7 Tesla MRI Brain Imaging to Decipher Filgotinib's Mode of Analgesic Action in Rheumatoid Arthritis

This is an experimental medicine, single-centre, observational test-retest study to evaluate Filgotinib's mechanism of analgesic action in RA patients.The investigators hypothesize that Filgotinib's mechanism of analgesic action is determined by at least two factors. The first is related to those CNS sensitization pathways seen in fibromyalgia, specifically DMN-insula brain functional connectivity and insular glutamate.The second is related to peripheral inflammation, specifically joint synovitis, blood cytokines/chemokines and DAN-LIPL functional brain connectivity. The CNS sensitization pain pathways related to fibromyalgia are more quickly modified compared to those related to peripheral inflammation and help explain Filgotinib's rapid onset of effect.

Inclusion Criteria:Patients with moderate to severe active RA who have been prescribed filgotinib in line with the Summary of Product Characterisation and are:Adults ≥18 years < 75 years.Right-handed (to reduce neuroimaging heterogeneity).Exclusion Criteria:Inability to provide written informed consent.Severe physical impairment (e.g. blindness, deafness, paraplegia).Pregnant or breast feeding.Severe claustrophobia precluding MRI.Contraindications to MRI.Major confounding neurological disease including MS, Stroke, Traumatic Brain Injury.Previous targeted synthetic (e.g. baricitinib, tofacitinib) DMARD exposure for RA.