Ibritumomab tiuxetan (pronounced /ɪbrɪˈtuːmoʊmæb taɪˈʌksɛtæn/[2]), sold under the trade name Zevalin, is a monoclonal antibody radioimmunotherapy treatment for non-Hodgkin's lymphoma.

The drug uses the monoclonal mouse IgG1 antibody ibritumomab in conjunction with the chelator tiuxetan, to which a radioactive isotope (either yttrium-90 or indium-111) is added.

This may be followed by an administration of indium-111 labeled ibritumomab tiuxetan (111In replaces the 90Y component) to allow the distribution of the medication to be imaged on a gamma camera, before the actual therapy is administered.

[9] It was given marketing authorization by the European Medicines Agency in 2004 for the treatment of adults with rituximab relapsed or refractory CD20+ follicular B-cell non-Hodgkin's lymphoma but.

[1] In September 2009, ibritumomab tiuxetan received approval from the FDA for an expanded label to include previously untreated people with a chemotherapy response.