Radioimmunotherapy with (131)i-rituximab in a patient with diffuse large B-cell lymphoma relapsed after treatment with (90)y-ibritumomab tiuxetan.

We report a case that demonstrates the efficacy of radioimmunotherapy (RIT) with radioiodinated rituximab ((131)I-rituximab) for relapsed diffuse large B-cell lymphoma (DLBCL). A 79-year-old male patient with DLBCL initially achieved a complete response (CR) after six cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) therapy. However, the lymphoma relapsed 20 months later. Although the patient had achieved a second and a third CR after two cycles of (90)Y-ibritumomab tiuxetan, he experienced a third relapse approximately 3 years later. Between March and June 2011, the patient received three cycles of (131)I-rituximab. Although he had achieved partial response after the second cycle, the disease progressed after the third cycle, and the total progression-free survival was thus 5 months. The patient suffered only relatively mild toxicity (grade 1 thrombocytopenia) during treatment. RIT with (131)I-rituximab is therefore potentially effective in patients with relapsed DLBCL, even after the failure of (90)Y-ibritumomab tiuxetan therapy.