Xenon Pharmaceuticals - Q2 2024
August 8, 2024
Transcript
Operator (participant)
Thank you for standing by. My name is Meg, and I will be your conference operator today. At this time, I would like to welcome everyone to the Q2 2024 Xenon Pharmaceuticals Inc. earnings conference call. All lines have been placed on mute to prevent any background noise. After the speaker's remarks, there will be a question-and-answer session. If you would like to ask a question during this time, simply press star followed by the number one on your telephone keypad. If you would like to withdraw your question, press star one again. Thank you. I would now like to turn the conference over to Mr. Chad Fugere, VP IR for Xenon. Please go ahead.
Chad Fugere (VP of Investor Relations)
Good afternoon. Thank you for joining us on our call and webcast to discuss Xenon's second quarter 2024 financial and operating results. Joining me today are Ian Mortimer, Xenon's President and Chief Executive Officer, Dr. Chris Kenney, Xenon's Chief Medical Officer, and Sherry Aulin, Xenon's Chief Financial Officer, along with Dr. Chris von Seggern, Xenon's Chief Commercial Officer, who will be available during the Q&A period. Ian will begin with a summary of our recent progress across our business, including a summary of our expanding preclinical pipeline programs. Chris Kenney will provide an overview of our ongoing clinical stage programs, including our plans in major depressive disorder, or MDD. Sherry will close with a summary of our financial results and anticipated milestones. We will then open the call up for your questions.
Please be advised that during this call, we will make a number of statements that are forward-looking, including statements regarding the timing of and potential results from clinical trials, the potential efficacy, safety profile, future development plans, and current and anticipated indications, addressable market, regulatory success and commercial potential of our and our partners' product candidates, the efficacy of our clinical trial design, our ability to successfully develop and achieve milestones in our clinical development programs, the timing and results of our interactions with regulators, our ability to successfully develop and obtain regulatory approvals, anticipated timing of the top-line data readout for our clinical trials of azetukalner, and our expectation that we will have sufficient cash to fund operations into 2027.
Today's press release summarizing Xenon's second quarter 2024 financial results and the accompanying quarterly report on Form 10-Q will be made available under the Investors section of our website at xenon-pharma.com and filed with the SEC and on SEDAR+. Now, I would like to turn the call over to Ian.
Ian Mortimer (President and CEO)
Thank you, Chad, and good afternoon, everyone, and thank you for joining us on our call today. This is an exciting time for Xenon as we expand our pipeline and further progress towards becoming a fully integrated biopharmaceutical company. We remain sharply focused on three key, key areas across the business, where we have continued to make significant advancements this past quarter. Number one, the continued execution across our phase III azetukalner epilepsy studies. Number two, preparation for our azetukalner MDD program, with a focus on finalizing our phase III protocol and study initiation later this year. And number three, the advancement of our portfolio of next-generation ion channel modulators. Over the last decade, epilepsy research has been a primary focus at Xenon, driven by a continued and significant unmet medical need, with many patients still struggling to control focal-onset seizures and primary generalized tonic-clonic seizures despite available medications.
For that reason, the continued progress of azetukalner in our broad phase III epilepsy program remains core to our business. As a reminder, azetukalner is the only Kv7 potassium channel opener in development phase II-B efficacy and long-term safety data in epilepsy patients. No other Kv7 molecules in development have efficacy and safety data in epilepsy or depression patients, and we have set an incredibly high bar for other Kv7 drugs in development to achieve the impressive attributes of azetukalner. Data from phase II-B X-TOLE epilepsy trial demonstrated the best placebo-adjusted clinical efficacy in the most refractory patient population ever trialed, as well as a favorable tolerability profile in adult patients with focal-onset seizures.
Furthermore, long-term efficacy data generated through our X-TOLE open label extension support increased seizure reduction, with patients out to 30 months on azetukalner showing a greater than 90% reduction in median monthly seizure frequency, while approximately one in four patients on azetukalner for at least 2 years have been seizure-free for a full year or longer. In addition, we now have over 600 patient years of exposure, as well as patients on azetukalner for more than 4 years in the OLE, giving us and the epilepsy community tremendous confidence around the future potential of azetukalner to address the need for new anti-seizure medication. With that in mind, we continue to progress patient enrollment across our ongoing phase III epilepsy studies, with top-line results from X-TOLE2 in focal-onset seizures anticipated in the second half of 2025.
Positive results would enable the submission of our NDA, with the goal of advancing azetukalner towards commercialization. Overall, we are very pleased with the progress in our phase III program, and it's exciting to be in a position to develop what we believe will be the next important medicine to treat patients with focal epilepsy. Focusing now on our azetukalner MDD program, we recently presented the phase II X-NOVA trial results at the American Society of Clinical Psychopharmacology, or ASCP, the annual meeting held in Miami in May. This medical meeting was a great opportunity for us to continue to raise awareness of data supporting azetukalner's potential differentiated profile versus standard of care agents in MDD, including a rapid onset of effect, tolerable safety profile, and a potential benefit on anhedonia, a common comorbidity with a significant unmet need.
These data form the basis of our decision to advance azetukalner into a phase III program in MDD, which we expect to initiate in the second half of this year. We are also continuing to evaluate additional clinical development opportunities for azetukalner, focusing specifically on other neuropsychiatric indications where a scientific rationale exists, as well as a commercial fit with epilepsy and MDD. Beyond azetukalner, we continue to expand Xenon's leadership in the small molecule ion channel space. Based on our extensive work in channelopathies over the past two decades, as we built out a world-class discovery team, we have recently expanded our pipeline by nominating multiple development track candidates or DTCs, targeting potassium and sodium channels.
Achieving DTC status is a critical milestone for our program, as it reflects a molecule that has met our rigorous criteria to be advanced into GLP toxicology studies, and if successful, will form the basis of an IND or IND equivalent submission. One of our key areas of focus are potassium channels, as we believe Kv7 offers potential Pipeline-in-a-Mechanism opportunities. The breadth and depth of potential therapeutic indications for the mechanism provides a compelling strategic rationale for the development of additional Kv7 product candidates that are chemically diverse from azetukalner and can provide additional development opportunities across a broad range of therapeutic indications, including seizure disorders, pain, and neuropsychiatric conditions. For that reason, we continue to advance multiple Kv7 molecules so that we can potentially extend the reach of this promising and differentiated mechanism to more patients in need.
Building on our extensive experience against the Kv7 target, developed over many years, we have made significant progress across several promising novel chemical series, and this past quarter, we nominated multiple Kv7 development track candidates, with a lead candidate now in IND-enabling studies to support our goal of filing an IND or IND equivalent in 2025. We believe these advancements in our Kv7 preclinical program, combined with the promising and robust clinical data we have generated to date with azetukalner in epilepsy and MDD, set Xenon at the forefront of both drug discovery and development for this important mechanism. Turning now to our sodium channel work. As an early pioneer in the space, Xenon scientists focus on identifying genetic targets associated with rare phenotypes.
Through this early work, it was uncovered that individuals with complete loss-of-function mutations in the gene encoding for NaV1.7 have an inability to perceive pain, while those individuals with gain-of-function mutations have non-precipitated, spontaneous, severe pain, leading to the identification of NaV1.7 as an important pain-related target, offering the possibility of a new class of pain medicines without the limitations of opioids. While other sodium channels involved in the transmission of pain signals, such as NaV1.8, have recently been clinically validated, we believe NaV1.7 has by far the strongest genetic validation. To date, efforts to develop NaV1.7 inhibitors have faced a number of different challenges, and we have learned a tremendous amount from these previous molecules. We are now advancing novel NaV1.7 inhibitors, which we believe will have the appropriate properties to evaluate the clinical potential of a selective NaV1.7 inhibitor.
In this past quarter, we nominated a lead NaV1.7 candidate, which is expected to enter IND enabling studies in the near term, with the goal of filing an IND or IND equivalent in 2025. If successful, this program has the opportunity to generate important and early de-risking human proof of concept data. We are also advancing potentiators of the sodium channel NaV1.1, which is based on a scientific rationale that a precision medicine therapy for Dravet syndrome should aim to restore NaV1.1 activity, specifically without impacting other neuronal targets. We are pursuing brain-penetrant small molecule potentiators of NaV1.1 in an oral dosing formulation, as we believe this approach could directly address the underlying etiology of Dravet syndrome and provide a potential disease-modifying therapy.
To round out our extensive CNS discovery work, we continue to make progress as part of our ongoing collaboration with Neurocrine Biosciences to develop treatments for epilepsy. In addition to the ongoing phase II study evaluating NBI-921352 in an orphan pediatric epilepsy, the next lead candidate, a NaV1.2/1.6 inhibitor, is now in IND-enabling studies with the intent to progress into human clinical trials in 2025 as a potential treatment for epilepsy. So overall, I'm extremely proud of the continued progress across the organization and our pipeline, including both clinical and preclinical efforts, and this positions Xenon with one of the most exciting CNS portfolios that exists today.
I'll now turn the call over to Chris Kenney, and Chris will provide more detail on the progress on our azetukalner clinical programs, as well as some near-term conferences where Xenon will have a presence. Chris, over to you.
Chris Kenney (Chief Medical Officer)
Thanks a lot, Ian. I'll start by echoing that this is indeed an exciting time at Xenon as we continue to receive enthusiastic feedback from opinion leaders and site investigators about the emerging clinical profile for azetukalner.... Beginning with our phase III epilepsy program, which includes X-TOLE2 and X-TOLE3 in focal-onset seizures, and X-ACKT in primary generalized tonic-clonic seizures, our phase III FOS studies continue to advance, with the first top-line data readout from X-TOLE2 anticipated in the second half of 2025. Our plan remains to submit results from X-TOLE2, along with the existing data package from phase II-B X-TOLE clinical trial and additional safety data from other clinical trials, with the goal to meet regulatory requirements in the U.S. for approval. We also continue to highlight the robust scientific evidence generated through the X-TOLE open label extension study with the medical community.
As Ian referred to, healthcare providers observe a high burden of illness within the epilepsy community despite current medications, so it's been important to share the long-term X-TOLE OLE data with the objective of gaining further insights on the potential benefits of azetukalner. We will have additional opportunities to engage with the treatment community at the upcoming European Epilepsy Congress, taking place in Rome, Italy, from September seventh to September eleventh, where we're presenting two posters on our ongoing X-TOLE OLE study, as well as participating in a scientific exhibit where we plan to showcase survey results related to quality of life measures from focal-onset seizure patients. In addition to seizure burden, patients reported other symptoms that illustrate the broad burden of epilepsy and its negative impact on quality of life, such as fatigue, lack of energy, or other comorbidities, including anxiety and depression.
Shifting to progress we're making toward our phase III MDD studies, we have now finalized and filed our protocol with FDA, and clinical site planning is well underway. Our phase III MDD program will include three phase III trials and approximately 450 subjects each, with moderate to severe MDD, assessing the efficacy and safety of 20 mg of azetukalner versus placebo. The primary endpoint will be the change from baseline in HAMD-17 total score at week six. Key secondary endpoints will include SHAPS total score and CGI severity at week six and HAMD-17 at week 1. We expect the first MDD study initiation to occur in the second half of the year, with study sites exclusively in the U.S.
As Ian noted, in addition to this extensive internal planning work, our clinical and medical teams highlighted our phase II proof of concept X-NOVA trial in patients with MDD at the ASCP meeting in May. This was the first time presenting these data at a major medical meeting, which demonstrated that treatment with azetukalner led to a clinically meaningful reduction in MADRS, a statistically significant reduction in HAMD-17, a rapid onset of effect, a statistically significant reduction in anhedonia, and a potentially differentiated safety profile compared to standard of care agents. Feedback on the data was received with great interest by the experts in the field.
There was recognition of the potential of azetukalner to be a meaningful treatment option for patients with MDD, with particular interest in the novel mechanism of action and potential benefit on anhedonia and a favorable tolerability profile, with no notable adverse effect on sexual dysfunction or weight gain. We're also looking forward to presenting encore X-NOVA data at the upcoming Psych Congress, taking place in Boston from October 29th to November 2nd. These opportunities to educate healthcare professionals on our MDD data are incredibly important, and we value the insights gained as we further our azetukalner clinical programs. Now, rounding out my comments on MDD, we also continue to support the investigator-led MDD study conducted by Dr. James Murrough of Mount Sinai and Dr. Sanjay Mathew at the Baylor College of Medicine.
This 60-patient, placebo-controlled phase II trial has a functional primary endpoint with the objective of evaluating the effect of azetukalner on brain measures of reward, as measured by the change in activation within the bilateral ventral striatum from baseline to end of treatment at week eight, as assessed by functional MRI. The study is also evaluating secondary clinical endpoints, including the MADRS and SHAPS. It is anticipated that patient enrollment will be completed this quarter, and we look forward to providing further updates in the coming months. To summarize, our team is driven to continue advancing our azetukalner late-stage clinical development programs in both epilepsy and depression, and we continue to be highly encouraged by the positive response to azetukalner from physicians and key opinion leaders. I look forward to updating you on our progress.
I'll now turn the call over to Sherry, who will provide an overview of our second quarter financial results and upcoming milestones. Sherry?
Sherry Aulin (CFO)
Great. Thank you, Chris. Beginning briefly with our financial results, we're well positioned with a strong balance sheet to support our plans for azetukalner in both epilepsy and MDD, and other earlier stage programs in our pipeline. As of June 30th, 2024, we had cash and cash equivalents and marketable securities of $850.6 million, compared to $930.9 million as of December 31st, 2023. Based on our current operating plans, including the completion of the azetukalner phase III epilepsy studies and fully supporting late stage clinical development of azetukalner and MDD, we anticipate having sufficient cash to fund operations into 2027.
I would refer you to our news release and 10-Q report for further details around our financial results. In summary, as you heard from the team today, we remain focused on our goal to improve outcomes for patients in areas of high unmet medical need. We believe azetukalner has the potential to be a paradigm-shifting, best-in-class medicine. The strong belief in azetukalner's compelling profile is centered around its unique mechanism of action and supported by the significant body of clinical data generated to date. Looking ahead, we anticipate a number of important milestone events and goals. We will continue to advance our azetukalner phase III epilepsy program, with X-TOLE2 topline data expected in the second half of 2025.
We expect to initiate the first of three phase III clinical trials in MDD in the second half of this year, and we will continue to explore other development opportunities for azetukalner. Lastly, we'll continue to advance our early-stage preclinical pipeline with the goal of filing multiple INDs or equivalent in 2025. Thank you all today for your attention, and we look forward to sharing more in the coming months. I'll now ask the operator to open the line for any questions.
Operator (participant)
Thank you. The floor is now open for questions. If you have dialed in and would like to ask a question, please press star one on your telephone keypad to raise your hand and join the queue. If you would like to withdraw your question, simply press star one again. If you are called upon to ask your question and are listening via loudspeaker on your device, please pick up your handset and ensure that your phone is not on mute when asking your question. Your first question comes from the line of Paul Matteis with Stifel. Please go ahead.
Paul Matteis (Managing Director and Head of Therapeutics Research)
Hey there. Good afternoon. Congrats on all the progress. As it relates to X-TOLE2, I was wondering if by now you have a good sense of how the patient demographics as it relates to baseline seizure frequency, refractoriness, et cetera, are comparing to X-TOLE. And then just as it relates to your updated timing guidance for top line, thanks for that. Is the expectation still that you'll complete enrollment around the end of this year, early next year? Thanks so much.
Ian Mortimer (President and CEO)
Thanks, Paul. I'll take the second one and maybe make a quick comment on the first one, then Chris Kenney, if you wanna add any of your perspective as well. So on the first question, just on demographics. So obviously, we track that. We see it on a blinded basis, and all the things that you'd expect us to track, we're looking at on a blinded basis. You know, we haven't historically given any information publicly on what we're seeing, just because as the study's ongoing, those demographic data are changing all the time. So but we are, we're definitely tracking it. So as we get to the end of patient screening and randomization, we can, we'd be in a position to give some of that information publicly, but Chris can add in a minute there also.
Yeah, and then in terms of guidance, I think you've kind of nailed it. We've moved to top-line data guidance now. So just to reiterate, I know we said it a few times, but X-TOLE2 top-line guidance, second half of next year. You know, just to take a step back, I think we've said it before, it's about six to eight months from last patient screened to top-line data, and that's because these patients go through a screening period. And then there's a two-month baseline period where they have to count seizures in an electronic diary. That's. We can come up with a monthly seizure burden. Then the randomization visit happens, then there's three months of the double-blind period, and then there is safety follow-up.
That safety follow-up, the timing depends a little bit on whether those last patients go into open label extension or not. So, you know, just to kind of back all that out, you know, where exactly screening will complete, you know, is we're comfortable with our guidance of second-half data, which means that you kind of back out 6-8 months from that is when we expect patient screening to be completed. So hopefully that just gives a little bit more background and color on kind of the process that we're going through. Chris, anything else on the demographics that you wanna comment on?
Chris Kenney (Chief Medical Officer)
Yeah. So just as a reminder, the seizure burden in the phase II-B study was pretty high. Patients had an average of 13.5 seizures per month at baseline. Half the population were taking three anti-seizure medications, and on average, patients had failed six anti-seizure medications even before coming into the study. And despite that, we saw really robust efficacy with the largest separation between the high dose and placebo from the perspective of median % change in seizure frequency compared to any other study we can find in focal-onset seizures. So we're pretty pleased with that. So the spirit of the subsequent phase III program is do the best you can to not deviate from what was done in X-TOLE, because that worked out pretty well. And so that's what we've tried to do.
More directly, as an answer to the question, what we're seeing so far is that the population has shaped up very similarly in the phase III program as it did in the phase II study. Obviously, we're keeping an eye on that in real time. That gives the opportunity to make an adjustment if you had to, if you were getting something unexpected, but we're not right now.
Paul Matteis (Managing Director and Head of Therapeutics Research)
Good to hear. All right. Thank you both very much.
Ian Mortimer (President and CEO)
Thanks, Paul.
Operator (participant)
Your next question comes from the line of Brian Abrahams with RBC Capital Markets. Please go ahead.
Speaker 13
Hey, it's Leo on for Brian. Thanks for taking my question. I had maybe one and then just a quick clarifying question as well. I guess on the MDD trial design, I guess, as you're thinking about how, azetukalner might position itself, and there's a number of other agents that are also potentially having effects on anhedonia. I guess, as those other competitive trials, and I think of the CAPLYTA start to read out, I guess, are you looking for any data there on how they perform on anhedonia to maybe inform on whether you want to change selection for anhedonia, or, you know, how that might impact market positioning for azetukalner?
And then just to clarify, I, I think you guys said that you're not running ex-U.S. sites for the MDD phase III program, and I think maybe before you had said that, that you would use both international and U.S. sites. So I guess, can you maybe talk about what, what drove that change, if I, if I heard you guys correctly, and maybe how that might impact any expectations on, on timing and how quickly you can move? Thanks.
Ian Mortimer (President and CEO)
Thanks, Leo. I can start and then, Chris Kenney, to add in on the MDD side. And Chris von Seggern, if you can provide perspective a little bit about the market and what we're hearing back in our market research and the importance of anhedonia, and maybe how we believe azetukalner can differentiate with some of the other molecules, both in development, but also those that are commercially available currently. So a couple of comments. Yeah, just on clarification in terms of the ex-U.S., U.S. sites, we've said that, you know, we're running three phase III clinical trials in depression. We had always... This isn't a change. We had always expected that definitely the first study, which will start in the next couple of months, would focus on U.S. sites.
As we get to the second and the third studies, we may move to some ex-US sites, but right now, that's where the phase II is run. I think that's where a lot of the clinical development for major depressive disorder is done in the US. So we'll definitely focus that for ex- what we're calling X-NOVA2, which is the first phase III. And then as we move into the other phase IIIs, there may be some difference in site selection as we move forward. So hopefully that helps. You know, in terms of the protocol, you know, how we may be informed by other readouts, you know, the protocol for us in the MDD study is locked.
So we, as Chris said in his prepared remarks, we have filed the phase III protocol with the FDA, and we expect to hear back shortly on that and initiate that study. So in terms of the inclusion/exclusion criteria as it relates to baseline, both depression and anhedonia, all of that stuff is now locked. And as we said on previous calls, I think we're very much informed by our phase II program using HAMD-17 as primary and also increasing the severity of the patients as we move from phase II to phase III. So although I think you know, additional readouts are always interesting, they're not gonna change in terms of our strategy or approach. But Chris Kenney, why don't you add to that? And then Chris von Seggern on just differentiation in the marketplace.
Chris Kenney (Chief Medical Officer)
Yeah, I would just zooming out from anhedonia for a second. I think why this, why azetukalner is so interesting in MDD is really kind of a constellation of features, not just anhedonia. So we've got the unique mechanism of action. We have the rapidity of onset, which also happened in focal-onset seizure patients, which makes you think it's, it may be real, and then the safety. So on the safety side, from an MDD perspective, we had, you know, no notable issues with sexual side effects or weight gain. And in fact, the drug at 20 mg was better tolerated in the MDD population compared to the focal-onset seizure population. So, you know, that safety tolerability data, no SAEs in any of the 10 mg or 20 mg treatment groups in X-NOVA. That, that is...
I think it's, you know, is important or perhaps even more so. But I would say it's more the constellation of all those features, not one per se. And maybe I'll turn it to Chris to see what his perspective is from the commercial perspective.
Chris von Seggern (Chief Commercial Officer)
Yeah. Thanks, Chris. So maybe just to ground everyone, when we think about the major depressive disorder treatment landscape, it's important to note that the mainstay of treatment in this space, SSRIs, SNRIs, notably do not have a benefit specifically on the anhedonia component of the disorder. And when we conduct our market research, as we think ahead towards commercializing azetukalner in major depressive disorder, clinicians have very clearly identified anhedonia as one of those constellation of features that Chris Kenney mentioned, but also the fact that having a benefit in this core symptom domain or comorbidity of major depressive disorder is something that is very, very encouraging. And clinicians are actively looking for, given the fact that the SSRIs and SNRIs don't provide benefit along that dimension.
So when we do our research and we do our testing, of a potential azetukalner profile, it's something that clinicians absolutely latch on to. In appreciating that, folks are now focused on this area, in large part because of the unmet medical need that exists in the marketplace today.
Ian Mortimer (President and CEO)
Thanks, Chris. Operator, we can move to the next question.
Operator (participant)
Again, if you would like to ask a question, press star one on your telephone keypad. Your next question comes from the line of Tessa Romero with JPMorgan. Please go ahead.
Tessa Romero (Biotechnology Equity Analyst)
Good afternoon, and thank you for taking our question. So, Ian, you've outlined top-line X-TOLE2 data in the second half of 2025. Picking back up on, like, an earlier question that was asked, maybe asked slightly differently, can you just provide a little bit of an updated view for us on how the pace of enrollment has been going? And, you know, just kind of curious, has it been pretty steady since all the sites were activated, or have you observed any changes due to competitive dynamics or anything else here in the U.S. or globally across sites?
Can you just remind us what the split is between U.S. and ex-U.S. sites, and what are the key regions outside the U.S.? Thanks so much.
Ian Mortimer (President and CEO)
Thanks, Tess. Yeah, I think I've got it all, but others can jump in if I've missed something. So, yeah, in terms of, you know, pace of enrollment and kind of top-line guidance, as you said, top line for X-TOLE2, second half 2025, I think that's really exciting for us, right? I mean, that's critical path now. We've with the data from X-TOLE, with X-TOLE2, we'll be ready to engage with FDA and file an NDA. So that's really exciting now to have that top-line data guidance out.
In terms of cadence or pace of enrollment, you know, we've said on previous calls that just the number of sites that you need to complete these studies, which is kind of in, you know, 100 medical centers, give or take, in each of X-TOLE2 and X-TOLE3, is that you just naturally do get some ebb and flow and up and down of enrollment. So we've been comfortable with where we are, and we're comfortable with the guidance that we're giving. You know, obviously, we have more experience in running these types of studies than anybody else out there right now, so I think we're in really good shape. You know, in terms of competitive pressures, we haven't seen anything. So we haven't seen the pace of enrollment change from a competitive perspective.
We're, you know, obviously, you know, when we were running X-TOLE, there's at times other studies that are being run, and the same thing when you're running, when we're running X-TOLE2, and that's not just all... You know, I think your question is probably a little bit more focused on drug trials, but there's device studies as well that are ongoing. So there's always other things that are happening often at these clinical centers. But, we haven't really seen any change in the last little while that has given us any pause or any concern. In terms of regions, so X-TOLE2, we've really tried to use X-TOLE as much as our guides.
We went back to a lot of the same centers from X-TOLE into X-TOLE2, and used investigators that have experience with the molecule. As a reminder, in the X-TOLE phase II study, we had sites, clinical sites in Europe and clinical sites in the U.S. At the end of the day, 60% of patient enrollment came from Europe and 40% came from the U.S. Again, you know, while we're partly through a study, I don't really want to comment on where we're coming from in X-TOLE2, but the same jurisdictions that we used in X-TOLE, we're using in X-TOLE2. I think I got all of your questions there, but if there's anything else, please let me know.
Tessa Romero (Biotechnology Equity Analyst)
You did. Thanks so much, Ian. Talk to you soon.
Ian Mortimer (President and CEO)
Thank you, Tess.
Operator (participant)
Again, if you would like to ask a question, press star one on your telephone keypad. Your next question comes from the line of Jason Gerberry with Bank of America. Please go ahead.
Speaker 11
Hi, good afternoon. This is Dina on for Jason. Thank you so much for taking our question. We just wanted to ask about the next generation KV7 asset that's in IND-enabling studies. Could you please provide some more color on the specific drug properties that led you to advance this asset? Is your aim to improve upon azetukalner's profile, or is this more of a lifecycle management play to advance Kv7 into neuropsych opportunities beyond the current, you know, epilepsy and MDD set? Thank you.
Ian Mortimer (President and CEO)
Thanks, Dina. Yeah, I think it's a really important question. Obviously, the success we've had with azetukalner now in late-stage clinical development, we think it's really important for us to continue to maintain and build upon what we think is really a considerable leadership position in this mechanism, which we're really excited about. So we've been working on additional molecules against the same target for quite some time. So completely diverse chemistries from azetukalner. As you mentioned, and we said in our prepared remarks, multiple candidates have been identified, including the lead one is in GLP toxicology studies. So we're excited to get that into human clinical development as well. You know, we touched upon what we call our DTC or development track candidate, and you asked a question around pro-drug properties.
It's quite a long list of things that we try to optimize all of these drugs for. Obviously, potency and selectivity on target, but a bunch of the drug properties as well. So what's really interesting about azetukalner is there isn't any one specific attribute of azetukalner, which we're trying to improve on. Right now, as we've gone through the data, as we've mentioned, you know, this is best in category efficacy on a placebo-adjusted basis, the novel mechanism, the rapidity of onset. So we think we have so many of the important attributes to be successful, both in epilepsy and depression, that these next generation molecules have diverse chemistries, have properties that meet our criteria, but we're not specifically trying to improve on any one attribute from azetukalner. There will be an opportunity, as you mentioned, to have some therapeutic diversification.
So as we move forward, you know, obviously for this mechanism, we continue to be excited about epilepsy, neuropsychiatry, pain, and other indications. So absolutely, you'll see the next molecules go into some indications that we're not going to with azetukalner as well.
Speaker 11
Got it. Thank you so much. And, I guess a quick follow-up to that. You highlighted some additional, you know, neuropsych indications. Will you be looking at data from Kv7 competitor in bipolar mania? And potentially migraine to kind of inform the indications you plan to assess with this next-gen molecule? Might be a little bit too mature of a question to ask, but thank you.
Ian Mortimer (President and CEO)
Yeah, and Chris Kenney, Chris von Seggern, feel free to add your perspective here. I'll start and if, please add to it. Yeah, we've done a significant amount of LCM work on the mechanism. You know, we're very much informed by what we learn, and the work that we do, rather than specific anchoring to any competitive product. And we're making decisions all the time and, you know, you know, the KV drug that you're probably referring to in development is years and years and years away from any efficacy data, and we'll be making decisions, far in advance of that. So, you know, we'll make decisions based on all of the work that we've done, where we think these molecules would be best suited for early clinical development.
But, we've done, you know, probably over the last year or more, we've done a lot of work to do commercial assessments and mechanistic assessments and a bunch of preclinical work to understand best where we can take these molecules in the future. But, Chris or Chris, anything to add to that?
Chris Kenney (Chief Medical Officer)
I'll just say something quick. You know, in his prepared remarks, Ian talks about Kv7 offering the potential for a Pipeline-in-a-Mechanism opportunity. And as Chris von Seggern and I and our teams have looked at life cycle management, there are a lot of different options. This is a mechanism that really should work in all types of epilepsy, which is what gave us the confidence to go into focal-onset seizures and primary generalized tonic-clonic seizures in parallel. There are a number of psychiatric indications of interest. I think we would probably put bipolar at the top of that list, but there are several others of interest, and then pain. So, I think, you know, it's an interesting target, and we have lots of different options with these backup compounds. Chris?
Chris von Seggern (Chief Commercial Officer)
Yeah, thanks, Chris. I, I think the only thing that I can add here is just reiterating that the extensive work that's been done, both from a commercial perspective, gathering input from potential prescribers in the future, as well as on the scientific side, where we've looked in depth at level of genetic validation and now emerging clinical validation based on the backbone of the azetukalner profile, really just creates a range of potential options that we're incredibly enthusiastic about, in part driving the decision for us to advance multiple products into the clinic.
Speaker 11
Thank you so much.
Operator (participant)
Again, if you would like to ask a question, press star one on your telephone keypad. Your next question comes from the line of Brian Skorney with Baird. Please go ahead.
Speaker 10
Hi, this is Luke on for Brian. Thanks for taking the question. On NaV1.7, can you talk about your biggest learnings from legacy challenges with the mechanism in the past? And then apologies if this is something you've discussed before, but can you remind us whether you intend to conduct non-human primate studies to get a better idea of the profile before entering the clinic, given it seems there's been challenges with translation utilizing rodent models in the past? Thanks.
Ian Mortimer (President and CEO)
Sure, Luke. Yeah, you're and when you're talking about non-human primate models, you're talking specifically with NaV1.7?
Speaker 10
Yeah, yeah.
Ian Mortimer (President and CEO)
Okay. Sure. Yeah, I can take this, and then others can add. Yeah, so I think what you're referring to is that, you know, NaV1.7 or the gene, which is SCN9A, was sequenced quite some time ago, and there's been a number of companies, us included, that have tried to prosecute against the target, and we just haven't made it into late-stage clinical development. There's kind of a number of reasons. There's not one reason. I think a lot of the drugs that other companies called selective 1.7 inhibitors were not actually selective. They were much more pan-sodium channel inhibitors. And so I think selectivity matters, and we've made, you know, really great progress on a selectivity profile and therapeutic index and selectivity across the other isoforms.
There were definitely some toxicity issues related to certain chemistries on the target historically, and so I think we've learned a lot there. And then, excuse me, I would say the last thing is around the pharmaceutical properties. I think we've learned a lot about the expression patterns and distribution and really where we need to get these molecules to be successful. So, I think we've learned a ton from the field and our own work that we've done over the past 15 years or so internally, where, you know, we have molecules that meet all of our criteria, that we're really excited to run the human clinical experiment. In terms of translatability, translatability is hard for this target, because the human NaV1.7 is different than in other animal species.
We do use some genetic models and human knock-in models to help us with that. But really, I think we need to run the human experiment. What we can do in animals is really understand the therapeutic index, and ensure that we have, you know, we run the appropriate tox species from a regulator point of view, but we really need to run the human clinical experiment to be able to answer that question. Nice thing is, you know, about pain, is there's an opportunity to run this earlier in human clinical development than proof of concept in some other therapeutic indications, and the early studies run quite quickly as well. So I think we've made tremendous progress on this target, and I don't think we're actually far away from being able to run the human experiment.
Speaker 10
Awesome. Thanks.
Ian Mortimer (President and CEO)
You're welcome.
Operator (participant)
Your next question comes from the line of Andrew Tsai with Jefferies. Please go ahead.
Andrew Tsai (Managing Director)
Hey, good afternoon. Congrats on the execution. Thanks for the updates. I wanted to ask on PGTCS, this time, could it be possible we get data in 2025, or, should we be assuming 2026 at the earliest? I think you guys have mentioned before how the study is powered to show what other drugs show, within this indication. So would it be fair to assume a 30%-40% type placebo-adjusted separation and seizure reductions could be the bar here? Thank you.
Ian Mortimer (President and CEO)
Thanks, Andrew. I can maybe talk about timelines. Chris Kenney, do you want to talk about power and kind of the expectations for moving from FOS to PGTCS and some of the changes there in terms of what our expectations are? And maybe actually just the baseline seizure burden coming in as well, I think would be helpful to put that into context. But Andrew, in terms of timeline, so we haven't guided yet on X-ACKT, which is our phase III clinical trial in primary generalized tonic-clonic seizures. I mean, if we look at the literature and the most recent studies that have been run, cenobamate, they're still running their PGTCS study, even though that drug is approved.
If you look at lacosamide, where they had data very late in the commercial life of that product, you know, these are more challenging studies to run. They run much slower than the focal onset seizure studies. So although we haven't yet given guidance on it, I just want to set expectations that these studies are slower than what we would expect in the X-TOLE program, given PGTCS is less common, and these studies take longer than the focal onset seizures. And at the appropriate time, we'll be able to update in terms of guidance to top-line data. But Chris, maybe you can just give, because we didn't in today's prepared remarks, a little bit of background on the study design and the powering assumptions.
Chris Kenney (Chief Medical Officer)
Yeah, sure. Thanks, Ian. I mean, one of the... You know, there are a few differences going from focal onset seizures to primary generalized tonic-clonic seizures. One is that the PGTCS population in general has a lower seizure burden, and it's difficult to find those patients. And so that's why you end up seeing the duration of the study take a little bit longer. And now, fortunately, when the drugs work, they work really well, and you need fewer patients to show efficacy. So as you look at the spectrum of what's been done in the past, on the low end, you have the study that was done with topiramate, just had about 40 patients per two, you know, per group, so 40x2. And I think lamotrigine had 60 patients per arm, so 60x2 for the total size.
Then there are three examples of studies, PGTCS studies, that had about 80 patients per arm, so a total of about 160 patients. Two examples include perampanel and levetiracetam, and that's what we've anchored to, sort of on the higher end of that spectrum of between 40-80 patients. I mean, the one exception that included even higher patients was the lacosamide study, but that was a time to event study with a different entry criteria, so it's sort of comparing apples to oranges. But, so we're on the higher end of that, and, you know, we don't... I mean, compared to focal-onset seizures, we don't have preliminary data, and so our study was simply powered over, you know, compared to those three examples of previous studies that used about 80 patients per arm.
Andrew Tsai (Managing Director)
Thanks.
Operator (participant)
Your next question comes from the line of Paul Choi with Goldman Sachs. Please go ahead. Excuse me, Mr. Choi, we cannot hear you. Kindly check your line, please. Thank you.
Ian Mortimer (President and CEO)
Operator, we can move to the next question, and then we can come back to Paul.
Paul Choi (Biotechnology Analyst)
Oh, hi. Sorry. Can you hear me?
Ian Mortimer (President and CEO)
Oh, hey, Paul. Yep, we can hear you now.
Paul Choi (Biotechnology Analyst)
Sorry, sorry about that. I just wanted to ask a follow-up on NaV1.7 with regard to development and pain. Can you comment, you know, pending the animal model work, what you see as the most logical development focus for that area? Whether you focus on an acute development clinical strategy or focusing perhaps on the larger chronic opportunity first or prosecute them in parallel. Thanks, Ian.
Ian Mortimer (President and CEO)
Yeah, Paul, I think it's a really good question. I would say it's probably a bit premature for us to... We haven't fully fleshed out what kind of a late-stage clinical development plan would look like. Obviously, we would do healthy volunteer work initially, make sure that we believe we're getting, appropriate exposure, where we can do some modeling and predictability, that we have enough receptor occupancy from an efficacy point of view. So that would be the early work. And then, as I was mentioned earlier, the nice thing about pain is we would likely run a bunionectomy study, right? And those studies can be run very quickly, at reasonable size, in terms of powering as well.
We haven't designed a study like that yet, so there's a whole bunch of questions there in terms of number of active doses and potentially active controls and other things, and we'll get to all of that in advance. But you're really asking a question more about kind of the acute and chronic longer-term studies, which, you know, I think are both on the table, at least based on the mechanism. There's nothing to suggest with the genetics or the mechanism that we should necessarily lean one way or another. But so I would say today's both, both are potentially on the table. We do want to really monitor how the NaV1.8 program is doing, and how they're doing in terms of accessing the commercial market, in terms of the acute market to start.
So I think that's going to be an interesting, you know, data point for to inform us as well. So I don't have a really good, you know, definitive answer for you today because I think it's just too early and too premature, but more to come on that over the next year or two.
Paul Choi (Biotechnology Analyst)
Okay. Thanks, Ian.
Ian Mortimer (President and CEO)
You're welcome.
Operator (participant)
Your next question comes from the line of Dane Bohnsack with TD Cowen. Please go ahead.
Speaker 14
Hi, guys. Thanks for taking our questions. I guess, could you talk a little bit more about the design of the MDD clinical program? I guess, in terms of just initiating studies and enrollment and then the data releases. Are you planning on staggering initiations on one, two, three, or are you going to initiate them all at once? And then for the data releases, basically the same question, will it be released all at once, or will it be done if the study analysis is completed? And then, just secondly, and real quickly, apologies if I missed this. Is MADRS still being measured in these studies? Thanks.
Ian Mortimer (President and CEO)
Thank you. Yeah, I'll take the first part of on the staggering, and then, Chris Kenney, I think it's probably helpful maybe just to go through some of the entry criteria into the study, 'cause, you know, we learned a lot from phase II as we're moving into the phase III program. I think we can kind of review some of that. We didn't have time to do that in the prepared remarks, and then maybe you can address the specific question on MADRS. So we're going to... We'll be staggering these studies. So, just naturally, they won't start at all at the same time. So our first study, we filed the protocol with FDA, and that should start later this year as we've guided.
Then we'd expect a natural stagger for the second and the third studies. That would be our expectation on the release of data as well, is that when the first study is complete and we've unblinded those data, we'll provide those data publicly, and then the second study and the third study would follow suit after that. Expect a stagger, not from a perspective that we're waiting for a readout on the first one before we start the second one. But so at some point, they will all be running near about the same time, but we would definitely start the first one and finish that and unblind those data and provide them.
But, Chris, maybe you can go through some more of the entry criteria, because I think that's important for this program, and then answer the question around MADRS.
Chris Kenney (Chief Medical Officer)
Sure. Thanks, Ian. Yeah, I would say three things about study design that should work in our favor. The first is that as we go from phase II to phase III, we'll just have one treatment group versus placebo, so that if you look at other studies, that definitely helps in terms of placebo response. The other thing is that the size of the study, you know, in the prepared remarks, we talked about a study size of 450 patients, so 225 per arm. So that's, you know, 3-4-fold higher than what was used in the phase II study, X-NOVA. And there were some imbalances, not dramatic, but subtle imbalances that occurred in the X-NOVA study, so that larger study design, you know, I think is guaranteed to iron those things out.
And then the other thing, more specifically directed to the question, we're still going after moderate to severe depression. What we learned mirrors what other studies have learned, which is that if you have patients that slip in with that are slightly on the more milder end of the spectrum, even though they meet the criteria for being moderate to severe, but if they're on the milder end of the spectrum, then they can skew the data a bit. And so we're just going to be more strict in terms of the cutoff that we use for the HAMD, and then there are some other criteria that we're just in general going to be more strict about making sure that nobody comes in the study on the milder end of the spectrum. Those are the big changes.
In terms of the MADRS, I mean, one of the guiding principles in depression is keep it as simple as you can, and that worked well with X-NOVA. I mean, we did actually use two scales, as you know, which is fortunate because it allowed us to choose the HAMD to go into phase III. But we went back and forth about whether MADRS should be included and ultimately decided not that, you know, assessing depression to, you know, to the least amount that still led to a successful outcome was the best approach. So we're going to focus on HAMD, which we saw in our study had dramatically less variability, and we've seen the same in other studies, and that's what we're focused on.
Speaker 14
Great. Thank you very much.
Operator (participant)
Your next question comes from the line of Laura Chico with Wedbush Securities. Please go ahead.
Speaker 15
Hi, can you hear me?
Ian Mortimer (President and CEO)
Yes, we can hear you. Yes.
Speaker 15
Thank you very much for taking my question. This is Dylan on for Laura Chico, and I'm not sure if this is a question for Chris Kenney or Ian, but we noticed within the SCN8A program, partner with Neurocrine, you're also looking at a next lead candidate that's NaV1.2 or NaV1.6 inhibitor for focal epilepsy, and we were wondering if you see positive outcomes with 352. Would this also read through to the broader seizure-related indications?
Ian Mortimer (President and CEO)
Yeah, I can take that, Dylan. Yeah, there's a little bit of history here, which is probably helpful and worth going through. So 352 is the molecule that. So these are sodium channel inhibitors that came out of Xenon's laboratories and were licensed as part of a transaction with Neurocrine, and Neurocrine is doing the development and paying for the development. So it's a milestone and royalty transaction for Xenon. So 352 is in the SCN8A phase II clinical trial, as you mentioned right now. They did run that in a focal-onset seizure study. That was a small proof of concept study, around 100 subjects, that read out last fall, and they're not moving 352 forward in focal-onset seizures.
The molecule that we referred to today on the prepared remarks has a little bit of a different profile. So although it's, it's highly potent on NaV1.6, it's also potent on another sodium channel called NaV1.2, whereas 352 was much more selective for 1.6. So we would consider this a dual inhibitor, that has potency on both channels. Both channels are involved in excitation in the brain, so both well-validated targets. This next molecule is still preclinical, and as it goes into clinical development, you know, Neurocrine at that point would guide in terms of what types of studies it would go into, but it would be into epilepsy studies as well. Is that background helpful?
Speaker 15
Yes. Thank you so much for taking the question.
Ian Mortimer (President and CEO)
Yep, no problem.
Operator (participant)
Your next question comes from the line of Marc Goodman with Leerink Partners. Please go ahead.
Speaker 12
Hi, this is Basma on for Marc. We have a question on X-ACKT. Could you please remind us what we should expect in terms of the efficacy of XEN1101 in the primary generalized seizures? Should we expect an efficacy in line with what we've seen in the focal onset seizures? We also have a question about the dose, the 25 mg. What kind of work you've done to actually feel comfortable about the use of this dose, and this indication on whether you believe this dose will be efficacious or not? Thank you.
Ian Mortimer (President and CEO)
Great, thanks for the question. Chris Kenney, over to you.
Chris Kenney (Chief Medical Officer)
Yeah, thanks. Thanks for the question. So as I sort of said earlier, we, the, one of the differences between the focal onset seizure population and the primary generalized, is that we don't have preliminary data. And so we powered the X-ACKT study based upon a few different examples of studies that were successful with other anti-seizure medications. And we took, on the higher end of the number of patients, just to be cautious. I mean, in general, what... The, the drugs that do work in primary generalized tonic-clonic seizures, when they're effective, they're, they're pretty darn effective. If, I, you know, judging whether it's going to be as effective in focal onset seizures, I think is, is anybody's guess.
I would just say that, you know, when we look at phase II-B data, and we look at the subset of patients who had focal seizures that then generalized, the data is incredibly robust. I mean, it was well over 80% reduction in those types of seizures in the high dose. And that's what gave us confidence to run the two indications, you know, in parallel. But it remains to be seen what's going to happen. As far as the high dose, you know, why choose 25 mg? Again, that goes along with what's been learned in the field with the other drugs that first worked in focal-onset seizures and then worked in primary generalized tonic-clonic seizures.
The path that's been laid down is that others have chosen the dose that was on the higher end of the spectrum and functional in focal onset seizures and then brought that forward, and they've been successful, and so we did the same.
Speaker 12
Thank you.
Operator (participant)
That concludes our question and answer. Ladies and gentlemen, that concludes today's call. Thank you all for joining. You may now disconnect.