Thank you, operator. Good morning, everyone and thank you for joining Kiniksa's call to discuss our first quarter 2023 financial results and recent portfolio execution. A press release highlighting these results can be found on our website under the Investors & Media section. As for the agenda, our Chief Executive Officer, Sanj K. Patel, will start with an introduction. Ross Moat, our Chief Commercial Officer, will provide an update on our outlook on commercial execution. Then Mark Ragosa, our Chief Financial Officer, will review our first quarter 2023 financial results. And finally, Sanj will return for closing remarks and to kick off the Q&A session for which Eben Tessari, our Chief Operating Officer; and John Paolini, our Chief Medical Officer, will also be on the line. Before getting started, please note that we will be making forward-looking statements today that are subject to risks and uncertainties that may cause actual results to differ materially from these statements. A review of such statements and risk factors can be found in our SEC filings. These statements speak only as of the date of this presentation and we undertake no obligation to update such statements, except as required by law. With that, I will turn it over to Sanj.

Thanks, Rachel and good morning, everyone. I'm happy to review our first quarter 2023 financial results today. We have continued to execute across our cardiovascular and autoimmune franchises, which positions us for success and growth in 2023. On the commercial side, Q1 represented another quarter of growth for ARCALYST with a net product revenue of $42.7 million. We are encouraged by our commercial execution to date. With recent increased prescriber adoption and patient enrollments, we're seeing clear signs of success from our field team expansion. We've also continued to see high patient satisfaction, strong payer approval rates, as well as longer duration of therapy. With that in mind, we have raised our 2023 expected ARCALYST guidance range to $200 million to $215 million. We also remain focused on building maximum value across our portfolio of clinical stage assets and that includes KPL-404 which is our CD40 antagonist program. We're currently enrolling the third and final cohort of our Phase II study in rheumatoid arthritis which is designed to evaluate the efficacy, dose response, PK and safety of chronic subcutaneous dosing over a duration of 12 weeks. We expect data from this study in the first half of next year. Additionally, we continue to pursue collaborative study agreements with mavrilimumab to evaluate its potential in rare cardiovascular diseases. This is a molecule that we continue to be excited about and it has the potential to impact a number of diseases. So with that, I'll turn it over to Ross to review our commercial execution for ARCALYST. Ross?

Thank you, Sanj. ARCALYST has now been on the market for 2 years and I'm delighted to share further details on our first quarter 2023 commercial performance and our plans for continued growth in recurrent pericarditis. We've been very encouraged by the meaningful acceleration in Q1 in both total and repeat prescribers in large part due to our expanded field force. Total prescribers since the launch of ARCALYST in recurrent pericarditis have now exceeded 1,000, which is a growth of more than 200 versus Q4 and is the largest jump we've seen to date. Additionally, repeat prescribers grew to 23% of the much larger total prescriber base. The underlying patient growth seen in Q1 drove a net revenue of $42.7 million, representing approximately 7% growth versus the prior quarter. Our revenue growth is despite the Q1 seasonal-related impacts to insurance plan changes and resets of copays, which are very typical for specialty drugs in the first quarter of the year. These impacts resulted in a gross to net of 10.7%, which is higher than in prior quarters. In addition to growing prescriber adoption, we're also continuing to see high reported prescriber and patient satisfaction and strong compliance and adherence when patients are on therapy. I'll also highlight that the payer approval rate in Q1 remains greater than 90% of all completed cases, as it has been every single quarter since launch. Moving to our commercial launch is focused on building the market and establishing ARCALYST as the standard of care in recurrent pericarditis. In the 2 years since launch, we've gained several insights that have helped inform our tactics. Some of those learnings led to the expansion of our field team from around 30 to around 50 representatives during Q4 of 2022. I'm pleased to share that in the early days of this expansion, our field team is executing well. We are seeing a significant jump in total activity and increased reach and frequency with our target doctors. As a result of those metrics, we are seeing an acceleration in the total prescriber base and a more meaningful jump in overall patient enrollments than we've previously seen. We believe these are all early indications of the type of impact we need to be making in the marketplace to continue to advance our business and help many more patients suffering from this debilitating disease. Additionally, we're continuing to make inroads into digital marketing, having built a database of approximately 4,500 pericarditis patients and caregivers where we are advancing education for patients themselves and advocating for ARCALYST when appropriate. Turning to our update on duration of therapy. As we follow more patients over longer periods of time in the commercial setting, we've seen an evolving picture in the average total duration of therapy. We have previously seen an average of approximately 18 months and now the latest data shows an increase to approximately 20 months. What we're currently seeing is patients are initially staying on treatment for around 14 months before trial cessation. This is an increase of 2 months over what we saw at the end of Q4. Then once patients stop treatment, given the persistence of the disease, many have experienced an unmasking of the disease with a return of symptoms until they restart ARCALYST. In fact, approximately 45% of all patients who stop ARCALYST do want to restart, with the vast majority doing so within 8 weeks of cessation. These factors will continue to evolve the total duration of the treatment and our efforts are placed on educating physicians and patients on the natural history of the disease, which is a median of 3 years. Continuous treatment with ARCALYST results in continued treatment response. We continue to be delighted with our ongoing commercialization efforts, including the early results from our expanded field team. These results, along with the feedback we are getting from physicians and patients, the growth in prescriber rates, strong payer approval dynamics and the growth in total duration of therapy mean that today, we are increasing our 2023 ARCALYST sales guidance from a range of $190 million to $205 million to $200 million to $215 million. We continue to have a growing profitable collaboration with ARCALYST and a significant opportunity ahead as we build and develop the marketplace. Two years post-approval, we are in a brilliant condition. With that said, we're highly ambitious and we now continue to do what we do best which is driving the opportunity and solidly executing to grow our business and help patients. I'll now hand over to Mark to cover our financial results. Mark?

Thanks, Ross. Good morning, everyone. Our detailed first quarter 2023 financial results can be found in the press release we issued earlier today. I'd like to call your attention to a few items and review our 2023 ARCALYST net product revenue guidance. First, total revenue in the first quarter of 2023 was $48.3 million compared to $32.2 million in the first quarter of 2022. Total revenue in the first quarter of 2023 included ARCALYST net product revenue of $42.7 million and collaboration revenue of $5.7 million from our vixarelimab global license agreement with Genentech. To date, we have recognized close to $94 million of the $100 million upfront and near-term supply payments received from Genentech. We expect to recognize the balance over the course of the next year. Second, ARCALYST collaboration operating profit continued to grow in the first quarter of 2023 and was $16.6 million compared to $4.5 million in the first quarter of 2022. Third, Kiniksa's net loss in the first quarter of 2023 was $12.3 million compared to $25.2 million in the first quarter of 2022. Fourth, we received a $20 million supply-related milestone from Genentech in the first quarter, limiting our net cash burn to approximately $3 million and bringing our end-of-period cash balance to $187.5 million. Importantly, these reserves, along with continued ARCALYST commercial execution, are expected to fund our current operating plan into at least 2026. Lastly, turning to our financial guidance. With an uptick in enrollment in new-to-brand patients from the recent sales force expansion, as well as slightly longer average duration of therapy, we now expect 2023 ARCALYST net product revenue of between $200 million and $215 million. This represents close to 70% year-over-year net product revenue growth at the midpoint and reflects our expectation for continued execution against our opportunity to help recurrent pericarditis patients by reshaping the treatment paradigm with ARCALYST. With that, I'll turn the call back to Sanj for closing remarks.

Thanks, Mark. As you've heard today, the team has a lot to be excited about in terms of the summary. In addition to our successful commercialization of ARCALYST, we also have a pipeline of mid-stage clinical programs that are aimed at making a meaningful impact on patients' lives. As a reminder, we're rolling in the third and final cohort of the Phase II study of KPL-404 in rheumatoid arthritis and that data is expected in the first half of next year. Importantly, as Mark just reviewed, we are well capitalized. Thanks to those growing ARCALYST revenues, non-diluted capital from strategic out-license transactions and our continued financial discipline, we now have our expected cash runway into at least 2026. Ultimately, our mission is to continue to help patients in need, create massive value, and make a generational impact. We believe we are strategically positioned to do exactly that. I do want to thank you all for your time today. I'm going to hand it back to the operator for the Q&A session. Thank you.

Congratulations on the quarter. One clinical question to start maybe for John, which is, as you look at the landscape in RA and the 404 CD40 program which you're now enrolling the next cohort on, how do you think about what you'd like to see with regard to potential disease activity scores as you top line data here? And what would sort of be the data you'd look for to think about a go-forward decision on your Phase II? And my second question for either Sanj or Eben is, as you survey the landscape for assets, what are your thoughts on valuations for assets that could either fit into the cardiovascular II phase that would be potentially synergistic with your commercial and/or R&D efforts?

So regarding the expectations for the Phase II study that's going on now in rheumatoid arthritis for KPL-404 and what we like about this program is that there's a lot of external proof of concept, as you know, benchmarks in this disease area as well as with this particular pathway of blocking the CD40, CD154 stimulatory interaction. We've looked at those benchmarks as a way of positioning the size of the study, which, as you know, with the parallel design which is going on right now, is really testing the efficacy of the essentially very practical 5-milligram per kilo subcutaneous dose administered either biweekly versus placebo and then asking the question whether 5 milligrams per kilo administered weekly, if you see higher plasma concentrations in the model delivers even more efficacy. Our intention is to then compare that against those established benchmarks, whether it was with our other assets in the rheumatoid arthritis phase where reductions in DAS28-CRP as well as attainment of low or no disease activity are really well-established benchmarks in the disease without going into specific numbers. Similarly, we can also look at two other assets that are in that space, one CD40 asset and one CD154 targeting asset, and those also have some established benchmarks. So we'll be looking at that while focusing on our own asset and testing how it is delivering using that practical subcutaneous dose.

In terms of BD, Paul, we continue to be very active, highly active, in fact. We've got a very strong team under Eben looking at a number of opportunities, as you can imagine. There are quite a few things for us to look at right now. We believe there are opportunities that could add substantial value. Our bar remains very high, so we'll be very discerning. To the extent we do find something that's tangible both scientifically and commercially, then we will obviously elucidate at that point.

Just had a few. The first is when you look at ARCALYST duration of therapy, you guys gave some stats on patients who have restarted after discontinuation. The question is, are there themes? And why would a patient discontinue? And obviously, there's a benefit from keeping them on, but wondering if there's an effort there to retain patients that initially start therapy. And then, just another one on 404; talk a little bit about how you see the kind of investments needed here to get to perhaps the next step. Is there a scenario that you could sort of co-develop some indications or some geographies and still retain broader rights?

Geoff, this is Ross. So maybe I'll make a start on the first part which is around the duration, which as we said in the prepared remarks showed growth in the average total duration of therapy around 20 months for patients now. So in terms of the restart rates, that's remained pretty consistent over the last couple of quarters at around 45% of patients who have stopped that eventually go back on to therapy. The vast majority of those are within 8 weeks of stopping. Of course, some patients do stop and go for several months before they probably have a flare again and then go back on treatment. There's not really any correlation right now; the numbers are still reasonably small, and the data builds over time in terms of which patients are stopping therapy and which ones are then restarting. Ultimately, it comes down to a judgment with the physician and the patients on how long they've suffered with recurrent pericarditis, which fluctuates against the timing of their ARCALYST treatments. There are multiple factors there involved in making that judgment call. Once patients do stop therapy, they have ARCALYST as a safe option to restart treatment, and that’s been proven that they regain control very quickly. We want continuous treatment throughout the course of the disease. So it's an evolving picture at this point. Sorry, Geoff, could you repeat the second part of your question?

Yes. No, that's a great question. It really depends on the data and the results. We're certainly open to it. You've seen that we're open to creative collaborative deals in the past. At the same time, the results are excellent, and we really believe there's an opportunity for us to move forward alone and create more value ourselves and capture most of the value. We've shown that we can commercialize and execute as well as develop. We'll consider all options available, determining which brings us the most value and then proceed accordingly. No, great. Thank you, everybody, for the questions and joining us on the call today. We clearly have an exciting year ahead of us and very much look forward to providing additional updates in the future. So with that, have a great day. Thank you.

This concludes today's conference call. Thank you for participating, and you may now disconnect.