Study of radiolabeled indium-111 and yttrium-90 ibritumomab tiuxetan in primary central nervous system lymphoma.

Abstract

Therapeutic options for refractory or recurrent primary central nervous system lymphoma (PCNSL) are limited. The blood-brain barrier makes many agents used in systemic lymphomas ineffective in CNS lymphomas. The objective of this study was to determine whether intravenous radioimmunotherapy using anti-CD20 antibody can be delivered to PCNSL. This was a single-institution prospective study. Indium-111 ibritumomab tiuxetan was used for imaging and dosimetry. Yttrium-90 ibritumomab tiuxetan at doses of 0.3 to 0.4 mCi/kg were subsequently given for the treatment of recurrent or refractory PCNSL. 111In data were used to estimate radiation doses to lesions delivered by 90Y ibritumomab tiuxetan therapy. Six patients (4 men, 2 women) with a median age of 60 years and median Karnofsky performance status of 70 received both indium-111 and yttrium-90 ibritumomab tiuxetan. The median absorbed dose delivered to the CNS lymphoma was 701 cGy compared with 70 cGy to normal brain. The median progression-free and overall survival times were 6.8 weeks and 14.3 weeks, respectively. The results from this study suggest that it may be feasible to deliver radiolabeled monoclonal anti-CD20 antibodies as a component of therapy for PCNSL.