What Kiniksa Pharmaceuticals International (KNSA) Said on Its Q3 Earnings Call

Key Points

• ARCALYST sales continued to accelerate: Third-quarter revenue rose 58% year over year to $286 million, prompting Kiniksa to raise its 2026 revenue guidance to $1.045 billion–$1.050 billion.
• Adoption is expanding in recurrent pericarditis: ARCALYST penetration reached 23% among patients with multiple recurrences, while total prescribers increased to approximately 5,450. Targeted outreach also significantly boosted website traffic and patient engagement.
• The pipeline advanced, but remains several years from potential commercialization: The pivotal Phase III KPL-387 study is enrolling, with data expected in the second half of 2027 and a potential launch in 2028–2029; a Phase I study for quarterly KPL-1161 is planned by year-end.

Kiniksa Pharmaceuticals International NASDAQ: KNSA raised its full-year 2026 revenue guidance after reporting third-quarter ARCALYST revenue growth of 58% year over year, as the company continued to expand use of the drug for recurrent pericarditis and advance its clinical pipeline.

The company now expects 2026 ARCALYST revenue of $1.045 billion to $1.050 billion. Third-quarter ARCALYST revenue totaled $286 million, while operating income reached $54.2 million and net income was $47.3 million, according to Chief Financial Officer Mark Ragosa.

“We continue to see robust growth with ARCALYST in recurrent pericarditis, driven by strong execution and strategic investments across the business,” Chief Executive Officer Sanj K. Patel said during the company’s earnings call.

ARCALYST Adoption and Commercial Investment

Kiniksa said ARCALYST penetration among an estimated annual population of 14,000 patients with multiple recurrences of pericarditis reached 23% at the end of the third quarter. Patel said the company is also focused on expanding use among an additional 26,000 annual patients experiencing their first recurrence.

Ross Moat, the company’s chief operating officer, said the 23% figure applies to the multiple-recurrence population and does not include first-recurrence patients. He said approximately 20% of prescriptions have historically come from patients at their first recurrence, though the company does not update that estimate frequently.

Moat said physician consideration of ARCALYST earlier in the course of disease has increased, including after a first recurrence. He cited physician survey data showing that about 50% of surveyed physicians now support using IL-1 alpha and beta inhibition after NSAIDs and colchicine and before corticosteroids. According to Moat, that proportion has doubled from levels observed during the three years before publication of the 2025 American College of Cardiology Concise Clinical Guidance for Recurrent Pericarditis.

Kiniksa reported approximately 5,450 total ARCALYST prescribers as of the end of the third quarter, an increase of around 450 from the prior quarter. Roughly 30% were repeat prescribers, up by about 170 prescribers sequentially, Moat said.

The company has increased commercial spending to support patient and physician outreach. Its Heart’s Home direct-to-consumer campaign uses artificial intelligence to identify and reach people likely to have recurrent pericarditis who are not currently using ARCALYST.

Moat said traffic to the ARCALYST website increased twelvefold from pre-campaign baseline levels, while engaged sessions increased eightfold. He added that about 55% of patients who saw the advertisement strongly agreed that it motivated them to speak with a healthcare provider about ARCALYST.

“This is not broad-spectrum, massive spend DTC,” Moat said, characterizing the campaign as targeted and designed for a rare-disease market.

Pipeline Timelines

Beyond ARCALYST, Kiniksa is developing KPL-387, a once-monthly subcutaneous IL-1 alpha and beta inhibitor for recurrent pericarditis. Patel said the pivotal Phase III study is enrolling and dosing patients globally, with data now expected in the second half of 2027. The company said it could potentially launch the treatment in the 2028 to 2029 time frame.

Chief Medical Officer John Paolini said a separate KPL-387 transition-to-monotherapy dosing and administration study is designed to inform potential labeling around moving patients from existing therapies to 300 mg monthly KPL-387 monotherapy. The study includes transitions from NSAIDs and colchicine, corticosteroids, and IL-1 pathway inhibitors including anakinra and rilonacept.

Paolini said the KPL-387 Phase III program remains necessary to demonstrate efficacy. Company executives said market research on the proposed product profile indicated that patients and healthcare professionals viewed a monthly liquid formulation, potentially delivered through an autoinjector, favorably. However, they emphasized that the program remains data dependent.

Kiniksa also plans to begin a Phase I study by year-end for KPL-1161, its quarterly IL-1 alpha and beta inhibitor. Paolini said the company has not disclosed target indications for the program, though the longer dosing interval could create opportunities in chronic or lifelong disease settings.

Financial Position and Expense Outlook

Ragosa said ARCALYST collaboration profit rose 67% year over year to $211.6 million in the third quarter, outpacing sales growth. The company ended the quarter with $568.8 million in cash, reflecting approximately $43 million in net cash generation during the period.

Kiniksa expects full-year 2026 research and development expenses of $160 million to $170 million, including continued development of KPL-387 and KPL-1161 and significant fourth-quarter pre-commercial manufacturing costs for KPL-387.

The company forecast full-year selling, general and administrative expenses of $270 million to $280 million. That outlook includes additional fourth-quarter personnel and promotional activity intended to increase disease awareness and improve targeting of patients and physicians.

Patel said Kiniksa continues to evaluate additional value-creating opportunities, including business-development opportunities, but described the company’s threshold for external deals as “exceedingly high” given its existing commercial product and pipeline programs.

About Kiniksa Pharmaceuticals International (NASDAQ:KNSA)

Kiniksa Pharmaceuticals International plc is a commercial-stage biopharmaceutical company focused on developing and commercializing therapies for patients with serious and often under-treated immunological diseases. The company's research and development efforts are centered on targeting specific pathways involved in inflammation and immune-system dysfunction.

Kiniksa's principal commercial product is ARCALYST (rilonacept), an interleukin-1 inhibitor. In the United States, ARCALYST is approved for reducing the risk of recurrence in patients with recurrent pericarditis and for the treatment of cryopyrin-associated periodic syndromes, including familial cold autoinflammatory syndrome and Muckle-Wells syndrome, in eligible patients.

The company also maintains a pipeline of investigational medicines designed to address autoimmune and inflammatory conditions.

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