Radioimmunotherapy with 177Lu-DOTA-rituximab: final results of a phase I/II Study in 31 patients with relapsing follicular, mantle cell, and other indolent B-cell lymphomas.

UNLABELLED The aim of this study was to determine the maximum tolerated dose (MTD) and to explore the clinical response to (177)Lu-DOTA-rituximab in the treatment of patients with relapsed follicular, mantle cell, or other indolent lymphomas such as marginal zone lymphoma. METHODS To evaluate the MTD, we adjusted the dosage of the radiopharmaceutical according to body surface area (BSA). RESULTS The MTD using (177)Lu-DOTA-rituximab was 1,665 MBq/m(2) of BSA. Thrombocytopenia and leukopenia were the dose-limiting toxicities. Significant anemia occurred only at dose level 7 (1,850 MBq/m(2) of BSA). We observed the nadir of platelets after a median of 36 d from treatment and the nadir of granulocytes after a median of 50 d. Median time to recovery to the next lower grade of toxicity was 7 d. Nonhematologic toxicity was negligible. We observed clinical responses at all dose levels and for all lymphoma entities. Some of the responses were durable; the longest follow-up is currently over 8 y. At present, 11 patients are alive and 8 patients are disease-free. CONCLUSION Our results demonstrate the safety and feasibility of (177)Lu-DOTA-rituximab treatment for the lymphoma entities tested in this study.