Kiniksa Raises 2026 ARCALYST Sales Outlook as Q3 Revenue Rises 58%

Kiniksa Pharmaceuticals International plc (NASDAQ: KNSA) raised its 2026 ARCALYST net product sales guidance to $1.045 billion-$1.050 billion after third-quarter revenue increased 58% year over year, driven by broader adoption of the recurrent pericarditis treatment. The company also reported higher operating and net income while continuing to invest in commercial expansion and its clinical pipeline.

ARCALYST generated third-quarter net product revenue of $286.0 million, up from $180.9 million in the same period of 2025. The treatment accounted for all of Kiniksa’s revenue during the quarter. The company estimated that ARCALYST had reached about 23% of the multiple-recurrence patient population by the end of September, indicating remaining room for further penetration.

Kiniksa reported operating income of $54.2 million, compared with $24.0 million a year earlier. Net income rose to $47.3 million from $18.4 million. Other income totaled $4.8 million, while the income tax provision was $11.7 million.

Total operating expenses increased to $231.7 million from $156.8 million as Kiniksa supported ARCALYST’s commercial growth and advanced its clinical programs. Collaboration expenses rose to $105.8 million from $63.3 million, reflecting the profit-sharing arrangement with Regeneron Pharmaceuticals. Research and development expense increased to $32.8 million from $24.2 million, while selling, general and administrative expense rose to $65.4 million from $49.1 million. Cost of goods sold was $27.8 million, compared with $20.3 million a year earlier.

ARCALYST adoption expands

Kiniksa said the number of clinicians prescribing ARCALYST for recurrent pericarditis continued to grow. More than 5,450 prescribers had written at least one recurrent pericarditis prescription by the third quarter, including more than 1,625 repeat prescribers with at least two prescriptions.

The company’s market research also indicated increased physician consideration of ARCALYST earlier in the course of the disease. In a survey of 200 cardiologists and rheumatologists, 51% said they considered the therapy at a patient’s first recurrence in 2026, while 80% considered it at the second recurrence. Separately, 51% placed ARCALYST ahead of corticosteroids in their preferred treatment sequence.

Kiniksa is seeking to deepen adoption among patients with two or more recurrences while expanding use in the larger first-recurrence population. Its direct-to-consumer campaign has also increased traffic to the ARCALYST website, according to the presentation. Weekly visits were 12 times the level before the campaign, and engaged visits increased eightfold. These measures represent company-reported commercial indicators rather than confirmed future prescription or revenue trends.

Pipeline and financial outlook

The pivotal Phase 3 PASTORALE trial of KPL-387 in recurrent pericarditis is enrolling and dosing patients, with data expected in the second half of 2027. Kiniksa also expects to begin a first-in-human Phase 1 trial of KPL-1161 by the end of 2026.

Along with its ARCALYST sales forecast, the company maintained full-year 2026 research and development expense guidance of $160 million-$170 million and selling, general and administrative expense guidance of $270 million-$280 million.

Cash, cash equivalents and short-term investments totaled $568.8 million as of September 30, up from $414.1 million at the end of 2025. Management expects the current operating plan to remain cash-flow positive on an annual basis and said the balance sheet provides capacity for continued investment in potential value-creating opportunities.

Kiniksa cautioned that its outlook remains subject to clinical-trial enrollment and execution risks, potential differences between preliminary and final data, safety or efficacy setbacks, regulatory delays, reliance on third-party suppliers and research partners, competition, healthcare-policy changes and broader economic uncertainty.