Greetings, and welcome to the Eledon Pharmaceuticals ALS phase IIa clinical trial update conference call. At this time, all participants are in listen-only mode. A question and answer session will follow the formal presentation. If anyone should require operator assistance, please press star zero on your telephone keypad. As a reminder, this conference is being recorded. It's now my pleasure to turn the call over to Paul Little, CFO. Please go ahead, sir.
Good morning, and thank you for joining Eledon's conference call. I'm joined on today's call by David-Alexandre Gros, Chief Executive Officer, Steve Perrin, President and Chief Scientific Officer, and Jeff Bornstein, Chief Medical Officer. Earlier this morning, Eledon issued a press release announcing top-line results from a phase IIa clinical trial of tegoprubart in ALS. You may access the release and download today's presentation under the investor tab on our company's website at eledon.com. I would like to remind everyone that statements made during this conference call relating to Eledon's expected future performance, future business prospects, or future events or plans may include forward-looking statements as defined under the Private Securities Litigation Reform Act of 1995. All such forward-looking statements are intended to be subject to the safe harbor protection provided by the Reform Act.
Actual outcomes and results could differ materially from these forecasts due to the impact of many factors beyond the control of Eledon. Eledon expressly disclaims any duty to provide updates to its forward-looking statements, whether as a result of new information, future events, or otherwise. Participants are directed to the risk factors set forth in Eledon's reports filed with the US Securities and Exchange Commission. Now, I would like to pass the call to Eledon's CEO, Dr. David-Alexandre Gros, DA.
Thank you, Paul, and thank you all for joining the call today. We are excited to discuss our phase IIa top-line results. At Eledon, we are building a company focused on patients for whom anti-CD40 ligand therapeutics may provide a potentially life-extending treatment option. In particular, as we can see on slide three, we are concentrating on three therapeutic areas. Transplantation, focusing on kidney and islet cell, autoimmunity, focusing on IgA nephropathy, and neurodegeneration, focusing on ALS. Today's update marks an important milestone for Eledon and for our ongoing clinical programs, since our ALS study helps elucidate the safety and tolerability of tegoprubart, provides insights into the role and potential impact of tegoprubart in ALS, and helps furnish some potential read-throughs to other indications through some overlapping biomarkers as well as safety. Moving on to slide four.
Our first indication, ALS, is a disease that affects approximately 30,000 people in the United States with about 5,000 new cases each year. It's characterized by gradual progressive muscle weakness, causing patients to lose the ability to ambulate, swallow, and breathe on their own. Although there are two approved treatments for ALS, morbidity and mortality remain high, with about half of ALS patients dying within only three years of diagnosis. I will now turn over the call to our president and CSO, Steve Perrin, to walk through the pathophysiology of ALS, explain the role we believe tegoprubart has in addressing that pathophysiology, and to review the just-announced top-line data. Steve?
Thank you, DA. Moving over to slide five, I'll give a brief overview of this schematic of the current understanding of the pathophysiology of ALS and the role that the immune system plays in that pathophysiology. We know from the genetics of the disease that ALS is a protein folding disorder. There's aberrant genetic mutations in RNA processing and quality control genes that ultimately leads to the accumulation of misfolded proteins that end up being toxic to motor neurons. There's clearly compensatory mechanisms that helps motor neurons deal with the buildup of misfolded proteins due to the fact that the disease typically starts later in life in the third or fourth decade.
Once these compensatory pathways stop functioning as we age, one of the first things that happens is that there is a decrease in the speed in which communication happens between the nucleus of the motor neuron and the spinal cord, and ultimately where the axon process innervates muscle fibers and the muscle groups. As that communication slows down, the neuromuscular junctions get weak, and the NMJ falls apart, and the motor neuron pulls back. The pulling back of the neuromuscular junction is initially recognized by the immune system, where macrophage and activated T cells infiltrate the muscle beds. They recognize these denervated nerves, and they actually start to phagocytose them. As that cascade of pro-inflammatory activation increases, activated pro-inflammatory macrophage and T cells cross the blood-brain barrier, and they activate the resident immune cells in the central nervous system called microglia and astrocytes.
The activation of those innate immune cells in the CNS ends up creating a toxic environment that's the further demise of the motor neuron. You get attack of the immune system on sick and dying nerves, not only in the periphery but also in the central nervous system. Moving over to slide six. One of the most potent ways that activates pro-inflammatory signaling is the activation of costimulatory receptors. CD40 ligand and CD40 are a critical pair of these receptors that were identified back in the 1980s, where initially they were identified on immune cells, where CD40 ligand is expressed on activated T cells. Whereas CD40 is expressed constitutively on cells of the monocyte lineage, including B cells, dendritic cells, NK cells, and other cells of the monocyte lineage.
When T cells are presented with antigen or foreign antigen via the MHC receptor to the T cell receptor, the activation of this second costimulatory pathway results in a pro-inflammatory cascade that results in clonal expansion of the T cell that's presented with the foreign antigen. Maturation of B cell populations then make high affinity antibodies to those antigens and clonal expansion of both of these populations, resulting in pro-inflammatory signaling and increases in pro-inflammatory molecules like TNF-α , IL-6, and others. Blocking this pathway has been shown to be very effective in slowing down and preventing disease progression in animal models of autoimmunity, including multiple sclerosis, psoriasis, rheumatoid arthritis, and others, as well as in the prevention of acute and long-term transplant rejection. Moving to slide seven.
The macrophage infiltration into the muscle groups that I described was first identified in rodent models of ALS, and interestingly, it appeared to be mediated by CD40 ligand signaling. There are rodent antibodies that block CD40 ligand signaling, and when scientists at the ALS Therapy Development Institute moved these blocking antibodies into rodent models of ALS, they saw very profound effects on ameliorating disease progression, which was shown on the graphs in these slides. Where I'll focus on panel B, which is a delay in body weight loss that's apparent due to muscle atrophy in these animals. When you block CD40 ligand signaling, you see a statistically significant improvement in body weight loss.
Similarly, down in panel C, if you block CD40 ligand signaling in these animal models, you see a slowing down of disease progression that ultimately leads to an improvement in survival, which is shown in panel D. Moving over to slide eight. The initial observation and identification of macrophage infiltration was again identified in these animal models of ALS. In these animal models, unbiased gene expression profiling and proteomics experiments showed on the left-hand graph that multiple different immune cell pathways were activated at the time of onset in the muscle beds of these animals around day 70, and that these pathways became highly activated very quickly thereafter. Initially, the hypothesis was that, inflammation occurs due to immune cells going into the atrophying muscle beds.
However, when we did immunohistochemistry on the muscle groups from these animals, much to our surprise, we showed that the macrophages were actually specifically accumulating on denervated nerves. In the immunohistochemistry in the right-hand panels, the nerve itself is being labeled with a marker that shows up in red, which is the myelin coating that coats the nerve. Infiltrating macrophages or CD68 + cells are labeled in green. You can see prior to symptom onset at day 30, you don't see immune cells accumulating into those peripheral muscle beds. By day 60, you start to see them starting to accumulate, and by day 100, the nerves are completely coated with macrophages that are phagocytosing those denervated nerves. Moving to slide nine.
As I mentioned, when you block CD40 ligand signaling in these animal models, you have profound effects on reducing pro-inflammatory amplification and the pro-inflammatory polarization of both T cells and macrophages. On the left-hand slide, what I'm showing here is immunohistochemistry, again, showing CD68 + macrophages labeled in green. When you treat these animals with a blocking antibody to CD40 ligand, you can see in the immunohistochemistry that you have a significant reduction in those macrophages accumulating in the peripheral nerves, and that data is quantitated in the box plots. On the far right-hand side is motor neuron counts in the spinal cord after treatment with the anti-CD40 ligand antibody.
Even though the antibody doesn't appreciably cross the blood-brain barrier 'cause it's a large molecule, you do see a nice translation into motor neuron survival, which accounts for the delayed disease progression and improved survival in these animals. Moving to slide 10. As I mentioned, one of the prominent features of disease onset in these animals is denervation or loss of neuromuscular junctions. Immunohistochemically, that's shown in that top left-hand graph, where you can see a neuromuscular junction should have a nice pretzel shape, if you will, where the green neuron that's coming into the myofiber will overlap with the postsynaptic side of the NMJ on the motor unit fiber.
If the immunohistochemistry for the postsynaptic side is in red, you see this nice yellow pretzel that means that the nerve is well attached to that myofiber, innervating it, and translating that electrochemical signal to cause muscle contraction. In ALS, those nerves get sick, and they die back, and you can see the green nerve is fragmented in that middle neuromuscular junction, and there's no overlap between that nerve and the postsynaptic, which is why the postsynaptic side is red and the motor neuron's dying back. The top neuromuscular junction, that motor neuron has completely died back. It's not even close to its neuromuscular junction. When you block the CD40 ligand, you have two profound effects. In the bottom left, you can see that you start to preserve those large caliber motor neurons.
They're surviving longer, they're well myelinated, and they have great structure. What that translates to is the far right-hand box plot. You can see, as I said, around day 70, there's a significant loss in neuromuscular junctions. When you treat these antibodies with a vehicle, you lose a significant amount of neuromuscular junctions between day 70 and 85, around the time of symptom onset. When you block with an anti-CD40 ligand antibody, you pretty much bring that neuromuscular junction occupancy back to normal. It's why you have better muscle function, it's why you slow down disease, and it's why you improve survival. These observations have also been translated into adult patients with ALS, and this table here, moving over to slide 11, shows that there's a long history of pro-inflammatory molecules that have been reported in adults with ALS.
In some of these studies, they were longitudinal in nature, showing that inflammatory markers like TNF-α and MCP-1 are associated with disease progression. In addition to that, CD40 ligand has been shown to be a prominent feature of ALS as well, showing that it's upregulated in about 56% of patients with ALS, and that soluble CD40 ligand levels actually correlate with disease progression as well. Moving to slide 12. This is a schematic of our ALS phase II study that we'll be presenting today. The study was a 12-week open label study with multiple ascending doses of tegoprubart.
There was four sequential dose escalations from 1 mg/kg to 2 mg/kg , up from in low doses, 1 mg/kg to 2 mg/kg and dose escalating in higher numbers up to 4 mg/kg and 8 mg/kg . In the lower two cohorts, we enrolled nine subjects per group as we were primarily interested in safety. As we dose escalated, we moved to 18 subjects per cohort. Tegoprubart was administered by IV infusion every 14 days, so each subject received six infusions. We collected bio samples at screening in addition just prior to first infusion for each subject so that each subject could serve as their own control in the study. The primary endpoint of the study was safety and tolerability, and we also wanted to further understand pharmacokinetic parameters as well as anti-drug antibody responses.
We did include secondary endpoints that were really critical to the mechanism of action of the drug, and these were biomarker studies. The first one being target engagement because of the fact that CD40 ligand is expressed on the cell surface of activated T cells, and because it communicates and induces the maturation of B cells, we wanted to look for target engagement in blood, and we could do that by looking at biomarkers of both T Cell and B Cell activation that we'll describe. The second biomarker endpoint that we're interested in looking at was the pro-inflammatory signatures of chemokines and cytokines that have been elevated in ALS that I just reviewed previously. Blocking CD40 ligand should have an effect in reduced pro-inflammatory chemokines and cytokines based on its mechanism of action.
We wanted to look at the impact on inflammation and circulation with exposure to tegoprubart. Then finally, we wanted to look and see if there was any association with target engagement in the induction of pro-inflammatory signatures with clinical outcomes such as ALSFRS. If you move over to the next slide 13, I'll overview the demographics of the study population. We enrolled 54 subjects into the study. As is typical for an ALS population, the majority of the subjects were male Caucasian. We did define enrollment criteria for subjects at time of enrollment to have an aggregated ALSFRS-R score of 35 or greater at screening and to have less than 24 months since diagnosis.
The ALSFRS is a functional rating questionnaire with 12 questions focused on motor skills, respiratory function, and bulbar function, with 4 points qualifying each question. Thus, a perfect score for the 12 questions is 48. The average ALSFRS at baseline in our study was 39.5. However, three subjects had an ALSFRS of less than 35 at time of first infusion, with two of those subjects decreasing by 4-6 points during the one to four w eeks between screening and their first infusion. Whereas an average person with ALS would typically only decrease 0.8-1 point per month. In addition, there were three questions focusing on bulbar function, measuring a patient's ability to speak, swallow, and salivate.
There were four additional subjects who at the time of first infusion had a score of four or less in the bulbar subdomain, suggesting a lack of ability to speak or swallow, and thus predicting a very fast progression rate for these subjects. Moving to slide 14, this is an overview of what we'll review in the data. We'll review the outcomes of safety and tolerability, pharmacokinetics and ADA responses, and as I mentioned, biomarkers of target engagement, changes in pro-inflammatory markers, and exploratory endpoints, including changes in disease progression as measured by ALSFRS and changes in neurofilament light chain, a protein that appears to be a prognostic biomarker of disease progression in ALS.
As we have stated since initiating this phase II study back in 2020, we consider these final endpoints as exploratory, since we expected the trial to be too short and lacking enough subjects to achieve them. As such, we considered any positive data related to the exploratory endpoints to be potential upside. We did also include a couple of key sub-analyses. We actually looked at and compared subjects who did not achieve target engagement as defined by changes in CXCL13. We then compared subjects who have target engagement but different in changes in pro-inflammatory markers. In other words, high versus low responders. Moving to slide 15, this is an overview of the safety and tolerability of the study.
An external data safety monitoring committee met to review the data prior to each dose escalation and after one-third of the subjects in the highest dose cohort had completed six infusions to ensure that the safety of the continuum of continuing that ongoing, last cohort. As you can see, 35% of the patients reported drug-related adverse events. However, there were no serious or severe adverse events related to study drug. The occurrence of adverse events were not dose-related, and the occurrence of treatment-related adverse events was balanced across the dose cohorts. Two subjects which withdrew from the study. One subject for worsening depression at the 1 mg/kg cohort, and one subject with faall-related injury in the 2 mg/kg cohort. Importantly, there were no signs of platelet activation or thrombosis in the participants.
The pharmacokinetic profile of tegoprubart continues to be as expected and predicted with nice dose-for-dose proportionality across the subjects. In addition to that, we only had nine of 215 samples that we collected had positive signals for anti-drug antibody responses, but these were very low. They were at the cut point of the assay with very low titers, and they did not impact the exposure levels of tegoprubart in the study population. Moving to slide 16. This is our first biomarker endpoints that I had described to you. As we discussed previously, it'd be really important to demonstrate reductions in CD40 ligand with exposure to tegoprubart. CD40 ligand is expressed on the cell surface of activated T cells, as I mentioned, and modulates their pro-inflammatory signaling.
As well, we wanted to look at reductions in CXCL13, which is a potent chemokine that's involved in B cell maturation and antigen presentation. As you can see on the table on the left, we showed there was a statistically significant reduction in both CD40 ligand and CXCL13 in a dose-dependent manner. In addition, we observed an increase in the percent of subjects who showed a reduced level of these biomarkers in a dose-dependent manner as well. As we previously discussed as well, we wanted to look at the downstream important outcomes downstream of target engagement, as this is important in the modulation of pro-inflammatory markers that are elevated in patients with ALS, and we wanted to look if tegoprubart would modulate these pro-inflammatory markers in a dose-dependent manner.
We identified six pro-inflammatory proteins from the literature that have been described to be elevated in people with ALS, including TNF-α, MCP-1, IL-6, IL-1β, RAGE, and C-reactive protein. As you can see in the right-hand table, we observed statistically significant reductions in four of the six of these pro-inflammatory markers, including TNF-α, MCP-1, RAGE, and CRP at the highest dose. IL-1β was not detected in our study population and was below the limit of detection in the assay. In addition to that, we looked at other pro-inflammatory proteins, given that we utilized a multiplex Luminex platform to look at protein levels in our study.
In total, we observed the reduction in 23 of 32 pro-inflammatory proteins that we measured in the study, including the myeloid markers CXCL9 and CXCL10, as well as complement C3 and the B Cell markers IgA, IgM, IgG, and others. This specific group of biomarkers is particularly important to our other disease indications such as our other disease programs such as IgA nephropathy, since reduction in IgA, IgG, C3, and CD40 ligand have been associated with disease progression and proteinuria in patients with IgA. While CXCL9, CXCL10, IgM, and C3 have been associated with kidney transplant rejection. Moving to slide 17. Finally, we looked to see if there were any changes in ALSFRS associated with exposure to tegoprubart in the study. We utilized data from the PRO-ACT database to serve as a historical placebo group.
The PRO-ACT database is a publicly available data collection from historical ALS clinical trials containing demographic data as well as clinical outcome measures, including ALSFRS. We built a cohort of ALS patients from the PRO-ACT database that were assigned to placebo groups in those studies and who had an ALSFRS of 35 or greater at time of enrollment. The database had approximately 1,500 patients fitting these criteria. As you can see, this cohort had a monthly decline of about 0.83%, which is representative monthly decline of ALSFRS in broader ALS populations. For our analysis, we combined the low and high dose cohorts to increase power and because these groups had similar changes in target engagement. The All group includes all 54 subjects who enrolled in the study.
The Low group consists of 18 subjects in the first two cohorts who received either 1 mg/kg or 2 mg/kg of study drug. The High group consists of 36 subjects in the 4 mg/kg and 8 mg/kg group. As you can see from the table, the Low dose cohort had a monthly decline very similar to the PRO-ACT database with a monthly decline of 0.89, which is about 7.2% higher than PRO-ACT. The High dose and the All group cohorts had a faster monthly decline than the PRO-ACT cohort, with monthly declines of -1.08 and -1.02, which is a 30% and 22% difference compared to PRO-ACT respectively.
This rapid decline was due to the inclusion of the subjects enrolled in the study who had ALSFRS that fell below 35 from the time of first infusion and who had scores of four or less at the time of enrollment in their bulbar subdomains. As you can see in this second column called Baseline criteria, if we remove these seven subjects that were present in the 4 mg/kg and 8 mg/kg cohorts, we see that our study population now looks much more similar to the PRO-ACT database and is probably more representative of a typical ALS population. In fact, as you can see in those cohorts, the actual slope is actually less than PRO-ACT, -0.66 in the high dose and 0.75 in the entire cohort, suggesting that the higher doses may actually be leading to therapeutic benefit.
If we now focus on target engagement, which is the third column over on the table, at 4 mg/kg and 8 mg/kg doses, there's 100% target engagement as measured by a reduction in CXCL13. Approximately 40% of subjects in the 1 mg/kg and 2 mg/kg cohorts did not show this target engagement. If we further exclude these subjects from the analysis, there's again an improvement in ALSFRS decline in the low dose group with a further reduction in decline from 0.89 to -0.68 points per month. Subjects who do not have target engagement also generally lacked pro-inflammatory changes seen in subjects with target engagement.
Of note, subjects in the low dose group who did not have target engagement progressed with a delta of negative 1.14 points per month, which is 70% more rapid in terms of ALSFRS than subjects who had target engagement. Finally, we looked at high dose response versus low dose responses as defined by the number of inflammatory markers that were decreased. High responders who saw a minimum of 10% reduction in 75% or more of inflammatory markers or a greater slowing of Δ-ALSFRS slope in both the high dose as well as the overall population. These data taken together suggest the inhibition of CD40 ligand signaling by tegoprubart results in a decrease in pro-inflammatory biomarkers that may result in a slowing of disease progression.
In summary, on slide 18, we continue to show a very favorable safety and tolerability profile for tegoprubart with 35% of patients having one or more drug-related adverse events. There was no serious or severe adverse events in the study, and the occurrence of adverse events was balanced across the dose cohorts. In addition, the pharmacokinetic profile and very low ADAs that we're observing with exposure to Tegoprubart was also very encouraging in the study. With biomarkers of target engagement, we showed a statistically significant reduction at the high doses at 4 mg/kg and 8 mg/kg with target engagement on both T Cells showing reduction in CD40 ligand as well as on B Cells with the chemokine CXCL13 respectively.
In addition to that, we showed that there was a reduction in modulation of pro-inflammatory markers in a dose-dependent way, with two dimensionality to that reduction. As one dose escalates, you see a larger increase in reduction of pro-inflammatory proteins in subjects with ALS, but you also, as you dose escalate, see a higher percentage of patients in each cohort showing those types of reductions. We observed these types of behaviors in 23 of 32 biomarkers, including the ones that we had been talking about, since 2020, where we would have liked to see a reduction, including TNF-α, MCP-1, and RAGE and C-reactive protein.
For the exploratory endpoints, it appears that target engagement and level of reduction in pro-inflammatory biomarkers is associated with a trend in slowing down of disease progression as measured by ALSFRS slope when compared to a cohort from the ALS PRO-ACT database. Thank you for your time, and I'd like now to pass it back to DA.
Thanks, Steve. Today's results give us conviction that tegoprubart has the potential to treat ALS as well as a broader range of inflammation-related indications by targeting the CD40 ligand pathway. We remain focused on executing our ongoing trials and look forward to sharing an initial view of the collected data on each of our other three programs towards year-end. 2022 continues to be an exciting period for Eledon, marked by multiple value-creating opportunities and the emergence of potentially transformative treatment options for persons living with ALS, IgAN, or undergoing kidney or islet cell transplantation. I'd like to conclude with how pleased I am with encouraging results we have just shared with you, as well as with the entire Eledon team that has worked so hard in furthering our mission to help patients with ALS and other unmet medical conditions.
I would also like to thank our investigators and most importantly, the patients and families who participated in this trial for their commitment to finding a novel therapeutic option for ALS. Finally, I would like to thank all of the patients and families who supported tegoprubart's early development, as well as ALS TDI, Augie's Quest, the Muscular Dystrophy Association, the ALS Association, and ALS One. With that, I will now ask the operator to please begin our Q&A session. Operator?
Thank you. We'll now be conducting a question and answer session. If you'd like to be placed into question queue, please press star one on your telephone keypad. You may press star two if you'd like to remove your question from the queue. For participants using speaker equipment, it may be necessary to pick up your handset before pressing star one. One moment please before we poll for questions. Our first question today is coming from Pete Stavropoulos from Cantor Fitzgerald. Your line is now live.
Good morning, DA and team. Nice to start the week off with some positive data. You know, congratulations. First question I have, I know this is early data, but like, you know, when you look at the patients that are slowing in disease progression, you know, as measured by ALSFRS, you know, were there any characteristics that could help inform a future study? You know, you touched on earlier stage versus later stage patients, but known rapid progressors by genotype or patients with a higher pro-inflammatory signature or higher soluble CD40 ligand. Specifically on slide 17, there were high responders that you highlighted. You know, was there anything about their baseline characteristics that could help enrich this patient population in a later stage study?
Great. Thank you for the question, Pete. I appreciate it. Let me turn that over to Steve.
Yeah. Obviously, it's a great question. We're obviously in the early days of thinking about how we can leverage this data for next study designs. Clearly what the study showed is that if you demonstrated clear target engagement, that appeared to correlate to a decrease in pro-inflammatory signaling in a very large group of proteins that are associated with inflammation, and ultimately, that looks like it has a trend towards slowing down disease progression. I think the question that you have as far as genetics, demographics, or other things, I mean, clearly we know that some forms of the genetic forms of the disease are faster progressors than the sporadic population as a whole. In addition to that, neurofilament light chain is a biomarker, a prognostic marker of fast progression.
We did see that in our study. We also saw that folks with bulbar onset at time of enrollment were also faster progressors, which is well described across ALS cohorts. I think the question that we need to understand as we think about our next study design is how we might wanna leverage, for example, target engagement into that study design.
Okay. In terms of target engagement, you know, you had 4 mg and 8 mg doses. Do you see the potential of actually, you know, expanding the window of dosing in the next study?
Steve?
Like I said, it's a great question. It's still kind of early days on how we might select a dose based on this data. We did show target engagement and knockdown of CD40 ligand at multiple doses as well as CXCL13. Those, as we said, as we dose increase from 1 mg to 2 mg/kg to 4 mg/kg to 8 mg/kg , the percent knockdown in those proteins got higher. They got statistically significant for CD40 ligand at 2 mg/kg and were more significant at 4 mg/kg and 8 mg/kg. For CXCL13, we saw statistical significance at 4 mg/kg and 8 mg/kg. The question is, do you actually go to higher doses or do you select a dose from the study?
Then again, I think we're still looking into the data and understanding the best way that we might leverage this data for the next study.
Okay. Thanks. Also, you know, for ALSFRS, you know, it measures the patient's degree of functional impairment, you know, by assessing speech, swallowing and other measures. You know, were there any key drivers in the reduction of the ALSFRS slope or, you know, was the trend, you know, basically evenly distributed across the scale?
The biggest thing that seems to impact ALSFRS progression based on the ALSFRS scale is definitely bulbar onset. Patients that have bulbar onset tend to be faster progressors than people with peripheral, limb onset, if you will. That's been true for quite some time across broad ALS populations, and we certainly saw that in our study as well. About 30% of people with ALS typically present with bulbar presentation rather than limb onset.
Thanks. One last question. There was a reduction of IgA, you know, observed in the study. You know, can you speculate if, you know, these changes would result in clinically relevant, you know, reductions in IgA nephropathy patients? You know, will it translate to clinical benefit? Okay. That's it.
No, it's a good question. Obviously, we weren't studying an IgA nephropathy population here, and one couldn't compare two different diseases across the populations. We did note that we saw a reduction in certain biomarkers, including IgA, IgE and complement, and that those same biomarkers have been implicated in disease progression in IgA nephropathy. It also just reinforces the mechanism of action of tegoprubart, and the fact that at least in this patient population, we saw biomarker movements that we would have expected based on the biology.
All right. Thank you very much for taking our questions.
Thank you.
Thank you. Next question today is coming from Thomas Smith from SVB Securities. Your line is now live.
Hey, guys. Good morning. Thanks for taking our questions and congrats on the data. Just a couple. On the biomarker data, I just wanted to clarify, were the reductions in the pro-inflammatory biomarkers dose-dependent between the high doses 4 mg/kg and 8 mg/kg ? And then separately, did you see any trends on changes in neurofilament light chain?
Thanks, Thomas. Appreciate the question. Steve, let me turn that over to you.
The first question about reduction in pro-inflammatory biomarkers, there was a consistent pattern of decrease in pro-inflammatory markers as one dose escalated from 1 mg/kg to 2 mg/kg to 4 mg/kg to 8 mg/kg . They typically became statistically significant for the 23 markers at 4 mg/kg doses. There were a few that we saw at lower doses as well. In addition to the greater decreases in protein expression as one dose escalates, there's that other two-dimensionality perspective that you have to keep in mind that we also saw an increase in the percentage of patients in the cohort that showed statistically significant reductions as we dose escalated. We kind of got both of those, a reduction in the proteins themselves, as well as an increase in the number of subjects that appeared to be responding.
For your second question, we did look at neurofilament light chains. As I described, it's a pretty well-validated prognostic biomarker that predicts disease progression at time of diagnosis. We didn't see changes in neurofilament light chain in the study. Much like many other companies have struggled to correlate a therapeutic change in NfL with a clinical outcome, we didn't see changes either. It was only a 12-week study. It's quite possible that we just are not looking long enough to show that a therapeutic will modulate NfL levels. Some other studies that I'm describing have gone out 6 months and have also not seen these types of correlations. It could be that we just have to go out longer than even 6 months to see a correlation between NfL and clinical outcomes.
It's still kind of young days to understand if NfL is going to be more than just a prognostic marker and actually be a marker of therapeutic efficacy.
Okay. Understood. Great. One on safety and tolerability profile looks pretty clean, you know, consistent with the phase I experience. Just on the Anti-Drug Antibodies. I know it's a pretty small percentage, and you said it, you know, kind of up against the limit of quantification within the assay, Steve, but were any of the ADAs neutralizing?
They were not. They didn't affect exposure levels of tegoprubart. No, they were not.
Okay. Maybe just lastly, just help us think through kind of the next steps here in ALS and maybe some of the timelines for laying out those next steps?
Sure. I'll take that question. Tom, we're obviously very excited by the data that we presented today. In terms of next steps for ALS, we plan to present, publish the data. We plan to work with KOLs, patient community, and regulators on what the next trial could look like. As we recently reiterated in our quarterly earnings release, we currently have sufficient cash into 2024 based on our ongoing transplant and IgA clinical studies. We also plan to explore a range of potential sources of financing before we would advance into another ALS trial.
Okay. Makes sense. Great. Thanks, guys. Appreciate you taking the questions, and congrats again.
Thank you.
Thank you.
Thank you. Next question is coming from Matt Kaplan from Ladenburg Thalmann. Your line is now live.
Hi. Thanks for taking the questions and, congrats on the results. Can you give us a little bit more color in terms of the magnitude of change in the inflammatory biomarkers and also in terms of CXCL13 and CD40 ligand engagement that you saw?
Sure.
Yeah. Do you want me to take that, DA?
Sure.
I mean, they were highly variable, as you can imagine. The percentage reductions decreased as we dose escalated, but even within a cohort, there was variability, but we saw reductions in target engagement markers, you know, 60%, 70% or more in 100% of responders in the higher dose cohorts for target engagement. A very potent reduction in target engagement markers.
Okay. Thanks.
In others, we considered response to be a change of a minimum of 10%. That, for us, a minimum change would have been -10% to be considered a successful reduction.
Okay. Can you talk a little bit about the durability of the reductions that you saw between doses from a PK point of view?
I didn't hear the last half of that, sorry.
Oh, just from a pharmacokinetic point of view or pharmacodynamic point of view, can you talk about the reduction that you saw and the durability of it between doses?
As I mentioned, the dose proportionality was really very consistent on what we had reported and published for the phase I study with really nice dose proportionality. The exposure levels within a cohort were actually very tight. It appears to be that tegoprubart's a very well-behaved IgG1 monoclonal antibody based on the data that we're seeing. The exposure levels from subject to subject were actually pretty close. We haven't completed all of the relationships between exposure levels and biomarkers stuff. That stuff is still going on.
Okay. Thanks for taking the questions.
Thank you. Next question is coming from Rami Katkhuda from LifeSci Capital. Your line is now live.
Good morning, guys. Congrats on the data, and thanks for taking my questions. As you mentioned, it's early days, but how does the change in ALSFRS Slope with tegoprubart compare to therapies like riluzole or edaravone?
I mean, I guess I could take a first pass at that if you want, DA.
Please. I mean.
I mean.
Obviously, it's hard to compare across trials and across drugs. Steve?
Yeah, Jeff, feel free to chime in as well. I mean, riluzole and edaravone are very different. I mean, riluzole obviously is a drug that was approved 30 years ago. It had mixed results in the large phase III trials that were conducted, of which I believe there was three of them. Two of them showed a positive decrease in ALSFRS slope. One of them did not. It's obviously been in the general population for a very long time. I think that the data for riluzole would suggest that it does impact disease progression, but it's in a very small percentage of people with the disease. As long as you're tolerating exposure to riluzole, people say to take it, but the percent changes were very, very small for riluzole.
Edaravone, if you remember from the published data from Japan, because clinical trials were not conducted in the US, it was approved based on data from Japan. The larger phase IIb study that was highly powered did not show a statistically significant difference between the edaravone and placebo group. However, a retrospective analysis identified a fast-progressing group of folks that looked like that they were seeing benefit. When they ran their smaller phase III study, they showed a statistically significant change in ALSFRS in that population. In the general population, since edaravone was approved back in 2017, there's been multiple publications globally that edaravone doesn't seem to have a very large impact, if any, on disease progression rates. For our study, as DA was alluding to, this is a pretty short study. It's only 12 weeks.
We did see a significant or a trend towards slowing of disease progression associated with tegoprubart exposure levels. I think we need to get to a larger study to really understand how to qualify that and quantitate it.
Got it. Just out of curiosity, were you surprised that IL-1β was not significantly detected in this study patient population?
Again, I didn't totally hear the question. DA, if you wanted to grab it, I'm sorry.
Oh, the question was whether we were surprised that we did not detect IL-1. It was something that we had expected to see based on the historical literature. We did not see it using our assays. You know, it's tough to know whether it was tied to the assay that we used or to the underlying patient population. Steve?
Yeah. No, I totally agree. I mean, IL-1β was just not detected in the Luminex-based platform that we utilized. It has specific sensitivity thresholds, and at least in our population, samples were not coming above the noise in that particular assay format.
Got it. Thank you, guys.
As we mentioned, we detected a wide range of inflammatory biomarkers.
Thank you. Next question is coming from Vernon Bernardino from H.C. Wainwright. Your line is now live.
Hi, thanks for taking my question, and congrats on the results. A couple of questions. In the phase IIa study, you did have multiple collections of samples, you know, through the study, the 12-week study. Could you at least characterize or do you have plans to perhaps show the progression of those biomarkers at those various time points? And as a follow-up to that, just wondering also about the progression and measurements of ALSFRS at any time during those time points.
Sure. Hey, Vernon, thank you for the questions. In terms of your question regarding from a time perspective, the progression of biomarkers, what we saw was that tegoprubart had quick onset of action and that we began to approach maximal reductions in about four weeks. With regards to ALSFRS and the delta, Steve, let me turn that over to you.
As you saw from, I think it was slide 17, across the entire cohort, we didn't see a big delta in ALSFRS, and it was probably due to the seven subjects that had significant disease progression in that two to four week period between screening and time of first infusion. You know, once you take those subjects out, including the ones that had the four points or less in the Bulbar domain, the study population became closer to what you might describe as a more representative ALS population. Albeit when you look at the high dose cohort in particular, you start to get some hints that high level exposures might actually be slowing down disease even when you just remove those seven subjects from the 4 mg/kg and 8 mg/kg cohorts.
Furthermore, as we started to investigate, you know, target engagement and not seeing full target engagement in the low dose cohorts, if you start to remove people where you didn't see obvious target engagement, again, you start to show this flattening of the ALSFRS curve, suggesting again, if you see good target engagement, that appears to trend towards an improvement in disease progression. Then finally, obviously, if you're hitting target, one would predict that you should be knocking down pro-inflammatory markers. As we described, we hit like 23 of 32 markers that sit downstream of CD40 ligand signaling are associated with pro-inflammatory signaling, both in T cells as well as cells of myeloid lineage. Of course, if you correlate target engagement to a reduction in pro-inflammatory markers, again, you see this flattening of the curve.
There's a trend towards it that appears to be slowing down disease progression, albeit that this is a 12-week study.
Yeah, it's exactly that last part where I wanted to go next. Slowing down disease progression, it's only a 12-week study, so ALS patients obviously want to see slowing down disease progression and the potential of your tegoprubart to perhaps even improve the condition of these patients. Do you think that perhaps a follow-up to this study would require a higher dose for evaluation?
I mean, Vernon, I think to our point so far, we're kind of still in the early days of thinking about the next trial design. Obviously, if Jeff wants to jump in, he's been thinking a lot about, you know, compared to other, what is the clinical development path, what's the regulatory path for approval to ALS, and how do we leverage this data to get there? Jeff, I don't know if you want to add any color to that.
No, I think it's DA. I think it's early days. We just got the data. We need to finish interpreting the data, have discussions with regulators, with our KOLs, and after that, we'll be able to come back with a more definite plan in terms of what the next steps from a development perspective could look like.
No, it's great results and very exciting, 'cause obviously the rapid response and the potential to not only slow but perhaps improve disease in these patients would make us even more excited if there is potential for greater effect at a higher dose. Thanks for taking my question, and congrats again on the results.
Thank you.
Thank you. We've reached the end of our question and answer session. I'd like to turn the floor back over to DA for any further closing comments.
Thank you very much, and thank you all for joining today's call.
Thank you. That does conclude today's teleconference. You may disconnect your line at this time, and have a wonderful day. We thank you for your participation today.