Which biological therapy is approved for SLE?

• A. rituximab
• B. abatacept
• C. belimumab
• D. epratusumab

Answer: (C)

Belimumab is the approved biologic for systemic lupus erythematosus because it specifically targets the B-cell–activating factor (BLyS/BAFF), a key driver of B-cell survival and autoantibody production in SLE. By inhibiting BLyS, belimumab reduces autoreactive B cells and lowers autoantibody levels, helping to control disease activity when added to standard therapy in patients with active, seropositive SLE. The other agents listed either lack FDA approval for SLE or are used off-label; rituximab is a B-cell depleting antibody used in refractory cases but not formally approved for SLE, while abatacept and epratuzumab have not been approved for lupus.