The efficacy of a fixed-dose rituximab schedule was prospectively explored in primary/acute refractory, relapsed or chronic (platelet count >10 ? 109/l and =50 ? 109/l) idiopathic thrombocytopenic purpura (ITP). Patients received two doses of rituximab (1000 mg) on days 1 and 15 and were followed-up on weeks 1-8, 12, 26, 39 and 52. A total of 122 patients were included in the safety population; efficacy was analysed in 108 patients. Overall response rate (ORR) at week 8, defined as the proportion of patients achieving complete response (CR; platelet count >150 ? 109/l) or partial response (PR; platelet count >50 ? 109/l) was 44 . Therapeutic response, defined as achieving a response at week 8, with at least a minor response (MR; platelet count >30 ? 109/l), sustained up to weeks 26 and 52 and accompanied by a reduction in ITP medications, was achieved in 44 (week 26) and 35 (week 52) of patients, respectively. Treatment was well tolerated with no safety concerns. While this study failed to meet its primary endpoint of an ORR of 50 , the efficacy of two fixed doses of rituximab appear to provide similar efficacy to the standard 375 mg/m2 four-dose schedule in relapsed/chronic ITP.