Step-down strategy of spacing TNF-blocker injections for established rheumatoid arthritis in remission: results of the multicentre non-inferiority randomised open-label controlled trial (STRASS: Spacing of TNF-blocker injections in Rheumatoid ArthritiS Study).

UNLABELLED: Tumour necrosis factor (TNF)-blocker tapering has been proposed for patients with rheumatoid arthritis (RA) in remission.

OBJECTIVE: The trial aims to compare the effect of progressive spacing of TNF-blocker injections (S-arm) to their maintenance (M-arm) for established patients with RA in remission.

METHODS: The study was an 18-month equivalence trial which included patients receiving etanercept or adalimumab at stable dose for ≥1 year, patients in remission on 28-joint Disease Activity Score (DAS28) for ≥6 months and patients with stable joint damage. Patients were randomised into two arms: maintenance or injections spacing by 50% every 3 months up to complete stop. Spacing was reversed to the previous interval in case of relapse, and eventually reattempted after remission was reachieved. The primary outcome was the standardised difference of DAS28 slopes, based on a linear mixed-effects model (equivalence interval set at ±30%).

RESULTS: 64 and 73 patients were included in the S-arm and M-arm, respectively, which was less than planned. In the S-arm, TNF blockers were stopped for 39.1%, only tapered for 35.9% and maintained full dose for 20.3%. The equivalence was not demonstrated with a standardised difference of 19% (95% CI -5% to 46%). Relapse was more common in the S-arm (76.6% vs 46.5%, p=0.0004). However, there was no difference in structural damage progression.

CONCLUSIONS: Tapering was not equivalent to maintenance strategy, resulting in more relapses without impacting structural damage progression. Further studies are needed to identify patients who could benefit from such a strategy associated with substantial cost savings.

TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT00780793; EudraCT identifier: 2007-004483-41.