Treatment With Ibritumomab Tiuxetan Radioimmunotherapy in Patients With Rituximab-Refractory Follicular Non-Hodgkin’s Lymphoma

PURPOSE: Rituximab is commonly used as a single agent or in combination therapy for non-Hodgkin's lymphoma (NHL). Ibritumomab tiuxetan radioimmunotherapy targets the same antigen as rituximab and has demonstrated efficacy in rituximab-naïve NHL. This study evaluated ibritumomab tiuxetan in the treatment of rituximab-refractory follicular NHL. PATIENTS AND METHODS: Eligible patients were refractory to rituximab; this was defined as no objective response to rituximab (375 mg/m(2) weekly for 4 weeks) or time to progression (TTP) of or = 5 cm, and all were extensively pretreated (median, four prior therapies; range, one to nine). The estimated radiation-absorbed doses to healthy organs were below the…