Hello, and welcome to the Denali Therapeutics Webinar on interim data from our Phase III study of BN-three 10 in patients with Hunter Syndrome or MPS II. I am Laura Hansen, Vice President of Investor Relations, and I'd like to thank you for joining our webcast today. Please note that the press release we issued earlier today and the slide deck for this webcast are available in the Investors section of our website, denaliatherapeutics.com. Before we get started, I'd like to note that the presentations given today and the responses to questions will contain forward looking statements regarding Denali's future plans, business strategy, product candidates, planned preclinical studies and clinical trials among other things. Such statements are subject to numerous important risks, uncertainties and assumptions.
Should any of these risks or uncertainties materialize or should our assumptions prove to be incorrect, our actual results could differ materially from these forward looking statements. These risks, uncertainties and assumptions are more fully described in our filings with the SEC, including our latest quarterly report on Form 10 Q and our latest annual report on Form 10 ks. Any forward looking statements are based on information available to us as of today, and we disclaim any obligation to update any forward looking statements except as required by law. On the webcast today, I'm joined by members of Denali's management team: Limewatch, Chief Executive Officer Carol Ho, Chief Medical Officer Alex Shuth, Chief Operating Officer and Steve Kroganis, Chief Financial Officer. I would like to take a moment to review the agenda and Q and A logistics for today.
We have scheduled approximately 1 hour for the webcast, including presentations and the Q and A session. Ryan will begin with introductory remarks and Carol will present the interim data from the Phase onetwo study of DNL-three 10. Then Ryan will provide concluding remarks and begin the Q and A session. If you would like to ask a question anytime during the presentation, you may do so by typing it into the Q and A box. We will do our best to answer as many as possible during the Q and A session.
And now I would like to turn the program over to our Chief Executive Officer, Ryan Watts.
Thank you, Laura. Very excited to be here today. Also very excited to share some of our data in our DNL-three 10 program, actually extensive data, biomarker data and clinical data. I'd like to start with our purpose. Denali has set out to defeat degeneration.
And as we've highlighted in the past, we have a number of ongoing studies or completed studies across all of these therapeutic areas, including rare neurodegenerative diseases, ALS, Parkinson's and Alzheimer's disease. Today, we'll focus on the rare neurodegenerative diseases, specifically lysosomal storage diseases. We follow a set of principles as we develop each of our medicines. These are our discovery and development principles. 1st is what we call the d genome genes, genes when mutated that cause neurodegeneration.
Today is the highlight of that as we focus on IDS in Hunter syndrome. 2nd is engineering brain delivery, so inventing medicines that readily cross the blood brain barrier. And again, today, we'll focus on our transport vehicle technology, which is designed to cross the blood brain barrier for large molecules such as antibodies, enzymes and antisense oligos. And our 3rd principle is biomarker driven development, and I think that's a major highlight of today's presentation. We'll show extensive biomarkers as we approach Hunter syndrome.
And then finally, our goal is to have a patient impact. To increase the likelihood of success, We follow these 3 principles in each of our programs. So just a reminder that our portfolio is split roughly between small molecules and biotherapeutics about fifty-fifty. We're focusing on the biotherapeutic portfolio today in our most advanced program in Hunter syndrome, DNL-three 10. We'd like to highlight, however, that we've now advanced DNL-one hundred and 26 for Sanfilippo into the IND enabling stage.
Let's talk about biotherapeutics in the blood brain barrier, and I'll begin with the blood brain barrier challenge. The blood brain barrier is a major obstacle for brain delivery of biotherapeutics. And the way that we've approached it is to use natural transport mechanisms in blood vessels in the brain and specifically the transferrin receptor as shown here. We've engineered molecules to latch onto the transferrin receptor, which is constitutively endocytosed bringing iron into the brain with the goal of bringing our biotherapeutics across the brain barrier and into the various cell types in the brain. To highlight the technologies that we're using, the transport vehicle technology, we published 2 papers last year back to back in Science Translational Medicine.
The first paper was outlined the invention of the transport vehicle technology and its application to antibodies with proof of concept in both small animals as well as non human primates. The second paper utilizes the transport vehicle technology to get an enzyme across the blood brain barrier for Hunter syndrome. Here we use the IDS, Hunter mouse model, and we can show robust reduction in substrate in brain, which correlates with reduction in cerebral spinal fluid, 1 of the key fluids that we use in our human studies. In summary, the transport vehicle achieved high concentrations and broad biodistribution of biotherapeutics in brain. It also can achieve a dose dependent reduction in brain substrate, and we're very excited to show data even at lower doses today for our DNL-three 10 program.
So important for us is the broader potential of the transport vehicle technology, both in various modalities, but also in therapeutic areas. Our initial focus is in neurodegenerative diseases as well as lysosomal storage diseases. However, we see potential in broader neurology, oncology and infectious disease. And importantly, we're applying the transport vehicle technology to antibodies, enzymes, proteins and even antisense oligos and are advancing a number of programs in this space. Before I hand it over to Carol, I'd like to summarize the interim data that we'll present today.
We're very enthusiastic about the ability to rapidly and durably reduce heparin sulfate and cerebral spinal fluid across all patients tested and across all doses. In addition, we'll be presenting data on exploratory biomarkers of lysosomal function where we see reduction consistent with improved lysosomal function. We see a high variability in neuro filament observed both pre and post treatment. We also show for the first time improvement over 24 weeks based on clinician and patient reported global impression of change in clinical outcome. In addition to this, we see enhanced PROPL activity.
All patients are switched from either sulfates to DNL-three 10. And here looking at both urine and serum, we see improvement in activity with DNL-three 10. And importantly, the safety profile is consistent with standard of care replacement therapy. The totality of this data has led us to make the decision to accelerate our program into a Phase twothree study. And with this, I'm going to hand it over to Carol to go into great detail on this data.
Thank you, Ryan. And I'm pleased to be able to present the BN-three 10 interim Phase onetwo data. So DNOL-three 10, as Ryan described, is an IV therapy that uses Denali's transport vehicle technology to deliver IBS, the enzyme that's missing or defective in MPS II to the brain and the body. The technology of a fusion protein of IBS to ETV has a differentiated binding profile with the transferrin receptor, which in preclinical models demonstrates broad distribution through the brain to neurons, astrocytes and microglia. The NL-three 10 is currently in an ongoing Phase onetwo study.
It's delivered systemically IV once per week, which is the same dosing frequency that standard of care aloprice uses. In this Phase onetwo study, patients on aloprice switched to DNL-three 10 in order to evaluate the effect of DNL-three 10 on both the body as well as the brain. The development of 3 10 is intended to replace current standard of care by delivering efficacy in the brain, a current unmet medical need, while also delivering differentiated efficacy to the body. This next slide outlines the study schema for the Phase onetwo study. This is an open label 6 month study followed by an 18 month safety extension in approximately 30 MPS II patients aged 2 to 18 years old.
Eligible patients are either treatment naive or on approved IDS therapy for longer than 4 months. In the data presented today, all patients were on IDS therapy and were switched to DNL-three 10 without a watch out period. There are 3 cohorts in the study designed to evaluate the safety profile of DNL-three 10 and enable dose selection for our subsequently planned Phase twothree study. The primary endpoints are safety, which includes adverse events, infusion related reactions and total urine periphery because patients switch off of IBS. These secondary endpoints and very relevant to the blood brain barrier crossing capability of this transplant vehicle include CSF heparan sulfate and then also urine heparan sulfate.
Exploratory endpoints include other DAG measures of dermatin sulfate, heparan sulfate and keratin sulfate, which we'll present today, including liposomal CSF lipid biomarkers and CSF and serum and neurofilaments. Clinical outcome results in cognition behavior and global impression are also assessed in this study and today we will present data on the global impression scale. Now I'll go through the detail of the cohorts. We'll present data today for Cohort A and B. Cohort A is a within patient dose escalation cohort and includes neuropathic patients 5 to 10 years old.
Today, we are sharing 6 month biomarker data and safety data up to 43 weeks. All patients in Cohort A remain in the safety extension study at 30 mgs per kg. Cohort B now is a dose finding cohort to evaluate lower dose regimen of DN-three 10 in both neuronopathic and non neuronopathic patients aged 2 to 18. Dosing modifications, as you can see, can be made in Cohort B1 after 12 doses have been administered. Cohort B2 and B3 study stable doses of 7.5 mgs per kg and 15 mgs per kg.
All patients in Cohort B will roll over to the safety extension at the end of the study at 15 mgs per kg. Cohort C is a cohort that will enroll neuropathic patients younger than 4 years of age and sibling pairs to further evaluate exploratory clinical endpoints such as behavior and cognition in an age before normal development is markedly impacted by this disease. Dose selection in Cohort C will be determined based on ongoing and emerging data from this study. So now I'll share the demographics of the patients that will be reviewed data in this interim data cut. The demographics are shown here.
The median age of both cohorts is 6 years of age and all 17 patients as noted were on IDS treatment prior to enrollment, except for 1 patient in Cohort B, these are all neuroneopathic patients. There are 5 patients in Cohort A, all of whom completed the 6 month study. Cohort B is ongoing with 12 patients included in this interim analysis. These 12 patients have completed 12 weekly doses. The largest racial group in this study so far is white and the majority of patients are non Hispanic or Latino.
This provides a further detail of the data that will be presented today as noted safety up to week 4325 in Cohort B, heparan sulfate, which is our key secondary endpoint in cohort A up to week 24 and in cohort B up to week 13. We'll be also presenting liposomal biomarker data up to week 24 in cohort A, specifically GM3, BMT and glufair. And we'll be presenting cohort B GM3 data up to week 13. In addition, we are presenting exploratory neuro filament data on cohort A up to week 24 and exploratory clinical global impression of change from both an expert clinician as well as a parent caregiver up to week 24. I'll start with the interim safety summary, which is in the safety population of 17 patients.
Very importantly, all patients remain in the study with no discontinuations. All 5 of the cohort A patients continue in the safety extension at 30 mgs per kg. And of the 12 patients presented today in Cohort B, 10 are continuing in the 6 month study period and 2 have advanced to the safety extension. All of the data presented today was reviewed by an independent data monitoring committee on July 9, 2021 and importantly recommended continuing study protocol. All treatment emergent adverse events were mild or moderate except for 2 severe treatment emergent AEs, which were IRRs in 1 patient, which I'll describe below.
Infusion related reactions were not unexpectedly the most common treatment emergent adverse event incurring in approximately 71% of the patients. The majority had mild and moderate IRRs, but 1 patient had a severe IRR, which was an SAE, which will be detailed below. Of the 12 patients with IRRs, 8 required standard interventions to prevent subsequent IRRs and 2 required additional dose and infusion rate reductions. Most IRRs to date have occurred between weeks 36 and the patients 3 of the patients who experienced IRRs in advance to the safety extension, most of the pre infusion medications have been discontinued. There have been 2 patients that have had SAEs related to infusion related reactions in this study.
1 previously reported was a patient who had an SAE at week 4 that was hospitalized for overnight hospitalization, but then was discharged without any further sequelae. The second patient had 2 SAE severe IRR that met Sampson criteria of anaphylaxis at week 34. These were managed with pre infusion medications, dose and infusion rate reductions. Importantly, this patient remains in the study and has now tolerated subsequent weekly doses, including dose increases. Regarding safety laboratories, there were no notable abnormalities or trends in safety laboratory evaluations except for anemia, which was also described previously.
There are 4 patients that have had treatment emergent events of anemia, all were considered not related to drug. These were graded mild in 3 and moderate in 1 and all 4 are improving or have resolved despite continuing dosing at either 15 mgs or 30 mgs per kg. In summary, the weekly IV infusions of DNL-three 10 for Cohort A and B were generally well tolerated at doses between 30 mg to 30 mg per kilogram with a safety profile that is consistent with standard of care therapy. I'll now move to the safety biomarker of urine gag. So as a reminder, this was collected in the study to monitor clinical response to BN L310, particularly given patients were washed off of IDS standard of care therapy.
Total urine GAGs were measured by a color metric CLIA certified assay and were used in the study to monitor peripheral response to 310. Across cohorts A and B, total urine GAG levels overall decreased, including in the lowest dose regimen of cohort B1 at 3 mgs per kg. After switching from IBS to DNL-three 10 without a washout period, total urine DAG levels declined almost in all patients suggesting improved peripheral activity with BN L310. Consistent with the improvement in the reduction of urine total GACs, we also assessed whether DNL-three 10 could further reduce elevated levels of heparan sulfate and other peripheral GAGs including dermatin and keratin sulfate. We have previously published an increase ranging from 2 to 3.7 fold in all of these 3 glycosaminoglycans in the serum of MPS patients, are depicted in orange and red.
Notably, these patients are on standard of care enzyme replacement therapy or had received hematopoietic stem cell transplant. You can see that these are elevated compared to the dots in gray, which are non MTS pediatric controls. We have observed now with treatment of BN-three 10 in cohort A across these 3 different serum glycosaminoglycans. There is a reduction at week 24. Notably, keratin sulfate is a dominant gag present in articular and growth plate cartilage where bone grows.
In certain MPS diseases such as MPS IV where keratin sulfate is the dominant gag that accumulates the disease course is characterized by skeletal dysplasia. This reduction in these peripheral GAGs including keratin sulfate suggests that BNL-three 10 could have increased potential long term effects on peripheral clinical endpoints including bone remodeling. Now I'll turn to the CNS penetrating capability of this transport vehicle technology and BN-three 10. So importantly, I want to highlight again a slide that we've shared previously that shows the importance of heparan sulfate in monitoring the effects of blood brain barrier crossing activity of DNL-three 10. So as you can see in the family of MPS disorders, those that have CNS involvement highlighted in white orange, you can see all have heparan sulfate accumulation.
So those diseases that do not have central nervous system disorders or cognitive symptoms, you can see that heparin sulfate is not represented here. So similar to the previous slide, I want to remind everybody about the increase in CSF heparan sulfate that is seen in MPS II patients even though they are currently on standard of care therapy as shown in the upper left. There's roughly a 10.7 fold increase in CSF heparan sulfate in MPS II patients compared to CONTROL. As you can see here across cohorts A, B1, B2 and B3, all 15 patients had normalization of heparan sulfate at the end of the dosing period up until this time with rapid response in 12 of these patients by week 7. This percent reduction is 90% in cohort A and ranges between 86% to 92 percent at lower dose regimen demonstrating the efficiency of DNL-three 10 for crossing the blood brain barrier and reducing the most important glycosaminoglycan in the CSF that is correlated with clinical symptoms across the MPS disorders.
Dermacent sulfate is also a key substrate of IBS and so we share the data here again. Again, we see a 31 fold increase in dermatin sulfate in the CSF and MPS patients compared to non MPS control. And what you can see is that there's a rapid response in 12 patients by week 7 in the reduction of dermatin sulfate in CSF. I think notably on data that we're now presenting in Cohort B also shows that at these lower dose regimen, we continue to have various efficient reduction in CSF dermican sulfate. So they extend the understanding of the effects of DNL-three 10 in the CMS.
As you know, we have profiled also lysosomal lipids, which accumulate in cells of both neurons as well as glia in the central nervous system and use this as a biomarker to get further evidence of effects in the brain. As you can see here, GM3, which is the key nervous system danglioside, this is elevated 3 point 7 fold in MPS patients compared to non MPS controls. As you can see here across cohorts A and B, 10 of 15 patients achieved normal CSF GM3, including a dose lower dose regimen as you can see in Cohort B. This demonstrates that BNL-three 10 is getting into the brain and is reducing these lysosomal lipids that accumulate. We also look at 2 additional lysosomal lipids that have been associated with lysosomal dysfunction including BNP and glucosaciramide.
As you can see here in natural history, cross sectional data, we do have an increase that is modest in BNP and glucosylceramide. And you can see in both of these biomarkers, there is a mean reduction in these biomarkers at week 24 in cohort A. So next, we explored neurofilament, a biomarker of neuronal structure, which has not previously been characterized to our knowledge in MPS II aside from publications from Denali. In 2020, Denali was the first to publish cross sectional data demonstrating an observed increase in CSF and CRM neurofilaments. We have extended this analysis now to look at natural history data to further characterize the longitudinal trajectory of neurofilament.
As you can see in the middle panel, these are 3 patients from our natural history study that is studying patients with MPS II and these significant patient As you can see here, there is significant patient variability that is best evidenced by collection of neurofilaments in short timeframes within a short span. You can also see that there is a mean increase, a market mean increase of 94% in the 4.5 to 6 months pre dose. After treatment, there is a modest increase of 15% 36% increase in neuro filament in the serum and the CSF. It's within patient variability in neuro filament as well as the increase in neuro filament that is seen in the natural history study. Leads us to conclude that at this time the utility of neurofilament in MPS II as a treatment biomarker requires further investigation across the field specifically in generating additional natural history data.
Notably, we also looked at another biomarker of neuronal structure tau, which shows no change in near normal levels over the 24 week dosing period. I'd now like to turn to our data on the cognitive effects based on clinical global impression change scale. Before doing this, I'd like to provide an overview of cognitive milestones in Huntington's patients. As you can see in this graph, this graph shows the correlation between developmental age on the y axis and calendar age on the x axis. As you can see in normal development, these should track very much along this 45 degree line.
However, you can see that there are 2 patient populations that are evident in Hunter syndrome. Those that have neuroprincipal involvement that show regression in their developmental age over time noted in orange compared to those that may have mild or no cognitive effects or no neurocognitive effects that track along a normal trajectory. As you can see that this change in the trajectory is very evident by Age 5 and all of the patients that we have studied in cohort A are above the age of 5. Therefore, we would expect very little change or regression in their cognitive development over time. So here's the data on the clinical and parent caregiver global impression change questionnaires, which were used to rank overall MPS II symptoms, cognitive abilities, behavior and physical abilities on a 7 point scale from very much worse to very much improved.
Worsening is depicted in shades of red and blue is depicting improvement. In cohort A, all patients were neuropathic and range between 5 to 8 years of age. Interim assessment of clinical outcomes by expert clinicians and caregivers suggest improvement in overall MPS II symptoms, cognitive abilities, behavior and physical abilities in 5 to 8 year old patients. In addition to the scales as shown below, we have also extracted excerpts from the comment field from the CGIC, the see the clinician global impression of change that was entered by the investigators into the database. These include comments such as language much improved more complex sentences, now able to hold a pencil, more conscious of conversations surrounding him, physical features that are much improved, building much more complex Lego towers, better 6 figure drawings and use of new words and completing 3 to 4 word sentences, less aggressive following directions.
In summary, this data suggests that a cohort pay patients who are greater than 5 years of age, assessment of clinical outcomes suggest improvement in overall MPS II symptoms, cognitive abilities, behavior and physical abilities as assessed by an expert clinician and parent caregiver. So in summary, the data from the ongoing study of DNL-three 10 in Phase onetwo supports a well tolerated safety profile of DNL-three 10 at doses ranging from 3 to 30 mgs per kilo weekly. DNL-three 10 demonstrates efficient blood brain barrier crossing, a durable reduction in CSF heparin sulfate and dervescence sulfate over 6 months with sustained normal levels in all 15 patients in this data cut. DANO-three 10 effects on DAGs and lysosomal lipids were also observed at all dose levels including 3 mgs per kg weekly demonstrating activity on lysosomal function. In addition, global impression suggests improvement in symptoms as assessed by an experienced clinician and caregiver.
The utility of neurofilament in MPS II requires continued investigation and additional natural history study data given the variability observed and the market increases in neurofilament observed in patients rolling over from the natural history study onto the Phase onetwo study. Our safety profile is consistent with standard of care enzyme replacement therapy and MPS II with safety data now up to 43 weeks of dosing. Based on this data, we look forward to enrolling in Cohort C designed to further explore clinical endpoints including behavior and cognition in an age range for which treatment effects on development milestones may have the highest likelihood of impact to be observed. In addition, we are accelerating our activities towards the registrational study to start in the first half of 20 22 to demonstrate patient benefit in both neuroneopathic and non neuropathic MCS2. And with that, I'll turn it back over to Ryan for conclusions and to start the Q and A.
Excellent. Thank you, Carol. So I'd like to summarize and we'll dive into the Q and A here. In conclusion, I think importantly, we show that 1 of the hallmark biomarkers of Hunter syndrome, specifically heparan sulfate, We saw a robust and sustained reduction, including normalization. I think importantly, even at low doses, such as 3 mgkg, we're seeing normalization.
I think this highlights the power of the transport vehicle platform and further validates this platform as we use it across other modalities. We also show for the first time global impression scales, improved improvement in cognition, behavioral and physical function, including some exploratory biomarkers such as lipids, which are downstream of heparan sulfate. The safety is consistent with standard of care. And then what does this mean in totality. So for us, we're now accelerating the Phase twothree study to begin next year and we're further building out our transport franchise with a focus on the enzyme transport vehicle in addition to other transport vehicle enabled programs, highlighting that we'll be bringing at least 2 more transport vehicle enabled proteins to the clinic in the next 6 months.
I think with that, we'll take questions. I see that there is a number of questions. Great. Excellent. So maybe we'll start here.
Let's see. Let's start with questions related to the infusion related reaction. So I think there's about 3 questions related to this. So how do the rates of IRR compared to eloprase? And Carol, I'll hand it to you.
Yes. So as noted, we believe that our current profile is very consistent with standard of care where per the yellow price label, there is a 57% to 69% rate of hypersensitivity reactions that are observed that are in line with what we've observed. In addition, there are severe hypersensitivity reactions involving more than 2 to 3 body systems that have been reported in eloprase in approximately 15% of patients. I think just in terms of our IRRs, these were managed by standard infusion related medications for IRRs. And so again, we feel that this is very consistent with standard of
care. I think we'll continue on this theme and maybe just ask 1 or 2 more questions related to IRRs. So how do we gain confidence that these IRRs are not related to the transport vehicle, but rather related to ELAPRASE or to IDS?
Yes. It's a great question. And I think this is something that we've observed and looked at our data very carefully. And I think the best data really that gives us confidence is that these patients in Cohort A remain in the study and at 30 mgs per kg. So these are the patients that have the longest dosing up to 43 weeks.
And as I've noted, we actually see a decrease in these infusion related events over time. Similarly, in Cohort D, those individuals that have had infusion related reactions continue in the study. And overall, we see that these are very manageable, very much like what we see with standard of care therapy and management with ongoing seizure related reactions. I think maybe the last thing that I'll say is that just in terms of very importantly looking at the durability of response of reduction in CSF HS, if infusion related reactions were related to antidrug antibodies, for example, decrease the efficacy of the enzyme, we would expect to see changes and we don't. And I think very importantly also with peripheral GAG, urine total GAGs are constantly monitored in the clinic by physicians.
And then as well, we have our mass stack, very quantitative assay that has shown no increases in these GAGs over time.
Several questions around ADAs. Any new understanding of ADAs to 310 or other related effects that we can speak to? And maybe I'll just ask 3 questions in a row because I think they'll be related. So for patients previously on IDS treatment before entering the study, were any positives for anti drug and anti drug? And if so, how did this impact biomarker reductions from the treatment?
I think you sort of highlighted this already, Carol, that there was no effect on the biomarkers. And could you characterize the private presence of any neutralizing antidrug antibodies? How does this compare to rates observed with pediatric patients treated with aloprase? So those are 3 questions around ADAs.
Yes. So, ADAs are quite common in this patient population. So yes, there were patients with pre existing antidrug antibodies. And we've mentioned this previously. So for example, in Cohort A, there was 1 patient that, as you may recall, had a slower reduction in their decline of CSF HS, but very clearly that patient has normalized at this time.
And so I think the ability to dose higher certainly allows us to dose that's something that we are evaluating further in cohort D where we have a more stable dosing across the 3 doses of the 7.5 and 15
I think I'll just add to that, which is heavily influencing our ultimate dose function as we go forward in the Phase twothree and the ability for us to be able to dose higher is pretty important because obviously the ADA is far for the course with enzyme replacement therapies. And we've definitely seen a correlation between pre existing ADAs and the ability to reduce happenstations. So for example, if you look at patients in the B1 cohort, the 1 that didn't respond immediately had higher pre existing EDA, very similar to cohort A. So that ability to have a higher dose is so let's turn our attention to anemia. So a question on do you still believe that anemia events are blood draw related?
Yes, we absolutely do. So the patients in Cohort A that initially had reductions in hematocrit, we followed those patients very closely and also made protocol modifications to reduce the amount of blood draws that we had over time. And as you may recall, also in the early part of the study, there were multiple dose escalations. So cohort A went from 3 to 7.5 to 15 in a short period of time. And every time we did that, we needed actually draw blood to monitor for PK, ADAs and other endpoints.
And so what we've seen is that these patients over time, despite dosing up to 30 mgs per kg have essentially either resolved or near resolved the anemia back to baseline levels. And so we're quite confident that this is not related to transport via GOLVE technology.
Okay. Some questions now related to neuro filament in the high variability and the following question. What do you know about variability of neuro filament in different diseases and the time course of changes dependent on the pathology of the disease and say, Hunter syndrome versus MS where you have relapses? And what does this teach us about the value in Hunter?
Yes. So that's a great question. And we're certainly learning as we go along the way. And I think we're a bit surprised to see the variability and then also the increase, the market increase that we saw in the natural history data. And as noted, we're the 1st to demonstrate effects or the increase in neurofilament even in this disease.
So we're really characterizing this and sharing the data as we go along. In terms of variability, there is variability, I would say, that AT and T across multiple indications ALS, AD, that we have performed on neurofilament. But I think that in there's also published data, for example, in COVID that they looked at neurofilament and MS. I'd say that over short periods of time, there can be quite a bit of variability in neurofilament, which certainly makes it challenging to And Ryan, if you want to add to that.
Yes. I'd love to add to that. What's interesting is the data that we published on neurofilaments showed a very widespread of neurofilaments in both serum and CSF. However, that was just a cross sectional look at neurofilaments. What is, I think, most interesting to us is that within a single patient, you're seeing high amounts of variability in short periods of time, including this increase at least in the 3 patients that subsequently enrolled in the treatment study.
Now I don't know how to compare that. People have generally thought the neuro filament was stable in some of these other diseases such as ALI. I mean stable within reason. But obviously, it makes it difficult to interpret, especially with such few patients, these data with that type of neuropathy. So let's stay on the neuro filament questions.
Is there evidence that heparan sulfate kills neurons slowly? So removing heparan sulfate might have a long tail of neuro filament follow-up, whereas the modest increase is more consistent with partial correction, likely implicating TKA and deeper regions in the brain. So maybe I'll take this 1 Carol and you can add to that. We're just really careful about not over interpreting the data from this market increase in patients to the modest on treatment. That being said, the other really interesting observation is that tau doesn't really change and it's near normal levels.
And a lot of times you're seeing this relationship between tau and neuro filament, which are not seen in MPS II. So I think just with this variability, we're going to need to get more data to imply something that's not in the question that this is actually evidence of deeper brain penetration. I think our strongest evidence of brain penetration is obviously the robust effect on both heparin sulfate, but also the downstream lysosomal bio markers, which are fully corrected. It's worth noting that we actually never achieved that level of correction in the animal models that we're seeing in humans. So when we looked at brain levels or CSF levels in animal models, probably the maximum reduction we had was about 70%, but it didn't return to normal level.
So in this case, I think that my conclusion is that there is a pretty big capacity for transport in the human brain, there's 400 miles worth of blood vessels. And using transfer receptor is a very efficient way to get across the blood room barrier. And just recall that for every capillary, there's an associate for every neuron, there's an associated capillary. There's only 1 or 2 cell body distances you have to travel once you've crossed that catheter. I think related to this, and here we'll ask this question on the preclinical data, which again I think is very challenging to compare, but we definitely have some insights.
So how do you believe the preclinical hunter mouse data is translated for exploratory biomarker such as neurofilament and clinical axon. The patients in the study with exception 1, 2 or older are a bit older. If you were to start treatment in younger age patients, can you speculate what neuro filament levels would look like over time perhaps according to what preclinical hunter models data show, that's of course our own data. Was there any notable stabilization or reduction in neurofilament for 2 year old patients? It's a great question.
Carol, I'll hand back to you. Yes.
So these are great questions. And I think going back to also the other question about variability in neurofilament over time, I would say that pediatrics, as compared to MSD, has much less data on what the normal trajectory is of neurofilament. I would say that probably the data, probably the best pediatric data comes from SMA1 and SMA2, but the correlation between treatment effects really responded to SMA1 and not so much with SMA2 and 3. So I think this is we look at these biomarkers as exploratory biomarkers. I think we really have to understand more about the trajectory.
So now going back to the question around starting early, we do certainly think that starting earlier will have a greater impact on the disease simply because at that earlier stage, you have lost fewer development milestones. And so there may be more of an opportunity to have a greater impact. As far as neuro filament, I think it's still just early days because even the natural course of neuro filament may be very different in 2 years. We know that neurofilament actually starts out much higher than there's a period of active pruning and remodeling in the brain that neurofilament starts to go down and then it increases fully over age in normal individual. But I think there's this dynamic period during development that you don't really understand what is happening with neuro filament and when there are changes in the neurocognitive status with treatment and intervention, how this affects the remodeling of the brain and therefore, the effects on neuro filament.
So it's maybe a long answer, but I don't think we know that we have how treating a 2 year old is expected to have her fulfillment changes. We could anticipate that that would look alike. I would say and the reason that we're going to cohort C is that from a clinical perspective, we're even more likely to see effects in younger age range. And given the exploratory data in Cohort A with regard to the older impression scale, we are very enthusiastic to explore further in younger patients.
I think that answers another question based on some of the other presentations at MPS 2021, obviously ongoing today. There appears to be an emerging trend of better response out of earlier treatment. While it may be early with cohort 8 or it may be early with cohort 8 subjects, any thoughts on how this may apply to DN L3P treatment? What can we do to facilitate earlier patient identification? I think, Carolyn, some ways you've answered that, but maybe just to reemphasize, it would be worthwhile.
Yes. Well, I think that this is something that we're really enthusiastic around engaging the community and in terms of newborn screening certainly would help identify patients earlier in some states that have now been added to the newborn screening panel. But for the most part, it is not currently the standard of practice to have newborn screening. I think just as we and others in the field are developing therapies for neurocognitive symptoms, there's certainly awareness and we're hearing every day from the patient community of individuals that are being diagnosed earlier and particularly siblings where 1 sibling already has the disease and the parents are then seeking diagnosis and treatment for the younger siblings. This is another opportunity to enroll earlier patients.
Definitely think the mantra earlier is better. I will say that we were very excited about the data that we saw, the clinical data treating these more severe patients in Cohort 8, albeit a small number of patients. With the understanding of the hazards associated with inter study comparisons, can you comment on how the 6 month phenotyping data may differ from JCR's IDS TFR molecule, JR-one hundred and 41, 6 month data. So I'll be happy to address that and Carol, you can add to this. So we actually at the mechanistic level, we compare the JR-one for 1 like molecule to BNL-three 10.
This paper is actually available on bio archives. We presented this data at world. It's really a question around architecture and BRAIN delivery. But I think what's really worth noting in that paper looking at both BRAIN and CSF reduction at different dose levels, the high differentiation of the transport vehicle enabled IDS or ETV IDS relative to the 601 like molecule in terms of architecture. We believe it's related to the affinity and narrow down tightly the trans femoral center not readily crossing the blood cell barrier.
In addition to that, although the assays are different, you can look at percent reductions, right? And we have we of course have internal control data. Now thinking about the clinical data comparing it, you asked what are the normal levels of a healthy individual versus MPS and then how does the treatment affect? And when we're seeing 96% reduction and normalization, that can contrast to maybe 30% reduction early on and maybe 60% max reduction. And so there's a very clear difference in both how rapid the response is.
And I think to add to that, even if dose is as low as 3 mg per kg, we're seeing a normalization in at least 3 out of those 4 patients, again, the 4 patients having higher ADAs, which we can then dose at a higher dose. I don't know, Carol, if you want to add to that, but
I think that summarizes it very well. I guess I would really just want to emphasize that here, it's kind of what the and this normalization in normal levels as opposed to say non neuropathic levels. And then I think just in terms of clinical data, we also are very pleased to see that the duodenin chlorate is also substantially reduced. And then just in terms of the overall activity of the enzyme and the penetration of the peripheral organ systems, we shared the serum data costs, heparan sulfate, dermacyl sulfate and differentiated.
Let's turn to the Phase twothree. So how do you think about powering Phase twothree study now to show neuropathy? How long does follow-up mean to how long is the trial and what is the basis for this company that we've accepted? And related to that, have you met with the FDA, what is the gain for starting on Phase IIIII at this point?
Yes. So we've certainly been thinking a lot about the Phase twothree study. We have met with global regulatory authorities to discuss this. I think as you may know, the regulators have spoken at national meetings in the recruiting world and they've indicated that the FDA would like to see a randomized study compared to and so that is factoring into our thinking around the size of the study and the duration of the study that would be required to see a treatment effect. In terms of looking at progression of neurocognitive symptoms, Lumenitis is a good indication of study in each patient in a randomized study for open label data to better understand these cognitive and behavioral reasons and start to understand whether we can see clear evidence of clinical impact when we would follow that, I mean, to complete the Phase twothree study.
Let's turn our attention back to neurofilament in a series of questions. A view on how neurofilms may be impacted by age? Could there be a different outcome in under 5?
Yes. I think we addressed that question earlier in that we don't really understand the natural history of natural gas and how not only do we not have a very clear picture of a normal development, how that changes as we know, again, that it starts high then goes down and then as people age into their decades, it increases again. But we don't know how it would be impacted by treatment paradigms.
Between the different levels at baseline of neurofilaments, including 1 patient that's relatively low and staying low, but has deemed neuropathic and saw cognitive benefit. So there seems to be a disconnect there. So it may be as much the nature of the mutation as it is the age and timing of intervention. Okay. Can you comment on the clearance for neurofilament?
Do you have enough data to suggest you are slowing neurofilament growth versus pre treatment? And I think maybe I'll answer this. We're not claiming anything actually that we're slowing the reduction. We're showing the data as is. We do not have enough data to be able to claim that.
That is 1 interpretation of our data. But it's a very good point that there's a balance between production and clearance and neurofilms has a relatively long half life. And what we can tell you is that it's variable between patients and within patients. And that's the nature of the lab. What might explain that you need that timing disconnect?
So if I should make this really clear and then Carol, you can if you want to add to this. We only have natural history data for serum. As you might expect, you have to do it requires anesthesia to take CSF. And in these observational studies, we are not taking CSF. So the data that you see is just in serum, pre and post and then just in CSL on treatment.
I think that answers that. So there's really not a disconnect. It's just you don't have the comparison.
Ryan, maybe I'll just add to that. They may have been referring to cross sectional data, which we do have cross sectional CSF in our data that we showed. But these are samples that were taken opportunistically before we enrolled our natural history study. And obviously, the limitations of cross sectional data is exactly why we started enrolling this natural history biomarkers study. And so this was really for us, it was a learning to see that in this longitudinal data, there was this market increase over time, which was not apparent that we would see that from cross sectional data.
Another question. Has there ever been data showing CSF neurofilament or other biomarkers in CSF with standard enzyme replacement therapy? How does DNLCreetin compare to those? I think the answer is no. There's no existing data that we're aware of besides the data that we've generated.
So obviously, the data we generated in our manuscript is on standard of care and the replacement therapy as well as stem cell therapy. So that's the data. It's cross sectional but not longitudinal. Okay. So, okay, another question here.
It seems like the plan for Cohort B may be changed a bit. It used to involve dose escalation versus 3 parts. Why the change?
Yes. So we were continuing to learn as we go along in this study and the changes in cohort B to better understand the difference between 3 mgs per kg, 7.5 mgs per kg. And as you can see, we're seeing clear activity at the lower sales level.
And that's the reason for the change is that because we have activated all 3 doses, we've decided to stay on dose longer, essentially stay on the lower doses. Related to lysosomal biomarkers, so GM3 data suggests lysosomal correction is incomplete. Do you believe that result might arise from the intermittent dosing? Will you explore other dose approaches with your improved enzyme? Explain Examples might include gene therapy or cell therapy.
So maybe I'll comment on this. I actually don't I mean, you can look at the data, it's either normalized or near normalized. So I guess I wouldn't interpret it as incomplete. And interestingly, even at the 3 mg per kg, we're seeing normalization in GM3. The reason that you may not see it completely all the time is, again, probably some variability in GM free, the way I'd interpret that.
I would agree with that interpretation. And note that I think where there may have been a question of incomplete, we're also looking at Cohort B data with time points as short as 7 weeks. We already know from our cohort A data that the effects on GM3 cannot follow the reduction in CSF GAGs, which happens much earlier, which would be logical that we would see the reduction first in the substrate and the improvement in lysosomal function.
Okay. So here's a question. Any comment time course for removal of standard of care peripheral treatment, mean, median and by dose. And maybe this just requires a little bit of clarification. So for DN L310, there's a switch from standard of care to DNL-three 10.
And so basically, they're no longer on standard of care. Basically, DNL-three 10 treats both peripheral and central. And I think it's an important point that we're seeing enhanced activity in peripheral biomarkers in addition to normalization in CSF, heparin sulfate and robust effects on lysosomal biomarkers. So the idea would be that DN-three 10, we're basically developing it to replace standard of care. Okay.
So again on Phase twothree plans in your fulfillment, how do you think about setting inclusion criteria with respect to baseline growth on the levels for the Phase twothree trial?
We would not use baseline growth on the levels for inclusion. I think there's really no data at this time that clearly demonstrates any sort of prognostic or predictive utility in neurofilters of treatment with mouse or prognostic biomarker.
Okay. So question here. Is it possible that for CSF neurofilament, there is a variable but dramatic higher progression and increase over time in the natural history for patients on hydrosulfase? If so, might the much more modest increase in CSF neurofilament and add serum seen on DN-three 10 represent improvement? And so I think as we commented that that could be 1 interpretation.
I think we don't have enough data to conclude that certainly. And then I think related to this, could we elaborate more on sort of our thoughts or our hypotheses on the neurofilament data? I don't know Carol if you want to summarize your thoughts or hypotheses on the data.
Yes. I think I've mentioned most of these points previously, but I think the variability that we see was surprising in the natural history data. And I think, again, just speaks to the importance of having longitudinal data, because these are pediatric patients again that are enrolled at different ages. And so baseline values are very different. We knew that actually already from cross sectional data, but you layer on the variability on top of that.
It's really, I think it becomes very challenging to make any sort of conclusions at this point. I think this is something that is going to take additional data and quite a bit more data, including natural history data, which can be very challenging to get. I think there are other programs that have samples that would be great to understand more about the neuro filament levels in well characterized data sets. But I think until that time, we really can't make any conclusions about the utility in mouse element.
So in the next 4 minutes, we're going to do some rapid fire Q and A here. So where do you think DN L310 could fit into the treatment paradigm for MPS 2 relative to a onetime gene therapy? Maybe I'll answer this and Carol, you can add to that. So I mean at this point what we're seeing with gene therapy is highly variable response when you look at for example heparan sulfate in the CNS And also gene therapy targeting the CNS is different than gene therapy targeting the periphery. So I mean, we view that there's certainly a major role for enzyme replacement therapy until you can have sort of absolute rescue.
Our goal is exactly that, to absolutely rescue both in the periphery and in the central nervous system.
Yes. I think I'll just add to that, that someday the vision would be for patients that there's a gene therapy that's a 1 time administration and it addresses both the central and peripheral manifestations of disease. At this point, I think until that happens, this really allows physicians if this continues to demonstrate the profile that we've seen to get weekly therapy that addresses both. So in certain gene therapy approaches, there may not be complete efficacy in the periphery. And therefore, patients may have to end up getting 2 therapies, 1 for the periphery and then the gene therapy, which would have addressed the central nervous system where this can address both.
Given the degree in variability in neurofilament you observed in cohort A patients, how are you thinking about the pooled cohort AB data? Do you still think there's a potential to observe meaningful reduction with additional time, longer numbers, larger numbers of patients?
Yes. So I can answer that. I think 6 months data, even with more patients based on what we've seen in the natural data variability and increase over time is not going to be informative. I think as we've seen other therapeutic areas, specifically, maybe I'll mention in lysosomal storage, for example, CLN2, it may take a long time before you can see changes in neuro filament. And I think based on our data and what we've characterized so far, again, very limited, I think our focus is going to be more on our lysosomal biomarkers, heparan sulfate reduction and clinical outcome measures.
I think I'll just add that the CLN2 data, the levels are actually substantially higher relative in terms of full difference than what we're seeing in MPS. This is related to that. So based on what we know about the pathophysiology of MPS II, do you think GAG levels are more important than neurofilament? Is there a significant neuronal loss in this disease that drives the pathology? So I think the last question, it's a great question.
We actually don't know if there's significant neuronal loss and that's obviously why we looked at tau. If there was significant neuronal loss, you would expect that tau would be elevated as it is in other diseases. And so it may be possible that what you're seeing in elevated neurofilament is some type of neuronal dysfunction or that it's within error in terms of variability. We most certainly think that gag levels are the most critical biomarker. It's what's correlated in the periphery with benefit.
It's what we believe will correlate in the central nervous system as well. And although sort of perplexing neurofilament data, the totality of the data very strongly supports that DN L310 is crossing the blood brain barrier, rescuing lysosomal function and is translating or should be able to translate into clinical medicine. And that's certainly the case. So to summarize, we're very enthusiastic about where we are at CNL-three 10. We're expanding the Phase III study, obviously, with Cohort C.
We're able to keep patients in the lower dose for longer because we have normalization even at lower doses, again sort of illustrating the robustness of the TB platform. And so we look forward to sharing more data as we go forward. So I think with that, we'll thank everyone and we look forward to connecting more on these data. Take care.
Okay. Thank you.