Ability to predict rheumatoid arthritis relapse after tumour necrosis factor inhibitor tapering by the Multi-Biomarker Disease Activity Score: a post-hoc analysis of the STRASS trial.

Objectives: The aim was to evaluate the ability of baseline multi-biomarker disease activity (MBDA) score to discriminate between patients with rheumatoid arthritis (RA) in remission who are at high risk versus low risk of relapse after TNF-inhibitor (TNFi) tapering.
Methods: The study is a post-hoc analysis of patients who completed the Spacing of TNFi injections in Rheumatoid ArthritiS Study (STRASS), a multicentre 18-month equivalence randomised controlled study, of TNFi tapering in RA patients in remission, and had baseline serum samples available for MBDA testing. The primary endpoint of this study was the ability of the baseline MBDA score to predict relapse at any time during the 18 months following initiation of TNFi tapering. Secondary endpoints were the ability of baseline MBDA score to predict TNFi discontinuation at Month 18, and structural damage progression on x-rays assessed by the change in total van der Heijde-modified Sharp score from baseline to month 18.
Results: 64 and 73 patients were included in the spacing (S)-arm and maintenance (M)-arm, respectively. In the M-arm, the mean MBDA score at baseline was higher among patients who relapsed during the 18-month follow-up than those who did not relapse: 32.5 compared to 27.2 (p=0.053) whereas no difference in the MBDA score was observed in the S-arm between patients who relapsed or not 27 compared to 26.2 (p=0.57) 13 patients (21.3%) of the S-arm were able to discontinue TNFi, for which the predictive value of the MBDA score was low (AUC=0.560). Radiographic progression in both arms, although low (n=9) was not correlated with the MBDA score at baseline with a poor discriminative value in both arms (AUC=0.558).
Conclusions: In our study MBDA score in baseline was not predictive of relapse, discontinuation of TNFi in patients with long-standing RA patients tapering TNFi.