A comprehensive safety analysis of bimekizumab (BKZ) demonstrated good long-term tolerability and consistent safety outcomes in patients with axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA), according to pooled data from six integrated phase IIb/III clinical studies published in Rheumatic Musculoskeletal Disease Open.
The analysis encompassed 848 axSpA patients (2034.4 patient-years of exposure) and 1407 PsA patients (2590.8 patient-years) who received bimekizumab 160 mg every 4 weeks. Treatment-emergent adverse events (TEAEs) occurred at comparable rates between the two populations, with exposure-adjusted incidence rates per 100 patient-years (EAIR/100 PY) of 136.9 and 139.6 for axSpA and PsA patients, respectively. Study discontinuation rates due to TEAEs remained low across both groups (2.7/100 PY in axSpA; 3.1/100 PY in PsA). The most frequently reported adverse events included SARS-CoV-2 infection (axSpA: 7.8/100 PY; PsA: 8.8/100 PY), nasopharyngitis (axSpA: 8.2/100 PY; PsA: 7.7/100 PY), and upper respiratory tract infection (axSpA: 5.0/100 PY; PsA: 5.6/100 PY).
Oral candidiasis occurred at rates of 3.7/100 PY in axSpA and 4.2/100 PY in PsA patients, with most cases being mild to moderate in severity. Importantly, discontinuation due to oral candidiasis was uncommon (0.3/100 PY in both populations). No systemic fungal infections or cases of active tuberculosis were observed throughout the study period. The analysis also revealed low incidence rates of other safety events of interest, including adjudicated inflammatory bowel disease, uveitis, major adverse cardiovascular events, and suicidal ideation or behaviour.
Bimekizumab is a humanized monoclonal IgG1 antibody that has recently been granted marketing authorization in the European Union and the UK. It selectively inhibits both IL-17F and IL-17A, key pro-inflammatory cytokines involved in inflammation and new bone formation, which contribute to structural damage in axial spondyloarthritis (axSpA). Unlike IL-17A-specific inhibitors, bimekizumab targets and neutralizes IL-17F/F, IL-17A/A, and IL-17A/F, offering a broader approach to modulating the inflammatory response.
A systematic literature review and network meta-analysis by Deodhar et al. reported that bimekizumab showed comparable efficacy across ASAS outcomes to most biologic and targeted synthetic DMARDs (b/tsDMARDs), including ixekizumab, TNF inhibitors, and upadacitinib. Notably, bimekizumab achieved higher response rates than secukinumab for certain ASAS endpoints in predominantly b/tsDMARD-naïve patients with non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) at 12–16 weeks. In the pooled axSpA network, its safety profile was comparable to that of other b/tsDMARDs.
Two-year findings from two Phase 3 studies by Mease et al. demonstrated that bimekizumab was well tolerated over the 2-year treatment period, with no new safety signals identified. Sustained clinical efficacy was maintained in both biologic DMARD-naïve patients and those with inadequate response to TNF inhibitors (TNFi-IR) with active PsA. Patients who transitioned from adalimumab to bimekizumab experienced further improvement in skin and nail symptoms, along with continued efficacy in joint manifestations.
Bimekizumab demonstrated a favorable long-term safety profile in both axSpA and PsA, with stable TEAE incidence rates over extended treatment periods. No new safety signals emerged, aligning with previously established safety data.
References
- Mease PJ, Gensler LS, Orbai AM, Warren RB, Bajracharya R, Ink B, et al. Long-term safety of bimekizumab in adult patients with axial spondyloarthritis or psoriatic arthritis: pooled results from integrated phase IIb/III clinical studies. RMD Open. 2025 Apr 6;11(2):e005026.
- Deodhar A, Machado PM, Mørup M, Taieb V, Willems D, Orme M, et al. Comparative efficacy and safety of bimekizumab in axial spondyloarthritis: a systematic literature review and network meta-analysis. Rheumatology (Oxford). 2024 May 2;63(5):1195-1205.
- Mease PJ, Merola JF, Tanaka Y, Gossec L, McInnes IB, Ritchlin CT, et al. Safety and Efficacy of Bimekizumab in Patients with Psoriatic Arthritis: 2-Year Results from Two Phase 3 Studies. Rheumatol Ther. 2024 Oct;11(5):1363-1382.