High-Dose RAIT May Improve Prognosis in Relapsed NHL Patients

NEW YORK--Attaching iodine-131 to the anti-CD20(B1) antibody (radioimmunotherapyor RAIT) may provide durable remissions in relapsed non-Hodgkin'slymphomas (NHL), Oliver Press, MD, PhD, said at a symposium sponsoredby the New York City-based Cancer Research Institute.

At the Fred Hutchinson Cancer Research Center and the Universityof Washington, Seattle, where Dr. Press is associate professorof medicine and biological structure, researchers have conductedphase I and II studies to define the biodistribution, responserate, response duration, and toxicities of maximally tolerateddoses of the antibody given in conjunction with autologous hematopoieticstem-cell rescue.

Bone marrow transplantation (BMT) with total body irradiationand chemotherapy has been found to be curative in fewer than halfof 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 possibleto deliver higher radiation doses to the tumor in an effort toimprove the rate of remission.

Dr. Press reported that his group achieved complete responsesin 85% of patients with relapsed NHL and partial responses in10%, using therapeutic doses of 131I-labeled B1. At a median follow-upof 2 years, 90% of patients were alive.

All patients in the trials had advanced-stage lymphomas with poorprognostic features, and had undergone an average of 3.2 regimensbefore referral. Bone marrow was purged after removal and cryo-preservedfor reinfusion. Escalating doses of 131I-B1 were administered.