To the Editor:

The National Heart, Lung, and Blood Institute (NHLBI) Transfusion Medicine/Hemostasis Clinical Trials Network has opened a clinical trial to study the role of rituximab in the treatment of thrombotic thrombocytopenic purpura (TTP). The Network was formed in 2002 as a consortium of 18 academic centers to provide opportunities for clinical research on uncommon hematologic disorders. The Study of TTP and Rituximab (STAR trial) randomizes patients to standard care (plasma exchange, corticosteroids) or standard care plus rituximab (the standard regimen of four weekly infusions), begun before the sixth plasma exchange. Eligibility is based on clinical criteria and does not require ADAMTS13 deficiency. Rituximab is supplied free of charge to the patient by Genentech, Inc. The primary objective is to improve early (before day 21) treatment response. Our hypothesis is that rituximab will reduce the failure to achieve an early treatment response from 38 percent to 18 percent. Two hundred thirty-eight (238) patients, 119 in each treatment arm, will be enrolled. The complete protocol is accessible at

We want hematologists to be aware of this study. If you are near one of the Network centers (listed on the Web site), you may consider whether a patient with TTP should be enrolled. We are enthusiastic about the potential of the STAR trial to define the appropriate role of rituximab in the treatment of TTP.

-Joseph E. Kiss, MD, University of Pittsburgh

-Lynne Uhl, MD, Beth Israel Deaconess Hospital, Harvard Medical School

-James N. George, MD, University of Oklahoma