Session Information
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: The goal of rheumatoid arthritis (RA) strategy is to reach remission or at least a low disease activity. When this goal is reached, no clear guideline exists to manage therapy. Recently, STRASS (Spacing TNF-blocker injections in RA Study) provided evidence of step-down therapeutic strategy with adalimumab or etanercept (1). So, we investigated if drug dosages and their antidrug antibodies (ADAb) could predict relapse during the 18 months of STRASS study.
Methods: We assessed 131 serum among the 137 included in STRASS study (60 and 71 for adalimumab and etanercept, respectively). Sera were collected at the time of randomisation. Adalimumab and etanercept blood concentrations and theirs ADAb were assessed by ELISA (Theradiag, Marne-La-Vallee, France). For this study, relapse was defined as DAS28>2.6 with DAS28 increase >0.6 since the previous study visit. Non parametric analysis was performed.
Results: Characteristics of the 131 patients similar to 137 from the initial STRASS study (data not shown). These RA patient characteristics are summarised in the Table 1 according to TNF blocker used. The median age was 54.5 [48.3-61.8] years. One hundred and two (77%) were female. The median disease duration was 6.5 [4.5-12.4] years. The median DAS28, ESR, and CRP were 2.0 [1.5-2.3], 10 [6-17]mm/hr, and 3 [2-4]mg/mL, respectively. Methotrexate was the main DMARDs used (n=91; 70%). No baseline characteristics were associated with relapse during tapering or not. Adalimumab or etanercept serum concentrations were not different in case of relapse or not (Table2). Some ADAb against etanercept or adalimumab were detected, but their concentrations were under the positivity threshold. Table 1. RA patients characteristics
| Adalimumab (n=60) | Etanercept (n=71) | P values | |
| Age, years | 54.1 [44.7-60.3] | 58.3 [52.0-62.8] | 0.062 |
| Female sex, n (%) | 44 (73) | 58 (82) | 0.294 |
| Disease duration, years | 7.9 [4.4-12.7] | 5.8 [4.6-9.4] | 0.937 |
| IgM RF positivity, n (%) | 32 (61.5) | 46 (74.2) | 0.349 |
| ACPA positivity, n (%) | 37 (75.5) | 52 (81.2) | 0.285 |
| DAS28 | 2.0 [1.6-2.3] | 1.9 [1.4-2.2] | 0.275 |
| ESR, mm/1st hour | 12.5 [6.7-18] | 8.0 [5.0-16.0] | 0.470 |
| CRP, mg/mL | 3 [2-4] | 3 [1-4] | 0.728 |
| Monotherapy (%) | 18 | 31 | 0.110 |
| Time to relapse, (months) | 9 [3-12] | 6 [3-12] | 0.273 |
Table 2. Adalimumab or etanercept serum concentrations at the time of randomisation according to relapse or not
| Adalimumab | Etanercept | |||||
| Relapse | No relapse | Relapse | No relapse | P value | ||
| Number | 43 | 17 | 35 | 36 | ||
| TNF blockers concentration (µg/ml) | 6.90±2.32 | 6.97±2.42 | 0.91 | 4.23±1.39 | 4.18±1.45 | 0.89 |
Conclusion: No difference was observed in adalimumab or etanercept serum concentrations at the time of randomization to predict relapse in RA patients with low disease activity. Further investigations at various time points during the tapering could be useful.
To cite this abstract in AMA style:
Marotte H, Rinaudo-Gaujous M, Paul S, Fautrel B. TNF Blocker Concentrations or Detection of Antibodies Against Anti-TNF before a Tapering Process Are Not Predictive to Relapse [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/tnf-blocker-concentrations-or-detection-of-antibodies-against-anti-tnf-before-a-tapering-process-are-not-predictive-to-relapse/. Accessed .« Back to 2016 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/tnf-blocker-concentrations-or-detection-of-antibodies-against-anti-tnf-before-a-tapering-process-are-not-predictive-to-relapse/