Short- and long-term effects of rituximab for the treatment of thrombotic thrombocytopenic purpura: four case reports.

We report four cases of thrombotic thrombocytopenic purpura (TTP) successfully treated with rituximab in combination with plasma exchange and other immunosuppressive agents. All four cases fulfilled the diagnostic criteria of TTP with severe deficiencies in ADAMTS13 activity and a detectable anti-ADAMTS13 inhibitor. Four weekly doses of 375 mg/m(2) rituximab were initiated on day 3-29 of presentation as a salvage treatment for relapsing/refractory disease in three patients and as a first-line treatment in one. Resolution of clinical symptoms and hematological abnormalities occurred as early as the second dose and, after the completion of treatment, all four patients achieved complete response (CR). They are currently free from relapse and the duration of CR has been 13-72 months. During the treatment course, the level of ADAMTS13 activity and the titer of the inhibitor correlated well with resolution or exacerbation of the disease. This report suggests that rituximab exhibits short- and long-term favorable effects for the treatment of TTP and that a severe ADAMTS13 deficiency and ADAMTS13 inhibitor positivity may support early administration of rituximab in both acute/refractory and relapsing cases.