Our aim is to investigate whether the use of drug levels can optimize treatment in patients with RA starting adalimumab. 1. Test the value of adalimumab serum levels based TDM in reducing dose in RA patients responding to adalimumab compared to a disease activity-guided dose reduction strategy. 2. Test if an adalimumab level of 2 mg/L is sufficient to control disease compared to 5 mg/L. 3. Test whether the response rate can be increased using TDM in those patients who fail adalimumab.
1. We expect that direct medical cost will be minimized using TDM, without an increase in disease activity.
2. 2mg/L is sufficient to control disease compared to 5 mg/L, without increase in disease activity.
3. We expect that using TDM is superior compared to usual care.
1. Consist of three phases: 1) a 16 week observational phase, followed by 2) a 36 week randomized, cost-minimization, non-blinded, non-inferiority, strategy trial, and concluding with 3) a 28 week extension.
2. 28 weeks randomized open-label, non-inferiority, trial.
3. 28 weeks randomized open-label, superiority, strategy trial.
1. Patients with RA starting adalimumab.
2. patients with RA treated for at least 28 weeks with adalimumab 40 mg every 2 weeks and an adalimumab concentration >5 mg/L.
3. patients with RA starting another bDMARD after adalimumab failure.
1. Patients are randomly assigned to TDM-guided or DAS-guided dose reduction.
2. Patients are randomly assigned to dose reduction aiming a drug level of 2 mg/L or 5 mg/L
3. Patients are randomly assigned to usual care (switch to the second TNFi, etanercept or non TNFi biologic) or TDM guided switch
PRIMARY OUTCOME MEASURES
1. Direct medical costs associated with the intervention (medication, non-scheduled visits due flares, cost TDM testing) over 52 weeks
2. Difference in mean time weighted DAS28 between study groups after 28 weeks
3. Difference in mean time weighted DAS28 between study groups after 28 weeks