Reducing transplant toxicity

Conventional myeloablative allogeneic hematopoietic cell transplantation pr oduces considerable morbidity and mortality. These generally limit this tre atment to patients in good medical condition who are younger than 55 years of age. T-cell-mediated graft-versus-tumor effects play a key role in the e limination of malignancy after allografting. Several investigators have sou ght to reduce regimen-related toxicities while optimizing graft-versus-tumo r effects. Strategies can be broadly classified as (1) reduced-intensity re gimens that retain some toxicity, and (2) minimally myelosuppressive regime ns that rely on immunosuppression for allogeneic engraftment and resultant graft-versus-tumor effects. Although follow-up has been short, preliminary results are encouraging. Current challenges include defining a regimen that will facilitate full donor engraftment while minimizing toxicities and gra ft-versus-host disease. If long-term efficacy is demonstrated, such strateg ies will expand the options for patients who would not qualify for conventi onal allogeneic transplants. (C) 2001 Lippincott Williams & Wilkins, Inc.