Fig. 2

An overview of the hypothesized trial design. The clinical study design closely follows current pharmacological treatment recommendations. Baseline period: Patients diagnosed with JIA and eligible for stable standard pharmacological treatment (12,5 mg/m²–15 mg/m²) will start with MTX. Intervention period: Patients who complete the baseline period without protocol violations continue to the second phase of the study and will be randomized double-blind to one of the following groups: control group (standardized stable treatment dosages of MTX as a continuation of the baseline period for 9 months) or pharmacological conditioning group (variable doses of MTX interspersed with placebos for 9 months). Primary outcome (MISS) will be measured at 15 months (T5). This study will be closed with an end-of-study one year after the intervention period (T6). Flare-ups and side effects will be monitored during clinical visitations.