Kiniksa Raises Outlook as Arcalyst Demand Drives Growth
Second-quarter revenue reached $243.6 million as Arcalyst use expanded.
Kiniksa Pharmaceuticals International (KNSA), a biopharmaceutical company, raised its annual revenue outlook after Arcalyst sales rose 55% and sequential growth accelerated.
The quarter extended a run of strong demand while changing its shape. Year-over-year growth eased from 56% in the first quarter to about 55%, while sequential growth quickened to roughly 14% from 6%.
Revenue, entirely from Arcalyst net product sales, increased from $156.8 million a year earlier and $214.3 million in the first quarter. Net income rose 43% to $25.4 million, trailing revenue growth, while operating margin narrowed to about 11.2% from 12.9% a year earlier and 13.7% in the preceding quarter.
Broader prescribing and deeper penetration supported the increase. Arcalyst reached approximately 21% of the 14,000 patients who had experienced multiple recurrences of pericarditis, up from 18% at the end of 2024. Cumulative prescribers surpassed 5,000, and average treatment duration reached about three years.
Spending grew faster than sales. Operating expenses increased 58% to $216.4 million, as research and development expense more than doubled to $40.9 million amid increased KPL-387 clinical and manufacturing activity and greater preclinical investment. Collaboration expense rose 68% to $88.1 million, driven primarily by Arcalyst collaboration profitability.
Kiniksa now expects 2026 Arcalyst revenue of $980 million to $995 million, raising both ends of its previous range by $50 million. The midpoint stands about 5% above the prior forecast and roughly 9% above the original annual outlook.
The company also moved KPL-387 ahead of its earlier timetable. After previously targeting Phase 2 results for the second half and a Phase 3 start by year-end, Kiniksa reported Phase 2 findings and began enrolling and dosing patients in the pivotal PASTORALE trial. The selected 300-milligram monthly dose produced median treatment and pain responses in four days and median C-reactive protein normalization in eight days, with efficacy sustained through the dosing interval.
Cash, cash equivalents and short-term investments increased to $525.9 million from $468.1 million at the end of March. Kiniksa remained debt-free and its operating plan should continue to produce positive annual cash flow.