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Outcome at 5 years following response to rituximab therapy in children and adults with immune thrombocytopenia (ITP)

Vivek L. Patel, Matthieu Mahévas, Soo Y. Lee, Roberto Stasi, Susanna Cunningham-Rundles, Bertrand Godeau, Julie Kanter, Ellis Neufeld, Tillmann Taube, Ugo Ramenghi, Shalini Shenoy, Mary J. Ward, Nino Mihatov, Vinay L. Patel, Philippe Bierling, Martin Lesser, Nichola Cooper, James B. Bussel

Abstract

Treatments for ITP providing durable platelet responses without continued dosing are limited. Whereas complete-responses (CR) to B-cell depletion in ITP usually last for one year in adults, partial-responses (PR) are less durable. Comparable data do not exist for children and 5-year outcomes are unavailable. Patients with ITP treated with rituximab who achieved CRs and PRs (platelets >150x109/l or 50-150x109/l, respectively) were selected to be assessed for duration of their response; 72 adults whose response lasted at least one year and 66 children with response of any duration were included. Patients had baseline platelet counts <30x109/l; 95% had ITP of greater than 6-months duration. Adults and children each had initial overall response rates of 57% and similar five-year estimates of persisting response (21% and 26% respectively). Children did not relapse after two years from initial treatment whereas adults did. Initial CR and prolonged B-cell depletion predicted sustained responses whereas prior splenectomy, age, sex, and duration of ITP did not. No novel or substantial long-term clinical toxicity was observed. In summary, 21-26% of adults and children with chronic ITP treated with standard-dose rituximab maintained a treatment-free response for at least five years without major toxicity. These results can inform clinical decision-making.

  • Submitted November 25, 2011.
  • Accepted April 16, 2012.