Yttrium 90-labeled ibritumomab tiuxetan radioimmunotherapy produces high response rates and durable remissions in patients with previously treated B-cell lymphoma

Clin Lymphoma. 2004 Sep;5(2):98-101. doi: 10.3816/clm.2004.n.015.


We report updated time-to-event variables of a phase III randomized study comparing yttrium 90-labeled ibritumomab with rituximab standard therapy in 143 rituximab-naive patients with relapsed or refractory low-grade, follicular, or transformed CD20+ non-Hodgkin's lymphoma (NHL). Most patients (79%) had follicular lymphoma. Patients were randomized to receive a single intravenous (I.V.) dose of 90Y ibritumomab tiuxetan 0.4 mCi/kg (n = 73) or rituximab 375 mg/m2 I.V. weekly for 4 doses (n = 70). The radioimmunotherapy group was pretreated with 2 rituximab doses (250 mg/m2) to improve biodistribution and one dose of Indium 111-labeled ibritumomab tiuxetan for imaging. The overall response rate was 80% versus 56% (P = 0.002) and complete response (CR)/CR unconfirmed (CRu) rates were 34% for 90Y ibritumomab tiuxetan versus 20% for rituximab. With a median follow-up of 44 months, the data are mature as all ongoing patients in both groups exceeded the median Kaplan-Meier estimated time to progression (TTP), duration of response (DR), and time to next therapy. Although this study was not powered to detect differences in time-to-event variables, the results from this randomized trial demonstrate trends toward longer median TTP (15 vs. 10.2 months; P = 0.07), DR (16.7 vs. 11.2 months; P = 0.44) and time to next therapy (21.1 vs. 13.8 months; P = 0.27) in follicular NHL patients treated with 90Y ibritumomab tiuxetan compared with the rituximab control arm. In patients achieving a CR/CRu, the median TTP was 24.7 months for patients treated with 90Y ibritumomab tiuxetan compared with 13.2 months for rituximab-treated patients (P = 0.41), and ongoing responses of > 5 years have been observed. These results confirm that 90Y ibritumomab tiuxetan produces high response rates and durable remissions in patients with previously treated low-grade, follicular, and transformed NHL.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Antibodies, Monoclonal / therapeutic use*
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20 / therapeutic use
  • Antineoplastic Agents / therapeutic use*
  • Cell Line, Transformed
  • Clinical Trials as Topic
  • Disease Progression
  • Follow-Up Studies
  • Humans
  • Lymphoma, B-Cell / drug therapy*
  • Lymphoma, Follicular / pathology
  • Radioimmunotherapy / methods*
  • Remission Induction
  • Rituximab
  • Time Factors
  • Treatment Outcome
  • Yttrium Radioisotopes / therapeutic use*


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20
  • Antineoplastic Agents
  • Yttrium Radioisotopes
  • Rituximab
  • ibritumomab tiuxetan