[Rituximab treatment of chronic idiopathic thrombocytopenic purpura. Results of a phase II study].

In a recent article we indicated that rituximab is an active and safe drug in patients with chronic ITP. We report now the updated results of this study. Twenty-five individuals with chronic ITP were treated with intravenous rituximab at the dose of 375 mg/m2 once weekly for 4 weeks. Rituximab infusion-related side effects were observed in 18 patients, but they were of modest intensity and did not require discontinuation of treatment. Long-term side effects included a decreased B-cell count of several months duration in most patients which, however, did not translate into a significant rate of infections. The overall response rate was 52%, with 7 cases showing a sustained response (6 months or longer). In 2 patients with relapsed disease, repeat challenge with rituximab induced a new response. In responders a significant rise in platelet concentrations was observed early during the course of treatment, usually 1 week after the first rituximab infusion. No clinical or laboratory parameter was found to predict treatment outcome. In conclusion, we confirm that rituximab can induce long-lasting responses in patients with chronic ITP and has a favorable side effect profile. Therefore, we suggest its use in refractory ITP cases.