Ross Moat
Analyst · TD Cowen
Thank you, Sanj. Our continued commercial execution has driven strong revenue growth in Q1, leading to an ARCALYST net revenue of $214.3 million, which represents an increase of more than $76 million compared to the first quarter 2025 and approximately $12 million over Q4 of last year. This revenue growth was driven by strong underlying commercial metrics, which outpaced the Q1 industry-wide headwinds related to co-pay resets and changes in insurance plans. In particular, growth was achieved by 2 key commercial dynamics. Firstly, we saw an acceleration in the growth of new prescribers through the quarter, which resulted in the highest quarterly increase in new patient enrollments since launch. This bodes particularly well for the rest of the year as the new larger prescriber base, along with the durability of average duration of therapy has enabled us to increase our full year revenue guidance from between $900 million to $920 million to between $930 million and $945 million. Secondly, in Q1, our gross to net increased compared to the prior quarter as expected. However, it was lower than Q1 of 2025. This was mainly driven by changes to our co-pay support program where we made enhancements to our assistance program design, which reduced the average co-pay payout per patient relative to prior Q1s. With the momentum created early in the year, combined with our strong underlying commercial foundation, we believe we are well positioned to continue driving ARCALYST growth through the rest of the year and believe there is substantial opportunity ahead to support many more recurrent pericarditis patients. In Q1, thanks to the strong execution from our team, approximately 400 new prescribers wrote ARCALYST for the first time, representing the highest quarter-on-quarter increase launched to date. This brings the total number of prescribers to more than 4,550. As a reminder, with more than 25,000 health care professionals seeing recurrent pericarditis patients in a given year, there is substantial opportunity ahead. We also saw growth in the number of health care professionals who became repeat prescribers during Q1, resulting in approximately 1,320 prescribers in total who have now prescribed ARCALYST multiple times. The acceleration we've seen in both the breadth and the depth of prescribing reflects our continued commercial execution as well as the growing understanding and adoption of interleukin-1 alpha and beta inhibition as the treatment choice following the prior use of NSAIDs and colchicine, as recommended in the 2025 ACC Concise Clinical Guidance. Earlier this month, we announced the initiation of our highly targeted direct-to-consumer campaign, Heart's Home. This campaign is designed to identify and target patients who may be suffering with recurrent pericarditis and not currently taking ARCALYST with the aim of empowering them to discuss ARCALYST with their healthcare provider. Through digital innovation, including the use of AI, we are able to deploy DTC in a way that's cost effective, highly targeted and ultimately applicable for a rare disease market. We have focused on utilizing our existing patient database and added search optimization and machine learning models informed by de-identified claims, demographics, and consumer market data to define an enriched population of potential recurrent pericarditis patients to deliver tailored content, opposed to a traditional DTC approach of broad-scale and high-cost marketing. The centerpiece of our campaign is a connected TV commercial that is directed to potential patients through their individual streaming accounts on platforms such as YouTube and Hulu, as well as across social media channels. This campaign is informed by our market research, which demonstrated that when a recurrent pericarditis patient inquires about ARCALYST to their provider, the healthcare professional is receptive to the inquiry, and it results in ARCALYST being prescribed in around 80% of cases. As previously mentioned, our ARCALYST franchise is growing, is profitable and has significant opportunity ahead, and this has allowed us to make disciplined investment decisions to expand our reach to capture the opportunity and help more patients. With that, I'll turn the call over to John to cover our KPL-387 development program.