Spondyloarthritis & psoriatic arthritis
Efficacy and Safety of Ivarmacitinib, a Selective JAK1 Inhibitor, in Patients With Active Ankylosing Spondylitis: Results From an Adaptive Seamless Phase 2/3 Trial
Authors' conclusion
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.
Study context
- Population
- Patients with active ankylosing spondylitis (AS)randomised over phases 2 and 3
- Participants
- 504 patients
- Comparison
- Ivarmacitinib 4 mg once daily vs placebo for 12 weeks
- Ivarmacitinib 4 mgn = 187
- Placebon = 186reference
- Primary endpoint
- ASAS20 response
- Follow-up
- Week 12
Methodological detailsdouble-blind, adaptive seamless phase 2/3, placebo-controlled, Phase 2: randomised 1:1:1:1 to ivarmacitinib 2, 4 or 8 mg or placebo once daily for 12 weeks; 4 mg selected as recommended dose based on interim analysis
- Double-blind
- Adaptive seamless phase 2/3
- Placebo-controlled
- Phase 2: randomised 1:1:1:1 to ivarmacitinib 2, 4 or 8 mg or placebo once daily for 12 weeks; 4 mg selected as recommended dose based on interim analysis
Primary result
As reported in the abstract
ASAS20 response rate
One-sided P = 0.0001
Secondary outcomes
ASAS40 response rate · week 12
ASAS40 response rate · week 12
- All other secondary end points also favored ivarmacitinib 4 mg
Efficacy through week 24 · 24 weeks
- Efficacy was sustained through 24 weeks
Safety
Treatment-emergent adverse events · placebo-controlled period
Original publication
Efficacy and Safety of Ivarmacitinib, a Selective JAK1 Inhibitor, in Patients With Active Ankylosing Spondylitis: Results From an Adaptive Seamless Phase 2/3 Trial. Arthritis Rheumatol. Published 5 August 2025. doi:10.
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