The Future of B-cell Activating Factor Antagonists in the Treatment of Systemic Lupus Erythematosus

To review B-cell activating factor (BAFF)-antagonist therapy in systemic lupus erythematosus (SLE), literature was searched using the search words and phrases, "BAFF", "B lymphocyte stimulator (BLyS)", "a proliferation-inducing ligand (APRIL)", "B-cell maturation antigen (BCMA)", "transmembrane activator and calcium-modulating and cyclophilin ligand interactor (TACI)", "BLyS receptor 3 (BR3)", "belimumab", "atacicept", "blisibimod", "tabalumab", and "lupus clinical trial". In addition, papers from the author's personal library were searched. BAFF-antagonist therapy in SLE has a checkered past, with four late-stage clinical trials meeting their primary endpoints and four failing to do so. Additional late-stage clinical trials are enrolling subjects to address some of the remaining unresolved questions, and novel approaches are proposed to improve results. The BAFF-centric pathway is a proven therapeutic target in SLE. As the only pathway in the past 50+ years to have yielded an United States Food and Drug Administration-approved drug for SLE, it occupies a unique place in the armamentarium of the practicing rheumatologist. The challenges facing clinicians and investigators are how to better tweak the BAFF-centric pathway and improve on the successes realized.