Negative selection and protection of normal progenitor cells for autografting

Autologous bone marrow transplantation (ABMT) after high-dose chemotherapy is recognized as a curative approach to treating hematologic malignancies and some invasive solid tumors. However, tumor cells present in the bone marrow at the time of harvesting are a potential cause for relapse. Ex vivo marrow purging with very high doses of cytotoxic agents has been introduced in an attempt to remove neoplastic cells contaminating the autograft. The procedure, however, has been limited by its high toxicity to normal bone marrow progenitor cells. In their purging procedures, investigators have used agents such as amifostine, originally developed to protect against the effects of radiation and chemotherapy. In this article, the appropriateness of protecting normal cells with amifostine during various purging procedures will be reviewed.