Dosimetry/Validation Study of 131Iodine-Anti B1 (Murine) Radioimmunotherapy for Chemotherapy Refractory Low Grade B Cell Lymphomas and Low Grade Lymphomas That Have Transformed to Higher Grade Histologies

Inclusion Criteria

* Patients must have a histologically confirmed diagnosis of low-grade non-Hodgkin's B-cell lymphoma or low-grade lymphoma that has transformed to intermediate-, or high-grade lymphoma (transformed lymphoma) according to the Working Formulation for Clinical Usage (IWF A, B, and C).
* Patients must have evidence that their tumor tissue expresses the CD20 antigen.
* Patients must have progressive disease of either low-grade or transformed lymphoma within one year of completion of the last chemotherapy regimen administered.
* Patients must have been previously treated with at least one chemotherapy regimen that included an anthracycline or anthracenedione.
* Patients must have a performance status of at least 60% on the Karnofsky Scale and anticipated survival of at least three months.
* Patients must have an absolute granulocyte count of over 1,500 /mm3 and a platelet count above 100,000 /mm3 within seven days of study entry. These blood counts must be sustained without support of hematopoietic cytokines or transfusion of blood products.
* Patients must have normal renal function (creatinine less than 2.0 mg/dL) and hepatic function (bilirubin less than 2.0 mg/dL) within seven days of study entry.
* Patients must have bi-dimensionally measurable or evaluable progressive lymphoma disease (at least a 25% increase in tumor size or new sites of disease when compared to the last best disease response). Progression must have occurred within 12 months of the preceding response.
* Patients must be at least 18 years of age.
* Patients must give written informed consent and sign an approved informed consent form prior to study entry.

Exclusion Criteria

* Patients with more than an average of 25% of the intertrabecular marrow space involved by lymphoma in bone marrow biopsy specimens as assessed microscopically at study entry.
* Patients who have received cytotoxic chemotherapy, radiation therapy, immunosuppressants, or cytokine treatment within FOUR weeks prior to study entry (six weeks for nitrosourea compounds) or who exhibit persistent clinical evidence of toxicity. The use of steroids must have been discontinued (except maintenance-dose steroids) at least one week prior to study entry and patients must then show evidence of stable or progressive disease.
* Patients with prior hematologic stem cell transplant following high-dose chemotherapy or chemo/radiotherapy .
* Patients with obstructive hydronephrosis.
* Patients with evidence of active infection requiring intravenous antibiotics at the time of study entry.
* Patients with New York Heart Association class 3 or 4 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 patient has been disease-free for five years.
* Patients with known HIV infection.
* Patients with known brain or leptomeningeal metastases.
* Patients who are pregnant. Patients of child-bearing potential must undergo a pregnancy test within seven days of study entry. Males and females must agree to use effective contraception during the study.
* Patients with previous allergic reactions to iodine. This does not include IV contrast materials.
* Patients who were previously given any monoclonal or polyclonal antibodies of any foreign species for either diagnostic or therapeutic purposes. This includes engineered chimeric and humanized antibodies.
* Patients who previously received radioimmunotherapy.
* Patients with progressive disease in a field that has been previously irradiated with more than 3500 cGy.
* Patients who are on another protocol involving non-approved drugs or biologics.