Rituximab Maintenenance Therapy in CD20+ B-Cell Non-Hodgkin-Lymphoma - Results of a Multicenter Prospective Randomised Phase II Study.

Clinical and pharmacokinetic data suggest that the effect of rituximab could be improved by prolonged exposure to the drug. To test for this hypothesis we performed a prospective randomized trial of rituximab maintenance therapy in patients with CD20+ B-cell Non-Hodgkins-Lymphoma. After completion of standard treatment patients were randomized to either observation or maintenance therapy with rituximab (375 mg/m²) every 3 months for 2 years. Patients after first line therapy as well as relapse patients were included in the study. Patients with aggressive lymphoma were enrolled if they had achieved a complete response (CR) after initial treatment. Patients with aggressive lymphoma with residual tumor mass were examined with positrone emission tomography (PET) and qualified for randomization if PET showed no signs of tumor activity. Patients with indolent lymphoma qualified for the study if at least a partial response (PR) was achieved. So far 162 patients (pts) with CD20+ B-cell Non-Hodgkins-Lymphoma were enrolled in this trial. Histological subtypes included diffuse large cell lymphoma (69 pts), follicular lymphoma (41 pts), mantle cell lymphoma (18 pts), primary mediastinal lymphoma (15 pts), marginal zone lymphoma (9 pts), Burkitt’s lymphoma (3 pts), immunocytoma (2 pts), primary intestinal lymphoma (1 pt), hairy cell leukemia (1 pt), chronic lymphocytic leukemia (1 pt) and unclassified B-cell lymphoma (2 pts). No severe adverse events were observed during rituximab maintenance therapy. We conclude that rituximab maintenance therapy is feasable, safe and well tolerated in patients with CD20+ B-cell Non-Hodgkins-Lymphoma. Results including event free survival and overall survival for the observation group and for the maintenance therapy group will be presented.