Kiniksa raises 2026 ARCALYST guidance, advances KPL-387 into Phase 3 pericarditis trial

Kiniksa Pharmaceuticals International, plc reported second quarter 2026 results and portfolio updates on July 28, 2026.

The company raised its 2026 net product revenue outlook for ARCALYST (rilonacept) to between $980 million and $995 million, up from prior guidance of between $930 million and $945 million.¹ ARCALYST net product revenue was $243.6 million for the second quarter of 2026.¹ As of the end of the quarter, approximately 21% of the 14,000 multiple-recurrence patients were actively on ARCALYST treatment.¹ Since launch, more than 5,000 prescribers have written ARCALYST prescriptions for recurrent pericarditis, and average total duration of therapy was approximately 3 years, in line with median disease duration.¹

On the pipeline, Kiniksa disclosed an interval analysis from its ongoing KPL-387 Phase 2/3 trial. In the 300 mg subcutaneous monthly dose group, patients showed rapid and sustained drops in pain and inflammation, with a median time to treatment response of 4.0 days (95% CI 3.0, 6.0).¹ Median time to CRP normalization was 8.0 days (95% CI 7.0, 9.0).¹ Effects held throughout the monthly dosing interval, and the drug was generally well tolerated, consistent with known IL-1 pathway inhibitor safety.¹

Based on that data, Kiniksa said it is now enrolling and dosing patients in the pivotal Phase 3 portion of the trial, called PASTORALE. PASTORALE is a randomized withdrawal study enrolling up to approximately 85 participants, testing KPL-387 300 mg SC once monthly in liquid form, with a primary endpoint of time to first adjudicated pericarditis recurrence.¹ Management said it expects to bring KPL-387 to patients in the 2028/2029 timeframe.¹

For the earlier-stage candidate KPL-1161, the company still expects to start a Phase 1 first-in-human trial by the end of 2026.¹

On the balance sheet, Kiniksa held $525.9 million in cash, cash equivalents, and short-term investments as of June 30, 2026, with no debt.¹ The company said it expects its current operating plan to remain cash flow positive on an annual basis.¹