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
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.