Successful treatment of metastatic renal cell carcinoma with a nonmyeloablative allogeneic peripheral-blood progenitor-cell transplant: evidence for a graft-versus-tumor effect.

PURPOSE: A 50-year-old man developed progressive pulmonary metastasis resistant to interferon alfa-2b treatment 7 months after he underwent left nephrectomy for stage III renal cell carcinoma. We performed a nonmyeloablative allogeneic peripheral-blood stem-cell transplant in this patient to exploit a possible graft-versus-tumor effect from allogeneic lymphocytes. MATERIALS AND METHODS: The conditioning regimen consisted of fludarabine and cyclophosphamide followed by a T-cell replete, granulocyte-colony stimulating-factor-mobilized peripheral-blood stem-cell transplant from his HLA-identical brother. Cyclosporine was administered from days -4 to +45 to prevent graft rejection and acute graft-versus-host disease (GVHD). RESULTS: Serial polymerase chain reaction analysis of hematopoietic lineage-specific minisatellites initiallyshowed mixed chimerism in CD14(+) and CD15(+) myeloid cells, CD3(+) T cells, and CD34(+) progenitor cells, with rapid conversion to 100% donor T-cell chimerism by day +60 and 100% donor myeloid cells by day +100. Serial computed tomography scans of the chest showed stable disease at day +30, slight regression of pulmonary lesions at day +63, and complete disappearance of all pulmonary metastatic disease by day +110. Mild transient acute GVHD disease of the skin occurred on day +60 and limited chronic GVHD of the skin occurred by day +200. CONCLUSION: The complete regression of metastatic disease, which has now been maintained for more than 1 year, is compatible with a graft-versus-tumor effect.