LUPUS-BEST - Treat-to-target in Systemic Lupus Erythematosus

Inclusion Criteria: * Patients with SLE according to validated classification criteria * Age at least 18 years * Not in a stage of remission due to 1. Clinical SLEDAI \> 0 AND/OR 2. GC dosage above 5 mg prednisone equivalent per day AND/OR 3. Physician global assessment ≥ 0.5 on a visual analogue scale (VAS) from 0 to 3 * Fluent German language skills * Written informed consent Exclusion Criteria: * Participation in other interventional trial(s) * Any disease or medical condition that, in the opinion of the investigator, would make the subject unsuitable for this study, would interfere with the interpretation of subject safety or study results, or is considered unsuitable by the investigator for any other reason. Examples could be: * Life-threatening SLE manifestations that require intensive care treatment * Active life-threatening diseases other than SLE * Active malignancies * Acute and chronic infections that do not allow the intensification of immunosuppressive treatment