Bimekizumab Long-Term Safety and Efficacy Across the Spectrum of Axial Spondyloarthritis Over 3 Years: Results from Two Phase 3 Studies

Objective 2-year safety and efficacy of bimekizumab, a dual IL-17A and IL-17F inhibitor, has been demonstrated across the full disease spectrum of axial spondyloarthritis (axSpA). We report bimekizumab long-term safety and efficacy over 3 years. Methods Patients completing Week 52 of BE MOBILE 1 (nr-axSpA; NCT03928704 ) and BE MOBILE 2 (r-axSpA; NCT03928743 ) phase 3 studies could enter an ongoing open-label extension (OLE; NCT04436640 ) and continue receiving subcutaneous bimekizumab 160 mg every 4 weeks. Safety outcomes for patients receiving ≥1 bimekizumab dose, and efficacy outcomes for all randomised patients, are reported over 3 years (164 weeks [112-week OLE]). Results During the overall safety period, 90.4% (519/574) of patients had ≥1 treatment-emergent adverse event. Fungal infection exposure-adjusted incidence rate (EAIR)/100PY was 9.4 (majority Candida infections: 5.3; most mild/moderate, none serious/systemic). Inflammatory bowel disease and uveitis EAIR/100PY were 0.5 and 1.5. No major adverse cardiovascular events or deaths occurred. EAIRs, including for Candida infections, were generally lowest in the third year. 2-year efficacy with bimekizumab was sustained to Week 164. At Week 164, 57.0% achieved ASDAS low disease activity (<2.1), including 28.7% achieving ASDAS inactive disease (<1.3). Bimekizumab treatment also led to sustained improvements in BASFI and HRQoL scores and sustained control of MRI inflammation to Week 164, with 59.4% and 77.8% achieving SPARCC SIJ <2 and Berlin spine ≤2, respectively. Conclusion Bimekizumab was well tolerated over 3 years, with no new safety signals observed. Across the full disease spectrum of axSpA, patients demonstrated sustained clinical efficacy and inflammation control over 3 years.