Dynamic Contrast-Enhanced MRI Confirms Rapid And Sustained Improvement Of Rheumatoid Arthritis Induced By Tocilizumab Treatment: An Italian Multicentre Study

Objective: This open-label study evaluated the effects of combined tocilizumab (TCZ) and disease-modifying antirheumatic drugs (DMARDs) on magnetic resonance imaging (MRI) changes in synovial membrane enhancement, bone marrow edema (BME), and erosions in the wrist and hand joints of rheumatoid arthritis (RA) patients inadequately responding to DMARDs alone.

Methods: The efficacy of intravenous TCZ 8 mg/kg administered every four weeks for 48 weeks was evaluated on six occasions. The primary endpoints were the changes in the extent and degree of wrist synovitis as measured using the RA MRI Score (RAMRIS) and dynamic, gadolinium-enhanced 0.2T MRI (DCE-MRI). A number of different parameters of DCE-MRI were evaluated.

Results: Fifty-eight patients were treated, eight of whom (13.8%) discontinued the study prematurely. The mean RAMRIS significantly decreased after two weeks and the decrease was maintained for up to 48 weeks. By week 4, the mean RAMRIS synovitis score had significantly decreased from baseline (-0.804±1.575; p=0.018), but not the mean early enhancement (REE) or relative enhancement (RE). However, there were significant decreases in RE at week 24, in REE and Ntotal (total number of enhancing voxels)*IRE (initial rate of enhancement) at weeks 12, 24 and 48, and in Ntotal*ME (maximal enhancement) at weeks 24 and 48. Mean BME decreased from baseline to week 48, and bone erosions did not progress. The patients' clinical parameters significantly improved from baseline until week 48.

Conclusion: TCZ in combination with DMARDs improved wrist synovitis, BME and clinical parameters, without any progression in bone erosions. The RAMRIS for synovitis rapidly improved from as early as two weeks after the first TCZ infusion. (Funded by F. Hoffmann-La Roche; ACTRACE EudraCT No. 2009 012185-32).