Rituxan Plus FavId (Idiotype Vaccine) for Low-grade Non-Hodgkin's Lymphoma

The purpose of this study is to evaluate the ability of patients treated with Rituxan® plus FavId™ and GM-CSF to mount an immune response (humoral and/or cellular) to KLH and their idiotype. Secondary objectives are the determination of overall objective response rate, duration of response and time to progression. B-cell malignancies express a unique antigen, the immunoglobulin idiotype (Id), on their surface. Each B-cell harbors a unique genetic sequence used in production of unique Id protein. No normal B-cells possess that Id on their cell surface. Hence, Id protein should serve as an ideal target for individualized active immune therapy of NHL. Many of the antigens expressed by tumors (including Id) are only weak immunogens. To augment the immune response against Id, the Id protein must be chemically coupled to a strongly immunogenic protein. keyhole limpet hemocyanin (KLH) is a commonly used protein carrier capable of augmenting the body's immune reaction against Id protein. For vaccines which produce primarily an antibody response, there is a concern that combining immunotherapy with Rituxan®, which produces a rapid and sustained (up to 6 to 9 months post-treatment in 83% of patients) depletion of circulating and tissue-based B-cells, would blunt any antibody response. For vaccines that induce strong T-cell responses like Id-KLH plus GM-CSF, there is evidence in mice that depleting the host of B-cells could actually increase the T-cell response to the vaccine. GM-CSF is a hematopoietic growth factor that stimulates T-cell proliferation. T-cell response to both the patient's Idiotype and KLH will be measured during this trial.