The FDA has approved ibritumomab tiuxetan (Zevalin, IDEC Pharmaceutical Corp, San Diego) as part of a two-step regimen for the treatment of patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin lymphoma, including patients with follicular non-Hodgkin lymphom refractory to rituximab (Rituxan, Genentech Inc, San Francisco).
Zevalin is an immunoconjugate that combines the linker-chelator tiuxetan with the monoclonal antibody ibritumomab, directed against the CD (cluster designation)–20 antigen restricted to B lymphocytes. The chelator allows for the antibody to be conjugated to a radioisotope. Step 1 of the regimen includes one infusion of rituximab followed by Indium-111 Zevalin. Step 2, administered 7-9 days later, consists of a second infusion of rituximab followed by Yttrium-90 Zevalin.
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