A recent study published in The Journal of Rheumatology found that bimekizumab, a dual interleukin (IL)-17A and IL-17F inhibitor, was well tolerated over 3 years with no new safety signals. It sustained clinical efficacy and inflammation control across the full disease spectrum of axial spondyloarthritis (axSpA).
Recommendations advise disease-modifying antirheumatic drugs (DMARDs), including tumor necrosis factor inhibitors, IL-17 inhibitors, and Janus kinase inhibitors, as second-line treatments for axSpA when nonsteroidal anti-inflammatory drugs, the first-line treatment, are ineffective or not tolerable. Bimekizumab, a monoclonal IgG1 antibody that selectively inhibits IL-17F in addition to IL-17A, is the only approved axSpA treatment that inhibits both cytokines. Overexpression of IL-17A and IL-17F, key inflammatory mediators, has been implicated in the pathogenesis of axSpA and other immune-mediated inflammatory diseases, such as psoriatic arthritis, psoriasis, and hidradenitis suppurativa.
The analysis included patients who completed week 52 of the phase III BE MOBILE 1 (nonradiographic axSpA) and BE MOBILE 2 (radiographic axSpA) studies and entered an ongoing open-label extension, continuing subcutaneous bimekizumab 160 mg every 4 weeks. Safety outcomes were assessed in patients who received at least one dose of bimekizumab, and efficacy outcomes in all randomized patients, over 3 years (164 weeks, including a 112-week open-label extension).
During the overall safety period, 90.4% (519/574) of patients had at least one treatment-emergent adverse event. The exposure-adjusted incidence rate (EAIR) per 100 patient-years (PY) of fungal infection was 9.4, with Candida infections accounting for the majority (5.3/100 PY). Most infections were mild or moderate, and none were serious or systemic. The EAIRs per 100 PY for inflammatory bowel disease and uveitis were 0.5 and 1.5, respectively. No major adverse cardiovascular events or deaths occurred. EAIRs, including those for Candida infections, were generally lowest in the third year.
The efficacy observed through 2 years was sustained through week 164. At week 164, 57.0% of patients achieved low disease activity on the Axial Spondyloarthritis Disease Activity Score (ASDAS < 2.1), including 28.7% who achieved ASDAS inactive disease (< 1.3). Bimekizumab also led to sustained improvements in the Bath Ankylosing Spondylitis Functional Index (BASFI) and health-related quality of life scores, along with sustained control of MRI inflammation through week 164, with 59.4% of patients achieving a Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint score < 2 and 77.8% achieving a Berlin spine score ≤ 2.
The findings support bimekizumab as a durable long-term treatment option for patients with nonradiographic and radiographic axSpA, with a positive benefit-risk profile.
Reference
Baraliakos X, Deodhar A, van der Heijde D, Van den Bosch F, Magrey M, Maksymowych WP, Tomita T, Xu H, Coarse J, Prajapati C, Manente M, Marten A, Gensler LS. Bimekizumab Long-Term Safety and Efficacy Across the Spectrum of Axial Spondyloarthritis Over 3 Years: Results From 2 Phase III Studies. J Rheumatol. 2026 Oct 1;53(10):1071-1082.