Phase 2 Study of Iodine-131 Tositumomab Plus Chemotherapy in Patients With Previously Untreated Mantle-Cell Lymphoma

Andrew D. Zelenetz, Leslie L. Popplewell, Ariela Noy, Thierry J. Horner, Thomas S. Lin, Gerard Donnelly, George Sgouros, Ivelise Rijo, Chaitanya R. Divgi

Research output: Contribution to journalArticlepeer-review


Background: Mantle-cell lymphoma (MCL) is sensitive to radiotherapy, and the CD20 antigen is relatively highly expressed in MCL. Therefore, radioimmunotherapy using radiolabeled anti-CD20 monoclonal antibodies has the potential to treat MCL. The objective of this study was to investigate the efficacy, pharmacokinetics, and safety of tositumomab (TST) and iodine-131 tositumomab (I-131 TST) followed by 6 cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in patients with previously untreated MCL ( NCT00022945). Patients and Methods: In this phase 2 open-label study, patients received dosimetric (day 0: 450 mg TST, then 35 mg I-131 TST [5 mCi]) and therapeutic (between days 7 and 14: 450 mg TST, then an individualized dose of I-131 TST [65-75 cGy]) TST/I-131 TST, with CHOP treatment commencing approximately 13 weeks after the therapeutic dose. The primary end point was the MCL response rate to treatment; secondary end points included confirmed complete response rate and total body residence time. Results: Twenty-six patients were enrolled, and 25 were included in the intent-to-treat population. The overall unconfirmed response rate was 84%, and the confirmed complete response rate was 44%. The median progression free-survival was 27.6 months. The median total body residence time was 94.5 hours. No new or unexpected safety signals were identified. Conclusion: Patients with previously untreated MCL who received radioimmunotherapy with TST/I-131 TST followed by CHOP had a high response rate and a long duration of response, indicating that radioimmunotherapy is a therapeutic option in this patient population.

Original languageEnglish (US)
Pages (from-to)749-756.e1
JournalClinical Lymphoma, Myeloma and Leukemia
Issue number11
StatePublished - Nov 2020


  • Anti-CD20
  • CHOP
  • Monoclonal antibody
  • Radioimmunotherapy

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Cancer Research


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