Cell Cycle-Based Purging of Lymphoma Cells from Bone Marrow Harvests Using Radioiodinated 5-Iodo-2′-Deoxyuridine

Minimal residual disease in lymphoma patients is a major problem in the clinical management of their cancer. High-dose chemotherapy followed by autologous bone marrow transplantation has been used to treat the disease. However, residual lymphoma may be reintroduced along with the marrow if it is present in the bone marrow harvest. In this report we describe results of experiments testing the efficacy of $5\text{-}[{}^{125}{\rm I}]\text{-}{\rm iodo}\text{-}2^{\prime}\text{-deoxyuridine}$ (^{125}{\rm IdU}$) for purging murine RAW117 large cell lymphoma cells (Joshi et al., Oncology 44, 180-185, 1987; Cancer Res. 47, 3551-3557, 1987) from bone marrow in a relevant animal model. Donor BALB/c mice were injected with murine RAW117 cells and euthanized on day 13, and their bone marrow that had been contaminated with tumor cells was harvested and treated in vitro with ^{125}{\rm IdU}$ or nonradioactive ^{127}{\rm Idu}$ (control). Nine of 10 mice receiving ^{127}{\rm IdU}\text{-treated}$ bone marrow contaminated with tumor cells died at an average of 17 days after injection. In comparison, 9 of 10 mice injected with ^{125}{\rm IdU}\text{-treated}$ bone marrow contaminated with tumor cells were still alive after 82 days. In addition, the ^{125}{\rm IdU}$ treatment did not diminish the formation of hematopoietic progenitor cell colonies in normal mouse and human peripheral blood stem cells.