Rituximab Produces Long-Term Responses in Immune Thrombocytopenic Purpura (ITP)

• Published in: Blood 2005-11, Vol.106 (11), p.3977-3977
• Main Authors: Case, Delvyn C., Hedlund, Jacquelyn A., Ebrahim, Kurt S., Boyd, Marjorie A.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V106.11.3977.3977

ITP in adults is an autoimmune disease characterized by antibody-mediated thrombocytopenia. A significant number of patients relapse after initial therapy with prednisone and splenectomy when necessary, and require other therapy for continuing thrombocytopenia. Rituximab, an anti-CD20 chimeric monoclonal antibody has been utilized in ITP refractory to other modes of treatment (Feurestein, M., et al. The use of Rituximab in 28 patients with immune thrombocytopenic purpura (ITP). Proc. Am. Soc. Clin. Onc. 22:187, 2003). We report on the long-term responses possible in ITP treated with Rituximab. Twenty-two patients with ITP refractory to initial conventional therapies with platelet counts 50,000/ul but 150,000/ul). Patient characteristics included 5 males and 17 females with ages 24–83 years (median 58). Twenty had undergone splenectomy. Thirteen patients (59%) responded to Rituximab. Six responses were PR with durations lasting 2, 2, 3, 3, 4, and 6 months. Continuing Rituximab monthly after initial therapy of 4 weeks did not produce improved platelet counts in patients who failed Rituximab or who achieved PR. Seven responses were CR with durations of 12, 20+, 25+, 29+, 38+, 40+, and 48+ months. The one patient who relapsed at 12 months was retreated with Rituximab but did not respond. There was no correlation between response and age, sex, or duration of ITP. Neither of the patients who declined prior splenectomy responded. There were no serious complications of Rituximab infusions. Twenty-five percent of patients had mild first infusion reactions. Rituximab can produce long-term CR in 27% of patients with ITP refractory to initial therapy.