Study of Veltuzumab and 90Y-Epratuzumab in Relapsed/Refractory, Aggressive NHL

The treatment portion of this study consists of study drug administrations each week for four weeks in a row (a total of 4 treatment days). Patients will then return at intervals up to 12 weeks for blood samples and for evaluations to see if their disease responded and to monitor any adverse effects related to treatment. Some blood tests may then need to be repeated at least a few times and/or until any abnormal findings at earlier evaluations have resolved. Otherwise, patients will continue to be evaluated every 3 months for two years, then every 6 months up to 5 years or until the disease worsens. Participation in the study will end when NHL disease worsens.