Kiniksa Pharmaceuticals International (NASDAQ:KNSA) reported second-quarter ARCALYST revenue of $243.6 million, up 55% from a year earlier and more than $29 million from the first quarter, as the company cited continued expansion in both new and repeat prescribers for the recurrent pericarditis treatment.
The company raised its full-year 2026 ARCALYST revenue guidance to a range of $980 million to $995 million, from its prior range of $930 million to $945 million. Kiniksa also announced dose-focusing data for KPL-387 and said the pivotal Phase III PASTEURAL trial is enrolling and dosing patients.
ARCALYST Growth and Commercial Strategy
Chief Operating Officer Ross Moat said the second quarter represented the largest quarterly increase in ARCALYST net revenue since the product’s launch more than five years ago. He attributed the performance to the company’s commercial strategy, including investments in sales infrastructure, machine learning and artificial intelligence tools, direct-to-consumer outreach, and dissemination of clinical guidance.
Kiniksa launched its targeted direct-to-consumer campaign, called Heart’s Home, in April. The campaign is designed to educate patients with recurrent pericarditis and encourage them to discuss ARCALYST with their healthcare providers. Moat said the campaign had reached thousands of patients and was showing early signs of engagement.
The company has also focused on communicating the 2025 American College of Cardiology concise clinical guidance for recurrent pericarditis. Moat said the guidance recommends moving ARCALYST earlier in treatment following nonsteroidal anti-inflammatory drugs and colchicine, and before corticosteroids.
- Penetration in the multiple-recurrence patient population reached approximately 21% at the end of the second quarter, compared with about 18% at the end of 2025.
- About 450 additional healthcare professionals wrote their first ARCALYST prescription during the quarter, bringing the total prescriber base to more than 5,000 since launch.
- The number of healthcare professionals who had written prescriptions for two or more patients increased by about 150 from the first quarter.
- Approximately 29% of the prescriber base had written ARCALYST prescriptions for at least two patients.
Moat said more than 25,000 healthcare professionals nationwide manage recurrent pericarditis patients. During the question-and-answer session, he said roughly 80% of new ARCALYST prescriptions were for patients with two or more recurrences, a population Kiniksa estimates at about 14,000 patients. The remaining approximately 20% were for patients experiencing their first recurrence, a group the company estimated at about 26,000 patients.
Moat said Kiniksa has not observed a meaningful change in the patient profile receiving ARCALYST. Rather, he pointed to broader recognition and diagnosis of recurrent pericarditis as contributing to growth.
KPL-387 Advances Into Pivotal Trial
Kiniksa said its Phase II/III program for KPL-387, an investigational IL-1 alpha and beta inhibitor, has moved into the Phase III portion following dose-focusing results. The company selected a 300-milligram subcutaneous monthly dose for the pivotal PASTEURAL study.
Chief Medical Officer Dr. John Paolini said Phase II data showed the selected dose produced a median time to treatment response of four days, with a 95% confidence interval of three to six days. The median time to pain response was also four days, while the median time to C-reactive protein normalization was eight days, with a confidence interval of seven to nine days.
Paolini said the 300-milligram monthly regimen demonstrated rapid and sustained activity throughout the monthly dosing interval and was generally well tolerated, consistent with the established safety profile of IL-1 pathway inhibition. The 300-milligram biweekly dose was efficacious but did not show incremental benefit over the monthly regimen, while the 100-milligram dose levels showed effects that did not support further development, according to the company.
PASTEURAL is a placebo-controlled, event-driven randomized-withdrawal study designed to evaluate reduction in the risk of pericarditis recurrence. The trial will enroll up to approximately 85 patients who experience a recurrence despite conventional oral therapies. Patients who respond during a single-blind run-in period will be randomized either to continue KPL-387 at 300 milligrams monthly or switch to placebo.
Paolini said the primary endpoint is time to first adjudicated pericarditis recurrence during the randomized-withdrawal period. Kiniksa said the trial design follows the approach used in its prior RHAPSODY Phase III program for ARCALYST.
Profitability and Cash Position
Chief Financial Officer Mark Ragosa said operating income for the second quarter was $27.2 million and net income was $25.4 million. ARCALYST collaboration profit increased 68% year over year to $176.1 million, growing faster than sales, according to the company.
Operating expenses increased from a year earlier due to higher cost of goods sold tied to ARCALYST revenue, increased collaboration expenses, KPL-387 clinical trial and manufacturing costs, preclinical investments, and commercialization-related selling, general and administrative expenses.
Kiniksa ended the quarter with $525.9 million in cash, representing approximately $58 million in net cash generation during the period.
Ragosa said year-to-date gross-to-net was 7.2%, down from 8.6% in the first quarter. He attributed the change primarily to lower co-pay expense following modifications to the company’s support program at the beginning of the year.
About Kiniksa Pharmaceuticals International (NASDAQ:KNSA)
Kiniksa Pharmaceuticals International, Inc is a biopharmaceutical company focused on discovering, acquiring and developing therapeutics for patients suffering from lifethreatening and debilitating immune-mediated diseases. Founded in 2013 and headquartered in Lexington, Massachusetts, Kiniksa applies a patient-centric approach to build a diversified portfolio of marketed medicines and clinical-stage candidates targeting inflammation and immunology. The company’s core mission is to address complex conditions with significant unmet medical needs by advancing both novel and differentiated therapies.
The company’s lead marketed product is Ilaris (canakinumab), an interleukin-1β blocker licensed for the treatment of cryopyrin-associated periodic syndromes, systemic juvenile idiopathic arthritis, adult-onset Still’s disease and Schnitzler syndrome.
