Systemic lupus erythematosus is a chronic autoimmune disease in which the body’s immune system mistakenly attacks its own tissues, leading to inflammation of the joints, skin, kidneys and other organs. When the disease stays active despite standard medicines, it is described as treatment‑refractory active disease. This study evaluates a new investigational drug called GLPG5101, which is administered by intravenous infusion.
The purpose of the study is to assess the safety, tolerability and efficacy of the investigational therapy in adults with treatment‑refractory active systemic lupus erythematosus.
Participants first enter a dose‑finding phase in which different amounts of the drug are given to determine a safe level, followed by a dose‑expansion phase where the selected dose is given for up to two years. The medication is delivered through an IV on scheduled visits, and participants are regularly checked for side effects and for signs that the disease is under control, including whether they achieve a state of remission (very low disease activity) after one year, with continued follow‑up through the study period.



Belgium
The Netherlands