Systematic review: Efficacy and safety of rituximab for adults with idiopathic thrombocytopenic purpura

Background: Rituximab, a monoclonal anti-CD20 antibody, is increasingly used to treat idiopathic thrombocytopenic purpura (ITP). Purpose: To systematically review the literature on the efficacy and safety of rituximab for the treatment of adults with ITP. Data Sources: MEDLINE, EMBASE, the Cochrane Library, abstracts from the American Societies of Hematology and Clinical Oncology annual meetings, and bibliographies of relevant articles and reviews were searched in duplicate until April 2006. Study Selection: Descriptive and comparative studies in any language that met predefined inclusion criteria were eligible. Efficacy analysis was restricted to studies enrolling 5 or more patients. Data Extraction: Platelet count response, toxicities, dose, previous treatments, baseline platelet count, duration of ITP, study design, and sources of funding were extracted in duplicate. Data Synthesis: We identified 19 eligible reports on efficacy (313 patients) and 29 on safety (306 patients). Weighted means for complete response (platelet count > 150 x 10(9) cells/L) and overall response (platelet count > 50 x 10(9) cells/L) with rituximab were 43.6% (95% CI, 29.5% to 57.7%) and 62.5% (CI, 52.6% to 72.5%), respectively. Responses lasted from 2 to 48 months. Nearly all patients had received corticosteroids, and 53.8% had undergone splenectomy. Nine patients (2.9%) died. Limitations: There were no controlled studies, and no studies met all criteria for study quality. Reported deaths could not necessarily be attributed to rituximab. Overall, the number of rituximab-treated patients with ITP reported in the literature is small. Conclusions: Rituximab resulted in an overall platelet count response in 62.5% of adults with ITP. However, this finding derives from uncontrolled studies that also reported significant toxicities, including death in 2.9% of cases. These data suggest that providers should avoid indiscriminate use of rituximab and that randomized, controlled trials of rituximab for ITP are urgently needed.