Lead investigator, John Sweetenham, MD, professor of medicine and head, Hematologic Malignancies and Blood and Marrow Transplant Programs, University of Colorado Health Sciences Center, Denver, Colorado, United States, presented the findings.

He warned that additional follow-up is needed to determine the long-term efficacy of frontline use of yttrium-90 ibritumomab tiuxetan followed by rituximab because of the study's small sample size.

Yttrium-90 ibritumomab tiuxetan is the first radio-immunotherapy agent approved by the US Food and Drug Administration for cancer therapy and is indicated for the treatment of relapsed or refractory low-grade, follicular, or transformed non-Hodgkin's lymphoma, including treatment after the first relapse.

The multicentre trial has a planned enrollment of 23 patients with previously untreated follicular lymphoma but has so far enrolled 10 patients with grade 1 or 2 follicular lymphoma (5 with stage III and 5 with stage IV disease), and only 8 of those are evaluable for treatment response. The median age of the 10 patients was 58 years.

On day 1 of treatment, patients received an initial dose infusion of rituximab (250 mg/m²) followed by an imaging dose of indium-111 ibritumomab tiuxetan (5 mCi). One week later, a second infusion of rituximab (same dosage) was given, followed by an injection of yttrium-90 ibritumomab tiuxetan (0.3 or 0.4 mCi/kg, depending on platelet count).

Rituximab maintenance therapy was scheduled every 6 months for 2 years.

The delivered doses of yttrium-90 ibritumomab tiuxetan have ranged from 21 to 32 mCi. All 8 evaluable patients responded to treatment; 5 (62%) had a complete response and 3 (38%) had a partial response.

Toxicities were mainly haematological and manageable, Dr. Cunningham said, and included grade 3 cytopaenia in 38% of patients. Nonhaematological toxicities were grade 1 in severity and included 3 (38%) patients with fatigue, and 1 (12.5%) each with cramps, headache, or nausea.

Dr. Sweetenham said that further study might determine the long-term efficacy of combining frontline radio-immunotherapy with antibody-based maintenance.


[Presentation title: Efficacy and Safety of Yttrium-90 Ibritumomab Tiuxetan (Zevalin) Therapy With Rituximab Maintenance in Patients With Untreated Low-grade Follicular Lymphoma. Abstract 0673]

Copyright © 2009 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. P\S\L shall not be liable for any errors, omissions or delays in this content or any other content on its sites, newsletters or other publications, nor for any decisions or actions taken in reliance on such content.