No erosive progression revealed by MRI in rheumatoid arthritis patients treated with etanercept, even in patients with persistent MRI and clinical signs of joint inflammation

The aim of this study is to investigate the course of magnetic resonance imaging (MRI) signs of inflammatory and destructive changes in rheumatoid arthritis (RA) wrist and metacarpophalangeal (MCP) joints during etanercept treatment. MRI of the non-dominant wrist and second to fifth MCP joints was performed in five clinical active RA patients before and 4 and 16 weeks after initiation of etanercept treatment. MRI was evaluated according to the EULAR-OMERACT RA MRI reference image atlas. The median 28-joint count disease activity score (DAS28; erythrocyte sedimentation rate based) was 5.6 (range 5.0-6.8) at baseline and 3.5 (1.5-4.1) at week 16 (decreased in all patients compared to baseline, Wilcoxon-Pratt, p < 0.05). The median MRI synovitis score was 18 (14-21), 18 (10-20) and 16 (10-20) at baseline, week 4 and 16, respectively (decreased in all patients compared to baseline, Wilcoxon-Pratt, p < 0.05), while corresponding MRI bone oedema scores were 4 (0-13), 3 (0-9) and 1 (0-3; NS). The median MRI bone erosion score was 27 (11-111; NS) at all time points. Four patients had identical total bone erosion scores at baseline and week 16, whereas one patient showed a reduced score. In conclusion, one patient showed erosive regression, while no patient showed erosive progression on MRI during 16 weeks of etanercept therapy; even though clinical and MRI signs of joint inflammation remained. This small study supports that erosive progression judged by MRI is minimal in RA patients treated with etanercept, even in joints with persistent inflammation.