Bimekizumab inhibits both interleukin 17A and 17F and two trials found it to be effective in both forms of axial spondyloarthritis
Bimekizumab has been shown to be effective in patients with both radiographic and non-radiographic axial spondyloarthritis in two phase 3 randomised trials by a European research group.
Axial spondyloarthritis is a chronic inflammatory disease involving the axial skeleton that gives rise to chronic back pain and spinal stiffness but which may also include peripheral and extra-musculoskeletal manifestations. The term axial spondyloarthritis embraces two forms: those with radiographic and non-radiographic disease, i.e., where patients are symptomatic but have no evidence of definitive damage on pelvic radiographs.
It has become recognised that the interleukin-17A (IL-17A) pathway is implicated in the pathogenesis of axial spondyloarthritis although IL-17F has also been shown to induce similar inflammatory changes to IL-17 in joints. In fact, use of bimekizumab, which is a dual IL-17A and IL-17F blocker, is effective in psoriatic arthritis, which can also present with axial involvement in up to 50% of patients.
With data from a phase 2IIb trial in active ankylosing spondylitis, proving that bimekizumab was effective, in the current study, researchers undertook two parallel randomised, double-blind, placebo-controlled phase 3 trials of the drug in patients with both forms, i.e., non-radiographic (nr-disease) and radiographic (r-disease) axial spondyloarthritis. Participants with active nr-disease were randomised 1:1 and 2:1 (r-disease) to bimekizumab 160 mg every 4 weeks and from week 16 through to 52, all patients received bimekizumab 160 mg every 4 weeks. The primary endpoint was based on the Assessment of SpondyloArthritis international Society ≥40% improvement (ASAS40), i.e., a 40% improvement is disease severity.
Bimekizumab and disease improvement
At baseline virtually all patients (> 97.6%) had high or very high disease activity. In total, 254 patients with nr-disease and a mean age of 39.4 years (54.3% male) and 332 with r-disease and a mean age 40.1 years (72.2% male) with were included in the analysis.
At week 16, there was a significantly higher proportion of participants achieving an ASAS40 in both trials (nr-disease 47.7% vs 21.4% and r-disease 44.8% vs 22.5%, p<0.001 in both cases). Moreover, improvements became apparent within one to two weeks after starting bimekizumab in both trials.
The most frequent treatment emergent adverse events (i.e. occurring in > 3% of patients) with bimekizumab included nasopharyngitis, upper respiratory tract infection, pharyngitis, diarrhoea, headache and oral candidiasis.
The authors concluded that the use of the dual IL-17A and IL-17F inhibitor bimekizumab gave rise to significant and rapid improvements in patients with both radiographic and non-radiographic axial spondyloarthritis and was well tolerated.
van de Heijde D et al. Efficacy and safety of bimekizumab in axial spondyloarthritis: results of two parallel phase 3 randomised controlled trials. Ann Rheum Dis 2023