Kiniksa Pharmaceuticals is a commercial-stage biopharmaceutical company focused on cardiovascular and inflammatory diseases. Its sole commercial product is ARCALYST (rilonacept), the only FDA-approved therapy for recurrent pericarditis — a chronic inflammatory disease where the sac surrounding the heart repeatedly becomes inflamed. ARCALYST works by blocking both IL-1α and IL-1β cytokines that drive the inflammation, and is administered as a weekly subcutaneous injection. ARCALYST is sold exclusively in the U.S. through specialty pharmacies, supported by a salesforce targeting cardiologists. Kiniksa licensed ARCALYST from Regeneron and splits U.S. profits evenly with Regeneron, with profit calculated as net sales minus cost of goods and commercial expenses — meaning collaboration expense scales with profitability. As revenue grows faster than commercial costs, more revenue flows through to net income. Kiniksa's pipeline centers on KPL-387, a wholly owned next-generation IL-1 receptor inhibitor targeting once-monthly dosing via autoinjector — a more convenient profile than ARCALYST's weekly injection. Phase 2 data are expected in the second half of 2026, with a potential launch targeted for 2028-2029. Because Kiniksa fully owns KPL-387, it would retain all economics rather than splitting profits with Regeneron. Kiniksa also has a preclinical asset, KPL-1161, engineered for quarterly dosing and potentially applicable across a broader range of chronic auto-inflammatory diseases.