Can Rituximab be Useful for Treating SLE-Associated Immune Cytopenias ? Results from a Retrospective Multicentre Study on 62 Patients

Introduction: Autoimmune cytopenias and mostly immune thrombocytopenia (ITP) are common manifestations of systemic lupus erythematosus (SLE). Rituximab (RTX) is used off-label in many countries for treating primary ITP and warm autoimmune hemolytic anemia (AIHA). In SLE, the place of RTX is controversial and the aim of this study was to assess the efficacy and safety of RTX for treating SLE-associated immune cytopenias.

Materials and methods: A multicentre retrospective study was performed throughout the French network of adult' immune cytopenias. Patients aged >18 years, with a definite diagnosis of SLE according to the usual criteria, treated by RTX from 2005 to 2015 specifically for a SLE-associated immune cytopenia could be included. SLE-associated ITP was defined as platelet count ≤ 50 x 10⁹L after exclusion of any other cause of thrombocytopenia. AIHA was defined by a hemoglobin level (Hb) ≤100 g/l with markers of hemolysis and a positive direct antiglobulin test. To assess treatment efficacy, the following criteria were used: for ITP, complete response (CR) and response (R) were defined according to the consensus international criteria. For AIHA, a CR was defined by a normal Hb level in the absence of recent transfusion and without ongoing haemolysis, and a response (R) by a Hb level ≥100 g/l with an increase of at least 20 g/l from baseline. CR and PR could be retained only for patients who were treated with corticosteroids and/or other immunosuppressive agents at a stable or decreasing dose.

Results: Sixty-two patients, 55 women (88.7%), with a median age of 36 years [range 31-49] were included. The median duration of SLE at time of first RTX administration was 6.7 years [3.4-11.4] and the reason for using RTX was ITP in 40 cases (64.5%), AIHA in 15 cases (24.2%) and Evan's syndrome in 6 cases (9.7%). One patient was treated for a SLE-associated pure red cell aplasia. Other SLE-related manifestations were: articular (54.8%), cutaneous (49.2%), serositis (14.5%), renal (11.1%) and/or neurological (14.5%). Patients had received an average of 3.1 ± 1.3 treatments prior to RTX including steroids (100%), and hydroxychloroquine (90.3%). The overall initial response rate to RTX was 82% (87% for ITP, 86% for AIHA, and 50% for Evan's syndrome) including 59% CR. Median follow-up after the first injection of RTX was 24.6 months [12.6-61.2]. Twenty-one (41%) of the initial responders relapsed and re-treatment with RTX was successful in 94%. Severe infections occurred after rituximab in three adults with no fatal outcome. No cases of of opportunistic infections of RTX-induced neutropenia were observed.

Discussion: RTX appears to be an effective and relatively safe option for the treatment of SLE-associated immune cytopenias.