Effectiveness of treat-to-target tapering of TNF inhibitors for psoriatic arthritis and axial spondyloarthritis in the Netherlands: 24-month follow-up of the DRESS-PS trial

Abstract

Background: Results of the DRESS-PS trial showed that a tapering strategy with TNF inhibitors is non-inferior to continuation of the same TNF inhibitor dose for up to 12 months in patients with psoriatic arthritis and axial spondyloarthritis. This study aimed to describe the effectiveness of TNF inhibitor tapering for up to 24 months in patients who participated in the DRESS-PS trial.

Methods: This study was a 12-month observational extension of the original 12-month, open-label, non-inferiority DRESS-PS trial conducted at the Sint Maartenskliniek, Nijmegen and Woerden, the Netherlands. Patients aged 16 years and older with psoriatic arthritis or axial spondyloarthritis and stable low disease activity for at least 6 months participated in the original DRESS-PS trial. Patients were randomly assigned to either a treat-to-target tapering strategy (the intervention group), which involved extending the interval between TNF inhibitor doses, resulting in doses of 100%, 66%, 50%, or 0% of the defined daily dose, or to a treat-to-target strategy without tapering (the control group). All patients who participated in the DRESS-PS trial were eligible to participate in this extension study, in which treat-to-target tapering was allowed for all patients, and treatment decisions were made through shared decision making between physicians and patients. The primary outcome was the difference between the original intervention and control groups in the proportion of patients with low disease activity at 24 months; this difference (adjusted for stratification factors at randomisation) was compared, without and with imputation, with the prespecified non-inferiority margin of 20% from the original DRESS-PS trial, and non-inferiority was determined from the adjusted 95% CIs. There was no involvement of people with lived experience of psoriatic arthritis or axial spondyloarthritis in the design, recruitment, conduct, analysis, or reporting of this extension study. The DRESS-PS trial was registered with the Dutch Trial Register, NL6771.

Findings: Between Jan 8, 2020, and Oct 10, 2022, 114 of the 122 patients from the DRESS-PS trial participated in this extension study: 79 from the original intervention group (40 with psoriatic arthritis, 39 with axial spondyloarthritis) and 35 from the original control group (18 with psoriatic arthritis, 17 with axial spondyloarthritis). Mean age was 50·0 years (SD 14·5). 70 (61%) patients were men and 44 (39%) were women. The proportion of patients with low disease activity at 24 months was 67% (45 of 67 patients) in the intervention group and 72% (23 of 32 patients) in the control group, with an adjusted difference of 5% (95% CI -15 to 24; p=0·64), which exceeded the prespecified non-inferiority margin. With imputation of missing data, the adjusted difference was 2% (-18 to 16; p=0·85), which fell within the non-inferiority margin. 78 (99%) of 79 patients in the intervention group and 31 (89%) of 35 patients in the control group had at least one adverse event over the full 24-month study period (difference 10% [-1 to 21]; p=0·060). There were no significant differences between groups in adverse events of special interest: infections and injection site reactions.

Interpretation: Treat-to-target tapering of TNF inhibitors remains effective and safe for the maintenance of low disease activity for up to 2 years in patients with psoriatic arthritis and axial spondyloarthritis. Future research should explore the challenges to implementation of tapering strategies in routine care in these patients.

Funding: ReumaNederland.