The goal of this clinical trial is to compare three different maintenance and step-down treatment strategies in children and adolescents with juvenile idiopathic arthritis in sustained remission. The main questions it aims to answer are:

• Is the proportion of study participants with a disease flare different between each of the two drug withdrawal arms and the stable treatment arm during 12 months?
• Does the proportion of study participants with a disease flare differ between the two drug withdrawal arms during 12 months?
• How long time does it take before a disease flare occurs, and how long does it take before disease remission is reestablished for participants in the different treatment arms?

Participants will be randomized to either A) continued stable treatment with methotrexate and tumor-necrosis alpha inhibitor (TNFi); B) gradual withdrawal of methotrexate while continued stable dose TNFi; or C) gradual withdrawal of TNFi.

Participants will be examined every 4 month, and with extra visits if they experience increased symptoms or suspect a disease flare. If a flare occurs, the medications received at study inclusion will be restarted.

Inclusion Criteria:

1. Participant must be 2-<18 years of age at the time of signing the informed consent.
2. Fulfilment of the International League of Associations for Rheumatology (ILAR) classification criteria for non-systemic Juvenile Idiopathic Arthritis (JIA).
3. Inactive disease for ≥12 months documented at a minimum of 2 consecutive visits and documented inactive disease according to Wallace criteria at inclusion, and no active uveitis for ≥24 months.
4. Stable treatment with methotrexate and Tumor Necrosis Factor inhibitor (TNFi) for ≥6 months. Weight adjustments permitted.
5. Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF).
6. Male participants: No contraceptive measures necessary.
7. Female participants: contraception guidance for women of childbearing potential (WOCP).

Exclusion Criteria:

1. Chronic widespread pain syndrome
2. Major comorbidity including uncontrolled infectious, neurological or mental disease, malignant disease, severe heart failure, severe renal failure, active ulcus ventriculi, and uncontrolled diabetes mellitus.
3. Use of oral, intra-articular, intramuscular or intravenous corticosteroids due to JIA less than 12 months prior to randomization.
4. Participating in an ongoing clinical randomized study..
5. Drug/alcohol abuse which hampers adherence to the study protocol as based on the investigators judgement.
6. Language barriers that hamper adherence to the study protocol.
7. Pregnancy or breastfeeding.
8. Any condition that in the view of the investigator would suggest that the patient is unable to comply with the study protocol and procedures.
9. Unwillingness to use safe contraception for sexually active WOCP.

A de-identified patient data set can be made available to researchers upon reasonable request.

10 years

The data will only be made available after submission of a project plan outlining a reasonable request and any proposed analyses, and will have to be approved by the the MOVE-JIA steering group. Project proposals can be submitted to the corresponding author. Data sharing will have to follow appropriate regulations.