Predictive value of immunological and imaging biomarkers on achieving remission at 6 months in rheumatoid arthritis patients treated by intravenous bDMARDs

Background: RA is the most prevalent chronic inflammatory rheumatism, responsible of functional impairment. Objectives: To investigate the value of biological and imaging biomarkers on predicting DAS 28 remission at 6 months, in RA patients initiating IV bDMARD. Methods: From 2008 to 2017, 317 RA patients fulfilling ACR 1987 and/or ACR-EULAR 2010 criteria for RA, initiated IV bDMARDs in our department of Rheumatology. Patients were excluded in cases of lack of information on disease activity assessment before and at 6 months of treatment and on immunological status and titers (ACPA, RF, ANA) at baseline. For patients receiving successive IV bDMARDs during this time period (n=30), a randomization permitted to select 1 treatment sequence. On 173 patients eligible to the study, 4 were lost to follow-up and 14 stopped treatment due to adverse events before 6 months. Clinical, biological and imaging (US and RX) data, were collected when available at treatment initiation. US examination was performed on 12 targeted joints (wrist, MCP2-3-5 and MTP2-3-5) with qualitative and quantitative evaluation on B mode and Power Doppler (PD) for synovitis, tenosynovitis and erosion. The modified Sharp/van Der Heijde erosion score was performed by 2 independent readers blindly from clinical and US informations. Remission was defined by a DAS 28 < 2.6 at 6 months. Only variables with a p<0.2 in univariate analysis were included in the multivariate model. Results: On 155 RA patients, 11 had a disease duration < 2 year, 44 (28.3%) were on first line of IV bDMARDs and 111 patients received at least one IV bDMARD (mean 2.5 (1.3)). Conclusion: In RA patients treated by IV bDMARDs, number of PD+ synovitis on ultrasonography was the only predictive biomarker of DAS 28 remission.