Effect of Proactive Therapeutic Drug Monitoring on Maintenance of Sustained Disease Control in Adults With Rheumatoid Arthritis on a Subcutaneous TNF Inhibitor: The Rheumatoid Arthritis Therapeutic DRUg Monitoring Trial (RA-DRUM)

The goal of this clinical trial is to compare therapeutic drug monitoring (TDM) versus Standard of care in patients with rheumatoid arthritis treated with a subcutaneous tumor necrosis factor inhibitor (adalimumab). The main question it aims to answer is: Is TDM superior to standard of care in order to maintain sustained disease control without flares? Participants will be followed with blood sampling every second month, measuring serum drug levels and anti-drug antibodies of the TNFi. In the TDM-group, the researchers will adjust the dosage of the TNFi based on knowledge on optimal therapeutic ranges. In the Standard of care group, the TNFi will be administered according to standard of care without knowledge of serum drug levels or anti-drug antibodies.

Inclusion Criteria: 1. A clinical diagnosis of RA 2. ≥ 18 and under 75 years of age at screening 3. On stable therapy with standard dose of a SC TNFi (adalimumab) for a minimum of 3 months and a maximum of 24 months 4. In low disease activity or remission (DAS28-CRP under 3.2) and indication for continuation of treatment according to the treating physician 5. Subject capable of understanding and signing an informed consent form Exclusion Criteria: 1. Major comorbidities, such as previous malignancies within the last 5 years, uncontrolled diabetes mellitus, severe infections (including HIV), uncontrollable hypertension, severe cardiovascular disease (NYHA class 3 or 4), severe respiratory diseases, demyelinating disease, significant chronic widespread pain syndrome, significant renal or hepatic disease, and/or other diseases or conditions which either contraindicate treatment with SC TNFi or make adherence to the protocol difficult 2. Hypersensitivity to sc TNFi (adalimumab). 3. Pregnancy, or subject considering becoming pregnant during the study period 4. Psychiatric or mental disorders, alcohol abuse or other substance abuse, language barriers, or other factors that makes adherence to the study protocol difficult 5. Changes in csDMARD co-medication, including dose changes of csDMARD or changes in the dose of corticosteroids within the last 2 months 6. Co-medication with bDMARD, tsDMARD, or other immunosuppressive drugs (excluding csDMARD and corticosteroids ≤ 7.5 mg prednisolone (or equivalent) once daily). 7. Active participation in any other interventional study. 8. In need of live vaccines during the study period.