Background Rituximab (RTX) is a chimeric monoclonal antibody against the protein CD20, which is primarily found on the surface of B cells. Originally developed for the treatment of B-cell non-Hodgkin’s lymphoma, RTX has increasingly been used to treat a variety of autoimmune and immune-mediated disorders, such as rheumatoid arthritis and in the last 11 years is also being used totreat SLE patients refractory to other therapies.

Objectives The aim of this study is to asses the prevalence, efficacy and safety of RTX in our cohort of patients with SLE.

Methods A retrospective study of patients with SLE (ACR 1982 revised criteria) who were treated with RTX in the Department of Rheumatology at the Parc de Salut MAR (Barcelona, Spain). For each patient, demographic and clinical information was collected as well as number of cycles and possible adverse effects

Results 135 patients were studied, median age 48.5 ±14.01 years. 6 patients were treated with RTX (prevalence 4.5%), 5 women and 1 man. Of these, 3 patients were Caucasians, 2 South American and 1 African. 4 of them associated an antiphospholipid syndrome, 2 a mixed cryoglobulinemia and one of them none (one patient associated an antiphospholipid syndrome and a mixed cryoglobulinemia both together). Patients had received a total of 19 cycles, 38 infusions (one patient had received 2 cycles, another 5 cycles, other 3 and other 1). All of them were SLE patients refractory to other therapies and there was permanent increase in concentration of acute phase reactants before of the treatment of RTX. The severe clinical manifestation resistant to conventional therapy was: thrombocytopenia, hemolytic anemia + thrombocytopenia, central nervous system vasculitis, persistent arthritis in two patients, pulmonary fibrosis + alopecy. The mean ±SLICC/ACR score was 3.5 ±2.88 at baseline. The pre-treatment serum Anti-dsDNA levels decreased from a median (P25-P75) of 84 (56-532) pre-treatment to 52 (34-462) post-treatment, which represented an improvement in 89.4% of the patients (p<0.05). The medians and the % of improvement of the remaining variables were: SLEDAI decreased from a median (P25-P75) of 5 (5-8) to 2 (1-4), improvement in 94.7 % of the patients (p<0.05), ESR decreased from a median (P25-P75) of 24 (18-44) to 23 (16-25), improvement in 63.1% of the patients (p<0.05), C3 increased from a median (P25-P75) of 100 (78-125) to 95 (79-134), improvement in 78.9 % of the patients, (p<0.05); C4 increased from a median of 15 (8-28) to 17 (10-31), improvement in 73.6 % of the patients, (p<0.05) (Table 1). Regarding to safety one patient had a severe thrombocytopeniaafter treatment with combined therapy with RTX plus cyclophosphamide for the treatment of central nervous system vasculitis

Conclusions Two randomized clinical trials with RTX (the EXPLORER and LUNAR studies) failed to prove efficacy of this drug in SLE. In contrast to this, uncontrolled clinical studies with RTX have shown promising results (1) as in our cohort of active SLE patients with severe systemic complications. From these findings we can conclude that RTX seems to be a therapeutic option in cases of refractory disease or recurrent flares despite the use of standard therapy.

1. Wiesik-Szewczyk E, Olesinska M. B-cell targeted therapy in systemic lupus erythematosus: potential of rituximab. Biologics. 2012;6:347-54.

Acknowledgements Acknowledgments Sergi Mojal. AMIB.

Disclosure of Interest None Declared