Experimental: Treat-to-target

T2T will be implemented based on shared decision-making (SDM), tight control and remission as a validated treatment target (disease activity score clinical SLEDAI-2k = 0 \& glucocorticoids (GC) ≤ 5 mg prednisolone equivalent \& physician global assessment (PGA 0-3) \< 0.5 ± immunomodulatory therapy); All intervention centers will receive T2T/SDM trainings. Patients not meeting their target criterion at study entry or at any time during the trial will be included in a tight control T2T loop of 24 weeks with assessments every 6 weeks to reach the target by adjustments of their immunomodulatory treatments. Patients in target will be assessed every 12 weeks as it is standard in clinical routine care.

No_intervention: Standard of Care

In the standard of care (SoC) arm, patients receive 3-to 6-monthly controls and treatment adjustments according to their physician's discretion.