Conditioning regimens

The preferred conditioning regimen should be capable of eliminating or reducing the tumor load from the malignant disorder, provide adequate immunosuppression to prevent graft rejection, and have manageable side effects or regimen-related toxicities. Traditionally, all allogeneic conditioning regimens were ablative, meaning that stem cell support was required in order to attain hematopoietic recovery of the bone marrow. More recently, there has been a trend in multiple patient populations to move toward reduced-intensity regimens (RIT), which are defined as any regimen that does not require stem cell support for hematopoietic recovery and results in low hematologic toxicity and mixed donor-recipient chimerism in a substantial proportion of patients in the early post-transplantation period.