Retreatment of Patients With Non-Hodgkin's Lymphoma Who Have Previously Responded to Iodine-131 Anti B1 Antibody

This multicenter study will determine the response rate, the complete response rate, duration of response, time to progression, time-to-treatment failure, safety, and survival following treatment with Iodine-131 Anti-B1 Antibody for the retreatment of patients with non-Hodgkin's lymphoma who previously responded with a duration of response of at least 3 months to Iodine-131 Anti-B1 Antibody therapy. Patients will undergo two phases of study. In the first phase, patients will receive a dosimetric dose of unlabeled Anti-B1 Antibody (450 mg) followed by Anti-B1 Antibody (35 mg) which has been radiolabeled with 5 mCi of Iodine-131. Whole body gamma camera scans will be obtained after the dosimetric dose and data from three imaging time points will be used to calculate a patient-specific dose to deliver the desired total body dose of radiotherapy. In the second phase, patients will receive the therapeutic dose of unlabeled Anti-B1 Antibody (450 mg) followed by 35 mg of Anti-B1 Antibody labeled with the patient-specific dose to deliver the desired whole body dose of radiation. Patients will be treated with thyroid blocking medication at least 24 hours prior to the first infusion and continuing for 14 days following the last infusion.

Inclusion Criteria:

• Patients with histologically confirmed initial diagnosis of non-Hodgkin's B-cell lymphoma
• Patients must have previously responded with a duration of response of at least 3 months to Iodine-131 Anti-B1 Antibody therapy
• Patients must have evidence that their tumor tissue had CD20 expression
• Patients must have performance status of at least 60% on the Karnofsky scale and an anticipated survival of at least 3 months
• Patients must have absolute granulocyte count (ANC) greater than 1,500 cells/mm3 and platelet count greater than 100,000 cells/mm3 within 14 days of study entry without support of hematopoietic cytokines or transfusion of blood products
• Patients must have adequate renal (serum creatine less than 1.5 x upper limit of normal) and hepatic function (total bilirubin less than 1.5 x upper limit of normal and hepatic transaminases, AST and ALT, less than 5 x upper limit of normal) within 14 days of study entry
• Patients must have bi-dimensionally measurable disease with a least one lesion greater than or equal to 2 cm x 2 cm by CT scan
• Patients must be at least 18 years of age
• Patients must give written informed consent and sign an Institutional Review Board/Ethics Committee- approved informed consent form prior to study entry

Exclusion Criteria:

• Patients with more than 25% bone marrow involvement
• Patients who have received cytotoxic chemotherapy, radiation therapy, immunosuppressants, or cytokine treatment within 4 weeks prior to study entry or who exhibit persistent clinical evidence of toxicity. The use of systemic steroids much be discontinued at least 1 week prior to study entry.
• Patients with active obstructive hydronephoresis
• Patients with evidence of active infection requiring IV antibiotics at time of study entry
• Patients with New York Heart Association class III or IV heart disease or other serious illness that would preclude evaluation
• Patients with prior malignancy other than lymphoma, except for adequately treated skin cancer, in situ cervical cancer, or other cancer for which the patient has been disease free for 5 years
• Patients with known HIV infection
• Patients with known brain or leptomeningeal metasteses
• Patients who are pregnant or nursing