Efficacy and Safety of Ivarmacitinib, a Selective JAK1 Inhibitor, in Patients With Active Ankylosing Spondylitis: Results From an Adaptive Seamless Phase 2/3 Trial

Ivarmacitinib 4 mg significantly improved the signs and symptoms of AS at week 12 compared to placebo, with sustained efficacy through 24 weeks and a tolerable safety profile. These findings support ivarmacitinib 4 mg as a new treatment option for active AS.