Abstract:
Background: Axial spondyloarthritis (axSpA) is a chronic immune-mediated disease characterized by inflammation of the sacroiliac joints
and spine. While biologics have transformed management, limitations exist in terms of parenteral administration, cost, and secondary failure.
Upadacitinib, a selective Janus kinase 1 (JAK1) inhibitor, offers a novel oral therapeutic strategy. Objectives: To evaluate the efficacy and safety of
upadacitinib in a prospective, 52-week, single-arm cohort of patients with active axSpA. Methods: Sixty-three patients with active axSpA (ASAS
criteria, BASDAI ≥4, elevated CRP or MRI inflammation) were enrolled and received upadacitinib 15 mg once daily. Outcomes included ASAS20/40,
BASDAI50, ASDAS-CRP, MRI SPARCC scores, and safety events. Assessments were performed at weeks 0, 12, 24, 36, and 52. Results: By week 52, 68%
achieved ASAS40 and 55% achieved BASDAI50. Mean ASDAS-CRP improved from 3.6 at baseline to 1.6 at week 52 (p<0.001). MRI SIJ SPARCC scores
decreased by a mean of –6.8 units (p<0.01). Clinically important improvement (ASDAS ↓≥1.1) was achieved in 73% of patients, with 39% reaching
inactive disease (ASDAS <1.3). Safety findings were consistent with the known JAK inhibitor profile: herpes zoster occurred in 2 patients (3.1%), no
venous thromboembolism (VTE) events, and one case of major adverse cardiovascular event (MACE).
Conclusion: Upadacitinib demonstrated rapid and sustained efficacy in active axSpA, with a manageable safety profile over 52 weeks. These
findings support its use as an effective oral alternative for patients with inadequate response to NSAIDs or biologics.
