Open Label Multicenter Study of CVP Followed by Iodine-131 Anti-B1 Antibody for Subjects With Untreated Low-Grade Non Hodgkin's Lymphoma.

This is a phase II, open-label, multicenter study of the efficacy and safety of sequential administration of CVP x 6 followed by tositumomab and iodine I 131 tositumomab (formerly referred to as tositumomab and iodine I 131 tositumomab). All patients who complete three cycles of CVP, regardless of response, will be eligible for treatment with tositumomab and iodine I 131 tositumomab. Subjects who have rapidly progressive disease prior to completing three cycles of CVP may be removed from study. In order to proceed to tositumomab and iodine I 131 tositumomab therapy, patients must have completed six cycles of CVP within 20 weeks as described. Patients may proceed to Iodine-131 Anti-B1 Antibody if they have progressive disease documented at the response evaluation following 6 cycles of CVP. In addition, patients must still meet the eligibility inclusion exclusion criteria based upon the week 20 assessments, as applicable. Patients must also have an average of ≤25% bone marrow involved by NHL to receive treatment with tositumomab and iodine I 131 tositumomab. The dosimetric dose of tositumomab and iodine I 131 tositumomab must be given within 28 days of the response evaluation following CVP and no later than 56 days from the first day of the sixth cycle of CVP.