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The following is a summary of “Effect of ixekizumab treatment on MRI sacroiliac joint structural lesions in patients with radiographic axial spondyloarthritis: post-hoc analysis of a 52-week, randomised, placebo-controlled trial with an active reference arm,” published in the February 2025 issue of Lancet Rheumatology by Maksymowych et al.  

The effect of biological disease-modifying antirheumatic drugs (DMARDs) on sacroiliac joint lesions over 52 weeks is unclear.  

Researchers conducted a retrospective study to examine the effect of ixekizumab and adalimumab vs placebo on structural lesions in sacroiliac joints assessed by MRI in individuals naive to biological DMARDs with radiographic axial spondyloarthritis from the COAST-V study. 

They conducted a trial over 52 weeks at 84 sites in 12 countries and enrolled adults (≥18 years) naive to biological DMARDs with active radiographic axial spondyloarthritis, sacroiliitis, and inadequate response or intolerance to non-steroidal anti-inflammatory drugs. The patients were randomly assigned (1:1:1:1) to 80 mg ixekizumab every 2 weeks (Q2W) or every 4 weeks (Q4W), 40 mg adalimumab Q2W, or placebo. At week 16, those on placebo or adalimumab were re-randomized (1:1) to ixekizumab Q2W or Q4W and analyzed MRI data at baseline, 16 weeks, and 52 weeks using the Spondyloarthritis Research Consortium of Canada sacroiliac joint structural scores. The ANCOVA was used for treatment comparisons, adjusting for baseline values, bone marrow oedema, and stratification factors. Subgroup analyses included sex, HLA-B27, and baseline bone marrow oedema.  

The results showed that 341 patients were enrolled, and MRI scans were available for 325 (95%) at baseline and week 16 and 301 (88%) at week 52, Of 325 patients, 264 (81%) were male, 61 (19%) were female, and the mean age was 41.5 years (SD 11.6). At week 16, erosion decreased with ixekizumab Q2W (–0.91 [SE 0.19] vs placebo 0.10 [0.18]; P <0.0001) and ixekizumab Q4W (–0.57 [SE 0.19]; P =0.0086), similar to adalimumab. Backfill increased with ixekizumab Q2W (0.52 [0.12] vs placebo 0.04 [0.12]; P =0.0042). Erosion changes differed by sex, HLA-B27, and bone marrow oedema. At week 52, further reductions in erosion and increases in backfill were observed, greatest with continuous ixekizumab Q2W (erosion –1.50 [SD 2.70], backfill 0.76 [SD 2.09]). Patients switching from adalimumab to ixekizumab at week 16 also showed erosion reduction.  

Investigators observed a decrease in erosion and an increase in backfill at week 16, with further changes at week 52 in patients receiving ixekizumab and found that ixekizumab, like adalimumab, modified structural lesions, but its effect on ankylosis required further analysis. 

Source: thelancet.com/journals/lanrhe/article/PIIS2665-9913(24)00312-6/abstract