Kiniksa Raises Arcalyst Revenue Guidance to $945 Million on Strong Q1 2026 Pericarditis Sales
Key Insights
Kiniksa Pharmaceuticals reported Q1 2026 Arcalyst net revenue of over $214 million, nearly doubling from $138 million in the same period last year.
GAAP net income more than doubled to $22.6 million ($0.27 per share), beating consensus analyst estimates for both revenue and earnings.
Management raised full-year 2026 Arcalyst net revenue guidance to $930–$945 million, up from the prior range of $900–$920 million.
Kiniksa Pharmaceuticals International posted first-quarter 2026 results that handily beat Wall Street expectations, driven by accelerating demand for Arcalyst in recurrent pericarditis (search). The company reported net product revenue of over $214 million, up sharply from under $138 million in the first quarter of 2025, while GAAP net income more than doubled to $22.6 million, or $0.27 per share, compared with $8.5 million in the prior-year period.
Both figures exceeded consensus analyst estimates, which had projected approximately $207 million in revenue and $0.21 per share in GAAP earnings. The stock surged nearly 24% on the day of the announcement.
Arcalyst Solidifies Position in Recurrent Pericarditis (search)
Arcalyst (rilonacept), a once-weekly subcutaneous inhibitor of interleukin-1 alpha and interleukin-1 beta, remains Kiniksa's sole commercial product and flagship asset. Originally discovered by Regeneron Pharmaceuticals, the therapy was licensed to Kiniksa in 2017 under an exclusive worldwide agreement excluding the Middle East and North Africa.
The FDA approved Arcalyst for recurrent pericarditis (search) in March 2021, following Breakthrough Therapy designation in 2019 and subsequent Orphan Drug exclusivity. The drug is also approved for cryopyrin-associated periodic syndromes (search) (CAPS), including familial cold autoinflammatory syndrome and Muckle-Wells syndrome, as well as deficiency of IL-1 receptor antagonist (search) (DIRA).
Kiniksa attributed the strong quarterly performance to increasing physician adoption and expanding patient awareness in the recurrent pericarditis (search) indication. The company markets Arcalyst across the United States through specialty pharmacies and shares profits with Regeneron.
Raised Guidance Reflects Confidence
Citing sustained commercial momentum, management raised its full-year 2026 net product revenue guidance for Arcalyst to a range of $930 million to $945 million, up from the prior forecast of $900 million to $920 million. Over the past three months, Kiniksa shares have risen 24.4%, compared with 2.2% growth for the broader industry.
Next-Generation Pipeline Advances
Kiniksa is advancing a pipeline of next-generation IL-1 (search)-targeted therapies to build on Arcalyst's success. KPL-387 (search), a monoclonal antibody IL-1 receptor antagonist, is currently in a phase II/III study for recurrent pericarditis (search). Phase II dose-finding data are expected in the second half of 2026, with the pivotal phase III study anticipated to begin by year-end. A supplemental phase II study is also underway evaluating the transition of patients from standard therapies to KPL-387 monotherapy.
A second candidate, KPL-1161 (search), is an Fc-modified monoclonal antibody IL-1 (search) receptor antagonist designed for quarterly subcutaneous dosing. The molecule is in preclinical development, with a phase I first-in-human study expected to commence by the end of 2026.
Kiniksa is also exploring additional indications for Arcalyst, including cardiac sarcoidosis, and expanding its global reach through a partnership with Huadong Pharmaceutical in China. The European Commission granted Orphan Drug Designation for Arcalyst in idiopathic pericarditis in 2021, further validating its therapeutic potential in inflammatory cardiovascular conditions.