The aim of this study was to evaluate the long-term response to rituximab in patients with chronic and refractory immune thrombocytopenic purpura (ITP). Adults with ITP fail to respond to conventional therapies in almost 30% of cases, developing a refractory disease. Rituximab has been successfully used in these patients. We used rituximab at 375 mg/m2, IV, weekly for a total of four doses in 18 adult patients. Complete remission (CR) was considered if the platelet count was >100 x 10(9)/l, partial remission (PR) if platelets were >50 x 10(9)/l, minimal response (MR) if the platelet count was >30 x 10(9)/l and