According to the American Cancer Society, it is estimated that approximately 70,800 individuals will be diagnosed with non-Hodgkin's lymphoma (NHL) and over 18,990 men and women will die of the disease in 2014. The survival rates for patients with indolent NHL remained unchanged from the 1950s through the early 1990s, but recent evidence suggests that outcomes are improving. Indolent NHL is a particular challenge because it is an incurable disease requiring multiple treatments; yet relatively long survivals elevate the importance of quality of life associated with treatment.~Agents such as rituximab are active in patients with a low burden of disease and result in high response rates and durable remissions for most patients. However, the optimal therapeutic approach to patients with low-grade lymphoma with a low disease burden is controversial as conventional chemotherapy also results in high rates of response. Regardless of whether patients receive immunotherapy, chemotherapy, or a combination thereof, they unfortunately exhibit a continuing pattern of disease relapse and the median survival for newly diagnosed patients is between 7-10 years.~Rituximab and GA101 both target the CD20 antigen. The CD20 antigen is located on the surface of normal and malignant B-cell lymphocytes. An attractive feature of this target is that CD20 is not on hematopoietic stem cells, nor is it expressed in any great extent on other normal body tissues.~Studies in vitro have shown that rituximab predominantly induces antibody dependent cellular cytotoxicity (ADCC), but also binds complement and directly induces apoptosis in lymphoma cells.~GA101 shows increased ADCC related to an improved binding of the GA101 to the different allotypes expressed by natural killer cells and monocytes. It also has increased direct cell-death related to an elbow hinge amino acid exchange and Type II binding of the CD20 epitope. The safety of GA101 in NHL so far appears to be similar to that observed with rituximab in patients with NHL, except for a higher incidence of infusion-related reactions.~Depletion of malignant B-cells using anti-CD20 monoclonal antibodies has an acceptable safety profile, particularly in patients with low-grade B-cell lymphomas with a low disease burden. To determine whether treatment with GA101 results in better outcomes than that seen with rituximab and to determine which anti-CD20 antibody to utilize in future studies, we will conduct a randomized Phase II trial of rituximab and GA101 in patients with previously untreated low-grade lymphoma. Patients will receive either rituximab or GA101 weekly for 4 weeks followed by re-staging. The endpoints of the study will be the Complete Response (CR), Overall Response Rate (ORR), time to next treatment, progression free survival (PFS), and safety of each treatment arm.~PrE0401 Sub-Study Evaluation of Corrected QT (QTc) Interval and Pharmacokinetic Parameters in Patients Participating in GA101 (Obinutuzumab)~Patients randomized to GA101 and who consent to the sub-study will have electrocardiograms obtained pre and post Week 1 and Week 4 to investigate the effect of GA101 on QTc interval. Pharmacokinetic blood samples will also be done to evaluate serum concentrations of GA101 at the same time-points.
Patients with previously untreated low tumor burden indolent Non-Hodgkin's Lymphoma (NHL) will receive either rituximab or GA101 weekly for 4 weeks followed by re-staging to determine response.~Rituximab, an anti-CD20 chimeric antibody, was approved by the United States Food and Drug Administration in 1998 for the treatment of patients with relapsed low-grade B-cell lymphomas. Clinically, four weekly doses of rituximab have proven to be well tolerated and effective in previously untreated as well as relapsed patients with low-grade lymphoma.~GA101 is an anti-CD20 humanized and glyco-engineered monoclonal antibody. GA101 has been shown to have increased antibody-dependent cellular cytotoxicity (ADCC) and direct cell-death induction compared to Rituximab. It is possible that GA101 may have greater efficacy than rituximab.~PrE0401 Sub-Study Evaluation of Corrected QT (QTc) Interval and Pharmacokinetic Parameters in Patients Participating in GA101 (Obinutuzumab)~Approximately twenty-five patients randomized to GA101 may participate in the sub-study. Electrocardiograms and blood samples will be obtained.