Dose-to-target of etanercept treatment in rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis.

Objective:

To determine the proportion of patients with RA, AS or PsA maintaining minimal disease activity (MDA) after dose interval prolongation of etanercept.

Secondary objectives: To study the cost-effectiveness of tapering down etanercept treatment, to investigate whether the lowest effective etanercept dose will reduce the risk of adverse events and to study the predictive value of serum etanercept trough levels for successful down titration.



Study design:

Open randomized controlled study of a dose-to-target step-down treatment strategy of etanercept which consists of 2 phases, including 150 rheumatoid arthritis, 50 psoriatic arthritis and 50 ankylosing spondylitis patients.



Intervention:

Patients with Minimal Disease Activity who are treated with etanercept for at least 6 months will be randomly assigned to continuation of etanercept every week or prolongation of the dosage interval to once every 2 weeks (phase 1). Patients will be followed for 6 months. Thereafter, the second phase of this study starts, in which patients, who are still in a state of minimal disease activity, will be further down-titrated to either etanercept 50 mg every two weeks (continuation group first phase) or discontinuation of etanercept. Patients will be followed for an additional 6 months.



Main study parameters:

Minimal Disease Activity define whether a patient is suitable for inclusion and randomisation. Definition of Minimal Disease Activity is specified for every disease separately. Etanercept serum concentrations, disease activity and cost related parameters will be measured during follow-up.

A proportion of patients with rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis with minimal disease activity can remain in a state of minimal disease activity with a lower dose of etanercept (50 mg every two weeks instead of every week) or even without etanercept.

After inclusion at baseline patients will be monitored every 3 months during the first (6 months duration) and second (6 months duration) phase of the study.

Phase 1:

Patients with low disease activity will be randomly assigned to continuation of etanercept 50 mg per week or etanercept 50 mg per two weeks. Patietns will be followed for 6 months.



Phase 2:

Patientens who remained in a state of low disease activity with etanercept 50 mg per two weeks will stop with etanercept. Patients who were still on standard treatment and who are in a state of low disease activity will continue with etanerceot 50 mg per two weeks. Patients will be followed for 6 months.