Filgotinib decreases both vertebral body and posterolateral spine inflammation in ankylosing spondylitis: results from the TORTUGA trial

Objectives To assess the effects of filgotinib on inflammatory and structural changes at various spinal locations, based on MRI measures in patients with active AS in the TORTUGA trial. Methods In the TORTUGA trial, patients with AS received filgotinib 200 mg (n = 58) or placebo (n = 58) once daily for 12 weeks. In this post hoc analysis, spine MRIs were evaluated using the Canada–Denmark (CANDEN) MRI scoring system to assess changes from baseline to week 12 in total spine and subscores for inflammation, fat, erosion and new bone formation (NBF) at various anatomical locations. Correlations were assessed between CANDEN inflammation and clinical outcomes and Spondyloarthritis Research Consortium of Canada (SPARCC) MRI scores and between baseline CANDEN NBF and baseline BASFI and BASMI scores. Results MRIs from 47 filgotinib- and 41 placebo-treated patients were evaluated. There were significantly larger reductions with filgotinib vs placebo in total spine inflammation score and most inflammation subscores, including posterolateral elements (costovertebral joints, transverse/spinous processes, soft tissues), facet joints and vertebral bodies. No significant differences were observed for corner or non-corner vertebral body inflammation subscores, spine fat lesion, bone erosion or NBF scores. In the filgotinib group, the change from baseline in the total inflammation score correlated positively with the SPARCC spine score. Baseline NBF scores correlated with baseline BASMI but not BASFI scores. Conclusions Compared with placebo, filgotinib treatment was associated with significant reductions in MRI measures of spinal inflammation, including in vertebral bodies, facet joints and posterolateral elements. Trial registration ClinicalTrials.gov (https://clinicaltrials.gov), NCT03117270.