Improved Pain, Morning Stiffness, and Fatigue With Bimekizumab in Axial Spondyloarthritis: Results From the Phase III BE MOBILE Studies.

Objective: To assess the effect of bimekizumab on pain, morning stiffness, and fatigue in patients with nonradiographic and radiographic axial spondyloarthritis (axSpA) in the phase III BE MOBILE studies (ClinicalTrials.gov: NCT03928704 and NCT03928743).

Methods: Patients were randomized to bimekizumab 160 mg or placebo every 4 weeks; and all patients received bimekizumab from week 16. Patients reported spinal pain, peripheral pain, morning stiffness, and fatigue to week 52. Total and nocturnal spinal pain were each assessed on a 0-10 numerical rating scale (NRS). Individual Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) items (0-10-point NRS) assessed peripheral arthritis pain (question [Q] 3), enthesitis pain/discomfort (Q4), morning stiffness (mean of Q5 and Q6), and fatigue (Q1). Functional Assessment of Chronic Illness Therapy Fatigue subscale score (FACIT-Fatigue) is also reported.

Results: At week 16, bimekizumab-treated patients reported lower mean nocturnal spinal pain, total spinal pain, and BASDAI scores (nominal except for nocturnal spinal pain; all ≤ 0.001), as well as higher FACIT-Fatigue scores (nominal < 0.05) vs placebo, indicating improved symptom levels. Improvements continued to week 52 in continuous bimekizumab-treated patients and in placebo-bimekizumab switchers. A higher proportion of bimekizumab- vs placebo-randomized patients achieved increasingly stringent thresholds for low spinal and peripheral pain at week 16; this was sustained or improved at week 52. Results were similar for morning stiffness and fatigue. At week 52, over half of patients were considered FACIT-Fatigue responders (≥ 8-point increase in score).

Conclusion: Bimekizumab treatment led to rapid improvements in levels of pain and morning stiffness. Substantial improvements were seen in all domains across the full disease spectrum of axSpA and continued to week 52.