Ladies and gentlemen, thank you for standing by and welcome to the First Quarter 2021 Xenon Pharmaceuticals Earnings Conference Call. At this time, all participants are in a listen-only mode. After the speakers' presentation, there will be a question-and-answer session. [Operator Instructions] Please be advised that today's conference is being recorded. [Operator Instructions] I would now like to hand the conference over to your speaker host, Jodi Regts. Please go ahead.

Thank you. Good afternoon. Thank you for joining us on our call and webcast to discuss our first quarter 2021 finical and operating results. Joining me on today's call are, Dr. Simon Pimstone, Xenon's Chief Executive Officer; Ian Mortimer, Xenon's President and Chief Financial Officer; and Sherry Aulin, Xenon’s Vice President, Finance. As a reminder, this coming June, at the time of the company’s Annual Meeting of Shareholders, Simon will be transitioning to his new role as Executive Chair of Xenon’s Board. At the same time Ian will be appointed President and CEO, while Sherry will be appointed Chief Financial Officer. Please be advised that this call we will make a number of statements that forward-looking, including statements regarding the anticipated impact and timing of the COVID-19 pandemic on our business, research and clinical development plans, and timelines and results of operations, the timing of and results from clinical trials and preclinical development activities of our proprietary and partnered product candidates, the potential efficacy, safety profile, future development plans, addressable market, regulatory success, and commercial potential of our proprietary and partnered product candidates. The anticipated timing of IND or IND-equivalent submissions and the initiation of future clinical trials for our proprietary products and those related to our other partner candidates. The efficacy of our clinical trial designs, our ability to successfully develop our proprietary development programs, the timing and results of our and our collaborated interactions with regulators, the timing and anticipated enrolment in our clinical trials, the potential receipt of milestone payments and royalties from our collaborators, our expectation of having sufficient cash to fund operations into 2023 and the timing of potential publication or presentation of future clinical data. Forward-looking statements are subject to numerous risks and uncertainties, many of which are beyond our control, including the risks and uncertainties described from time-to-time in our SEC filings. Our results may differ materially from those projected on today's call. We undertake no obligation to publicly update any forward-looking statements. Today's press release summarizing the results of Xenon's first quarter financial results and the accompanying quarterly report on Form 10-Q will be made available under the Investors section of our website at www.xenon-pharma.com and filed with the SEC and on SEDAR. Now, I would like to turn the call over to Ian.

Thanks Jodi and good afternoon. Thanks everyone for joining us. I hope everyone is healthy and well. We have made significant progress over this past quarter and I'm excited to provide an update today as we enter a period of important clinical data readouts over the coming quarters. I'll focus on our two proprietary Kv7 programs XEN1101 and XEN496. Later on the call, Simon will update you on our XEN007 CAE program, as well as partnered programs with academic and industry collaborators, followed by a financial update from Sherry. We'll then open the call up for your questions. So, I'll begin with XEN1101, which is a novel next-gen Kv7 modulator being developed for the treatment of epilepsy and potentially, other neurological disorders. We are very encouraged about the compelling product profile that is emerging for XEN1101. In addition to my comments on XEN1101, Simon will provide some commentary on our work examining XEN1101 in indications outside of epilepsy. In the near-term, our focus on the upcoming data readout from our Phase 2b Phase 2b X-TOLE study. As a reminder, X-TOLE is defined as a Phase 2b randomized double-blind, placebo-controlled, multicenter clinical trial to evaluate the efficacy, safety, and tolerability of XEN1101 administered as adjunctive treatment in approximately 300 adult patients with focal epilepsy. The primary endpoint is the median percent change in monthly focal feature frequency from baseline compared to the treatment period of active versus placebo. We believe that this is a well-powered and well-run study, which gives us confidence in the integrity of the key efficacy endpoints as captured by eDiary. I am pleased to report that we have now completed patient screening with the final patients now in the baseline period of the study. Patient randomization is expected to be completed in June, with topline data anticipated…

Thank you, Ian. This is an exciting time for Xenon as our partnered and proprietary programs continue to make great progress. As Ian mentioned, we're exploring other neurological indications for XEN1101 outside of adult focal epilepsy. I wanted to highlight for you today the recent Costi et al article published in the American Journal of Psychiatry examining the use of ezogabine on the reward circuit activity and clinical outcomes in patients with depression in a randomized clinical trial. ezogabine compared with placebo was associated with a significant improvement in depression as measured by the Montgomery Aspect Depression Rating or MADRS Scale and associated with a significant improvement in hedonic capacity as measured by the Snaith-Hamilton Pleasure or SHAPS scale. We believe these new data provide further validation of the great potential of the Kv7 mechanism to differentiate from other anti-seizure medicines in patients with epilepsy and the comorbidity of depression or a standalone to treat MDD. We recently announced a collaboration with the Icahn School of Medicine at Mount Sinai in New York and we expect that an investigator-sponsored Phase 2 proof-of-concept randomized parallel arm placebo-controlled clinical trial, examining XEN1101 as a treatment for MDD and anhedonia, as measured by specific functional and clinical endpoints will be initiated in the coming months. In parallel, we're planning a company-sponsored study in MDD, focusing on clinical endpoints. Both of these planned MDD studies are supported by promising preclinical data with XEN1101 as well as clinical data generated from open label and randomized placebo-controlled studies that explored targeting the Kv7 mechanism using ezogabine as a potential treatment for MDD. We're excited about this focus on the potential of the Kv7 mechanism and the related promise for XEN1101 to be the only in-class drug in adult focal epilepsy with the potential for broader opportunities…

Thanks Simon. We are in a solid financial position today and I believe we are well-situated to support Xenon's business objectives and the advancement of our clinical development programs. Today, I will focus on some highlights from this quarter's financial statements and would refer you to our news release and 10-Q report for further details. Following up on Simon's comments on the progress made by our partner Flexion, this quarter, we recognized $3 million in milestone revenue and we are eligible to receive additional milestones and royalties in the future. This past quarter, we also closed an oversubscribed $115 million public offering with strong support from both existing and new high quality institutional investors. Cash and cash equivalents and marketable securities as of March 31, 2021 were $274.7 million compared to $177 million as of December 31, 2020. Based on current assumptions, which include fully supporting the planned clinical development of the XEN1101 actual trial, and MDD proof-of-concept study, the XEN496 EPIK study, the XEN007 physician-led proof-of-concept study, as well as funding are preclinical and discovery activities, we anticipate having sufficient cash to fund operations into 2023. Excluding any revenue generated from existing partnerships or potential new partnering arrangements. We plan to revisit our cash runway guidance post actual data with increased visibility on our spend in 2022 and beyond. With our strongest balance sheet to-date, we continue to have a lot of flexibility as we manage our business and continue to advance our product candidates. As of March 31, 2021, there were approximately 41 million common shares outstanding, 1.1 million pre-funded warrants, and 1 million Series 1 preferred shares outstanding. I would refer you to today's press release and our 10-Q filing for other specific details from this quarter's financial statements. At this point, I will turn the call back to Ian who will summarize the key milestone events we are anticipating for the remainder of this year. Ian?

Thanks Sherry. Looking ahead, our key corporate objectives include; the continued advancement of our EPIK Phase 3 clinical trial in patients with KCNQ2-DEE; the development decision and results from a larger data set in the second half of the year from the physician-led XEN007 proof-of-concept study in CAE; continued support for our partner program with Neurocrine biosciences, including the anticipated initiation of two Phase 2 clinical trials with NBI-921352 in 2021; results from Flexion's FX301 Phase 1b trial anticipated in late 2021; anticipated initiation of an investigator led Phase 2 proof-of-concept study; as well as the ongoing planning for a company-sponsored clinical trial examining XEN1101 in MDD. And importantly, within our XEN1101 Phase 2b X-TOLE clinical trial, we expect patient randomization to be complete in June with topline data anticipated by the end of the third quarter of this year. In summary, we are incredibly proud of the breadth and depth of our neurology pipeline. There is an immense amount of momentum in both our proprietary and partner programs. For the first time in Xenon's history, we can have up to eight clinical trials underway with five different molecules led by us, our corporate partners, and academic collaborators in 2021. Before we open the call up for your questions, Simon has a couple of concluding remarks. Simon?

Thank you, Ian. So, this is my last quarterly call as Xenon's CEO. As you know, I'm handing that baton over to Ian who has worked alongside me for the past seven years. I leave this role with great anticipation and optimism, in part driven by the strength of our current pipeline, in part driven by the exciting data readouts ahead of us, and in part driven by the strong leadership of Xenon, that will continue to work tirelessly for you, our shareholders, as well as the patient communities we serve. It's been a privilege to serve such a talented executive team and to work alongside such wonderful colleagues. This has been an incredible honor and a mission for me, a journey I'll always treasure. As you know, I'll be working in a different capacity as Executive Board Chair and in that capacity; I look forward to continuing to support Xenon and to interacting with all of you. I wanted to thank you all for the faith that you have shown in me, and the faith you've shown in Xenon. I firmly believe that our best is yet to come. I'll now ask the operator to open the line for any questions. Operator?

Thank you. [Operator Instructions] And our first question coming from the line of Paul Matteis with Stifel. Your line is now open.

Paul can you hear us? Operator, perhaps we got to the next question just while Paul tries to solve the technical issue. Operator?

And our next question coming from the line of Laura Chico with Wedbush Securities. Your line is open.

Best wishes, Simon and congratulations to Ian and Sherry again. I guess I have one question on 1101. So, obviously, exciting to hear that the Exo [ph] readout is coming up in the third quarter. Beyond the primary endpoint, I'm wondering if you could talk about the communication strategy around some of these perhaps non-seizure related assessments, quality of life measures? And then I just have one follow up for you.

Thanks. Yes, thanks Laura. Maybe I'll answer that by providing a little bit of background and color. So, as we mentioned, we'll have topline data by the end of Q3. That will be by way of a press release, we'll have key added points, we haven't mapped out everything that will be in that first press release. It will come after we un-blind data, just how much of the data analysis we can do balancing getting out that topline data in this quicker manner as we can. Key efficacy endpoints primary and secondary for sure, as you know, the primary we talked about on today's call. Key secondary endpoints focus on a lot of the responder analyses and we'll have some data on those. We'll definitely comment on safety and tolerability and some other metrics within the study and as you mentioned, we do have some additional endpoints around quality of life, how much of that full data analysis will be completed and ready for the topline data? We don't know right today. So, we will be ready to talk about that at the next quarter and advance of data. And then as a standard, we'll have more detailed analyses, upcoming and scientific meetings, we may be able to get just under the wire for a late breaker at AES this year, which would be excellent. And then obviously, we have AAN next spring, our conferences that that we're looking forward to presenting additional analysis.

That's great Ian. Thank you. And then maybe one follow-up on a commercial market in the focal epilepsy setting. It's been about a year since XCOPRI has been on the market. Obviously, there'll be some additional studies to conduct with 1101, if successful here, but I'm just curious if you could talk about any learnings or takeaways that you can take from Cenovo made on the market? Thanks very much.

Its Simon. I'll make a comment and I'll hand over to Ian for some additional color. Yes, look, I mean, just this conjecture, I'm not going to give you a perspective from a detailed analytical review. But look Cenovo-made [Indiscernible] has shown at its final dose to have a good effect size in a proportion of patients with this condition. It is a significant titration required to get there, three to four months of those titration. And so I think what needs to still play out in terms of the real-world usage of the drug is really how well that can be integrated into a refractory focal epilepsy patient population. These are patients that are having regular seizures and having to waits this amount of time to get drug to a final concentration required for maximal effect. I think we'll have some limitations. And it's one of the key differentiators with 1101, we don't need to titrate the drug and we appear to reach a maximum steady state exposure at around plus or minus two to three weeks with no long-term accumulation. So, I think that's a really significant differentiation. Of course, we've not seen any of the Hypereosinophilic Syndrome that was observed in studies with higher dose XCOPRI in our studies to-date, and we don't have any reason to believe we will. But of course, the dose titration differential I think is going to be very, very important. Ian referred to the ease of use and once-a-day, I think both of those are going to be very, very important differentiating concepts. And I think you can look to a drug like Vimpat, or lacosamide, which is far less effective in terms of median seizure frequency reduction, 35% to high 30%, in median seizure versus plus or minus 50% with XCOPRI yet is selling about $1.5 billion to $2 billion a year, largely because of its ease-of-use in this indication. So, I think that that's some of my own personal color. Ian?

Yes, maybe just a couple of comments. So, we don't have perfect information on your specific question on how the launch has gone for XCOPRI, but our understanding is that it's gone reasonably well. And obviously, this is a large market opportunity with still significant unmet need where there's absolutely room for a number of branded drugs to do well. I think Simon walked through a lot of the differentiating points. The other thing that I would mention that we didn't cover on this call, but we have presented recently is that we've generated some really nice preclinical data of 1101 in combination with Conovo-made. Obviously, different mechanisms of action and when you dose these drugs together, you can get quite significant efficacy in the in-vivo models that we've run. So, we look forward to having 1101 as another drug available for physicians and their patients.

Thanks very much guys.

And our next question coming from the line of Paul Matteis with Stifel. Your line is open.

Hey. Thank you. Can you guys hear me?

We can.

We now can, yes.

All right. Awesome. Thank you. Sorry about that. Well, first-off congrats, Simon and congrats Ian on your new roles. Always appreciate the dialogue we've had. I wanted to ask the question on the MDD plans, and then also on the 007 plans. On MDD, what's your kind of current thinking on when you're going to engage the FDA what the next study could look like? And how are you thinking about dosing and MDD? Is it same as epilepsy or might you try to go a little bit lower due to just tolerability dynamics? And then for 007, I guess, similar question just plans to engage the FDA. Would you do that after this initial investigator data? Would you start before? And how do you think about next steps? Thank you.

Sure. I'll start Paul, and then Simon can add. So, on the MDD side, we don't believe we need any upfront engagement with the agency to move ahead with a company-sponsored MDDs or we're not looking for any specific feedback, obviously, we'd need to follow a protocol and get up and running. But there's not specific feedback that we're looking for. I think what the ezogabine experience from Dr. Morrow and his group at Sinai and other trials that have been running MDD. We have a pretty good protocol synopsis already that we're working on. We are looking to use -- we haven't finalized the dose, but we'd be looking to use the dose that we're currently using in the epilepsy study, where we just have a lot of experience. That said from just an order of events perspective, before we start the MDD study, the Sinai study will start before -- the Sinai study will start and then we'll have the X-TOLE data. So, we will have some information on un-blinded X-TOLE data of 1101 before we initiate the company-sponsored MDD study. So that is another data point that we can take into consideration as we refine our thinking. On 007, our plans are really in parallel. So, this year is both to expand the data set from those few number of patients where we saw some intriguing data at AES last year. So, that's the goal for the second half of the year. And then in parallel, we do expect to have some regulatory interaction to talk about next steps in the development, and obviously, are planning if the data continues to support it, in the CAE as to run company-sponsored development. Exactly what that looks like, is really what we're doing in terms of our development planning right now. And then we expect to have that regulatory interaction later this year.

Paul, its Simon. The only thing I'd add is just going back to the MDD, key distinctions, I guess from the ezogabine study and also from the current study Dr. Morrow will run with 1101 is in those studies, functional MRI was the primary endpoint with clinical secondaries. We're much more interested in our sponsored study as clinical primaries. I think the other unknown at this point, which will define X-TOLE is going to be the interplay with anhedonia in our sponsored study. So, as you know, the ezogabine study was done in MDD and anhedonic patients and will similarly be tested with Dr. Marrow's 1101 trial. We're currently sort of looking through that to decide whether we'll have a purer MDD patient population meeting thresholds of severity in terms of inclusion. I think that's the only additional comment I'd make.

Great. Thank you, Simon. Appreciate it.

Okay.

Operator--

Our next question in queue coming from the line of Marc Goodman with SVB Leerink. Your line is open.

Yes, hi. Simon in the past you kind of hinted at work that's going on behind the scenes, you're talking about disclosing some of that work soon. I was just wondering, are we getting closer? What's going on behind the scenes? Maybe you could just give us a little hint. Thanks.

I mean, you're probably referring to what's our non-clinical programs Marc. Yes, look, we have some very exciting work underway. Some of which we've talked about in the past, we do have a Kv7 program that obviously is looking at next generation molecules, which has made outstanding progress. We have a NaV 1.1. program, targeting [Indiscernible] and potentially are the indications which has also made some very exciting progress. And then we have a few other programs in addition -- which we aren't yet ready to talk about, but certainly over the coming months, we'll be speaking a bit more. So, this is really just a stage of the programs. Marc, we'll make disclosures when we think they've really moved to a material stage and up until then, we'll keep the program's under wraps. Those are just two of the programs we have referenced in the past. There are others. But that's about what we'll cover for now.

And then just one quick follow-up from a previous question or two 007. When -- I guess how many patients do we have right now that's already been enrolled? And how many is the goal for this year?

Hey Marc its Ian. So, we haven't -- just like any other clinical trial that we run, we don't give updates kind of quarter-to-quarter on where we are in enrollment only when we hit kind of key inflection points. Our goal is we've always said that the first three patients, the data looked really intriguing. And if we could get to kind of 10 plus patients and then continue to enroll patients and study in that population. As we add more and more subjects in that study, it just gives us more confidence in that opportunity and that indication. So, the goal was to increase from the handful into double-digits and then grow from there.

Okay. Thanks.

Our next question coming from the line of Tim Lugo with William Blair. Your line is open.

Thanks for taking the question and congratulations to the team as well on the new roles. For -- going back to 1101 in MDD, I believe the Mount Sinai study is going to take relatively long to enroll given the NIH's role on the study as well. Can you just talk about maybe the company-sponsored study and how that might -- I assume that's to be faster to conduct, especially if you're using clinical endpoints versus the fMRI?

Yes, that's right, Tim. I think the way we think about it and you're probably referring to the clinicaltrials.gov posting from the Sinai that that study may take a few years. I think, unknown right now, and hopefully, as that study gets up and running, we can get a little bit more granularity on when we may see topline data. But our expectation is that the Sinai study will start first, our study would follow but our study would likely readout first. And really for the reasons that you talked about, primarily, Sinai is going to be at two centers, we would go to more than two and with our control with a CRO that we would -- it would likely enroll more aggressively than the Mount Sinai study.

Okay, thanks for that. And I guess given the low DDI risk in epilepsy, have you explored kind of adequate DDI information for some of the classes use an MDD as well or was that all work done, kind of concurrently, the epilepsy DDI information?

So, we've done -- I -- where we are in development for 1101, we haven't completed all of the DDI work that would be required. We've done standard DDI work regardless of therapeutic indication. So, a lot of the in-vitro work and other profiling that we believe overall, it's going to have low DDI risk. The Mount Sinai study, this is dosed as a single agent, we haven't made a final decision on our MDD study on whether there'll be con meds or not. But overall, the profile of 1101, we believe it has low DDI risk. We're also initiating more detailed PK/PD modeling with the initial data set being the clinical data that we've generated today in Phase 1 to start building that model. But once the once we have all of the Phase 2 X-TOLE data in hand, then our PK/PD modeling can become more robust and we can see if there's any differential exposure from 1101 or other con meds depending. As you know all of the patients on -- in X-TOLE will be on those background therapies and so we'll be able have a better understanding of any DDI as we generate more data and do more modeling.

Great. Thank you for the color.

Our next question coming from the line of Andrew Tsai with Jefferies. Your line is open.

Hi guys, thanks and good afternoon. Big congrats on the progress as well. For the X-TOLE study, very nice to see that it's wrapping up soon. So, can you talk about what you would construe as positive safety data? I mean, presumably I'll show AES in the topline, but will you, for example, share biomarker data or other measurements like eye exams, [Indiscernible] and so forth? Can you just talk a little bit about that?

Yes, look, as Ian said that, Andrew, we haven't nailed exactly what's going to be disclosed in the topline yet. So, of course, sort of high level safety tolerability will be. I think we need to think this through carefully. We obviously recognize there are certain safety tolerability data sets, which are going to be very, very relevant, we understand that. Some of that I think will be particularly important over time. So, eye measurements are being done. Obviously, urine is being looked at. Urinary hesitancy and/or retention, of course, is being captured, if any, has occurred. So, we will have that data. I think Ian made the point earlier, which I think is always the, the point in topline is balancing the speed to present with that material information in hand with the amount of data analysis one needs to do. And so typically we would do these staged releases, driven by at least having this topline material data in hand, press release that, as Ian said, with a press release, and then follow-up with a number of what we know are important analytics, which will come between now -- then and AES, as your likely time points. So, hard to pinpoint exactly at this point what's going to be in that first press release, Andrew. But we'll come up with a plan. As when Ian said I think before data after the second quarter, we'll probably be in a position to upload and -- sorry to download on what is exactly going to be presented.

That's very clear. And my second question is actually back at SN Conference. I believe one of your team members affirmed that a handful of patients had completed the open label phase, none of them had seen any safety issues. If that's true, I'm wondering if there have been more patients who have completed the open label phase and the safety profile still looks pretty pristine as you had expected? Thanks.

Yeah. I mean, we -- I won't make any specific comments on safety. I will confirm, so the way the study on the open label extension, the way the study was designed, initially, as we know, it's an eight week double blind with the opportunity for every subject, regardless of dose group work placebo to go on to open label extension, and we've said we've had a very high conversion rate into OLE. OLE is a single dose, which is 20 milligrams and that OLE was initially designed as 12 months, which is quite standard. We had starting at the end of last year and into the early part of this year, as patients were rolling off of 12 months, we had questions and asked from physicians and steering committee members for a continuation of the open label extension. And we did that and we extended OLE out to three years. And we've gone through a number of key regulatory filings to extend that. And I think we're that maybe to link back to your earlier question. I think where some of our long-term safety data is going to be important is your question around some of those safety events that showed up with ezogabine after cumulative dosing over a longer period of time. So the more data that we can collect for patients going out more than a year or multiple years, when we talk about pigmentation risk, to be clear, the position from us at the company is we don't believe 1101 has any pigmentation risk, but the more data that we can generate and release over time from open label extension is going to be important for a number of our constituents.

Great. Thanks for the color.

[Operator Instruction] And our next question coming from the line of Serge Belanger with Needham. Your line is open.

Hey, good afternoon. Couple of questions for me. The first one on 1101, more specifically the MDD program. Just wanted to clarify something, you plan on initiating the company sponsored study before you get results from the physician study and at this point, maybe I miss any prepared comments, but is this going be open label or placebo controlled and dose ranging? And then secondly, on the 496, EPIK trial like it's too early to give an enrollment update here, but maybe just give us an idea of how many sites are up and running and maybe, with COVID restrictions as they've been a serious impediment to enrollment and should we expect a significant improvement once restrictions are lifted? Thanks.

Thanks, Serge. So on the MDD question. So from an order of events, yes, we expect the Sinai study is ready to be up, that study will start in the near term. So that one's ready to go. And then yes, our current plan is to initiate a company sponsored MDD study in advance of that physician sponsored Mount Sinai readout. And in commentary we made in Q&A, is that our expectation, although we can't predict with certainty today, but our expectation is that we'd have a readout of our study likely before the Sinai readout would be the likely order of events. You also had a question just on that trial design. We're still -- we have a protocol synopsis. We're still in the planning stages of that study. But we would expect it to be a randomized study with placebo control. Maybe not dose range finding, we wanted to answer a number of questions in the X-TOLE study around dose, dose response, minimum effective dose, where is likely and a proof of concept study in MDD, we would choose a dose in a placebo controlled study. Moving to EPIK. So the study is up and running so it was actually on 496 for Phase 3 program. And we have kind of what we said in the past and we don't get kind of granular on specific site numbers. But we expected it starting in the US that really for the first few quarters of this year is when we were looking to get a number of sites up and running in the US. And then other jurisdictions outside of the US would come online as the year progresses. So we're still on track for that. I would say there's probably been some COVID impact. We do hear from sites that some of them have been -- and that's probably lessening over time. But they have been focused on either COVID clinical trials or sites that have just been busy dealing with the pandemic and dealing with COVID patients. So it's likely had some impact, it's always difficult to know exactly how much. But that's some of the feedback we've received. And then we've also mentioned, as we get a couple of quarters into enrollment, that's when we'll be in a position where we'll feel comfortable trying to give some top line guidance on when we should see data from that study.

Next question coming from the line of Yatin with Guggenheim Your line is open.

Hey, guys. Thanks. This is Eddie on for Yatin. Just the high level question on 1101. How should we think about the potential efficacy coming next quarter in comparison to the old ezogabine data? Do you need to show an enhanced efficacy profile over those older data? Or is it really just a story about safety and dosing regimens? How should we think about those top line data? Thanks.

Yeah. So Eddie, that's a good question. It's a question we often get. And we did design the statistical analysis plan and the powering for the study, taking into consideration the ezogabine data, we know ezogabine same mechanism. The data that ezogabine generated over a decade ago in adult focal epilepsy was statistically significant and was impressive. And so that was data that we've looked at and thought about, as we've put in our assumptions into the modeling and the powering calculations. We've taken that into consideration. That said, ezogabine or potiga is no longer commercially available, it's not on the market. This isn't an active competitor. Our -- and the treatment and the drugs that are available for these patients are different today than when ezogabine been was trialed. And so, overall, although I think that that's a backdrop that we think about, I don't think we need to necessarily compare it to the ezogabine data, we want to compare to where 1101 is going to fit currently in the anti-seizure market, both from an advocacy point of view. But importantly, as we talked about a lot on today's call, and we've done a significant amount of market research is on the safety and tolerability profile and the ease of use attributes.

Got you. Thanks. And then just one really quickly on AE profile. In the Phase 1, you did show some mild cognitive effects. I'm just wondering if that's something that you think could be exacerbated in a larger study that we can tend to be concerned about?

I'll take that Simon, Eddie. Yeah, look, any Phase 1 study with a CNS acting drug in volunteers is likely to exaggerate the tolerability of the drug. When you go to a community based study and patients or an outpatient based study, it's generally very, very different. These are patients that are used to taking are more used to taking anti-seizure meds. Remember, these individuals in our trial have been on many, but are on one to three additional meds at the time of inclusion. So they are quite used to the tolerability. And we have also, as you probably recall, designed the study such that with dosing in the evening, which was different from our Phase 1 setting, which were the dosing was in the morning, but dosing in the evening in this trial as Ian mentioned in his notes earlier, we should see Cmax during sleeping hours and that was specifically designed given the PK of the drug to allow for any of the more significant CNS tolerability issues to hopefully be slept through. And so we don't expect the AE profile to be the same as Phase 1. I will just say and reiterate that actually the Phase 1 safety was relative to other drugs actually good, and relative to ezogabine was excellent. I mean, we have almost over mild and they were reversible. And clearly a dose dependency with the aggregation of AEEs of the 25 mg dose, remember our that this study is dosed at night and in a patient populations, our population is quite distinct, and we expect to see much improved tolerability. I think Ian mentioned earlier, the very low dropout rates, and the very high conversion to overly suggest would suggest that at least the patients are tolerating a drug to a degree where they stay in the study and move into the open label where they and the investigators know, they're getting the active drug.

Got you. Thank you. And then just one final one. Is there any possibility that this Phase 2 could be potentially pivotal that being considered? And then if it's successful like do you have a baseline assumption on how many other trials you need to get approval?

Yes, that's a good question. We don't know because it's going to require an FDA discussion. But certainly if the study is very significant, remember, it's a one sided Phase 2 trial, so we'd have to essentially double the effect size in the terms of the p-value for this to potentially be deemed significant at a two sided, which will be a requirement for this to be deemed registration. But assuming we were to see that, so in other words, if p less than 0.025, rather than less than 0.05, we would certainly engage the FDA on that discussion. And then of course, the obvious discussion is, do we just require one additional for the US at least, one additional Phase 3 trial for Europe, it's almost certain one would require two distinct studies, 12 weeks dosing designed as two sided. But for the US, it is possible that this could be deemed a registration, or should we say one of two registration trials. Remember, we still have to have a certain number of subjects in the safety database, and that numbers around 1,500, but they don't all have to come from efficacy trials. They can come from clin pharm studies, open label studies, single dose studies, et cetera. So we're going through that, Eddie, right now, but our goal would be to engage the FDA on that exact discussion if we see a highly statistically significant effect.

Thank you, and congrats Simon.

Thank you.

Our next question coming from the line of Antonia Borovina with Bloom Burton. Your line is open.

Hi. Thanks for taking my question. I just have one, which was kind of related to a question asked earlier for maybe another way of asking it. So I know that your actual trial is power to show a 15% delta between placebo and active. So I'm just wondering if you just reach this threshold, do you believe this is competitive commercially from an efficacy perspective?

Okay. Ian, do you want to go and I’ll add color. Yes?

Yes. I mean, that's a difficult question to answer, because I think in all of these things, any prescribing decision is based on totality, right? It's not just based on a single data point. And it's interesting when you talk to a lot of the community based prescribers, I'm not sure that they can rattle off the clinical trial efficacy data like we can, right? So they're really thinking about the experience they've had with a drug. How their individual patients have done on that drug? What the characteristic of that patient is and the prescribing decision that they're making? So I would never want to think about one single data point as being a driver of the ultimate commercial success for this -- for 1101. I would also say, yes, the statistical, it's a well-powered study from a statistical perspective, to show it's a linear trend test, to show a dose response and separation, and if you look at it, you're correct, that the placebo versus the high dose of 25 milligrams, the modeling is a 15% differential. Obviously, that a bunch of other things go into that model at the end of the day in terms of the standard deviation, and other things that would provide the p-value at the end of the day. So the way we think about it is if we're in that range of that 30% to 40% median reduction, we need to be statistically significant then we believe we're absolutely comparable to what the market is for efficacy and anti-seizure medications. And then when you start thinking about some of the other attributes, which are really a massive driver of how decisions are made 1101 as you line it up against the other drugs, both generic and branded drugs and adult focal epilepsy, that's where 1101 lines up really well. And I won't list those off right now. But we have gone through those in our prepared remarks, where we believe both on an ease of use and safety and tolerability so far 1101 looks very strong.

Thanks.

And our next question coming from the line of David Koh with SMBC. Your line is open.

Hi, Thanks for the update and fitting my questions in. So I just had a couple quick ones. With 1101, I know the inclusion criteria, for the Phase 2b study allows one to three concomitant or background AEEs. So I was just wondering if you had a sense of how many patients are actually on only one background therapy? And in the real world setting, do you think that you'd be able to pick up some patients in second line usage? Or would it mostly be third line plus that you expect?

Thanks, David, good questions. We don't have neither Simon or I are in the details of exactly what the patient demographics look like in the current study. We purposely kind of stay away from that. So I don't know the answer today of your question on how many are on one, two or three background meds in the study? Obviously, we'll be able to disclose that data once the trial is complete. When we think about the prescribing decisions, I mean, why don't we just spend a quick minute walking through them, because we've done a lot of this work recently. So generally, yes, at first line, many of these, so first line, meaning newly diagnosed patients, they are going to be on a generic drug. At second line, you're going to you often see branded Keppra show up. And again, not every patient is the same and not every physician prescribing habits are the same. But you often see branded Keppra show up or other generics. And at that point, still we see a percentage of patients often it's quoted in the 30% to 40% range that are still not well controlled. And that's when physicians are starting to think about rational polypharmacy. That's where Vimpat often shows up as the first branded agent. And I think we believe that's where 1101, based on its attributes, also has the opportunity to play a role based on it's going to be the only in class drug at launch with a Kv mechanism. So it'll be a novel mechanism. And some of the other ease of use attributes that we've seen. And obviously, once we have the safety and tolerability and efficacy data in hand. But that's generally, as we think about the progression of a patient, and potentially where 1101 could fit in there, or as additional agents are added to treat these patients.

Got it. Thanks for applying [ph] color. That's really helpful. And then my second question was 007. I know the active ingredient is narizine, and there's been some experience commercially with that molecule. So just trying to get a better sense of what has the experience historically been with 007 or flunarizine in terms of safety, tolerability and efficacy and such?

Yes. Thanks. So it's approved on label outside of the US in a number of countries, European, South American and others for chronic migraine prevention and vertigo. It's a CNS acting primarily calcium channel modulator, but it has some other effects. And one of the actual very interesting features of the drug, which was compelling for us is not only had there been some non-clinical data supportive of the use in CAE, but actually the tolerability of the drug particularly in the pediatric population is actually very, very good. So there are some side effects known flunarizine particularly in an elderly population. Depression and pyramidal or extrapyramidal features can be observed again at low frequency, but in the elderly. I'd say the only AEE outside of that population that one would need to consider is some weight gain. It's not that significant, but it is there in some subjects. But interestingly, in the pediatric population, this drug is very, very well tolerated, which is actually very important, because often drugs used in kids for their seizure control independent of type of seizure, this could be focal, this could be generalized, this could be absence, is often -- these are often drugs that impair the scholastic ability of these kids that have cognitive impairment and kids feel sleepy. And so this is a drug which appears to be mostly devoid of those certainty relative to the gold standard drugs in this indication being valproate, ethosuximide this would be a very good alternative from a CNS perspective. So it's actually one of the reasons David we wanted to move this product forward in this population, was because of the predicted excellent, safety, tolerability that's now being shown in 10s and 10s and 10s of 1,000s of uses of flunarizine around the world.

Okay. Thanks.

Yeah. Seven other way if the drug fails, I don't think it's for safety, tolerability. That would be my guess in this population. I think we don't -- obviously, we don't know the final efficacy, albeit it looks very good in a small subset, but safety, tolerability is well understood. Okay.

No, I'm not showing any further questions at this time. I would now like to turn the conference back over to Jodi Regts for any closing remarks.

Thank you. On behalf of the Xenon leadership team, we look forward to updating you on our progress over the coming months. Operator, we will now end the call.

Ladies and gentlemen, that does conclude our conference for today. Thank you for your participation. You may now disconnect.