Cyclerion Therapeutics, Inc. (CYCN) Earnings Call Transcript & Summary

Hello, everyone, and welcome to this special webinar hosted by the United Mitochondrial Disease Foundation entitled Clinical Data Update from study of CY6463 and MELAS. We're really excited to be with you today and do this webinar in partnership with Cyclerion. If I can have the next slide, please. Because some of you perhaps are not familiar with UMDF. I thought we'd take just a minute to introduce the foundation. We are a 26 year-old foundation based in the United States, national in scope, but global in reach. We have 4 main components of our mission. Research, education, support and advocacy. I represent the research side of the of the foundation. And today, we're going to talk about some specific aspects of that. And on the next slide, for the patients that have joined us today, I'd like to just remind you of a couple of really important initiatives that fit perfectly within today's webinar. First of all, we have a very active clinical research taking place right now in mitochondrial disease. And our clinical trial finder on the website is a perfect place for you to find out where there may be relevant clinical studies for you to participate in. So I encourage you to visit the website and check out the clinical trial finder and see if there is a study that's right for you. Next slide, please. Of course, a really important component of therapeutic development for any disease is access to patient registries. And UMDF was really excited to launch Mito share in March of this year. We've had a great response. We already have over 500 participants on the platform. This is one way in which you can be engaged in clinical research, share your perspective and find out about clinical studies that may be relevant for you. So again, please check out Mito share and consider joining. I want to mention Mito U, another part of what we have on the UMDF website. Mito U is a place where you can go to learn about mitochondrial disease as the name implies. And in this case, it will also be the place where the recording of today's webinar will be available. So please visit umdf.org, Mito U to find a recording of this today and a lot of other information. And then I'll wrap by saying that, of course, we are a charity and we're highly dependent on donor dollars. We really appreciate anyone who is interested in checking out one of our energy for life walks. This is our major fundraising mechanism. Spring, summer, fall, spread out across the United States. In addition to fundraising, it's also a great social networking opportunity for our community. If you can't attend in person, there are virtual options and you can make donations through the website. So thank you for checking out our energy for life walks as well. Okay. Finally, then just a little bit of housekeeping for today's webinar. First, if you haven't used Zoom before, please go to the View Options menu and select side-by-side mode so that you see the full screen, and it fits whatever device that you're watching this webinar today on. A reminder that everyone who has joined the webinar today will be muted. There will be a question-and-answer session at the end of the webinar today. And so please use the Q&A box that you see at the bottom of your screen to type in any questions you may have. It will be moderated and our moderator will sort through those questions and select the ones that are best suited for today. Apologies in advance because of time limitations, we may not be able to answer all questions, but please do send your questions in through the Q&A function. And lastly, if you see a close caption option on your screen on the bottom right, you can toggle that on and off to be able to view a live transcript. Okay. With that, I'm going to briefly introduce the speakers for today. In addition to myself, I'm joined by Dr. Amel Karaa from Mass General Hospital. Dr. Karaa takes care of a lot of Mito patients, and she is a member of our Scientific and Medical Advisory Board, and we thank Dr. Karaa in advance for participating today. We're also joined by 3 representatives of Cyclerion Pharmaceuticals; Chris Winrow, Chad Glasser and Peter Hecht. So you see the agenda for today on the screen through the course of it. You'll hear from each of the speakers. And as I said, at the end, we'll have a Q&A session where we can discuss the content of today's webinar further. With that, I'm going to turn it over to Peter Hecht to kick off the presentation. Peter?

You can hear me? Can you see me?

Cannot see you, but we can hear you. There you are.

You can see me?

Yes. You're ready to go on.

Excellent. I can't see me, but if you can, that's great. Thank you very much, Dr. Yeske for the introduction and for hosting the discussion this morning, it's a terrific event and a great opportunity for us at Cyclerion. Thank you also to you and to your organization for the really terrific job that you do in organizing, communicating and helping patients and caregivers to give voice to their disease and to leveraging the collective strength of the Mito community. I was at the annual meeting in Phoenix a couple of weeks ago, and it was really very powerful to see the collective community, both of the researchers and many of the patients and their caregivers and to hear from them as well. So thank you for all that you do. And before I turn it over to Dr. Karaa and Chad and Chris to go through the main part of the event this morning, I'd like to do a couple of things quickly. First, if you can click to the next slide, I'd like to remind those of you that know us and inform those that don't that we're a publicly traded company and we're regulated by a number of different agencies, including the SEC. And we may make some forward-looking statements during the course of today's conversation, and this statement will cover us from that. For those of you that don't know the company, that are new to Cyclerion particularly patients or folks in the MELAS community, we're a public company that's working to develop some novel drug candidates that we hope will help improve the symptoms and disease of MELAS. And more broadly, we're working on a critical pathway that you'll hear about from Chris Winrow we called the NO-sGC-cyclic-GMP pathway that we believe has multiple domains of action and is involved in regulating critical aspects in the nervous system, and we believe may have important benefits for patients. And we're very excited about the results of the small study that we've just completed, and you'll hear about it. If you'll turn to the next slide, please. I'd like to emphasize just a few key points and then turn it over to Dr. Karaa. First, as I think those that live with the disease know and those that are new to the area or learn more and more. This is a devastating and progressive disease. It's an orphan disease. Dr. Karaa will describe it in much more detail. There are no approved medical therapies today. And what we saw from our exploratory study demonstrated some very exciting attributes of our molecule that we think may offer a real benefit for patients if we're able to repeat it and extend the findings in further development and regulatory studies. And what you'll hear from Chad is that we saw improvements in multiple domains of the MELAS disease, particularly around biomarkers associated with mitochondrial function. Reduction in a big panel of inflammatory biomarkers. We saw improvements in cerebral blood flow across all of the brain regions that we studied and we saw connectivity improvements in different domains of the brain, which we measured by fMRI BOLD. And again, you'll hear all of that from Chad. This is all with a convenient once daily oral pill that we were able to design and which showed very good distribution into the nervous system, and we saw a very good safety and tolerability. So we're very encouraged by what we've seen. And we're very focused now on working closely with Dr. Karaa and other investigators in the field and with the regulatory authorities and with the patient communities to focus and develop this drug evaluate it fully and see if we can get it to me last patients as quickly and effectively as we can. So with that, I'd like to turn it over to Dr. Karaa, She, as I think many of you know, one of the leading practitioners in this field, and she's the director of The Mito clinic at Mass. General. She also was an investigator on the study that we're going to talk about this morning and was one of the key enrolling physicians. So with that, let me turn it over to Dr. Karaa. Thank you very much for joining us this morning.

Thank you, Peter, and thank you, everyone. I'm honored to be here today to talk to you about MELAS. And as you may have -- as you have heard I am primarily a clinician. I am an internist and a clinical geneticist by training. And I do practice mitochondrial medicine at the Mass. General Hospital in Boston, and I do follow hundreds of patients with mitochondrial disease, including MELAS. I have also been involved in clinical trials, including this specific trial and clinical research. I am the immediate past President of the Mitochondrial Medicine Society and the Chair Elect of the Scientific and Medical Advisory Board of the UMDF. And so I think I speak for all of my colleagues in saying that we are really eager to see more trial like Cyclerion get us to that cure that we are all hopeful for our patients' populations. So with that, I'm just going to briefly talk to you about MELAS. Next. So what is MELAS? We use a lot of acronyms in medicine and MELAS is based on the very initial description of the syndrome in the literature. So every letter of this acronym stands for something. So M is for Mitochondrial. This is a mitochondrial DNA disease that affects how the mitochondrial functions. E stands for Encephalomyopathy, so the mitochondrial DNA dysfunction cause symptoms that are specifically related to the to the brain, encephalo and the muscle, myopathy, so primarily affecting neurological system in the body. And the mitochondrial dysfunction leads to elevated lactic acid, LA and lactic acidosis -- lactic acid elevation in the blood creates more acetic blood. And all of these over time, lead to S, strokes or stroke-like episodes that are the hallmark of the MELAS syndrome. Next. So more than 80% of all MELAS cases worldwide are caused by one specific mutation in the mitochondrial DNA, the m.3243A>G mutation. And this mutation is notorious for creating a very heterogeneous disease that accounts for almost the majority of all maternally inherited mitochondrial diseases. MELAS can affect any age group from children to late adulthood. It can affect any race and any gender, boys, girls, men, women, everyone is a risk of developing MELAS when they carry this mutation. MELAS is a severe disease that is relentless. It's progressive and has high morbidity and mortality and sometimes with early demise. And so we in the clinic struggle a lot to try to take care of these patients with MELAS because of the complexity and the severity of the disease. Next. So as all mitochondrial disorders, which MELAS is part of, there is a very heterogeneous presentation and symptoms. As you know, we like to say that mitochondrial diseases can affect any organ system can present in any way and shape and can present at any age. Next, for MELAS specifically, the majority of the symptoms at presentation are neurological. Next. So most of these symptoms arise between the ages of 2 and 40, so early on in life and do present with typically seizure disorder, recurrent headaches that can be very severe and difficult to treat, stroke-like episodes, vision loss, muscle weakness, recurrent vomiting due to gastrointestinal dysmotility which is caused by both muscle disease and nerve disease and many other symptoms. Next. And as the disease progresses, the neurological symptoms become more severe, but patient also developed more multisystemic issues. They can develop other organ system involvement like the heart, the kidney, the -- and many -- and occurring problems. And so it becomes a very complex heterogeneous disease that affects multiple organ system with the neurological involvement being the primary cause of morbidity and mortality in these patients. Next. And so MELAS causes multiple burdens for patients and their families. And when you have so many multisystemic systems that are involved, it creates this chronic lingering burden of the disease that is represented here by all these terms that the patients have reported to us. Multiple studies have shown that this chronic burden includes things like exercising tolerance and fatigue and weakness and headache. And on average, we know that mitochondrial disease patient complaints of at least 16 symptoms at any given point in time, and MELAS is no exception when the disease has progressed over time. Next. But the specific issues with MELAS are really related to the acute decompensations that we see in patients. So on top of all the burden of the disease that the patient has to live with on a day-to-day basis, very suddenly and sometimes for no apparent reason, they do develop these acute issues that are the stroke-like episodes. So most often, we see what we call metabolic drugs means there are strokes in brain areas that are not typical for where you would get a stroke if you had high blood pressure or heart or high cholesterol or other typical common disorders and these brain lesions can linger for a long period of time and can cause damage to the brain tissue itself. We do see elevated lactate in the brain on what we do imaging on the brain. There are also calcifications of the brain where certain parts of the brain become rich in calcium and become dysfunctional. But we also see seizure disorders that can be deep and diffused and can be so severe that it creates swelling in the brain and sometimes we can't really tell whether we are dealing with a stroke or we are dealing with seizures that are severe and both seizures and the strokes as well as the lack of energy produced within the brain, which is a high-energy tissue, patients develop severe headaches and migraines that are sometimes very difficult to control. So when a patient starts having these acute stroke-like episodes, they typically do not resolve at 1 episode or 2 episodes. They become periodic and they get them more and more often. And every time they get they do cause damage. And the sad thing about this disease is that the more damage the brain is accruing the more dementia, the more early cognitive decline the patient will develop. And it's devastating really to see patients that I have followed over the years coming year after year with more and more cognitive decline. I have very young, very active professionals that have become bedridden because of these episodic acute compensation, which we cannot necessarily treat properly. Next. So what are we doing for our patients with MELAS as in 2022? Well, honestly, not that much. We know that the disease is caused by dysfunction in the mitochondria and mitochondria makes energy. So we try to minimize energy losses and optimize energy gains. But as you see on the slide, we ask them to avoid stressors and get adequate rest and sleep and eat well and exercise as much as they can. But these are lifestyle changes that we recommend for every patient regardless of their underlying disease. So what are we really able to do for MELAS specifically. Next. So we try to provide symptomatic care as much as we can. So for every organ system that is dysfunctional, we provide organ-specific treatment. So if there is a seizure, we do antiseizure medication, headache, we treat with headache medication. If there's a stroke, we admit them to the hospital and try to the system, make sure that the blood pressure is well regulated that they are getting adequate calories to help promote the healing of the brain. But what are we doing specifically to enhance the mitochondrial function? Well, right now, we're really restricted to providing dietary supplements in the form of vitamins and something that we all know as the mitochondrial cocktail. But these are vitamins that we hope enhance the energy production in the mitochondria and help support the system and the brain. But these work sometimes not for everyone for the chronic symptoms. So what about the acute phase when the damage is being done to the brain. So we do provide at least in the U.S. an amino acid called L-arginine, intravenously during the acute episode of stroke like events and in between acute episodes, we recommend that our patients take oral L-arginine or similar immunoacid L- Citrulline or Taurine to help prevent these strokes from happening and if they happen to -- hasten or speed up their recovery. L-arginine and L-citrulline are precursor for something called nitric oxide, which helps dilate the blood vessel into the brain and hopefully brings more oxygen and enhance the energy making of the mitochondria. But these are not optimal. We do see some mild improvement, and this is not a very widely accepted therapy across the globe. We'd like to do this in the U.S., but our colleagues elsewhere are not convinced that this is really helpful. Next. And because we are lacking that cured or what we call the disease-modifying intervention that can help prevent these acute episodes and limit the severity of the chronic burden of MELAS, we do a lot of supportive care, as you see here. Next. So to conclude this very brief introduction of MELAS, I wanted to say that MELAS is one of the most common mitochondrial DNA syndromes that we deal with in the clinic. It's a very heterogeneous disease. It affects not just one individual because of the maternal inheritance of these types of medical diseases, several members within the same family can get affected. And because the disease starts early in life, the burden and the disability that it creates are tremendous. There's high morbidity and very poor prognosis because we lack the disease-modifying therapy and intervention at this time. Next. So this is really a disease that has a major unmet need in our community. Thank you. So I am going to introduce our next speaker now, Dr. Chris Winrow, the Vice President of Translational Medicine and Development Program Lead at Cyclerion.

Thank you very much, Dr. Karaa. We're really excited to Be here today and in particular, to discuss our clinical Trial with CY6463 in patients with MELAS and where we've seen improvements across multiple domains that you hear from Peter, Chad Glasser is going to be going into greater detail about the clinical data, but at the highest Level, we're really encouraged across the different objective markers that we saw move. These include improvements in biomarkers mitochondrial disease cerebral blood flow as well as markers of inflammation and imaging markers a function within the central nervous system. And all of these are key domains that are impacted in patients with MELAS. We look forward to discussing these findings in the next section of the presentation. But first, I'd like to talk to you a little bit about the mechanism behind CY6463 and the opportunity that we see for potentially helping patients with MELAS. So there's strong scientific rationale for targeting the NO-sGC-cyclic-GMP pathway for MELAS and CY6463 is the first brain penetrant positive asteric modulator that stimulates STC, which is a central component of this important pathway. And by amplifying the upstream nitric oxide signaling, we see the potential to benefit patients. This pathway has been linked to mitochondrial function. And in fact, efficiencies in nitric oxide signaling in this pathway have been associated with things like impaired blood flow, increases in inflammation reduced endothelial function among other things. And as you heard from Dr. Karaa, unfortunately, there are no approved therapies for MELAS. However, the Mitochondrial Medicine Society does recognize the use of nitric oxide precursors, including arginine and citrulline, as you heard. And the goal there is to boost nitric oxide levels. As you can see from the figure on the left, arginine is actually the precursor, the starting point that's used to produce a nitric oxide. But as an sGC stimulator, CY6463 sensitizes the enzyme, the STC enzyme nitric oxide and then increases production of cGMP. It does amplifies the endogenous and signaling and increases overall cGMP levels. And this is important because cGMP is a critical downstream signaling molecule in the brain as well as in the rest of the body. Because CY6463 was the first simulator designed to act within the central nervous system, we conducted a range of different nonclinical studies to understand the opportunities that this molecule might provide. What was really interesting was that we found consistent effects across 4 primary domains. And all of these are impacted in patients with MELAS. So in these nonclinical studies, we found CY6463 improved markers of mitochondrial function reduced inflammatory markers, increased cerebral blood flow and improved neuronal function. So based on these strong nonclinical results based on the literature rationale and the press for using nitric oxide precursors, we engaged in a clinical study to evaluate the potential for CY6463 to provide benefits to patients with MELAS. So at this point, I'd like to turn it over to Chad, who will discuss the clinical study design and our exciting results. Chad?

Thank you, Chris. Next slide, please. So let's start with the study design. This was an open-label study, meaning that all participants received 29 days of 1 dose daily oral 6463. To be eligible for the trial, participants needed to have both a genetic confirmation and mitochondrial disease as well as CNS symptoms that were consistent with the MELAS phenotype. So as we talked about, these are things such as stroke-like episodes, seizures as well as headaches. Patients could continue taking all of their other medications, including mitochondrial cocktails as well as nitric oxide precursors like arginine and citrulline. The primary objective of the study was to evaluate the safety and tolerability profile of a 15-milligram dose of 6463 given once daily over the course of 29 days. And again this, of course, included evaluating that profile on top of nitric oxide precursors. We looked at the pharmacokinetics of 6463 both in the plasma as well as in the CSF for the cerebral spinal fluid. And then finally, really, the majority of the assessments that we conducted in the study were aimed at measuring the impact of 6463 on various aspects of mitochondrial disease and getting a feel for its overall pharmacodynamic profile. Given that this was a fairly small open-label study, and we didn't have a placebo comparator, we really wanted to incorporate a number of objective measures that were both relevant to the pathophysiology of patients with MELAS and then, of course also to 6463's mechanism and supported by the data that Chris just spoke to that we've generated in the preclinical side. So to evaluate mitochondrial function, we measured biomarkers of mitochondrial dysfunction in the plasma including lactate, which we heard about as well as GDF-15 and FGF-21. And then to evaluate impacts on inflammation, we implemented a quite large panel of plasma inflammatory biomarkers that we use really across all of our clinical studies evaluating 6463. We used advanced neuro imaging to measure changes in cerebral blood flow using arterial spin labeling and then we looked at neuronal function connectivity using functional MRI. So although we tried to prioritize these objective measures, both in how we design the study and in the overall interpretation of the results we still did want to evaluate whether 6463 has the potential to provide a clinical benefit over the course of the study period. So we implemented a few subjective patient-reported outcome measures. The first is the PGIC or the patient global impression of change, which basically asks how the patient feels and go back to the previous slide, please. At the end of treatment. So do they feel better? Do they feel worse? Do they feel the same? And then we also implemented a couple of PROs that assessed fatigue as well as cognitive function. Next slide. So this is our baseline characteristics slide If you're all familiar with some of the challenges of clinical research in mitochondrial disease and again going back to some of the comments made by Dr. Karaa, that it shouldn't surprise you to hear that we enrolled a range of heterogeneous patients into the study. And that's what's shown on the slide and what we saw in the 8 participants that we enrolled. So the age range was from 19 all the way up to 54. We had 5 women and 3 men. Our eligibility criteria can require that these patients had to have a neurological phenotype that was consistent with MELAS. So they all had at least one CNS symptom most commonly stroke-like episodes, seizures, headaches. And then again they also have general fatigue as well as exercise and tolerance as we heard about previously. Consistent with what we expected and based on the use of nitric oxide precursors in the treatment paradigm. The majority of these participants, 6 of the 8 were on stable doses of arginine or citrulline. Biomarkers associated with mitochondrial dysfunction and inflammation also showed a range of baseline concentrations. Lactate is obviously one of the most commonly referenced biomarkers of mitochondrial dysfunction. A normal lactate is less than 2, and we enrolled a couple of participants with lactate concentrations within that normal range and the rest that were above the normal range with the highest concentration of 5.6 millimoles per liter. Two plasma biomarkers that are gaining more traction in the field because they are often considered a bit more sensitive and specific to mitochondrial dysfunction compared to lactate especially when used in combination, our GDF-15 and FGF-21. You can see that GDF-15 concentrations were all above the lab normal range with about a tenfold difference from the lowest to the highest concentration. And then similarly, though the concentrations were overall just a little bit lower for FGF-21, there was still a tenfold difference between the lowest and the highest concentrations. Inflammation, like I said, was evaluated using a panel of 40 inflammatory biomarkers that we implement across all of our ongoing studies. In the participant with the lowest degree of inflammation, you can see that only 6 biomarkers were above the normal range, while in participants with more advanced disease, almost half of the panel was elevated. Baseline scores for the 2 PROs are shown here as well and also exhibit the range of disease burden reported by these participants. For example, Score 3 was reported by 1 participant on MFIS where a score of 0 means the participant reports basically no clinical manifestations of their disease. And then that goes all the way up to a score of 66 out of 84 showing obviously more impact of the disease on their life. Similar range of scores was also observed, as you can see from the promised cognitive function matter. Next slide, please. Okay. So let's move on to the data that we received from this trial. Next slide. So safety, like I said, was really the primary endpoint. So let's start there. 6463 was a little tolerated, both with and without co-administration of arginine and citrulline. Most of the adverse events were mild. We had no severe adverse events. We had no serious adverse events. We had no treatment discontinuations and the most common adverse event was headache, which was reported in 3 participants, the majority of which were mild and all were transient and short lived. We looked, of course, at clinical labs, vital signs, ECGs and we also implemented a suicidal rating scale and didn't observe any sort of safety signals upon review of those assessments. In terms of pharmacokinetics the once-daily dosing PK profile 6463 in this patient population was consistent with what we observed across our Phase I studies in healthy volunteers. And that applies both to the data we collected in the plasma as well as in cerebrospinal spinal fluid. And then when we looked at the CSF to plasma concentration ratio, and it was also consistent with the data that we generated in Phase I. So exposures in a patient in our first patient population are consistent with exposures we've seen in healthy participants. Next slide, please. So now let's move to the objective measures across these disease domains as we've been calling them. The first domain is mitochondrial function. So 6463 improved biomarkers linked to mitochondrial dysfunction that we know are elevated in patients with MELAS. I mentioned it on the baseline characteristics slide, but concentrations in these key biomarkers were, in fact, elevated at baseline which supports their relevance to the pathophysiology of this disease. On the left, you can see the forest plot showing the mean change from baseline for each of them. Improvements in lactate and GDF-15 were observed with effect sizes of minus 0.5. Although the mean change in FGF-21 was smaller in magnitude and had an effect size of minus 0.2. It still did trend in the right direction and actually moved in tandem with these other biomarkers. And that's what's shown in the table at the bottom of the slide. This table has shown the correlations between the changes in each of these biomarkers on day 29, which was the last dose of 6463 as well as the trough plasma concentrations of 6463 on that same day. So each of the 3 biomarkers have their own column and they have their own role. And then the darker green boxes represent very strong correlations with our values of at least 0.8 in magnitude and boxes in lighter green represents strong correlations with our values, at least 0.6 in magnitude. And you can see the changes in lactate concentrations were in fact, correlated with changes in GDF-15 and FGF-21 and GDF-15 changes were correlated with FGF-21 changes on day 29. When we looked at the trough plasma concentrations of our drug, we saw correlations with the changes in FGF-21 and GDF-15, meaning that in participants that have higher concentrations of 6463, they had larger decreases In these biomarkers and mitochondrial dysfunction. Next slide. The next domain is inflammation. So central as well as peripheral inflammatory processes as we know are elevated in patients with mitochondrial disease. And again that was evidenced by the fact that in many of these baseline biomarkers were elevated. 6463 improved a broad range of inflammatory biomarkers, some of which do have direct links to mitochondrial disease as well as endothelial function, which is at play in these patients. In fact around 65% of the biomarkers in the panel improve wood treatment and had an absolute effect sizes of at least 0.3 in magnitude, which is fairly substantial considering the small sample size and the heterogeneous nature of these patients. Biomarkers with the largest effect sizes are shown on this slide. So you can see beta 2 microglobulin had a very large effect size of minus 1.0. Serum Amyloid P component had a similarly large effect size of minus 0.9 and involved by tumor necrosis factor receptor 2, which had an effect size of minus 0.7. So while the first 2 biomarker shown here, have probably stronger links to other indications that we're pursuing with 6463 in parallel particularly Alzheimer's disease, TNF receptor 2 is known to be elevated in the muscle fibers of patients with mitochondrial disease. And then concentrations of endothelial dysfunction markers also known to be elevated in endothelia cells with patients with MELAS such as VCAM-1 also improved the 6463 treatment and also had a moderate effect size. I'll go into a little bit more detail on a subsequent slide but I do want to mention here that similar to those biomarker and mitochondrial dysfunction, these biomarkers did tend to move together within participants. Next slide, please. Next domain is cerebral blood flow. In terms of pathophysiology, vascular as well as neuro injury occurs as a result of nitric oxide deficiency in mitochondrial failure. And then this injury leads to dysregulated perfusion in the brain and then overall reductions in cerebral blood flow. And it's these reductions in this dysregulated perfusion that has links to stroke-like episodes as well as other CNS symptoms that Dr. Karaa talked about. So we observed increases in cerebral blood flow with 6463 treatment, as Peter mentioned, across all the regions that we analyzed at the end of the treatment period. And that's what's shown on the forest plot to the left of the slide. Permits in cerebral blood flow, also strongly correlated with clinical improvement as measured by the patient Global Impression of Change Scale, which we'll show at the patient level on a later slide. The R value for that correlation was minus 0.84. Now this overall increase in perfusion has some advantages, has the potential to provide a protective effect and ensure that when there is a metabolic deficit that occurs in the brain that there is enough blood and then with oxygen delivered to the tissue to compensate and prevent the development of a more significant clinical event as we've been hearing such as a stroke-like episode. Next slide, please. And then the final domain -- objective domain is neuronal function. So for this, we measure functional connectivity between brain regions, both at resting state as well as activation of brain regions when the participant was shown a visual stimulus while in the scanner. And for this study, we used a flashing checkerboard pattern as the visual stimulus. The signal or the fMRI BOLD response to the stimulus is markedly reduced in symptomatic MELAS compared to controls, and this is a deficit that we did observe in our participants at baseline. We observed increases in activation of the occipital brain region in response to the stimulus, and we observed the greatest activation on day 29. And that's what is shown in the figure on the right, which shows the [ voxels ] activated at each visit compared to screening. So the green shows the signal on day 1 compared to screening before the first dose of 6463 and in fact that there is very little green, shows the stability of this measure between the screening and the day 1 visit. And then the red shows the signal detected at the end of the treatment period compared to screening, and you can see the larger volume of [ voxels ] that were activated. We also observed improvements in resting state functional connectivity in regions that are involved in executive function and sensor sensorimotor processing. And overall, these signals measured via fMRI were consistent with and complementary of the improvements that we observed in cerebral blood blow. Next slide, please. So given that this is a relatively small study in a rare and what we know as a heterogeneous population, we feel that it's very important to look at each participant individually. So that's what we're showing on the slide and the following slide. So like I said, other than safety and PK, we prioritized objective biomarkers given the overall nature of the study. This table is basically a listing a participant level data, specifically percent change from baseline at the end of treatment with each participant serving as a column and then each objective endpoint serving as a row. Changes in the right direction or that are representative of improvement are shaded in green. White boxes represent no change, and the gray boxes represent a decline. The take-on message of this slide is that we observed very promising changes across all of the objective domains of mitochondrial disease at the end of the treatment period. And you should be able to see that by the large amount of green on the table. So starting with the top few rows, you can see lactate, GDF-15 and FGF-21. So 7 of the 8 participants had improvements in at least 1 of these biomarkers. 6 of the 8 participants had decreases in lactate which were up to 46% and the participant with the highest baseline lactate concentration. Reductions in GDF-15 were observed in 4 of the 8 participants and similar to lactate those reductions were greatest in the participants that had elevated concentrations or higher baseline concentrations. And then finally, in terms of FGF-21, we observed improvements in 5 of the 8 participants. And overall, as I mentioned, you can see that there's a nice concordance in the movement of these biomarkers in the majority of the participants that we enrolled. 5 of 8 the participants had broad reductions across the inflammatory biomarker panel. You can see that in the first row, which is titled Overall Panel showing the number of biomarkers that increased and the number that decreased. And under that row, the biomarkers as the largest effect size that we talked about on the previous slide. And similar to the mitochondrial dysfunction biomarkers, you can see that in the majority of participants that again, these biomarkers tended to move together. And then the final row shows the changes that we observed in cerebral blood flow using neuroimaging where 5 of the 8 participants had quite large increases in perfusion ranging from 19% all the way up to 60%. So in summary, we believe that the overall color and the overall pattern of this table is extremely promising and that really 6 of the 8 participants enrolled had nice consistent signals across all of these domains of interest. Next slide. So we did collect, as I said, some subjective endpoints. So we do want to briefly talk about the dose. Like I said, in order for us to feel confident in any subjective report of disease improvement from these patients. We really needed support from objective disease biomarkers considering this was an open-label study. Each assessment is shown here as its own row, starting with the PGIC, then the fatigue sale and then the promised cognitive function battery. And in terms of the PGIC, 1 participant reported their disease was much worse 4 reported their disease is the same as baseline. And then 3 participants reported that their disease had improved from minimally to very much improved. In general, you can see that the participants reporting more improvement in their disease had a more consistent response across each of the objective domains and that the subject reporting much worse disease actually had a less of an objective response. I mentioned in a previous slide, with the strongest correlation that we observed between objectives and subjective biomarkers was between the PGIC and the changes that we observed in cerebral blood flow, which hopefully is very apparent when looking at this slide. As for the fatigue and the cognition assessment, it's a little bit harder to make strong conclusions related to those changes. For a few of the participants, there is a bit of a disconnect between how they felt their disease had changed and what was measured via the other 2 instruments. But I think what we can say is that except for participant A that in all of the participants that reported some degree of improvement in their disease via any of the PROs. There is strong support of biomarker data that could explain why that clinical improvement may have occurred. So I hope that this data summary is going to clear why we're really encouraged by this data, the fact that we were able to observe a strong signal despite the small sample size and the heterogeneous nature of this population. But we're looking to move as quickly as possible to further evaluate 6463 and this mechanism as a potential treatment for patients with MELAS. But before we wrap up our discussion about the data, I do want to turn it back over to Dr. Karaa to provide some of her thoughts on the data and her perspective because, again, she was one of the investigators on the study. Dr. Karaa.

Thank you, Chad. Great data. I would like to start by saying that I have been very fortunate and very grateful to be one of the investigators on this trial, and I really would like to thank all the patients and their families that have participated in this trial. This happened in the midst of the pandemic and it was very difficult to enroll. And despite everything going on, they came and they stuck with us, and I really wanted to thank them for that. Now to the trial. Before I talk about the data, I would like to say that it's refreshing to see a drug that crosses the blood brain barrier because that really is hopefully going to take care of a lot of the unmet needs that -- for MELAS and other mitochondrial disorders where central nervous system issues are prominent. And we know that there are about 80% of all mitochondrial diseases have some central nervous system involvement. So this is very good news for the community. The other thing that I wanted to say is that it's also nice to see a trial that focuses on specific organ system and not just on the chronic burden of the disease that I explained where the fatigue and the exercise intolerance and the muscle weakness are the major issues we have had many trials do that. This is, I think, one of the very few trials that is addressing something other than myopathy which is great because we need the diversity. In terms of the data, I want to say that I'm very encouraged, as you said. It's rare to see a trial where in such a short period of time, 29 days, you see changes in the endpoints in the same direction across different modalities that we looked at. And so this that, to me, shows that there is a true signal here that we need to further pursue this to see what else we can learn this drug. I am very encouraged that we are seeing a signal in all the different modalities that we looked at from the mitochondrial function to the cerebral blood flow to the connectivity in the brain and to the decreased inflammation. And so I feel like this is a one-stop shop. It's really affect taking all aspects of MELAS, which is great as opposed to just working on one specific pathway. It's good to see this holistic effect on all these pathways. I am also encouraged that we are seeing improvement in objective and some subjective findings that patients have reported. And so to me, this even though the sample size is small, this is only a study that has looked at 8 patients. And as I said, enrollment was difficult due to the pandemic, but I am very hopeful and I am very optimistic that we should further pursue this program and work on the next phase of these trials to see what else we can learn. And congratulations to Cyclerion for all this great data. Okay. I'll turn it back to Chris now to tell us what the next exciting steps are.

Thank you, Dr. Karaa and Chad as well. Thank you for going through the data. And as you can see, this is a really exciting time in the development of CY6463 and the potential that this may provide for patients with MELAS. So currently actually on the next slide, we're working actively with expert advisers to refine our clinical development plan and understand what the next study might look like. And the goal here is to meet with the FDA to discuss the potential design for a registrational study and aligned with the regulators on the path forward towards regulatory approval. We've established a number of assumptions as we think about this development plan and just -- we're still evaluating all the data from the study, and we're talking with experts. And so please recognize that this plan may be subject to change. We're preparing to meet with the FDA to explore an expedited path for registration for CY6463 MELAS. In addition, we're planning to see orphan drug designation in consultation with regulators. In terms of the study design itself, we are working with experts both within Cyclerion and external experts. And we see the potential for a 3- to 6-month treatment duration study that would also have an open-label extension. And the endpoints are going to be guided by the data that you've just heard about and we've already collected and will likely include measures of cognition, fatigue as well as biomarkers associated with mitochondrial disease. And finally, we're also planning for this to be a global study and to work closely with centers of excellence across the world. So in the next slide. So just to close out the section, this really is a remarkable time for us at Cyclerion, and we're really encouraged by the potential that CY6463 holds for patients with MELAS. I think as you heard we're all aware that this is a devastating disease, and there's no approved therapies. And what we are really enthusiastic about and hope we've conveyed that to you as the clinical results that we've seen, including improvements across multiple biomarkers that are associated with important domains and patients affected by MELAS and these include improvement in biomarkers associated with mitochondrial function disease, the effects across a broad panel of inflammatory markers. And you heard from Chad about the exciting data in terms of changes in cerebral blood flow critical aspect of the disease as well as functional changes and indications of functional connectivity as we look at the fMRI BOLD data. I think it's really important to understand that we've had a very good safety and tolerability profile with no serious adverse events. And I think what's also really important to recognize is this is a therapy that's designed as an oral once-daily pill with good CNS exposure. So I think that really provides a great option as we think about the movement forward in the next clinical design. And finally, I'd like to close out of the section by saying we really appreciate the hard work and contributions of the teams at UMDF and Cyclerion, but really are very thankful to all the investigators, the clinical staff and especially to the patients and their families. So at this point, I'd like to turn it over to Cheryl for the Q&A section.

Great. Thank you very much, Chris, and thanks to all of our speakers here this morning. Thank you to everyone who entered questions into the Q&A tab. We have a few minutes left in our time together. So let's get started with some questions. The first one. Are any of your end points suitable for registration with FDA? What are the accepted regulatory endpoints? And can Cyclerion access an accelerated development pathway? So maybe for that question, I'll invite you, Chris, to share your thoughts and then maybe we could also hear from Dr. Karaa.

Sure. So I think we -- as I spoke about the last slide we're really eager to meet with the FDA and continue to meet with patients and groups to understand the opportunities here. And particularly, the meetings with the FDA are looking at the way to most efficiently move the program forward given the unmet need that you heard about the lack of therapies. And the FDA is encouragement to work early and often with companies. We're really excited about this opportunity to potentially develop this therapy for mitochondrial disease and MELAS. So we're going to be open to finding a way that prioritizes the speed and safety and the patient needs as we have these discussions, and we'll continue to gain alignment from the FDA and other regulators as we think about the most appropriate endpoints that matter to patients, their families and everyone else. So now Dr. Karaa, if you have other comments?

Yes, I think I agree with that, I think we, in the community, along with the UMDF and other advocacy groups like [ Mito action ] have had many interactions with the FDA and they clearly understand the huge unmet need of our patient community. There have been many efforts to try to better educate them to have them hear patients' voice. And so they are very aware of the complexities of conducting clinical trials in mitochondrial disease, then they are very open to new innovative pathways and clinical trial designs. And I think with the data that we have seen today, there is clear path forward, and I feel confident that we will find a common understanding and as to how to move this forward. We continue to work with them. We are lucky to now have a rare disease division at the FDA that has expertise in mitochondrial disease. So they understand much better what we are dealing with. And I'm hopeful that all the stars are going to be aligned, and we can find something quickly.

The second question, I'm going to blend 2 together here. The question is if it took this long to enroll 8 patients, how long will it take to enroll the next study, which will be bigger and for patients who want to participate in the next phase, what can they do to be involved? So maybe for that one, I'll turn it over to Chad, if you want to get us started? And then maybe it'll also be great to hear from both Dr. Karaa and from Phil, their perspectives as well.

Right. So yes, great question. I think this is -- it's challenging, enrollment is challenging, especially during COVID, but we talked a lot about this with Dr. Karaa as well as Phil, ways to increase enrollment. Unfortunately a lot of these patients have been in other trials. And those trials have failed or they've had bad experiences and other clinical studies and nothing has really worked to date. So I think it's a bit of that. It's also some education that I think is likely needed about the importance of clinical trials and also access to clinical trials. But we're hopeful. Obviously, this was our first patient study. We're hopeful that the data that we generated from the study will create a large amount of enthusiasm across patients and sites and advocacy groups as well to ensure that the next study enrolls are much quicker than the current study. But we've also learned a lot from this trial. This was a very scientific heavy with a lot of assessments that, again, we're looking at a lot of objective disease biomarkers. So neuroimaging, we're taking CSF samples. So our next study is going to be much more streamlined and hopefully much more attractive to patients. But Amel, do you want to comment just a bit on the COVID?

This was a tough study because it was started right, within and during the pandemic. I am hopeful that now that the pandemic is partially behind us that we will be more successful. And I think with the positive data that we showed today, patients might be more amenable to being part of the after-study. But you're right, there are many obstacles that we face in our community. And I'm sure Phil will speak further on this, we had a whole session of the United Mitochondrial Disease Foundation Symposium this year discussing those obstacles and how to fix them in terms of education and how to make sure that trials are designed in a way that puts the least amount of burden on patients and traveling to sites and all of that. We have also been working on the clinical trial consortium to address all of these issues. So there are obstacles, that's true. We are dealing with complex diseases and very small numbers of patients, but there are many efforts out there to try to remedy this.

Yes. No, I think just to amplify on your comments. The time we spend at the symposium discussing clinical trial readiness is really about creating a culture of clinical trials within our patient community. And I think we all recognize we're still in the early days of therapeutic development for mitochondrial disease. There's a very strong educational component to it. And for the patients that joined us today, every one of these webinars is an opportunity to learn about clinical research and how you can be engaged in it. We've also created some materials on our website that have a whole lexicon, a glossary around clinical trials and clinical research. You have to educate yourself first to really see what role you might play. But of course the one thing I really want to emphasize once again is the critical importance of a robust patient registry. If you are a patient and particularly in this case, if you have been diagnosed with MELAS, we really encourage you to join Mito Share to become a part of the community there, share your health information, share your perspective and be assured that we will make sure that you are aware then of clinical research opportunities that are relevant for you going forward, including this opportunity with Cyclerion.

Great. Thanks to all of the panelists for their comments on those couple of questions. Apologies, we're not going to have a chance to get through all of them this morning because we're right at the sort of top of the hour. So maybe I'll invite Peter and Phil to close out the session.

Great. Thanks. Let me just say before I turn it over to Phil quickly. Thank you to all the participants and thanks to all of you for listening in. I found it a very inspiring conversation, especially hearing the voice of the caregiver and the treating physician and the patient community. I think that's a very, very important part of the dialogue for us as a company working hard to see if we can develop a medicine that can help. And we're very grateful to you to host this conversation this morning and make the time available. So thank you for partnering with us on it. So especially grateful to you in the UMDF. Thanks for the time.

Well, you're very welcome. Likewise, we're very appreciative of Cyclerion and your interest in developing a therapeutic for mitochondrial disease. Of course, I do have to thank Dr. Karaa for all the time that she spends with our patients and volunteering to UMDF and many other organizations to advance therapeutic development for mitochondrial disease. I just want to wrap up by saying great content, really exciting. We will be here to share additional updates as they become available. Should you know someone who would be interested in this webinar or perhaps even yourself, if you'd like to review the webinar because of the amount of information that was contained within the webinar, please visit umdf.org in Mito University we will be posting a full recording there very shortly. So with that, I'm going to wrap up. I thank the patient community for coming out today, everyone that joined us and look forward to seeing you at a future UMDF webinar.