in some patients, a fraction of the patients actually decrease the symptoms of cholestasis and also the biochemical effects of cholestasis. The point is that I inhibitors do not work in all conditions. And the major one to consider is you do need at least some bile acids to be secreted from the liver into the intestine because these I inhibitors are not absorbable in the intestine and only prevent the reuptake of secreted bile acids. Therefore, in conditions that bile acids are not or minimally excreted only into the bile, IBAT inhibitors do not work. And that is, for many diseases, the case that the bile production and the biliary secretion of bile acids is severely compromised, which is expected not to be amenable to IBAT inhibition. Rather, for those conditions, you would prefer to have a prevention of bile acids secretion in the liver where they are, of course, expected to liver to damage. So therefore, this uptake inhibition pathway or strategy to inhibit MTCP bile acid uptake is actually clearly needed perhaps for these diseases to some extent, but certainly also for other diseases. In the hepatocyte, this is the picture here to the bottom right bottom, and that's boxed with the red line, try to -- the concept tries to prevent bile acids entering the liver by inhibiting NTCP. What is the background of this approach? Because you would maybe guess that an increase in bile acids in the systemic circulation is a bad situation in a bad condition. I think the whole medical field has thought the same way until this paper appeared in 2005, that was, I think, 2015, 10 years ago, in which there was an NTCP deficiency patient identified actually in the Netherlands. And these patients appear to have an NTCP deficiency without a very clear phenotype. But for example, this child did not have conjugated -- did not have pruritus and also no liver disease to an appreciable amount. This slide shows, for example, over time, this is a girl with values between 0.8 years of age to 5.3 years of age. And these are the liver, the conventional liver enzymes like transaminases and look at this, they are in a normal range between 30 and 40. Bilirubin, normal between 5 and 14, ALP normal and [ gamma-glutamyl ] normal, although at the expense, quite interestingly, the total serum bile acids, which are normally about up to 15 or 20 were between 400 and actually 1,225. So extremely high bile acid levels, no pruritus, no clinically significant liver disease. And actually, this child only had a problem with -- problem with too much but at least symptoms of a little bit well absorption of fat-soluble vitamins, which is the function of conjugated bile acids in the intestine, but this could be overcome by secretion. If you have these high bile acids not in the liver, you still have them, of course, in the plasma, in the systemic circulation. But the good news is that the liver and other organs can take care of it that you can sulfate bile acids that actually can allow their secretion into the urine. So the sulfation or other approach of bile acids that are circulating in the systemic circulation, they make them more hydrophilic, less hydrophobic and actually enhance their disposal from the body. So it's not that these bile acids continue to increase every day and live longer. But in contrast, you get rid of it and partly by excretion via the urine. One specific NTCP inhibitor, bulevirtide has been approved for hepatitis D, and this illustrates the power of this approach to decrease an activity, not only for the hepatitis D, but also for the secondary effects on the liver physiology. First, as expected, if you do increase -- if you do inhibit NTCP, the bile acid increase. And in this case, this was 3 to 4 -- two to fourfold in plasma over time in 30 weeks up to 50 weeks, 1 year. Interestingly, dose dependently, this drug in these patients decreased liver stiffness significantly and also improved on the bottom panels, the initially abnormal liver enzymes. Even in patients that did not respond theoretically. So the inhibition of bile acid accumulation and the bile acid uptake by NTCP blockade is suggested to have anti-inflammatory effects on different immune cells and actually confers hepatoprotection in this condition. And the company has chosen for 3 independent parameters that complement each other to allow an unequivocal conclusion that if they all go in the same direction, indeed decrease NTCP-mediated bile acid uptake. The first, as can be derived already from what I explained just before, if you do decrease NTCP activity and the transplant activity, one can expect that total bile acid levels in plasma do increase. because, as said before, NTCP is the single-entry point for conjugated bile acids and -- which make up the majority of bile acids in serum anyway in the plasma. So the first parameter is a change and in fact, an increase in plasma total bile levels. Secondly, and that goes to the composition of bile acids, bile acids are in different forms and compositions as species, but the major discrimination is conjugated bile acids versus unconjugated bile acids. NTCP is particularly involved in the process of conjugated bile acid uptake by the hepatocytes. And accordingly, not only total bile acids will increase if you do decrease NTCP level activity, but particularly the change will be in plasma conjugated bile acid levels as a second parameter to confirm that there is a mediated bile acid uptake decrease. Finally, and completly independent experiment to further delineate an effect on conjugated bile acid uptake, it has been chosen to go for an administration of a conjugated bile acid, which is quite uncommon in physiology of humans, although it's used therapeutically in other cases, it is a bile acid with a specific name taurine conjugate tauroursodeoxycholic acid or TUDCA or TUDCA. Since this is very lowly present in the condition of a healthy human, by administration, you can tailor its cause in the system. If you do administer this specific bile acids orally, it will be taken up by the intestine and appear in serum. And since this is a perfect substrate for NTCP, its disappearance from the plasma compartment will be strongly dependent on NTCP activity. And accordingly, if NTCP-mediated uptake is decreased by the therapeutic manipulation and the mRNA impairment, it will be expected that the clearance of UDCA from the plasma compartment will be delayed compared to the condition in which there has been no manipulation. So by these 3 different mechanisms and parameters, it's possible to assess the effect on the transport activity for total bile acids, the specificity for NTCP of conjugated bile acids and also of a conjugated exogenous bile acids to further prove the point. And this information will on top of this more mechanistic information, also likely inform on dosing regimens for future trials in the disease population. In summary, I hope to have illustrated to you that there is a high unmet medical need for different cholestatic liver diseases, for example, PSC, which is both an adult and a pediatric disease as well as biliary atresia, purely pediatric liver disease. And unmet medical need extends even to the need for liver transplantation, which is very high in these diseases and particularly for PSC also leads to retransplantation. The mechanism that these diseases are actually playing out in the body is that there is an inadequate metabolic adaptation to the bile acid overload of hepatocytes. The different -- the disease is different. So we are sure that the other factors play a role as well. But the concept of hepatocyte stress and death that trigger inflammation and fibrosis is a common denominator in these types of diseases. Since NTCP is the key transporter mediating bile acid uptake from bam into the liver, blocking NTCP decreases is expected to decrease the uptake of bile acids into the hepatocyte and thereby has certainly the potential to reduce hepatic stress and cell death and secondarily then reduce liver inflammation and fibrosis or progression of fibrosis. This is an interesting assessment of target engagement. It needs first-in-human safety and tolerability, of course. And I'm quite interested to look at the future of the development of this drug. Thank you very much for your attention, and I would like to give the word back to Cristina.

Thank you, Professor Verkade, for this excellent presentation and your insights into cholestatic disease biology, NTCP targeting and relevant biomarkers. I would now like to give you more details on the design of our first-in-human study, which will assess AX-0810 in healthy volunteers. We are very pleased that our innovative study design, which does not require a traditional single ascending dose approach has been positively reviewed and supported by regulatory agency in Europe. This design offers several important advantages. It allow us to properly assess pharmacokinetics, safety and tolerability at different dose levels, while also enabling generation of pharmacodynamic data. Ultimately, this approach is designed to position us to move rapidly and confidently into patients. The study will enroll 33 healthy volunteers with 24 participants receiving active treatment and 9 receiving placebo across 3 dose cohorts. The design includes 4 subcutaneous injections. With the first 2 injections given 15 days apart, we will fully assess the effect of single doses on safety, tolerability and PK. And with the following injections given weekly, we aim to achieve meaningful concentrations in the liver in order to relatively quickly understand the pharmacodynamic readouts. After the dosing phase, there will be a 12-week safety follow-up period. An independent data monitoring committee will conduct safety reviews before each step of dose escalation. For pharmacodynamic assessment, we plan to investigate biomarkers related to target engagement. This will ensure we capture the most relevant data and signals to guide the next steps of AX-0810 development. I will provide more details of these biomarkers in the next part of my presentation. We expect initial safety, tolerability and PK data towards the end of the year. And furthermore, we will present the target engagement data in the first half of next year. We are excited about this progress, and we look forward to sharing these important updates with you very soon. Let's take a closer look at the study objectives, starting with safety and tolerability. Our study design and optimized dose regimen in this first-in-human study enable us to achieve pharmacologically active liver concentrations efficiently. This approach ensures that we can robustly assess the safety and tolerability of AX-0810 for potential long-term use in patients with cholestatic liver disease. Next, let's look at how we are capturing relevant outcomes to guide future development using a carefully selected panel of biomarkers designed to provide meaningful insights into therapeutic activity. Our PD assessment is designed to capture the full picture of AX-0810's potential in humans. Specifically, we are measuring NTCP engagement via multidimensional assessments. 3 key biomarkers will be assessed, chosen for their ability to provide information about target engagement, selectivity and discriminatory potential among doses for future therapeutic intervention. Total bile acid levels in plasma to assess the effect on bile acid transporter activity, bile acid profile to measure the ratio between conjugated and unconjugated for specificity and via TUDCA challenge, which mimics the abundance of bile acid in plasma in the disease and will inform dosing regimen. Additionally, we are collecting samples to further investigate exploratory biomarkers to further elucidate what will happen in the disease compared to healthy volunteers. Zooming in on each of the key biomarkers, let's have a look at total bile acids in plasma. NTCP transporter is responsible for more than 90% of total bile acid reuptake from the bloodstream back to the liver. By modulating NTCP function with AX-0810, we then expect to see an increase in plasma total bile acids as they cannot enter in the liver anymore. A twofold change in plasma total bile acids as presented by Professor Verkade will be considered clinically meaningful in cholestatic patients. And our preclinical studies confirm that Axiomer treatment can lead to more than twofold increases in plasma bile acid levels. With that foundation, the next step is confirming AX-0810 specificity for NTCP. NTCP is the main transporter responsible for the uptake of bile acids and has a specificity towards conjugated bile acids. As such, a step-wise increase in these specific bile acids in the plasma will further demonstrate that increasing bile acids is driven by AX-0810 specificity for NTCP transporter only. And this data were also confirmed from our preclinical model in mice, where a shift of conjugated versus unconjugated bile acids in the plasma was achieved. To further strengthen the evidence, we introduced a TUDCA challenge to mimic an overall boost of bile acids in the periphery as would happen in cholestatic diseases. Tau conjugated bile acid or TUDCA, it is produced in very limited quantity in human and exclusively taken up into the liver by NTCP. Thereby, external administration of TUDCA mimics the disease in healthy volunteers, help us to assess in a very targeted and specific manner, NTCP bile acid function. The TUDCA challenge will also provide a discriminatory effect between doses to inform dose regimen selection. A decrease in plasma clearance as reported by an increase in TUDCA plasma levels is expected to further confirm AX-0810 target engagement. In our preclinical studies, a decrease in TUDCA clearance was observed. To ensure that these readouts are robust, we have also optimized how and when we capture biomarker changes. We know bile acid levels fluctuate naturally through the day, depending on circadian rhythm and diet. To address this, our first-in-human study has carefully standardized conditions, including optimized time points, meals and controlled diet. This rigorous design gives us confidence that we can distinguish between baseline variability and drug-induced changes compared to placebo. To summarize, our plan is designed to meet multiple objectives: one, to demonstrate precise target engagement; two, to confirm disease relevance; and three, to provide a detailed mechanistic understanding as well as dose response and durability of the effect. Together, these factors give us conviction in the translational potential of NTCP as a therapeutic approach in cholestatic diseases. When translating these learnings into the disease population, we expect to see a consistent pattern in bile acid biomarkers. In patients with cholestasis, plasma total bile acids are already elevated. As such, AX-0810 intervention is expected to further increase in plasma. And in addition, we expect an increase in the conjugated versus unconjugated ratio. What is critical is that this change in bile acids will help to release hepatocytes from excessive toxic bile acid levels. And this is expected to be accompanied with meaningful clinically relevant improvements in patients such as reduction in liver enzymes, decrease in cholestasis markers and decline in fibrosis. Finally, let's look ahead at the development path and the upcoming milestones. We anticipate announcing safety, tolerability and PK data from Cohort 1 towards the end of the year, followed by target engagement data in the first half of 2026. In parallel, activities to include a patient cohort in this first-in-human following completion of the healthy volunteers part are already underway. The objective here is to generate early data in a disease setting in a timely manner to support next steps in clinical development. This cohort will proceed following additional regulatory approval. We expect to have some data from this around the end of 2026. We will provide guidance when the cohort is started. We are very excited about the progress of AX-0810 and the milestones ahead. We are confident our first-in-human design will deliver a comprehensive safety, PK and PD profile and position AX-0810 for rapid advancement into patients. And with that, I will hand it over to Dennis Hom, our Chief Financial Officer, to share more.

Thanks, Cristina. I'd like to wrap up by emphasizing some of the key value drivers that Daniel covered today. I joined ProQR about 6 months ago because I was super excited by the scientific innovation happening here and the broad potential of the Axiomer platform. ProQR invented RNA editing as a therapeutic modality and holds the foundational patents in the field. We have been making good progress with the pipeline. And as you heard today, we're entering the clinic with AX-0810 for cholestatic diseases, the first-in-human study using Axiomer. Beyond this, we're advancing applications in CNS with AX-2402 for Rett syndrome and in broader indications such as NASH and cardiovascular disease. Together, these pipeline programs illustrate the breadth and scalability of the platform. We have done all of this alongside our strong partnerships with Lilly and the Rett Syndrome Research Trust. These collaborations validate the strength of our science and provide valuable resources and expertise to accelerate Axiomer progress. From a team perspective, we've strengthened leadership this year with the addition of Dr. Cristina Lopez Lopez as our Chief Medical Officer. She brings deep development and translational expertise, particularly in CNS. I bring a background spanning investment banking, big pharma and biotech across finance and corporate development roles. Finally, we're fortunate to be funded well into mid-2027, having ended June with about EUR 120 million on the balance sheet, providing us runway that funds multiple clinical and platform milestones. Taken together, these value drivers position ProQR to advance RNA editing medicines for patients and create long-term value for shareholders. Thanks for joining us today, and we look forward to updating you in the months ahead. We will now open the call for Q&A with our covering analysts.

Our first question comes from Steven Seedhouse at Cantor Fitzgerald .

Actually, I had 3. I'll just ask them one at a time. The first is on the patient cohort that looks like you're planning to add in Phase I. What indication are you planning for there? Or will it be a mix of different cholestatic patients?

Steve, thank you for the question. I'll let Cristina address this question.

Thank you so much, Steve. For our patient cohort that we are planning to initiate after we have the data in healthy volunteers, we are planning to include PSC patients.

Great. And then one of the differences between NTCP and IBAT inhibition, I think, would be the expectation that NTCP inhibition would also reduce de novo bile acid synthesis. Curious if you could comment on that and if there is a circulating biomarker, something like C4 that might allow you to assess that. I didn't see that in the plans. And I'm just curious if there's a reason why not or if there's sort of a weakness in that biomarker in healthy volunteers or something.

As I mentioned before, our key biomarkers for target engagement, selectivity and discriminatory effect are the ones that I described in the presentation, total bile acids, the profile and the TUDCA challenge. However, we are collecting biomarkers for exploratory purposes, samples that will be analyzed at the end of the study. And this indeed includes C4. So we are basically assessing the entire bile acid pathways to elucidate potential feedback loops.

Terrific. Last question, just -- there's some recent data from a, I guess, next-generation NTCP inhibitor. This is Assembly's molecule. It drove a lot of increase in circulating bile acids like several hundred-fold in healthy volunteers at their highest dose. I'm just curious, assuming you saw those data, what you make of those data, does it change your expectations at all for what the dynamic range of circulating bile acids would be and what sort of effect you might be able to drive with an RNA editing oligo.

Thank you. Actually, we are following that to better understand that data, but we still are convinced that our -- the potential of AX-0810 fulfill the unmet medical need -- potential fulfill of the unmet medical need for the indications that we are interested.

Our next question comes from Gavin Clark-Gartner at Evercore.

Really informative event. Let me just follow up on Steve's -- one of Steve's questions. So let's just say that your NHP data translates really well into healthy volunteers. Like let's say you get four or fivefold plasma bile acid increases from baseline or maybe even more. How do you think about which dose you'll take into patients? Like what is the level you believe may result in very strong or kind of near maximal efficacy in patients?

Gavin, thanks for the question, Cristina.

In the current study, we are really trying to explore the entire dynamic range of potential -- based on the preclinical data of the potential editing change in bile acids while also assessing the safety and tolerability profile. We know that from 5% editing onwards, we will start to see changes in bile acids. In principle, we will really try to target and to maximize the editing, but always with an acceptable window in terms of safety and tolerability.

Yes. So to add to that, Gavin, we complete the healthy volunteer cohorts. And on the basis of the readout of those cohorts, we will select the dose that will go into the patient cohorts that will conclude in the second half of next year.

Okay. Great. And then maybe on the safety side, can you just walk through the key elements you're looking to derisk in the Phase I study, I guess, specifically kind of calling out pruritus or any transient liver enzyme elevations or anything else you're looking to not see?

Absolutely. So in terms of the safety assessments of the first in humans, we are doing the standard safety and tolerability assessments. This will include any potential adverse events. We will perform ECG data. We will perform labs. And as part of those labs, for example, we are going to measure, of course, liver enzyme. Based on the paper presented by Professor Verkade, this increase in bile acids in the periphery did not translate in pruritus. So we don't have evidence that we will have pruritus. However, of course, we are going to be measuring any potential skin or dermatological reactions, including itching as part of our safety data set.

Awesome. I'm just going to squeeze in one last one. What's the relative focus we should place on some of the different pharmacodynamic measures? Or really is the key point that the different measures should be concordant?

For the bile acids, the total bile acids, what we are really trying to assess is the type of -- to assess the modulation of AX-0810, blocking the uptake in general of the bile acids and therefore, preventing the uptake into the hepatocytes where they can cause toxicity. With the second, the conjugated versus the unconjugated, meaning the bile acid profile, what we are assessing is the selectivity of our RNA editing because we know that NTCP blocks primary sorry, by blocking the binding pocket of NPCP, we block specifically the conjugated bile acids. The third biomarker is a challenge so that we are performing in healthy volunteers, a, to mimic the disease because we are giving orally a pool of an external bile acid to increase the bile acids in plasma. So we expect, if we are very selective to impact the clearance of TUDCA because it will not go inside the hepatocyte. Additionally, TUDCA will give us additional discriminatory effect to distinguish between doses because sometimes when we look at total bile acids, we could have different variability. As I mentioned in my presentation, to minimize the variability, we have really standardized the conditions when we give the meals as well we take samples at the same time of the day to minimize impact of card variability.

Our next question comes from Jon Wolleben at Citizens.

A couple for me. You guys have given us preclinical data before for some first-generation oligos. And now that we have the in-human dosing, hoping you could talk a little bit about what you saw preclinically at this dose range to give you confidence you're in the right range there? And if you expect this 3-milligram per kilogram dose to be therapeutic? Or is this just kind of the first low dose, and we'll have to wait to see more from the higher doses?

Thanks for the question. So preclinically, we've seen the proof of target engagement in several species. We've been looking into humanized mouse model to understand the impact on bile acids while editing. We have been using NHP data to basically inform us about safety dosing regimen and liver concentration. And basically, the combination of those data helped us to get excited to move forward into the clinic. So basically, the combination of the data helped us to determine target engagement markers and to move forward. So that's the basis of our current moving forward.

And Jon, you asked a question about if the 3-milligram level would potentially lead to PD biomarker changes. We think that could be the case, but we're going to review all the 3 cohorts together. And on the basis, there of draw conclusions on the response and the potential dose response curve.

Yes. Just on that point, Daniel, so the data around year-end is just going to be safety, PK, tolerability, and then you'll be giving us the target engagement from that first cohort with every -- with all 3 cohorts later in 2026.

Correct. Our next question comes from Ryan Deschner at Raymond James.

Thanks for the question. How broadly do you think an NTCP targeted therapy like 10 could be applied to cholestatic diseases? And do you think the therapy like this could be effective in diseases where IBAT inhibitors are currently used? And do you have any feel for why bulevirtide is not being used or developed in BA and PSC?

Ryan, thank you for the question. So we think that the NTCP therapeutic approach is a novel and very differentiated approach from anything else that is out there and has been tested before. NTCP is a target that directly sits on the liver. And because of that, we think it may have a much more direct effect on the disease of cholestatic diseases, which is largely driven by the accumulation of bile acids in the hepatocytes that leads to inflammation to fibrosis and ultimately liver failure. We believe that with this approach, we could target a wide variety of different cholestatic diseases, including PSC and BA, which are the ones that we are currently predominantly focused on. But there is a potential to expand into other indications as well. You asked why bulevirtide, the peptide by Gilead for hepatitis D has not been tested in cholestatic diseases. We can't comment to that. It's not our molecule. So we don't know why that has never been tested.

Got it. And maybe one more quick one. Do you anticipate looking at liver stiffness or pruritus at all in Phase I?

At the moment, we don't have finalized the protocol for the addition of the patient cohort. However, based on the treatment duration because the study will mimic in terms of the doses because we want to replicate the biomarker signature that we see in healthy volunteers. For the duration of the study, we will not anticipate to see changes in biomarkers, for example, FibroScan. However, we can definitely as soon as the protocol develops together with regulators, we could potentially add specific measurement as exploratory endpoints. But I should mention that the main objective for this patient cohort is to replicate the biomarker signature and to determine that we are actually engaging the target in patients with cholestatic diseases.

Our next question comes from Andreas Argyrides at Oppenheimer.

Also for this very informative presentation. Two from us. Can you provide additional color on kind of ongoing discussions with regulators around the use of these biomarkers to support potential accelerated approval? And then what factors would go into the decision to advance AX-0810 in biliary atresia?

Thank you, Andreas. Cristina, go ahead.

Yes. So I will split my answers in the 2 buckets. I mean, first, about the biomarkers and the clinical significance of those biomarkers and to address about the potential accelerated approval. So in terms of the meaning of those biomarkers, these biomarkers were selected specifically to address the objectives of the first-in-human trial, not to assess clinical efficacy as it will happen in subsequent trials. These biomarkers we discussed with regulators and was part of our interactions in the CTA. They basically just approved and they approved the scientific validity, and there was no questioning about the use of these biomarkers also in terms of the decision-making. When we are talking about the population moving forward for Phase II onwards. We are still having both indications and our investigation. We believe that both BA and PSC, both there are 2 indications that have a very high unmet medical need. And based on the scientific rationale and the tractability of the hypothesis, we believe that we could develop both clinical development plans. After we get the results for the first in human for the Phase I, we will provide additional guidance about what will be our indication of interest. When we are talking about potential biomarkers to be used as surrogate end points or potential for accelerated approval, we have planned additional health authority interactions when we present the data from our first-in-human trial.

Our next question comes from Keay Nakae at Chardan.

Two questions. First, in terms of the dosing interval, does your preclinical data suggest that, that could be stretched out at all beyond what you're evaluating here?

Keay, thank you for the question. Cristina?

Yes. So the dosing interval, so with the dosing interval that we are implementing in the first-in-human trial, basically on one side, we use this dosing interval based on what we have learned preclinical. And we have 2 main objectives with this particular dosing interval. The first one is after the first injection, we don't provide the second injection after 15 days. And the reason is we would like to fully assess the safety and tolerability and potential PD after a single dose administration. The subsequent injections, what we are really trying to do is to get sufficient exposure into the liver as fast as possible in order to understand the safety and in order to get pharmacodynamic readouts of therapeutic potential. You also mentioned about the stretch the dose regimen. Can you please further elaborate what did you mean?

Yes. Can the dosing interval as you enter into patients be longer?

The dosing interval that we are using in our first-in-human trial do not reflect the dose regimen that we are going to implement subsequently. It was only to achieve our objectives in a timely manner to get into the patients as quick as possible.

Yes. okay. We -- our TPP says that we want to dose every few months. Just for the purpose of the first-in-human study, we're dosing weekly to load up as much drug in this 4-week window as we can.

Great. So I appreciate that. And then in terms of the plasma bile acid biomarker, while you mentioned that a 2x increase would be clinically meaningful in patients, at least at your starting dose, how much of an increase in the healthy volunteers would you hope to see?

Yes. So we believe that a twofold increase in bile acid is indeed where the disease changes. So that's what we see as a minimum for the first-in-human study. As we indicated before, we're testing several doses to hopefully establish a dose response curve with levels that are increasing the total bile acids beyond that. And in addition to that, we will better understand the dynamics of the bile acids, as Cristina alluded to in her presentation, using the different measures of both conjugated bile acids as well as looking at the TUDCA challenge.

Our next question comes from Catherine Novack at JonesTrading.

I have a question about the TUDCA challenge in NHPs. Can you tell us whether this was AX-0810 or a different Axiomer? And was this delivered with GalNAc or LNP?

So thanks for the question. That was done previously, and that was with another research tool molecule that we tested for the TUDCA challenge. However, the pharmacodynamic effect of that was completely the same. So it showed editing of the target to actually show the target engagement and thereby also the reduced clearance of TUDCA. So it was like that.

And was it GalNAc?

No. I think the initial studies, if you may recall, we tested different formulations to get the drug into the NHP. And these particular experiments were done with LNPs. Subsequently, we went over to GalNAc molecules for the subsequent development of the molecule for AX-0810, sorry.

Okay. And then for the EON Axiomer, you also used LNP to deliver, I think, up to 4 mg per kg dose. How do we think about translating this LNP data from EON-A into GalNAc in humans? You've given us data comparing Axiomer AX-0810, but I'm not sure how to look -- how to think about the LNP dose versus the GalNAc.

Yes. I think the general way that we view is that LNP provided us with a very useful tool to get tissue exposure of the drug, but the subsequent development of GalNAc liver targeting or hepatocyte targeting extrapolating from the LNP data provides us with the basis for the next, let's say, development. And I think GalNAc in our hands is preferable for development further into the clinical setting.

And what was the reason for weight-based dosing versus fixed dosing of the oligo in humans?

This is a good question. And in this first in human, we really wanted to minimize variability and to really adjust exposure very precisely to the healthy volunteers to really optimize the study design and to get robust conclusions.

[Operator Instructions] So our next question comes from Ananda Ghosh at H.C. Wainwright.

I have 3 questions. The first one would be, is there any idea of what's the turnover rate of NTCP and how does it correlate with the editing efficiency and also with respect to the durability of the ADAR? That will be the first question.

Yes. Thank you for the question. Gerard, do you want to address this?

I think the turnover rate of the protein itself is relatively short. I can't give you a day rate or something like that, but it's relatively fast. I think that is also the reason why the bulevirtide needs to be dosed on a daily basis. And could you?

Yes. Maybe to add to that, the durability of the effect is not driven by the stability of the protein. It's driven by the stability of the EONs that subsequently lead to the edit. And we believe the EONs are catalytic, so they can edit multiple target messenger RNAs. So the durability of the effect is driven by the stability of the molecules.

Great. Maybe from the safety perspective, the elevated bile acids, particularly hydrophobic bile acids are considered to be toxic. Is there a protocol to measure hydrophobic index in your -- the HV trial?

Well, what we really like about this target is that we're essentially mimicking what human genetics has already established. So there is a wild-type healthy population -- sorry, there's a healthy population that's living with this specific variant that do not have any side effects from living with the variant. So the change that we're introducing does not negatively affect individuals, and that's already established. And therefore, we don't expect any side effects of just the change in NTCP function.

And we are measuring the entire profile of bile acids. So in case that we see anything, we can do some subgroup analysis to better understand any potential signal for the hydrophobic bile acids.

Got it. Very helpful. And maybe the last one. The increase in bile acid is also known to be linked with FGFR and FGF19 and FXR expression in intestine. Did you see any change in the preclinical model so far? And does it -- and can those changes act as another validation of the biomarker data, which you plan to see with respect to the bile acid profile?

So thank you for the question. Very interesting. Yes, we do feel that, that's an important market to follow. And as Cristina alluded to, we will be -- as an exploratory market, we'll be monitoring that in a subsequent clinical trial. But for sure, it's an important market to follow, yes. Thank you.

Great. Thank you for the questions. So this concludes today's Q&A session and the event. Thank you, everyone, for joining. You may now disconnect.