Drug Interaction Report

ADJUST DOSING INTERVAL: The safety and efficacy of hematopoietic growth factors such as colony-stimulating factors (G-CSF and GM-CSF) and stem cell factors (SCF) given simultaneously with radiolabeled ibritumomab tiuxetan have not been established. Theoretical concerns exist regarding their concomitant administration because hematopoietic growth factors stimulate myeloid cell proliferation while radiopharmaceuticals like yttrium-90 and indium-111 radiolabeled ibritumomab tiuxetan primarily target rapidly dividing cells.

MANAGEMENT: Some authorities recommend that patients not receive hematopoietic growth factors for 3 weeks prior to administration of radiolabeled ibritumomab tiuxetan and for 2 weeks following completion of the treatment in order to assess for adequate bone marrow reserve correctly and also because of the potential sensitivity of rapidly dividing myeloid cells to radiation.