Impact of bimekizumab on CANDEN spinal MRI inflammation & structural lesions in radiographic axial spondyloarthritis: 2-year phase 3 results.

OBJECTIVES: To evaluate the impact of 2-year treatment with bimekizumab, a dual IL-17A and IL-17F inhibitor, on spinal MRI inflammatory and structural lesions in patients with radiographic axial spondyloarthritis (r-axSpA) in BE MOBILE 2 and its open-label extension (OLE) using Canada-Denmark (CANDEN) scoring. METHODS: Patients in BE MOBILE 2 and its OLE with spinal MRIs at baseline, Weeks 16, 52 and 104 were included. MRIs were evaluated using CANDEN scores/subscores for inflammation, fat lesions, erosions and new bone formation; mean change from baseline (CfB) is reported. All data are observed case. RESULTS: Of 332 patients in BE MOBILE 2, 102 had MRIs eligible for CANDEN scoring at all four timepoints. Mean reductions from baseline in total inflammation score were observed with bimekizumab at Week 16 (CfB: -7.3), with minimal further change at Week 104 (-6.6). Largely similar patterns were observed in inflammation subscores to Week 104, including the posterolateral inflammation subscore. In bimekizumab-randomised patients, total fat lesions score increased from baseline to Week 16 (CfB: 1.6), with minimal further change at Week 104 (1.8). These increases were reflected in patients with baseline inflammation; those without baseline inflammation had minimal change at all timepoints. Minimal changes were observed in total erosions and new bone formation scores. CONCLUSIONS: In bimekizumab-treated patients with r-axSpA, comprehensive MRI CANDEN scoring showed reductions in spinal inflammation at all anatomical locations at Week 16, sustained at two years, initial increases in fat lesions with minimal subsequent change and minimal changes in erosions and new bone formation.