Obstacles facing therapeutic trials in systemic lupus erythematosus (SLE) include the low incidence, seriousness, complexity, and clinical polymorphism of the disease. A large-scale multicenter design has been required in most cases. Over the last few years, several biologics have been evaluated as treatments for lupus nephritis or for the skin and joint manifestations of SLE. The central role for the B-cell in SLE, together with improved knowledge of the targets on the B-cell surface, has prompted efforts to develop monoclonal antibodies as treatments for SLE. The two available monoclonal antibodies are rituximab (anti-CD20 antibody) and belimumab (anti-BlyS antibody). The results obtained with belimumab were used to develop a new measurement tool, the SLE Responder Index (SRI), and prompted an application for a license to use belimumab in SLE. Other targets identified on the B-cell surface are being evaluated.