Background Magnetic resonance imaging (MRI) is a useful tool for evaluating disease activity and therapeutic efficacy in rheumatoid arthritis (RA). Magnetic resonance imaging (MRI) allows a highly accurate detection of synovitis, bone edema, and erosions, constituting the ideal instrument for the evaluation of treatment response.
Objectives The aim of this study was to assess the disease activity in rheumatoid arthritis (RA) patients treated with the anti-interleukin 6 (anti-IL 6) receptor antibody tocilizumab in terms of responsiveness at a six months to disease activity and ability to predict structural damage at six month and one year.
Methods A cohort of patients with RA (n=22) treated with tocilizumab were included in the study. All patients were evaluated clinically including disease activity score 28 (DAS28) andby low field dedicated MRI (dominant handand wrist) at initiation of treatment with anti-IL 6 receptorantibody agents and after 6 months. The MRI images were scored using the Outcome Measures in Rheumatology Clinical Trials RAMRI score (OMERACT RAMRIS). Conventional radiography for both hands and wrists and foot was performed at baseline 6 and at 12 months. Responsiveness was assessed by standardized response means (SRM). Areas under the curve (AUC) for measures at baseline, and 6 months were correlated with DAS28-ESRand structural damage at six month.
Results Among the laboratory and clinical parameters, DAS28-ESR was the most responsive with a large effect size of SRM. Baseline DAS28 was superior to 3.2 in all patients (ranging from 4.8 up to 7.8). At 6 months, 16 patients have responded, however without having achieved clinical remission, as DAS28 was still above 2.6. MRI showed that synovitis was reduced in 13 patients to a score of 1, bone edema was slightly reduced (8% of reduction), and erosive score was unchanged. Structural damage progressions for radiography and MR erosion were correlated with AUC of MR bone erosion.Thus Despite persistent low disease activity, patients treated with tocilitumab had stable RAMRIS erosive scores over 6 months.
Conclusions In the evaluation of disease activity in RA patients in the first few months after starting anti-IL 6 receptor antibody tocilizumab treatment, the MRI RAMRIS score of the hand is responsive and predictive of structural damage progression at 6 months.
Disclosure of Interest None Declared