A Study Evaluating the Effects of GLPG3970 Given as Oral Treatment for 12 Weeks in Adults With Systemic Lupus Erythematosus

Inclusion Criteria

• •SLE diagnosis defined by American College of Rheumatology (ACR) 1997 criteria ≥4
• •Active arthritis in \>=4 active joints (according to 28 joint count) and/or cutaneous lupus erythematosus disease area and severity index (CLASI) score \>=6.
• •Anti-dsDNA antibodies \>15 IU/mL.
• •Stable standard-of-care (SoC) therapy (defined as no change in prescription for at least 2 weeks prior to first IP dosing) consisting of the following permitted SoC medications:
• •* Corticosteroids \<=20 mg/day (prednisone or equivalent) for at least 2 weeks prior to first IP dosing; AND/OR
• •* Non-steroidal anti-inflammatory drug (NSAIDs); AND/OR
• •* One single antimalarial at a stable dose (hydroxychloroquine \<=5 mg/ kg/day, quinacrine 100 mg/day, or chloroquine 2.3 mg/kg/day) for at least 8 weeks prior to first IP dosing; AND/OR
• •* One single immunosuppressant at a stable dose (azathioprine (AZA) \<=2 mg/kg/day, methotrexate (MTX) \<=20 mg/week, or mycophenolate mofetil (MMF) \<=2 g/day) for at least 8 weeks prior to first IP dosing.
• •estimated glomerular filtration rate (eGFR) \>=60 mL/min (according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI))