Good morning, everyone. I'm Heather Francis from Indiana University, and on behalf of AASLD Liver Fibrosis Special Interest Group, I want to welcome you to our webinar on PSC and Hepatic Fibrosis. Today, we have two experts from the field, Dr. Robert Hebert from Mayo Clinic, who's going to give us an update on the basic side of research and PSC work, and Dr. Cynthia Levy from the University of Miami, who will also provide a clinical update in areas of potential treatment. We'll hear from both of these speakers shortly, and I would ask that you put any questions in the chat, and we'll moderate these after their presentations are concluded. So in addition to these updates from the scientific and the clinical world, we've also partnered here with the PSC Partners Seeking a Cure organization to recognize PSC Global Awareness Day. So the PSC Partners is a very special organization to me. They were the first organization outside of my internal institution to fund my work when I was starting my independent career, and the money was actually very critical to my future federal funding endeavors. However, of course, beyond the money, I've really benefited more, exceedingly more from the friendships and the relationships that we've developed together through this fantastic organization, and we're really excited to be able to bring them here this morning to provide an update on their organization, and I'm very happy to welcome Mrs. Rikki Safer, who is the CEO of PSC Partners. She's gonna kick off our webinar this morning, provide a brief overview of the organization, and then we'll hear from our experts in the field. Rikki, please take it away. Thank you so much. I'm honored to have the opportunity to tell you about our patient advocacy organization and the ways that we collaborate with clinicians, researchers, regulators, and industry to move closer to our shared goal of finding new therapies and eventual cure for PSC. Our patient community is truly grateful to all the clinicians and researchers who devote so much energy and expertise to unraveling the mysteries of our rare disease. Next slide. We also appreciate that this webinar was scheduled today to coincide with Global PSC Awareness Day. For the first time, we have 12 patient organizations collaborating internationally to spread the word about our debilitating disease and urgent unmet needs. Next slide. I have nothing to disclose. Next slide. Before my devastating PSC diagnosis 17 years ago, I had lived the life of a health, nutrition, and exercise fanatic. Then suddenly in March, 2004, I found myself in the emergency room with what I would later learn was my first cholangitis attack and the beginning of my unpredictable PSC journey. I will never forget the words that my physician said about my diagnosis, a rare, possibly terminal, progressive disease with an estimated 10 years to live. My family and I went into action researching and setting up a nonprofit organization, and we launched PSC Partners Seeking a Cure on a Shoestring in January, 2005. The mission of PSC Partners Seeking a Cure is to drive research to identify treatments and a cure for primary sclerosing cholangitis while providing education and support for those impacted by this rare disease. We work seamlessly with our Canadian affiliate, PSC Partners Seeking a Cure Canada on research and community-related projects. Next slide. Throughout the years, ASLD has expanded our research exposure and opportunities. Since 2007, at the liver meeting, PSC Partners has sponsored an annual research award, and in 2020, we also sponsored an ASLD PSC pilot award. We host a lively booth every year at the liver meeting. We have co-authored two poster presentations, and this year, Dr. Ruth Ann Pye, our Director of Research Strategy, is presenting another. PSC Partners has a representative on the ASLD Communications and Technology Committee. Next slide. Please inform your PSC patients about our educational and support offerings. In 2014, as part of an NIH pilot project, we launched our patient-reported registry, which now has over 2,000 participants. The registry has become a tool for clinical trial development, recruitment, and quality-of-life research. In conjunction with multiple U.S. medical institutions, we have hosted 17 annual patient caregiver conferences to offer scientific education and patient caregiver support. In 2020, we launched our enhanced website, a hub for our patient and medical communities. We distribute a comprehensive online monthly e-newsletter and monthly podcast, have a peer-to-peer mentor program, and several moderated social media support groups. Early in the pandemic, we created a COVID-19 survey to capture PSC patients' experiences with COVID and to ease the fears of our community. Next slide. PSC Partners facilitates the advancement of PSC research, drug development, and clinical trials while representing the voice and needs of PSC patients. Here are some of our recent accomplishments. We have allocated over $5.5 million in international PSC research grants. PSC Partners initiated the launch of the PSC Forum, an independent multi-stakeholder group that addresses the regulatory challenges of PSC to advance therapeutic interventions. In October 2018, after a year-and-a-half-long effort, we applied for, testified, and obtained the all-important PSC-specific ICD-10 code, K83.01. In October 2020, we held an all-day, externally-led, patient-focused drug development meeting with FDA clinicians, researchers, and industry to bring the patient voice into drug development. The detailed meeting report will be published next month. In preparation for this PFDD meeting, we created an in-depth survey, Our Voices, to assess the impact of PSC on patients and to identify research priorities. Nearly 900 patients responded to the survey, and we're planning to publish some of that data from the survey. In 2020, PSC Partners was thrilled to receive a RARES-1 grant, which provides us financial support, mentoring, and resources to strengthen the patient voice and, ultimately, to create an international collaborative research network. This grant has empowered us to embark on major collaborative projects with clinicians and researchers that are crucial to accelerating PSC research. Since the pandemic has prevented us for the second year in a row to hold our conference in-person, we created our roadmap initiative, Research Objectives and Development Meetings to Accelerated Progress, which is a series of 10 webinars to educate our community and create monthly opportunities for patients, caregivers, researchers, and clinicians to engage in collaborative, meaningful discussions on a variety of PSC research topics. We invite all of you to participate in future roadmap webinars. Past webinar recordings are posted on our website. The roadmap webinars are building the foundation for our June 2022 Annual Patient Caregiver Conference in Boston, co-hosted by Dr. Josh Korzenich from Brigham and Women's Hospital and Dr. Dan Pratt from Mass General. At this conference, we will launch our international collaborative research network, and we hope that many of you will attend. To help close the many challenging gaps in PSC research, PSC Partners is currently developing two major patient-driven scientific projects that FDA and researchers have identified. First, in collaboration with an international group of researchers with existing PSC natural history databases, we are creating a robust global PSC natural history cohort with two aims, to identify validated surrogate markers that are acceptable to FDA and EMA for conditional drug approval, and to establish a cohort to serve as a placebo arm for required confirmatory trials. We are also discussing possible biobanking opportunities. Secondly, we are working with a team of medical experts to help us develop a uniquely PSC-specific, fit-for-purpose patient-reported outcome measure for use in future PSC clinical trials. We welcome input and guidance from clinicians and researchers as we progress through these projects. We also need your help in closing a gap that we are unable to close alone. Our current active community is inclusive, but does not accurately represent the racial and ethnic diversity of the PSC population. Please let all your patients know about PSC Partners and our dynamic and welcoming community. Next slide. We are a passionate and tenacious group of PSC patients and caregivers who firmly believe that collaborations between the patient and medical professional communities will accelerate reaching our shared goal of a cure for PSC. As patients, we will continue to do all we can in the search for a cure. We do know one thing. No matter how hard we work, we can't do it without you. We hope that together we can create a world where a PSC diagnosis comes with a cure. Thank you. Thank you so much, Ricky, for that important update from PSC Partners, and we're excited to partner with you today in our ASLD webinar. So our next speaker is Dr. Robert Hebert, who is an associate professor of medicine at Mayo Clinic in Rochester, Minnesota. He's a transplant hepatologist and the current program director for Advanced Transplant Hepatology Fellowship. And he's also an NIH-funded physician scientist with a primary focus in cholestatic fibrogenesis and epigenetics. And today he's gonna give us a basic science update on epigenetic regulation of cholestatic fibrogenesis. Thanks, Heather. Thanks to everyone for attending and thanks to the organizers and ASLD for having me here today. So although this is a basic science talk, we've tried to keep it a little more conceptual without too much dense data because we have non-scientists in the audience as well. So the learning objectives here are to understand basic aspects of the pathophysiology of biliary fibrosis and to appreciate some emerging research themes in epigenetics. So you're all aware that the liver parenchyma is comprised 95% of hepatocytes and the other 5% of the parenchyma are cholangiocytes, which are the specialized epithelial cells that line the biliary tree. And they form this anastomosing fractal drainage network of bile ducts that delivers bile to the intestines. The cells themselves are highly specialized. They contain a primary psyllium, which serves as a mechanosensor, a chemosensor and an osmosensor to sense and modify bile. There are also specialized transport proteins on their surface that facilitates secretion and absorption. And then many people think that cholangiocytes may serve a role in repair after injury and in epithelial mesenchymal crosstalk, which I'll focus on some today. So the cholangiopathies are this diverse group of liver diseases that target the cholangiocytes. And many of these are obliterative in nature, meaning that they lead to destruction of the cholangiocytes and ductopenia. And this results clinically then in cholestasis, fibrosis and a predisposition to malignancy. The end stage cholangiopathies are currently untreatable without liver transplantation. So this is just a mnemonic vitamin K to remind you that the cholangiopathies have a variety of idiopathogenesis. So I won't go through them all, but there are vascular cholangiopathies, infectious, toxic, autoimmune, metabolic, idiopathic and neoplastic. And then the K is for karyotype, which reminds you of the genetic cholangiopathies. Of course, today we'll focus on the idiopathic cholangiopathy PSC. So PSC is a rare idiopathic fibro obliterative cholangiopathy in which the normally smooth contour of the bile ducts becomes irregular with inflammation and scarring. And again, this manifests clinically then with things like biliary strictures, cholestasis and organ dysfunction. And there are currently no effective medical treatments for end stage PSC, just surgical ones like liver transplantation. So the pathogenesis is unclear. There've been genetic studies that have been ongoing for many, many years. And despite this simple genetic causes of PSC really have not been identified. And so the thinking now is that the pathogenesis is complex and multifactorial. So it probably involves certain environmental triggers in certain genetically susceptible individuals. And then there's a complex set of interactions with the immune system, the bile acid milieu, the metabolome, the microbiome. But we think that many of these signals are ultimately integrated and activated at the level of the epigenome. And so that's why we've focused on epigenetics. So if you look under the microscope, this is what you see in PSC. A couple of prominent features are this periportal concentric fibrosis known as onion skinning and this ductular reaction, which is a proliferation of small immature cholangiocyte-like cells. So we'll talk a little bit more about both of these. So the fibrosis progresses in stages from a normal liver through a periportal fibrosis, eventually bridging fibrosis, and eventually this chicken wire characteristic biliary cirrhosis. And as patients progress through these stages, it correlates with clinical events. So initially a patient may have no fibrosis and be undiagnosed. Eventually they may have liver test abnormalities and get a diagnosis of the disease. Later there may be clinical events like cholangitis or strictures. And ultimately at end stage disease, liver transplantation is being considered. And then it's important to remember that there can be post-transplant biliary complications and PSC is one of the diseases that can recur after liver transplantation. So although we're in line with PSC partners seeking a cure, we don't necessarily need to cure the disease. What we do need to do though is to bend this fibrosis curve just enough so that patients are not having these clinical events and requiring liver transplantation. So again, the pathogenesis of this fibrosis is complicated with a lot of interacting features. So again, there can be genetic and environmental factors. There can be interactions with the innate and the adaptive immune system, interactions with bile and gut liver crosstalk. And then what we focus on is this area of epithelial mesenchymal crosstalk. And so the general paradigm here is that a cholangiocyte injury of whatever variety, be it autoimmune, inflammatory or toxic, damages the cholangiocytes. They become senescent, which is a state of being metabolically active but under replicatory arrest. And associated with this, there's a phenotype of secretion where they tend to secrete lots of growth factors, cytokines, et cetera. And this is the mechanism by which you have epithelial mesenchymal crosstalk, where there can be activation of periportal myofibroblasts and hepatic stellate cells that then lay down the extracellular matrix. So what is epigenetics? So epigenetics is beyond the linear sequence of DNA. This is features that are on top of the DNA and this can be DNA methylation. This can also be post-translational modification of histone proteins, which are these small epigenetic factors or marks. And these marks activate gene expression patterns across the genome. So just to tell you the difference between genetics and epigenetics. So again, genetics is the linear sequence of base pairs, A, Cs, Gs and Ts. And epigenetics is all the nuance. It's all of the marks on top. It's whether the chromatin is open and accessible or closed and inaccessible. It's how the chromatin folds upon itself to give you these enhancer promoter interactions. So if you think of a musical analogy, genetics is just the linear sequence of notes. So this is guitar tablature. It tells you which notes to play, but you can't really play or learn a song from this information alone. For that, you need all the nuance. You need the key signature and the timing, the length of the notes, whether to play a note loudly or softly, et cetera. So these are the four histone proteins that can be post-translationally modified on their tails by several different modifications, such as methylation, acetylation, ubiquitination and phosphorylation. And there are certain epigenetic factors that influence these marks. So there's three basic classes. So epigenetic writers, which deposit the marks, epigenetic readers, which interpret the marks and recruit transcriptional machinery, and then erasers, which remove the marks. So this is all very dynamic and occurring constantly. And this affects gene expression patterns globally. And this really is what defines cellular identity. So this is why a skin cell is a skin cell. This is why a bile duct cell is a bile duct cell. And this is how stem cells differentiate toward a different fate over time. And that's shown here in the Waddington's epigenetic landscape. So we know that hepatocytes and cholangiocytes have a common precursor, which is the hepatoblast. And the hepatoblasts are guided to their fate based on the epigenetic landscape in which they find themselves. And just like there's epigenetic differences between hepatocytes and cholangiocytes, there's epigenetic differences between cholangiocytes in health and cholangiocytes in disease. And this is what we try to understand that these small epigenetic barriers and try to overcome these and coax cholangiocytes back toward health. So a general paradigm in the lab is this epithelial mesenchymal crosstalk. And in general, what we study is an abnormal signaling event leads to epigenetic changes that gives you an altered transcriptome and then an altered secretome. And that leads to this activation of myofibroblasts and deposition of the extracellular matrix. So I'm just gonna very briefly show you a little bit of data from some projects by three postdocs in the lab that focus on three different epigenetic regulators. One is EZH2, which is a member of a silencing complex and leads to gene silencing. CAT2A is a acetyltransferase that leads to H3K9 acetylation, which is an activating mark. And then P300 leads to H3K27 acetylation, which is also an activating mark. These two are in the context of fibrosis. The third one is in the context of the ductile reaction. So Nidhi Jeylaland-Sakrikar did this work where she looked at TGF-beta, which is sort of a master regulator of tissue fibrosis. And she saw that cholangiocytes treated with TGF-beta upregulated a large number of genes. And when she did pathway analysis on that, many of the genes were associated with fibrosis, with hepatic stellate cell activation. And it included a large number of genes that are sort of known paracrine activators of hepatic stellate cells. And some additional bioinformatics led her to this polycom repressive complex, which is an epigenetic complex, including EZH2. And I won't go through all the data. This is published in Hepatology in 2019. But the message that she gave here is that EZH2 sort of homeostatically silences pathological genes. And on the influence of TGF-beta, EZH2 gets ubiquitinated and it gets degraded in the proteasome. And this then leads to dynamic loss of the silencing mark and transcription and secretion of certain stellate cell activators. Obi Asim in the lab did additional work with TGF-beta and he did some additional epigenomic analysis involving ChIP-seq and ATAC-seq studies. And so here you can see the ChIP-seq plots where he showed that although H3K27 is broadly activated across the genome by TGF-beta, there's a much more select pathogenic subset of genes that is dependent on H3K9 acetylation. And that mark is laid down by this protein TAT2A. And he also further showed that this involved an interaction with SMAD3, which is a transcription factor downstream of TGF-beta. So there are just some of the ChIP-seq tracks where you can see that these certain promoters include H3K9 acetylation, H3K27 acetylation and SMAD3 all occurring. And then here's the ATAC-seq data where he looks at how open or closed the chromatin is. And again, TGF-beta leads to broad opening of a large number of gene promoters, but just a subset of those is really dependent on H3K9 acetylation and this protein CAT2A. So this is an inhibitor of CAT2A and you can see that many of the targets that are not open. So while H3K27 is broadly activated, the pathogenic subset of genes is dependent on these other mechanisms. So in a schematic form, he showed here that TGF-beta leads to SMAD activation, translocation of that to the nucleus where it interacts with CAT2A. And then this complex is delivered to certain gene targets leads to H3K9 acetylation and secretion of stellate cell activators. And this work is published in Gastroenterology earlier this year. Lastly, I'll talk about one other project that focused a little more on the ductile reaction. So this is a normal liver with a normal portal tract. And in biliary disease, we often get this phenomenon of the ductile reaction, which is this sort of histologic lesion where there's expansion and activation of immature, small cholangiocyte-like cells that form these primitive duct-like structures. And this is thought to be sort of an abnormal regenerative response. So probably the tissue is trying to repair itself here, but this is often associated with additional extracellular matrix deposition and progression of disease. So it's important to study this. So Amaya looked at a project involving long non-coding RNAs. And what she showed is that activated cholangiocytes form this three-part complex, which includes a long non-coding RNA, ACTA2AS1, a transcription factor ELK1, and this epigenetic regulator P300. This complex activates certain proliferative gene targets, including PDGFB and others. And so this helps to promote the proliferative ductular reaction that occurs. This work will be published soon. And then the last thing I wanted to do was to just give a teaser for a talk that Niti is going to give at the liver meeting in about two weeks. This is on Sunday afternoon. So if you'll be at the liver meeting, she's going to show that epigenetically mediated telomere attrition contributes to the pathogenesis of PSC. So the red dots here are representing telomere length, which shortens as PSC progresses. So sort of suggesting that PSC is in part a telomere biology disorder and that it's epigenetically mediated. So I'm not going to go in much detail because I don't want to steal Niti's thunder, but certainly worth checking out if you're interested. So in summary, cholestatic fibrogenesis involves complex and multifactorial mechanisms. But we think that many of the fibrogenic and proliferative signals are integrated at the level of the epigenome. And this is important because there are small molecule inhibitors of these specific epigenetic regulators and epigenetic complexes. And so we think that epigenetic pharmacology may ultimately develop into novel treatment options. And I just wanted to acknowledge a few of the funding sources. And with that, I'll hand it back to the moderator. Thank you, Robert, for that fantastic presentation and update on the work that's being done in epigenetics. And again, I'll ask participants to please put your questions in the chat for Robert, and then also again for Cynthia as soon as she finishes her talk. So our next presenter is Dr. Cynthia Levy is a Professor of Medicine in the Division of Digestive Health and Liver Disease at the University of Miami. She's also the Associate Director of the Schiff Center for Liver Disease. And Dr. Levy is going to present a clinical update for us today. And her research program focuses on clinical trial development and the conduct for autoimmune and cholestatic liver disease. And so we're really excited to hear from her on the clinical side of things. So Cynthia, can you please take it over? Sure. Thank you, Heather. It is a great pleasure to be here today on PSC Awareness Day to discuss clinical updates on PSC and hepatic fibrosis. So I want to thank the Fibrosis SIG for inviting me to present. So here are my disclosures. All right, so bringing you back to the clinical aspects of PSC, you'll recall this is an immune mediated inflammatory condition that leads to destruction and fibrosis of the intra and extrahepatic bile ducts leading to cholestasis, hepatic fibrosis, and eventually progress into biliary cirrhosis. This is a rare disease affecting roughly one to two per 10,000 people. And it affects predominantly males presenting usually in their mid 30s. One of the most striking aspects of this disease is its association with inflammatory bowel disease, which in the United States happens in up to three quarters of patients with PSC. You heard a lot about pathogenesis. And although there are a lot of missing links still, we believe that there are both environmental and genetic factors involved both in disease development and progression. Factors such as gut dysbiosis that then goes into microbial exposure of the biliary tree with breakdown of immune tolerance and pathogenic T cells leading to biliary inflammation, apoptosis and necrosis of cholangiocytes, and then activation of stellate cells with deposition of collagen and fibrosis in and around the bile ducts eventually leads into this disease. So it doesn't matter the order that these factors occur, but we have concomitantly chronic cholestasis, inflammation and fibrosis playing a role here and all potentially representing therapeutic targets for us to use in this disease. This slide briefly summarizes the clinical aspects of PSC. So usually the diagnosis is brought up by abnormal liver chemistries, typically in a cholestatic pattern. Although of course we can have PSC even with normal liver tests. That usually triggers an MRI with MRCP, which will show the typical findings of biliary dilatations and strictures leading to the diagnosis of large duct PSC. Note that liver biopsy is not done routinely. It's only required in specific situations when we're looking for, for instance, small duct PSC or overlapping features of autoimmune hepatitis. And autoantibodies, even though they are common, they're definitely not sufficient for diagnosis of PSC. Half of our patients present with symptoms, fatigue, pruritus, radiopropagin pain, jaundice, or an episode of cholangitis. High-grade strictures previously called dominant strictures can affect up to half of our patients. They can be present early at the time of diagnosis or later on with disease development. And even though most of these high-grade strictures are actually benign, they always bring the concern for malignancy. They can also be associated with episodes of cholangitis and more biliary tree manipulation with our instrumentation with ERCP. So these patients can progress to biliary cirrhosis and all the complications that come with that, including portal hypertension, and the diseases associated with a high risk for malignancies, cholangiocarcinoma, gallbladder cancer. And if they have PSC with IBD, then risk of colorectal neoplasia is also increased. So where are we with management of PSC in 2021? Well, unfortunately, we still do not have an FDA-approved drug. Clinically, ursodiol remains widely used worldwide. More than 50% of the patients, close to 60%, use ursodiol, usually in a medium dose of 15 to 20 milligrams kilo a day. And it does improve liver chemistries, but the effect on long-term outcomes is largely, it's still unknown, right? Vancomycin is also often used, especially in the pediatric population, again, without enough randomized clinical trial data to support its use. The management of our patients with PSC also includes endoscopic treatment in cases of biliary obstruction leading to cholangitis, or when there is suspicion for malignancy that we need to investigate. If they have IBD, annual colonoscopy to screen or survey for colon cancer, and surveillance for cholangiocarcinoma with imaging and C99 once a year. So why is it that we don't have drugs? What are some challenges that we have in drug development for PSC? Of course, it's a rare disease, so we start there. We have an incomplete understanding of the disease pathogenesis. The disease has a slow heterogeneous, and as you heard from Ricky, an unpredictable disease course. Our mice model is imperfect. We often use MDR to knock out mice, but they don't really represent or don't really mimic what we see in humans with PSC. And we lack reliable surrogate endpoints for clinical trials. We'll see today some limitations of alkaline phosphatase, and we know that liver biopsy is invasive and there's sampling variability as well. Here we see the therapeutic targets that are currently being explored in PSC. We have FXR agonists, BPAR agonists, not so much in the U.S. yet, but they are being explored as targets. FGF-19 agonists, NORUDCA, which acts as a stabilizer for the bicarbonate umbrella. It also has anti-cholestatic and anti-inflammatory properties, probably also anti-fibrotic. There are specific anti-fibrotic agents being developed, and of course, drugs that modulate the microbiome. In this table, then, we see the pipeline. We see drugs that either have recently completed some phase two evaluation or drugs that are currently in development or with ongoing clinical trials. We see drugs modulating bio-acid homeostasis, some anti-fibrotics, modulation of microbiome, and others here. And typically, the endpoint for these studies will be alkaline phosphatase. Although for the studies using anti-fibrotics, we're starting to see endpoints focusing on fibrosis. So on this, the rest of this talk today, I'm gonna focus on lesson learned, lessons learned from studies that have been completed looking at fibrosis, and then what is going on now in terms of clinical trials. So lessons learned. I wanna talk about two trials that have recently been completed. The first one is the Syntuzumab trial. So Syntuzumab is a humanized monoclonal antibody directed against LOXO2, right? LOXO2 acts by stabilizing the fibrotic matrix. It catalyzes the cross-linkage of collagen and elastin. And we know from animal models that, and actually human studies as well, that both serum and hepatic levels of LOXO2 correlate with more severe fibrosis. So based on that, it is speculated that LOXO2 inhibition could lead to reversal of fibrosis, or at least stabilization of fibrosis. So a randomized controlled trial was designed and conducted over two years. This was one of the largest trials ever conducted in PSC, controlling 234 patients, for which the primary endpoint was really the mean change in hepatic collagen content. The study also evaluated clinical and biochemical endpoints. And unfortunately, there was no benefit from Syntuzumab, but we learned a lot. On the graph here on the left, we see the mean hepatic collagen content in the three treatment arms, Syntuzumab 75 milligrams, 125, or placebo. At baseline, one in two years, and you can see there is really no difference across the board. There was also no difference in the proportion of patients with worsening or improvement of fibrosis. But what have we learned with respect to this endpoint of progression to cirrhosis? Well, we learned that at baseline, only the ELF score and the presence of bridging fibrosis were associated with progression to cirrhosis. And I want to remind you that ELF has been shown in a few studies, including this larger international study with over 500 patients, that ELF can accurately discriminate patients with increased risk for progression. And as you can see here, using different cutoffs that stratify patients according to fibrosis, well, this is according to the ELF score, but indicating mild, moderate, or severe fibrosis. And by severe fibrosis here, we have the patients with ELF score greater than 9.8. Okay, and you can see how these patients have a significantly increased risk of death or transplant. So going back to our trial, the other endpoints that we looked at was survival-free of PSC-related events, so clinical endpoints. What have we learned? Well, baseline alkaline phosphatase and the presence of advanced fibrosis at baseline were associated with PSC-related events after two years. However, the median change in alkaline phosphatase was not associated with clinical events. Now, when we look back at ELF, more patients with high ELF, greater than or equal to 9.8, experienced an event comparing to patients with low ELF. And different from alkaline phosphatase, a change in ELF was predictive of clinical events. We also looked at liver stiffness measurement to predict clinical events and found that the most optimal cutoff was liver stiffness greater than 8.7 kilopascals to predict clinical events. A spinoff from the Synthosomab trial was this study in which we looked at exactly what was happening with alkaline phosphatase, why its change really didn't predict outcomes. And we found that ALP had significant inter- and intra-individual variability as shown here. But what was most striking to me was the presence of spontaneous reductions in alkaline phosphatase and even normalization. In the longer duration of follow-up, the more of these reductions that we see. So for example, patients who started out with alkaline phosphatase greater than three times the upper limit of normal, okay? Almost 20% of these patients had the reduction greater than 40% in ALK-phosph spontaneously. So this obviously impacts our sample size calculation. And this study also provided with some statistical calculations as to how many patients we would need per study arm if we use ALK-phosph as an endpoint. And without going too much into details, the point is it varies according to the level of alkaline phosphatase at study entry, whether our endpoint is an absolute reduction or a proportion from baseline reduction, what is the duration of the follow-up that we're gonna have one year, two years, and what proportion of patients we expect to have a response. So all of that impacts our ability to calculate sample size, so keep that in mind. Now, moving to the second study that I wanted to talk about, this is the, it will be the MGM282 study. So MGM282 is an FGF19 mimetic, and in MDR2 knockout mice, we can appreciate how it reduced hepatic inflammation and fibrosis, and it also improved the liver chemistries, which I'm not showing here. So with that in mind, a proof of concept phase two randomized control trial was conducted. 52 patients were randomized into one of three arms, either placebo or two doses of the MGM282. Primary endpoint was reduction in alkaline phosphatase. To enter the study, patients had to have an ALK-phosph greater than 1.5 times per limit of normal, and there was no difference across groups. So the study failed the primary endpoint. However, we could see target engagement, right? We see a reduction in C-form, patients receiving MGM282, reduction in total bioacids. In other studies, we see that it's predominantly the hydrophobic bioacids that come down. There was improvement in ALT and AST. And now given the proposed anti-fibrotic effects of this drug, as shown in the mice model, we also looked at ALF and the impact of the drug on ALF scores. And there was a significant reduction. Now, when we stratify patients according to how high the ALF score was at baseline, we'll see that the predominant effect was exactly on patients with high ALF. There is those patients with increased risk of progression are the ones who benefit the most. And there was also improvement in Procit-3, which is another marker of fibrosis. Indicating, therefore, that this drug may have an anti-fibrotic effect, right? However, the study failed the primary endpoint and it's not moving forward. Let's now talk about two studies that are ongoing and they explore fibrosis as an endpoint. The first one is the Isalofaxor, which is an FXR agonist. In mice models, FXR agonists, in addition to showing anti-cholestatic and anti-inflammatory effects, it also down-regulates TGF beta pathway and has some anti-fibrotic properties. This was better shown actually in rat mice, sorry, rat models of NASH with improvement in fibrosis and even portal hypertension, not shown in humans. So, as a proof of concept, this phase two trial was designed. Again, this is an FXR agonist, so it modulates bioacid homeostasis. It includes patients who were non-steroidic with large PSC and they were randomized to receive 100 milligrams versus 30 milligrams of Isalofaxor or placebo when treated for 12 weeks only. The entry criteria was elevation in alkaline phosphatase greater than 1.67 times the preliminary of normal, if I believe it would have been below two. And there was a reduction in alkaline phosphatase that was dose dependent. You can see here in panel B that the reduction was greater in patients with a dose of 100 milligrams daily. And 35% of patients receiving that dose had a greater than 25% reduction in alkaline phosphatase. Furthermore, this response was independent of UDCA use and different from the first generation FXR agonist, pruritus was not a major problem. So, with this initial results, we are now moving forward and we have a phase three study, large randomized controlled trial with 400 patients. And the study is actually fully enrolled now, exploring the dose of 100 milligrams a day, treatment duration is two years. And the primary outcome here will be proportion of patients with progression of liver fibrosis greater than or equal to one stage. These patients have liver biopsies done annually and MRI with MRCP done annually. In addition to following clinical events and the labs. So we're looking forward to these results. The other study that is ongoing, that is also very exciting is the PLIAN study, exploring the use of anti-integrins or integrin inhibitors. So we know that integrins are this family of 24 heterodimeric receptors, and its expression is dependent on cell type and context. In the epithelial cells, or in case the cholangiocytes, we have alpha V beta six, and in fibroblasts, the alpha V beta one. This integrins bind to and activate latent TGF beta, which you heard a lot in the previous talk about how this is involved in pro-fibrogenic gene expression. Right, so by blocking this interaction with TGF beta, we expect to have a profound anti-fibrotic activity and preventing the upregulation of pro-fibrogenic genes. This study is also ongoing. Currently, it consists of two parts. Part one compared placebo to 40 milligrams daily of the PLIAN drug, and this part one is complete. Now, two additional doses were added, 80 milligrams or 160 milligrams. Patients will be treated for 12 weeks, and we'll evaluate at that point the effects of the drug. The primary endpoint here, again, are changes in liver fibrosis biomarkers from baseline to week 12. And importantly, because we need to enrich the study with patients who are more likely to have an event or to have progression of fibrosis, for entry criteria, patients should have a liver stiffness already indicating the presence of fibrosis, okay? All right, and the last topic to discuss, what are some other possibilities, right? And I wanted here, so what could the future hold? I wanted here to look at examples that we can learn from our sister disease, PBC, and look into NOX1-4 inhibitors. So this family of enzymes is involved in response to cellular stress with production of free radical species of oxygen that will then activate multiple inflammatory and fibrogenic pathways. Cetanixib is a selective NOX1-4 inhibitor, and in animal models of both cholestatic diseases and metabolic liver diseases, it has been shown to have marked anti-inflammatory and anti-fibrotic activity. So a phase two randomized control trial was conducted in patients with PBC, enrolled 111 patients who were randomized to placebo versus 400 milligrams daily or 400 milligrams twice a day of cetanixib treated for six months. And we did see improvement in alkaline phosphatase and GGT at the end of the study, but more importantly, focusing here on liver stiffness. In PBC, a liver stiffness greater than 9.6 kilopascals identified patients that increased risk for disease progression to compensation death for transplant. And we see that in patients with baseline liver stiffness greater than or equal to 9.6 kilopascals, there was a significant improvement in liver stiffness from a medium of 12.2 to 9.1, indicating perhaps an anti-fibrotic activity in this disease. So in conclusion for this presentation, there's several new drugs in development and more to come. The outcomes of interest are rare in PBC, and we do need better biomarkers that can serve as surrogate endpoints. So this is actually a large unmet need in PSC. We have learned recently that alkaline phosphatase shows high variability and change in alk-phosph may not correlate with endpoints. So it can be used to stratify patients at study entry, but it's probably not the best endpoint. Now, ALF and liver stiffness should be studied further as potential clinical trial endpoints in PSC. And I just want to conclude with a special thank you to my patients with PSC for participating in all these studies and trusting us with their lives. Thank you very much. Thank you so much, Cynthia. So we have about 10 minutes here for some questions and answers, and we've got some in the chat and some also that were put into the Q&A. So I'm going to backtrack and go back to the first presentation. So Robert, this one's for you. Can you speculate which subsets of cholangiocytes or segments of the biliary epithelium in the human undergo senescence or secrete the SAST that you spoke about and how they may influence cholangiocytes in HSCs? Yeah, so that's, it's a good question. I think that the questioner is referring to heterogeneity along the biliary tree. So the fact that we have large bile ducts, medium-sized bile ducts and small bile ducts, which are affected to various degrees during the progression of PSC. And so, you know, I don't know the answer, but I think that as we move into this age of single cell transcriptomics, we're really going to be able to get a much better handle on that by looking at cholangiocyte subpopulations and differences in the transcriptome between them, which should also define the senescence state of those cells quite well. So I think the answer will be forthcoming. Okay, and then the next one, this is also from the same person. Can you speculate which is more predominant in activating HSCs, the EMT or the senescence? EMT or the senescence. So yeah, so EMT, I think refers to the idea of a cholangiocyte, you know, becoming a myofibroblast-like cell or becoming more mesenchymal-like. So that may occur to some degree. And then the senescence, which through paracrine effects, you know, activates existing mesenchymal cells. So I think both of these processes are probably going on to some degree. Again, it's a question of which is more active and where, and again, this is the nice part about the age we live in is that you can, even though the questions are hard, you can always point to a technology that's coming that's going to answer the question definitively. So, you know, the idea of spatial transcriptomics where we're going to be able to look at the gene expression patterns across the tissue at, you know, sort of cellular level is going to really define what's going on in which cell population. And, you know, these technologies are getting more and more accessible and cheaper. So it's an exciting time to be a scientist actually. Great, thank you. So I'm going to skip down just a little bit and let's do one for Cynthia. Can Dr. Liddy give her thoughts about future research possibilities of evaluating ALKFOS over a longer duration of time or focusing on patients with higher levels of ALKFOS or is it just two variable? Which I think you sort of mentioned in your very final slide. Exactly. I think ALKFOS, my impression seeing the behavior in all these trials and what we learned with Synthozomab is that ALKFOS varies so much. I was highly impressed by that. Well, there were already previous descriptions about this spontaneous normalization of ALKFOS, right? But we think, we thought it was maybe 5% of the patients, a small proportion. Then looking at the data from this 234 patients for two years and thinking that almost 20% of the patients reduced by 40% spontaneously in two years, I think it's hard to trust ALKFOS. I'm convinced that the change in ALKFOS, especially for drugs that will modify fibrosis, the change in ALKFOS in three weeks is not what's going to determine the long-term outcomes for these patients. Great. Thank you. So, okay, Robert, going back to you, the epigenetic study is focused on targeted methylation genes. Are there studies that are focused on whole genome sequencing, like whole genome bisulfite sequencing to identify the most important epigenetic regulatory area in the genome of PSE? Yeah, yeah, for sure. So to be clear, what we did is ChIP-seq and ATAC-seq, which are genome-wide techniques, but they're looking at modifications to histone tails as opposed to DNA methylation. But they are genome-wide. But yes, people have also looked through bisulfite sequencing at the DNA methylation itself. And so Angela Chung did a study of that nature a year or two back. I can't remember where that was published, but yes, people are looking at that. It's also equally important. And then the third area that's also sort of considered epigenetics is microRNAs and other small RNA molecules and their sequencing techniques to look at that on a wide scale as well. Great, thank you. Ricky, this one's for you. How can investigators and scientists working on new treatments for PSE engage with the PSE community on patient-reported outcome measures that can be incorporated into clinical trials? Yes, we are glad to work with anybody. All you have to do is just contact us and we will work things out. That'll work for both of us. Thank you. Okay, great. So we've got still several other questions here. I'm just kind of flipping through here. Are there studies to suggest that extracellular vesicles play a role in the pathogenesis of PSE? Yes, there are several folks looking at that. And, you know, it's sort of part of this senescence-associated secretory phenotype is the secretion of vesicles. And, you know, they typically contain a large number of products that are upregulated in disease. So whatever's upregulated in the cells tends to find its way into the extracellular vesicles that are secreted. And so, you know, teasing that out, which ones are pathogenic and which ones aren't is a big role for the future. Right. So besides the targeted therapy trials, are there clinical trials, phase one or two, based on monoclonal antibody or mRNA vaccine technology like in other autoimmune diseases? Not that I'm aware of for PSE. No, there was a question here about the fibrates. And in Europe, they're more largely used in cholestatic diseases. In the U.S., there has been some experience in a couple of centers with beneficial results in terms of alkaline phosphatase. We don't have long-term data, but I'm aware of other PPAR agonists that will be explored in PSE soon. So looking forward to that. Here's another one. How are researchers and manufacturers working with patient groups like PSE partners to identify the parameters on developing validated PROs? Additionally, could some of the work that Dr. Hebert presented on provide novel pathways in gene expression that might be pulled from these patient registries? Seems kind of like a global question for all of you. If anybody wants to comment on that. Anybody have any thoughts on this one? The next one here, how about Ricky, has PSE partners reached out to collaborate with organizations like 23andMe? Actually, no, we haven't done that. Nope. That's a good thought. That's a good thought. Yep. Okay. So in your NGM study, Cynthia, did those patients with high ELF and PROC3 at baseline who appeared to benefit the most also show a significant reduction in ALP and GGT? That was not looked at specifically, that I'm aware of, it's not published. But in general, the drug did not affect levels of alkaline phosphatase. Okay. And then going back to you, Robert, it is difficult to slow down the decreases in biliary senescence, which may be a better approach, is to activate the progenitor compartment, which may replenish the damaged senescent compartment. Any speculation on this? Yeah, that was an intriguing question. It's not something I've thought too much about. I mean, you know, in fact, many people try to target the duct to the reaction as a way to slow down disease progression, because as these, you know, like I sort of said, as they're sort of probably a regenerative response and trying to repair injury. And so, yes, trying to activate that in a controlled way is a intuitively attractive idea. I think the concerns would be, will you exacerbate disease? That's one. And then two, I guess, if you're promoting progenitor cell activation, the other theoretical concern would be malignancy or driving malignancy that way. So I think if it could be done in a very controlled way and we could understand how to do that, it would be attractive. So we only have like seconds left. I think we're going to have to wrap this up. We had a lot of dynamic discussion here, and I would encourage you to reach out to any of these speakers. If you have further questions, need more clarification. I want to thank all of you for joining us, and especially Robert, Cynthia, and Ricky for giving us these updates. And moving forward, I can see that we have a lot, a lot more work to do, a lot of good collaborations, and I'm sure will be developed after this webinar. And again, I appreciate all of your participation and hope to see everyone in person very soon. Thank you.

primary sclerosing cholangitis

hepatic fibrosis

epigenetics

cholangiocyte injury

fibrogenesis

drug development

clinical trials

surveillance

biomarkers

Novita Lee

TGIF