Morning, everyone. Welcome to the Jefferies 2026 Global Healthcare Conference. My name is Roger Song, one of the senior analysts covering mid-cap at Jefferies. It is my pleasure to have a fireside chat with the next company, Kiniksa Pharmaceuticals. We have Ross, the Chief Operating Officer, and then also the CMO, John. Welcome, gentlemen. Thanks, Roger. Thanks very much, Roger. Awesome. All right. Maybe, either Ross or John, you want to give us a state of where Kiniksa is right now? I think the momentum is so strong, the commercial sales are not even launched, right? Still very just strong. The people are expecting that the growth trajectory continues. Obviously we have the monthly and the lifecycle management even cannot continue the tailwind from here. Yeah. Thank you very much, Roger. This is Ross, Chief Operating Officer at Kiniksa, and joined with John Paolini, our Chief Medical Officer. It's a privilege to be here. Thank you very much for joining in the room and online, and Roger, to you and the Jefferies team for hosting us here today. It's always good to be here. Thank you. Before I make a start, maybe I'll just share that today we will be making some forward-looking statements which are subject to risks and uncertainties, and a copy of which can be found in our SEC filings or on our web pages. With that said, maybe I'll give a high-level overview of the organization and where we are, before I hand on to Roger for the Q&A. We're pretty excited about where we are across the business. You may know that Kiniksa is now around 10 years old as an organization. We've made phenomenal progress up until this point. We've been a commercial-stage biotech company for the last five years. The commercial progress is working along very nicely, as you may have followed in our earnings calls and through some of the commentaries with Jefferies to this point. We'll go into that more today. In Q1 of this year, we saw strong growth. We increased our net revenue guidance for ARCALYST in recurrent pericarditis from $900 million to $920 million, up to between $930 million and $945 million as a net revenue for 2026. Additionally, we're also excited about the pipeline opportunity that we have and we're building. You will know that we're in clinical trials with KPL-387 in a phase II/III clinical study. We are expecting data from the dose-focusing portion of the phase II clinical study in recurrent pericarditis in the second half of this year, and we're anticipating starting the phase III study by the end of the year also. For our other assets in our pipeline, KPL-1161, we have said that we are moving forward and accelerating into the clinic, in a phase I study by the end of this year also. You may know that that's an Fc-modified monoclonal antibody, with a target profile of a quarterly regime for an interleukin-1 alpha and beta inhibition drug. We're pretty excited. Great to be here, and happy to crack on and go through your questions, Roger. Awesome. All righty. I think I say the momentum for the sales of ARCALYST in recurrent pericarditis is so strong. As the Chief Operating Officer and then the commercializer, and then what are the key drivers here? The more interesting thing is that we're going to continue this momentum, and then you're going to do something new or incremental to continue the trajectory. Thank you very much. Acknowledging that we're five years out from the launch, when we came with our Q1 earnings call a little while ago now, it was interesting to share that in Q1 of this year, we actually saw the highest ever quarter-on-quarter growth of new prescribers, as well as the highest ever quarter growth of enrollments, meaning new patients gaining a prescription for ARCALYST, which I think is quite some feat five years out from launch. I think it speaks to the momentum, as you say, Roger, but also to the opportunity that we have ahead. We've always said that the launch in recurrent pericarditis is going to be one that we build over time. We are establishing this marketplace. We are changing the treatment paradigm and changing physicians' mindsets in from historically how they treated and identified patients and looked after this disease, to this new way of doing it, utilizing a biologic, and really understanding that recurrent pericarditis is a disease that is ultimately driven from the two key cytokines, interleukin-1 alpha and beta. By inhibiting both of those cytokines like we do with ARCALYST, you have pretty tremendous efficacy and a very solid safety profile with ARCALYST. As more and more physicians gain familiarity with that and with prescribing ARCALYST, and they see the effects that it has on their patients, we think that builds momentum over time, and that's ultimately what we've seen. It's also against the backdrop that unlike in many other rare disease spaces, this is a disease that patients are kind of pretty dispersed across the country. It's not generally looked after by a very small number of concentrated key centers of excellence that are looking after a very high proportion of the patients. What that means is that we've got to go and educate and change the treatment paradigm with a large number of doctors all over the country, and we see it really as a one-by-one challenge of educating and informing and sharing best practices. As that's grown over time, and now we have around 4,550 total prescribers, that's actually out of a base of around 25,000 physicians, cardiologists, or rheumatologists that actually see a recurrent pericarditis patient in a year. You can see that we're making penetration into that, but the opportunity of switching on more and more for the future is very much there. We're very focused on that challenge. We also have a lot of publications and, for example, the ACC Concise Clinical Guidance, which was published in August of last year, which is also emphasizing this change in the treatment paradigm that we've really been focused on since the time of our launch. Ultimately, placing interleukin-1 alpha and beta inhibition after the use of NSAIDs and colchicine and before the use of corticosteroids, which is really how we've promoted this drug since our launch five years ago. It's nice to see that other angles are also helping to kind of shift that treatment paradigm. Good progress so far, but very excited by the future. What you would know about Kiniksa, hopefully, is that we're an organization that does not rest on our laurels at all. Yes, we've built good momentum, and we've got very strong fundamentals of the business, but we very much see this as the start and the foundation for what we want to achieve in the future. Yeah, it's a great start. It's getting towards the $1 billion already. I know the initial targeted population or the right now the focused population is multiple recurrence, the pericarditis. That population is the initial, and then you do see some penetration into the first. Maybe focus on this one first, and I think that based on the recent estimate of about 18% penetration rate, just curious about what are the seeding factors you cannot get to 30%, 50%, even more. One of the dynamic is, my understanding is, this population is dynamic. It's not like you have this one person all within this pool. Even you say 18%, you're actually treating a lot more than 18% of this. People will have the multiple recurrence in any given time. Maybe just walk us through how you think about this TAM and then also the penetration rate here. Thank you. When you think about the target addressable population in this disease space, there are around 40,000, four zero thousand patients, in any given year. Acknowledging that this is a disease for many patients that goes on for many years. It's certainly a chronic multi-year disease. For most patients, it's probably not a lifelong disease. What happens in any given year is that there are patients that naturally stop having the disease, but there are new patients that go in and start having it. You've got a static 40,000 population with a lot of turn within that, which means that you've constantly got opportunities for identifying new patients and helping them as they come into the patient pool. The target addressable population is really 40,000 patients, and then that's broken down into patients that are on their first recurrence or multiple recurrences. Out of the 40,000, there are around 14,000 that have two or more recurrences in any given year. Certainly at the time of the launch, that was really our main focus. I think logically so because that was where we had the majority of the data from the RHAPSODY, the phase III clinical study, which was for patients that had two or more recurrences. It's also the patient population that has the highest burden of the disease. They've been suffering for the longest, and generally in this disease, the more recurrences you have, the more severe the disease is, the longer the disease goes on. Clearly, there's a significant need to help those patients. We also acknowledge that the label of ARCALYST is very broad and is actually completely agnostic to the number of flares that a patient has to have suffered before they actually get the help that they need through blocking interleukin-1 alpha and beta. As we've seen time move on since the very early launch months and years, we've seen a shift in using ARCALYST earlier on in the disease. Today, we're in a situation where we have around 20% of all of the prescribing that happens for ARCALYST is for patients that are on their first recurrence, and around 80% on the 2+ recurrences. When you look at the 2+ recurrence group, we shared at the end of last year, we were around 18% penetration into that 2+ recurrence group. Which again, shows good progress, 18% I think also tells you that there's a lot of patients there that are on 2+ recurrences that have currently not got the help that they need with ARCALYST, let alone obviously the first recurrence group, which is a much larger group with a smaller penetration. The opportunity is really there to help patients across the broad label of ARCALYST. I think what we've seen over time is that as physicians treat their patients with ARCALYST and they see the magnitude of the effect that it has and how patients generally get on very well with ARCALYST. We've seen patients on ARCALYST for many years now. The mindset rather than short treatments of just treating the flare of the disease through to actually treating for the duration of the natural history of the disease over the long term, which is what ARCALYST was really designed to do, has really got cemented within the healthcare professional population. We've seen patients on therapy for a long time now. The opportunity to grow much further into the 2+ and the first recurrences is very much there. As people get more familiar and see those impacts that the patient has, I think that gives people the confidence to prescribe earlier on and to really take the mindset of why does a patient that may have signs of severe disease, but they're on their first recurrence, why should you have to wait until they suffer more recurrences before they get access to this therapy? That's what we've seen, and I think that's a positive shift in the physician community over time. Yeah. Maybe also, John, you can comment a little bit on this population because I think as Ross mentioned, this is a kind of dynamic population. Some of them have a multi-year disease, but at some point they think, "I don't have a disease anymore." Right? How does churn in this even just entire 40,000, maybe more importantly for the 14,000 multiple recurrence, when those patient will start to think about. Okay. I don't have that disease anymore. I don't need the treatment, including the ARCALYST. Thank you, Roger, that's a great question about the duration of the disease, because as Ross mentioned, it's very important that the duration of therapy be matched to the duration of the disease. I think what the clinical trials have shown, as well as our RESONANCEy registry data show is that, and the epidemiology data show, it's a long disease. Ross mentioned the three-year median duration of disease, with a third of patients still suffering at five years, a quarter of patients still suffering at eight years, and that was the end of the data set. Right? Other orthogonal data sets also point to a very long duration. That is an interesting question because there are no direct biological markers that tell you at any given time, especially while on therapy, whether the disease is still present. A lot of that thinking actually begins when the patient is identified. There are, for example, risk scores that look at a variety of different presenting clinical characteristics that can tell you, at a minimum, what is the likelihood that this patient could achieve drug-free remission at one year, at three years, at five years. Those are important variables for a clinician to think about when they initiate therapy. As that time then goes along, patients, while on therapy, certainly on IL-1 pathway inhibition, have done incredibly well, right? The pain, inflammation, other markers usually go quite flat. So what we've shown in the clinical trials is that when a clinician decides with their patient that if they're interested in seeing if the underlying disease is present or not, and if therapy could be stopped, there is an approach that we have tested in the clinical trials, which is that it actually takes advantage of the long duration of action, if you will, of ARCALYST. Upon suspension of therapy, it takes approximately six weeks for the drug to gradually wash out. Then there's usually a two-week prodrome, that we saw in the clinical trials, where pain gradually increased. So it's that seeing that the pain is gradually increasing, that's the marker of the fact that the disease is still present, and that the IL-1 pathway activity has resumed. While in the clinical trials, we follow that all the way to the point of an actual flare, but in actual clinical practice, it's not necessary to do that. If you see the increase in pain, that would then indicate that disease is still present and then therapy could then reinitiate with rilonacept, with ARCALYST, and putting the disease back under control. Those are the tools that are available to clinicians at the current date, but that allows for the long-term management of these patients so that, again, the duration of treatment matches the duration of disease for as long as they need it. Got it. Okay. That's very helpful. I visited your office a couple of years ago when we started to cover you guys. I think you're building a real company, right? Commercial-wise and then clinical-wise. I think Ross, you mentioned this targeted physician group is 25,000 cardiologists and rheumatologists. What's the current outreach look like, and then intensity-wise, and then how your sales rep on the ground to cover those population. I believe you have about 50% of the prescription coming from repeat prescriber. How this will change over time, and what's the average patient number for those prescribers? Thank you, Roger. There's a lot there. We have been very focused with both our field force execution, what we do on medical affairs as well is incredibly important because we are really shifting mindsets and the treatment paradigm and changing the learning of how people think about this disease. We're also very focused on other ways of constructing dialogue with physicians, and also with patients as well. For example, we have been supporting the American Heart Association initiative, called Addressing Recurrent Pericarditis, which I think is a very important initiative that has helped to evaluate and work with centers that really want to become pericardial disease specialist centers across the country. There are now around 18 of those centers across the U.S., and the importance of that collaboration is also how those centers share knowledge between them and the best ways of approaching and looking after pericardial disease patients per se. Of course, which of recurrent pericarditis is one of several pericardial diseases. We think that is very important for changing the education across the country. We also recently launched initiatives such as our DTC campaign, in a very targeted, very structured way of going out to patients who we believe are suffering from recurrent pericarditis. In order to enable us to do that, we've actually utilized a lot of more modern learning and ways of analyzing data using artificial intelligence and machine learning to really try to specifically target the base of patients that are suffering from recurrent pericarditis, and enable to serve up ads through DTC that are empowering to those patients. It increases the knowledge of not just the disease, but ultimately of treatment that is available to them. We've looked at that route as well, which is very supplementary to what we do in the field. We think that's very important because one of those metrics to share with you on why we stepped into the DTC campaign is partially because historically, really DTC is something for bigger pharma and big disease spaces. Now by using modern technology, you can do things in a very targeted, structured way, and a cost-effective way. We know that when we do surveys with recurrent pericarditis patients who are suffering with the disease and ask them what their unaided awareness is of ARCALYST as the only approved treatment therapy for this disease, it was 14%. Generally, the awareness among the patient community is not very high. Maybe that's a construct of how dispersed the patient population is and where we are with building this market and helping the patients. Conversely, when patients are aware of ARCALYST and when they go in and speak to their healthcare professional and discuss ARCALYST with them, a prescription for ARCALYST is written in 80% of those cases. We know that it's actually very powerful if you can identify patients that are suffering from the disease, inform them of ARCALYST, and empower them to go to their physicians to discuss ARCALYST. That's an area that we've been very focused on. A lot of it is just continued execution in the field, in the doctors that we call upon and how we try to create a halo effect with every doctor that you switch on, and then how they become repeat prescribers over time. Obviously, because the patients are dispersed, there are many doctors that just don't see many recurrent pericarditis patients in a given year, so sometimes it's a matter of time of waiting until they see the next patient, they identify the next patient to help. Sometimes there's a lag there. As you said, Roger, we're now in a situation where about 50% of the prescriptions in a given quarter come from repeat prescribers, and around 50% come from new prescribers. I think that's actually a very healthy metric given that we're five years out from the launch and the opportunity that we have ahead, as I said, to continue to switch on up to the 25-odd thousand prescribers that look after recurrent pericarditis patients and where we are with the penetration rates and the opportunity we have. That kind of 50/50 mix, I think, actually kind of speaks volumes of the progress we've made, but the future that we have. Yeah, I think that's pretty encouraging. You do have a relatively low awareness among patients, but once they are aware, and then the conversion rate is very high. The physician part is that once they prescribe and you have 50% of people they are wanting to repeat, but not because they don't like the drug, because they're probably not seeing the patient too often, right? Yeah. Okay, got it, the dynamic. All right. Understand the commercial for ARCALYST is still the dominant conversation among the investors, but also people are starting to pay a lot more attention on the pipeline. 387, that's probably the monthly one. It's upcoming pretty soon. What's the latest method? Because we've been talking about this for a while. I think now we're about to get to the level we're going to have some disclosure or updates for the phase II portion of the study, and then what will be the profile to support the next stage of phase III? I understand the study design is a pretty smooth transition. Sure. Thanks for the question and your interest in KPL-387. We're very excited about the KPL-387 program because of the possibility that this could enable once-monthly dosing in a liquid formulation for self-administration. What we've disclosed so far is that the phase II/ III clinical trial is underway, right? That we anticipate data from the phase II portion of the trial in the second half of the year, and that we anticipate starting the phase III portion of that trial by the end of the year. That gives you a little bit of the timeframe of how that is going. In addition, we have ongoing the transition to KPL-387 monotherapy study, which is really about dosing and administration. The phase II/ III study is certainly the phase II portion of that is a dose-focusing study. We have four arms that are ongoing, the four arms that are in the trial. The purpose of that is to define, if you will, the PK/PD relationship of KPL-387. Understanding that it's a phase II trial, right? It really focuses on onset of action. It focuses on that cadence and magnitude of effect, as well as the durability of that effect as you look at different dosing intervals. It's really that totality of information that comes together that will help us understand the dose that we would take forward into the phase III portion of the trial. That's kind of where we are and what we anticipate for the second half of this year. Mm-hmm. All right. Also we want to set the right expectation. This trial or the phase II portion of the trial is not supposed to see statistical efficacy or anything like that. Maybe just what are the key data points that we should be looking at? Then as you made the clinical strategy. How you will make decisions, say, "Okay, I will move this dose to phase III.'' Sure. No, that's a very interesting question. You're absolutely right that, for example, with ARCALYST, the registrational endpoint came from the phase III portion of the trial in the randomized withdrawal portion. When you see that 96% relative risk reduction, that came from the randomized withdrawal portion of the trial. That's a very phase III kind of endpoint, and that's what we have, as we've discussed, for the phase III portion of the KPL-387 trial as well. The phase II trial is a different focus, and you have to dial back essentially to the 2018, 2019 timeframe when we did the initial studies of rilonacept. At that time, what we were looking for, and we were taking patients who were on oral therapies, and then looking who are flaring despite those therapies, and then added on top rilonacept at the time. That what we were looking for was the cadence or the speed at which the drug took effect, and we saw that as quickly as after the first dose. The magnitude of effect, meaning how much it lowered NRS and the inflammatory markers, right? That durability of effect that we saw by using weekly dosing, that in that phase II program, we were able to see a consistent effect throughout the dosing interval. In that sense, that's kind of what we saw in the phase II portion. In fact, at our last earnings report, we kind of re-shared a little bit about what that phase II experience looked like. Of course, we refined and extended that at the front end in the run-in period of RHAPSODY, which was the pivotal trial. It was in that run-in portion that was roughly similar. In that sense, the KPL-387 study actually takes four dose levels into that, it achieves different peak levels of drug, as well as different trough levels of drug over time and works different dosing intervals. Those are the kind of pieces of information that would come out. In terms of how we then put that together, this is part of our experience that goes back over practically a decade, to put that together into using the totality of the information to select the dose level that we believe would be the best for patients, and to lead to what we would hope to be the best outcome as we proceed then into that randomized withdrawal kind of trial. Got it. Okay. Because this is a once-monthly liquid formulation self-injection, you do have the ARCALYST that's launching pretty well, sells pretty well, how should we think about if 387 is also successful, how you're going to position those two products in your portfolio? Not to mention that you have a partnership with or at least a collaboration with Regeneron, so how should we think about that relationship with 387? Yeah, thanks, Roger. There's a lot to be determined there, we're just very focused on what we're doing around ARCALYST and the potential that ARCALYST has, which we think it has a very bright future, given all the things that we've discussed today and where we are at the time of our launch and the opportunity ahead. We think ARCALYST has an incredibly strong future, and we're 100% focused on that. At the same time, we're very excited about a potential new treatment option in KPL-387, with the target product profile that you mentioned of an interleukin-1 alpha beta inhibitor with high efficacy and potentially a good safety profile in a monthly format. We think that could provide a good future treatment option for patients as well. We're very focused on the clinical picture and moving along our pipeline. A lot more to be discussed over time. Yeah. It's a good problem to have, and once you have a successful 387, and then you're going to decide on what's the strategy over there. Got it. Maybe just last minute, what's the financial guidance? I think you raised the revenue guidance for the year, and then the cash, and I think you are profitable. Just maybe last wrap-up. Yeah. Thank you, Roger. Maybe just to close out and thank everyone for attending today. We are very pleased with where the business is overall. We have growing commercialization with huge potential left. In Q1, we increased our net revenue guidance to between $930 million and $940 million as net revenue for full year 2026. We're also focused on KPL-387, and bringing in the phase II data in the second half of this year, hopefully initiating the phase III study by the end of this year. We're also focused on KPL-1161 to move into the clinic in a phase I by the end of this year also. Clearly, we have substantial catalysts ahead of us. Maybe as a reminder, Kiniksa is a profitable organization at this point. We have strong cash reserves of around $468 million as of the end of Q1, and we are incredibly excited about the future. Thank you very much. Excellent. All right. Thank you, everyone. Thank you, Roger.