Daclizumab to Treat Chronic Immune Thrombocytopenia

INCLUSION CRITERIA: Male or female greater than or equal to 18 years old Immune thrombocytopenia, and all of the following: at least three months since initial diagnosis lack of sustained response to initial treatment with prednisone, characterized by failure to maintain a platelet count of at least 30,000/ul for at least six weeks using prednisone at a dose of at least 10 mg per day baseline platelet count (as determined by an average of platelet count values over two months immediately prior to study entry) of less than 30,000/ul *Note: In patients receiving IVIG or anti-D, platelet values immediately prior to infusion of the drug (i.e., at platelet nadir) will be considered in the determination of the baseline platelet value. Splenectomy or prior use of second-line immunomodulatory treatments (such as, but not limited to, CSA, danazol, azathioprine or cyclophosphamide) will not be considered a requirement for inclusion. EXCLUSION CRITERIA: ECOG performance status greater than 1 Concurrent symptomatic autoimmune hemolysis (Evans syndrome) characterized by hemoglobin less than 10 gm/dl or requirement for more than two units red cells within three months of enrollment, due to hemolysis Concurrent autoimmune disorders requiring treatment for involvement of organ systems other than cytopenias Initiation of any new immunomodulator agent, or increase in dose or frequency of any existing immunomodulator agent (such as, but not limited to, CSA, danazol, azathioprine or cyclophosphamide; IVIG and anti-D excepted) within two months of study entry Autologous transplantation for immune thrombocytopenia within one year of study entry Concurrent bleeding diathesis Echinacea use within three months of study entry Pregnancy or lactation Chronic or current clinically significant infection, including HIV positivity and acute or persistent hepatitis B and C virus infection (characterized by elevated transaminases and positive hepatitis B surface antigen [HBsAg], or anti-hepatitis C virus [anti-HCV] antibody) History of active M. Tuberculosis infection Diagnosis of malignancy (with the exception of non-melanoma skin cancer and other malignancies which by virtue of surgical resection and no recurrence for at least five years prior to enrollment are considered to be cured) Inadequate mental capacity to give informed consent