Kiniksa Pharmaceuticals International Plc Q4 FY2025 earnings call

Commercial Execution - ARCALYST

• Full year 2025 net revenue was $677.6 million, a significant increase from 2024.
• ARCALYST franchise is profitable, allowing investment in commercial infrastructure and digital marketing.
• Focus in 2026 includes driving physician awareness of 2025 ACC concise clinical guidance, advancing digital marketing, utilizing AI and machine learning for targeting, and exploring expansion of pericardial disease centers.
• At the end of 2025, over 4,150 prescribers had written ARCALYST prescriptions, with growth in total and repeat prescribers.

Clinical Progress

• Announced development program for KPL-387 in recurrent pericarditis, initiated Phase II/III clinical trial in 2025, continuing to enroll and dose patients in Phase II with data expected in second half of 2026. KPL-387 could address key patient needs with potential monthly dosing and auto-injector.
• Plan to be in clinic with KPL-1161, an Fc-modified IL-1 alpha and beta inhibitor, by end of 2025.

ARCALYST product revenue grew 65% year-over-year to $202.1 million in the fourth quarter and 62% to $677.6 million for the full year 2025. ARCALYST revenue growth has been profitable since the fourth quarter of 2021. The primary driver of growth is the expanding adoption of interleukin-1 alpha and beta inhibition with ARCALYST as a second-line treatment in recurrent pericarditis. At the end of 2025, more than 4,150 prescribers had written a prescription for ARCALYST, with around 29% or more than 1,200 prescribers writing for 2 or more recurrent pericarditis patients. Penetration into the 2-plus recurrence target market increased to approximately 18% at the end of 2025 compared to previous periods.

Revenue Guidance

• Reiterated full year net revenue guidance of between $900 million and $920 million for 2026.

Clinical Guidance

• KPL-387 Phase II data expected in second half of 2026, with plans for subsequent Phase III trial and long-term extensions.

Forward-Looking Statements Risks

• Forward-looking statements 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 SEC filings.

Q: You guys have reported continuing increased penetration in the multiple recurrent setting. So I'm kind of wondering what do you think the peak penetration is for ARCALYST in this setting? And how could that evolve with the potential approval of KPL-387?

A: Sanj Patel and Ross Moat responded that they haven't commented on peak penetration yet, believe there's still a lot of growth to capture with ARCALYST, with current penetration in 2-plus recurrence target market at ~18% and a large opportunity in first recurrence population.

Q: You've mentioned several times now that 20% of ARCALYST patients are in first recurrence versus 80% in 2 plus. And I guess my question is, is the pace of growth in these 2 different patient populations the same in terms of like ARCALYST? And does your market research suggest potential changes to the 20:80 ratio?

A: Ross Moat stated that the percentage of first recurrence patients has grown over time, view it as positive as physicians are prescribing earlier, but how it evolves is to be seen. No meaningful difference seen in persistence rates between the two populations, and health care professionals are shifting mindsets in treating the disease.

Q: The first on the pipeline, so 387 or even 1161, what's the extent of FDA interactions of late? It does seem that the agency is maybe more open for novelty on design or maybe adding analytics just to speed up the development and maybe down the road, the review process. Just curious your thoughts on that and maybe how you could take advantage of that. And the second one, another one on first recurrence versus second or later. Are there differences in persistent rates between those 2 populations?

A: Sanj Patel and John Paolini discussed that they value FDA interactions, KPL-387 development program has had productive interactions with FDA, integrated development program assembled. For 1161, preclinical development ongoing. Ross Moat stated no meaningful difference in persistence rates between first recurrence and 2-plus recurrence populations.

Q: Just given the current Phase II/III and this Phase II transition from the standard of therapy, those study design and the planned studies, will this -- the label and then the potential reimbursement test will be similar to the ARCALYST when 387 launched? And then ultimately, when it's available, basically led the physician -- patient to choose between 387 versus ARCALYST? Is that the base case here?

A: John Paolini said KPL-387 program has a similar regulatory framework with a full BLA package, core Phase III study design resembles RHAPSODY. Ross Moat stated ARCALYST has substantial future, KPL-387 aims to address key patient needs with target product profile preferred by 75% of patients and highly likely to be prescribed by health care professionals