Efficacy and safety of rituximab in adult patients with idiopathic relapsing or refractory thrombotic thrombocytopenic purpura: results of a Spanish multicenter study.

BACKGROUND: Between 30% and 60% of patients with thrombotic thrombocytopenic purpura (TTP) relapse and mortality remains at 15-20%. Limited clinical data suggest that the administration of anti-CD20 antibody (rituximab) may be useful in preventing acute refractory and chronic relapsing TTP. DESIGN AND METHODS: We studied the clinical response to rituximab in 24 adult patients (median age 42 years, range 24-72 years) from 15 Spanish centers with an acute refractory (14 patients) or acute relapsing (10 patients) episode of idiopathic TTP. On admission, every patient received daily plasma exchange (PE). Rituximab was administered at a dose of 375 mg/m(2) weekly for a median of 13 days (range 0-57 days) after starting PE for a median of 4 doses (range 1-8 doses). RESULTS: No severe acute or delayed toxicity was observed in the patients treated with rituximab. Three (12.5%) patients died because of TTP-related causes. The remaining 21 (87.5%) patients achieved complete remission in a median of 21 days (range 2-35 days) after initiating rituximab. After a median follow-up of 30 months (range 7.5-74 months), 18 patients are in remission and 3 patients have relapsed at 7, 29, and 29 months. CONCLUSIONS: Rituximab appears to be a safe, effective therapy and has a high response rate for the treatment of acute refractory or relapsing idiopathic TTP in adult patients.