NEW YORK--Attaching iodine-131 to the anti-CD20(B1) antibody (radioimmunotherapy or RAIT) may provide durable remissions in relapsed non-Hodgkin's lymphomas (NHL), Oliver Press, MD, PhD, said at a symposium sponsored by the New York City-based Cancer Research Institute.
At the Fred Hutchinson Cancer Research Center and the University of Washington, Seattle, where Dr. Press is associate professor of medicine and biological structure, researchers have conducted phase I and II studies to define the biodistribution, response rate, response duration, and toxicities of maximally tolerated doses of the antibody given in conjunction with autologous hematopoietic stem-cell rescue.
Bone marrow transplantation (BMT) with total body irradiation and chemotherapy has been found to be curative in fewer than half of all cases of relapsed B-cell lymphomas. Morbidity is high, and the treatment is fatal in 5% to 10% of patients, he said.
Targeted radiotherapy with monoclonal antibodies makes it possible to deliver higher radiation doses to the tumor in an effort to improve the rate of remission.
Dr. Press reported that his group achieved complete responses in 85% of patients with relapsed NHL and partial responses in 10%, using therapeutic doses of 131I-labeled B1. At a median follow-up of 2 years, 90% of patients were alive.
All patients in the trials had advanced-stage lymphomas with poor prognostic features, and had undergone an average of 3.2 regimens before referral. Bone marrow was purged after removal and cryo-preserved for reinfusion. Escalating doses of 131I-B1 were administered.