Rituximab and Prednisone as First-Line Therapy in Treating Patients With Immune Thrombocytopenic Purpura

DISEASE CHARACTERISTICS:

• Diagnosis of immune thrombocytopenic purpura (ITP)
• Diagnosis must be made according to American Society of Hematology diagnostic guidelines by a member of Mayo Rochester's Division of Hematology/Oncology within the past year
• ITP must be confirmed by bone marrow aspiration and biopsy in all patients ≥ 60 years of age*
• Bone marrow studies performed outside Mayo must be reviewed by a Mayo hematopathologist to confirm diagnosis and exclude evidence of other hematologic disorders NOTE: *Bone marrow evaluation is discretionary for all other patients
• Requires treatment, as defined by 1 of the following parameters:
• Platelet count ≤ 30,000/mm³
• Platelet count ≤ 50,000/mm³ with episodic bleeding (i.e., spontaneous or with minimal trauma) requiring treatment
• No concurrent diagnosis of a condition known to cause secondary immune (or nonimmune) thrombocytopenia, including, but not limited to, any of the following:
• Rheumatological conditions, such as lupus, rheumatoid arthritis, scleroderma, or mixed connective tissue disorder
• Patients with positive serologies and no concurrent, clinically evident condition are eligible
• HIV positive or AIDS
• Non-Hodgkin's lymphoma, Hodgkin's lymphoma, chronic lymphocytic lymphoma, multiple myeloma, or other malignant hematological conditions
• Clinically evident antiphospholipid antibody syndrome* or heparin-induced thrombocytopenia
• Clinically overt liver disease, hepatitis B surface antigen positive, hepatitis C serology positive, or evidence of a microangiopathic hemolytic anemia, such as disseminated intravascular coagulation, hemolytic-uremic syndrome, thrombotic thrombocytopenic purpura, or preeclampsia NOTE: *Positive laboratory tests without the defined clinical criteria for a diagnosis of antiphospholipid antibody syndrome is allowed

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Creatinine ≤ 2 times upper limit of normal (ULN)
• Direct bilirubin ≤ 1.5 times ULN
• Total bilirubin ≤ 1.5 times ULN
• AST ≤ 2.5 times ULN
• Hemoglobin ≥ 10 g/dL
• WBC ≥ 3,000/mm³
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No hypersensitivity to murine or chimeric proteins
• No other disease, metabolic dysfunction, physical examination finding, or clinical laboratory finding giving reasonable suspicion of a disease or condition that contraindicates the use of an investigational drug or that may affect the interpretation of the results or render the patient at high risk for treatment complications
• Able to take a proton-pump inhibitor while on corticosteroids
• No unresolved or incompletely treated infection within the past 14 days

PRIOR CONCURRENT THERAPY:

• No prior corticosteroid therapy since the diagnosis of ITP
• Corticosteroid therapy is allowed for up to 14 days prior to study entry, once the baseline CBC has been established
• No prior rituximab
• No other concurrent therapy for ITP, including androgens, IV immunoglobulins, RH_o (D) immune globulin, cyclosporine, or azathioprine sodium