Yttrium-90 (90Y) ibritumomab tiuxetan for treatment of relapsed or refractory non-hodgkin’s lymphoma: The Western Pennsylvania Cancer Institute experience

Abstract

12511 Background: Yttrium-90 (90Y) ibritumomab tiuxetan (Zevalin) radioimmunotherapy is an effective agent for treatment of CD20+ B-cell lymphoma (NHL).It is approved for treatment of relapsed or refractory, follicular or transformed B cell lymphoma. An overall response rate ranging from 74% to 82% has been reported. Median response duration of 11.5 to 28.1 months has been reported. Methods: We identified, retrospectively, 37 patients treated at our institution with relapsed or refractory NHL who were treated with 90Y ibritumomab tiuxetan at a dose of 0.3mCi/kg or 0.4mCi/kg. Response rate and survival were assessed. Median age was 60 years (range 28–82 years) of which 65% were male. Follicular lymphoma was present in 57% (n = 21) and diffuse large B-cell lymphoma in 22% (n = 8) of patients. Advanced disease (stage III or IV) was present in 84% (n = 31) of patients. All of the patients had received at least one prior regimen and 68% (n = 25) had received ≥ 3 regimens before 90Y ibritumomab tiuxetan. Results: Overall response rate was 65% (24/37); CR 43% (16/37); PR 19% (7/37); SD 3% (1/37). Duration of response was 13.3 months (range 4 to 48 months) with response duration greater than 12 months in 35% (n = 13) of the patients. Of responders, 67% (16/23) had failed to respond to prior immediate therapy. The only toxic event was pancytopenia, which predictably occurred after treatment. No patients died of toxicity and all toxicity was reversible. Conclusions: 90Y ibritumomab tiuxetan was well tolerated and effective for our patients.We document durable response in our patients with relapsed or refractory NHL and with advanced stage disease. Further study of ibritumomab tiuxetan using different doses and in combination with chemotherapy is warranted. No significant financial relationships to disclose.