Phase II study of first-line ¹³¹I-rituximab radioimmunotherapy in follicular non-Hodgkin lymphoma and prognostic ¹⁸F-fluorodeoxyglucose positron emission tomography

Abstract

First-line ¹³¹I-anti-CD20 radioimmunotherapy of indolent non-Hodgkin lymphoma (NHL) achieves durable remission with low toxicity. The phase II INITIAL study comprised 68 patients with follicular NHL followed up to 7 years (median 4 years) after outpatient ¹³¹I-rituximab radioimmunotherapy (RIT) in conjunction with rituximab, followed by maintenance therapy for 1 year. Baseline and 3-month ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) imaging, analyzed according to Deauville criteria, was used to evaluate response and predict prognosis. The overall response rate at 3 months was 99%, with 88% achieving Deauville category 1–3. These satisfactory responders did not reach median time-to-next-treatment, versus a median of 29 months for a category 4–5 response (p < 0.0001). Grade IV hematological toxicity (9%) was self-limited without clinical sequelae. ¹³¹I-rituximab radioimmunotherapy in newly diagnosed, advanced stage, symptomatic follicular NHL is an effective, practical and affordable alternative to existing conventional chemotherapies, with lower toxicity and durable remissions. Response assessment at 3 months by ¹⁸F-FDG PET Deauville five-point scale permits prognostic stratification.

Keywords::

• ¹³¹I-rituximab
• radioimmunotherapy
• chimeric anti-CD20
• follicular lymphoma
• prospective

Acknowledgements

The authors wish to thank Anna Chiam for collation of data, Suet Mei Yu for statistical analysis and Jenny Lavin for preparing the manuscript. WA Cancer and Palliative Care Network provided funding for data management.

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