Pharmacology of agents used in bone marrow transplant conditioning regimens

Disease state, donor histocompatibility, effective immunosuppression, antineoplastic activity and creation of physiological hematopoietic space are all key determinants of succesful bone marrow transplantation (BMT). Preparative BMT regimens have evolved from the use of single fraction total body irradiation (TBI) to elaborate combinations of multidrugs and fractionated TBI regimens. Many of these newly developed conditioning regiments have increased engraftment rates and curative potential. The purpose of this review is to critically examine the pharmacologic behavior of the most commonly used agents in bone marrow transplantation conditioning regimens. The known immunosuppressive, antihematopoietic and antineoplastic properties of each agent are discussed. In addition, the pharmacokinetics and toxicity profiles are evaluated. A thorough understanding of the pharmacology of agents used in BMT may aid in the design of patient specific conditioning regimens.