New Entries to the Recipe Book of Allogeneic Transplantation

by John R. Wingard, Editor

The three prime ingredients of allogeneic hematopoietic cell transplantation (HCT) are conditioning regimen, graft, and posttransplantation supportive care. For decades, much of the research interest has focused on the latter two ingredients. Characterization of graft hematopoietic and immune constituents and manipulation of these elements have led to important insights, new knowledge, and improved outcomes. Similarly, development and testing of hematopoietic growth factors, new immunosuppressive regimens, and new antimicrobial agents have resulted in improved outcomes. Meantime, interest in conditioning regimens languished. The backbones of most regimens have remained some mix of total body irradiation, busulfan, or cyclophosphamide.

In recent years all that has changed. Indeed, testing of new conditioning regimens has become hot again and new recipes are being sampled. Much of this renewed interest has come about because of fundamental changes in our concepts of how allogeneic HCT cures cancer: less about the brute force of intensive cytotoxic bludgeoning of cancer cells, and more about facilitating immunotherapy. Much of this new emphasis has been made possible by new immunologic agents such as the purine analogues, potent T-cell antibody preparations, and more recently new ways to deliver irradiation by radioimmunoconjugates or lymphoid instead of total body irradiation.

This issue contains a transcript of a symposium, which was presented at the 2005 BMT Tandem Meetings in Keystone, Colorado, that addresses the topic of new conditioning regimens. In the first presentation, Dr. Pulsipher describes preclinical and clinical experience with various reduced-intensity regimens. In the second presentation, Dr. Soiffer describes his group’s experience using the intravenous formulation of busulfan with fludarabine for transplantation for acute myleogenous leukemia and myelodysplasia. In the third presentation, Dr. Nagler recounts his group’s experience with intravenous busulfan in ablative and nonablative regimens. In the fourth presentation, Dr. de Lima discusses his center’s experience using busulfan with fludarabine and contrasts it with busulfan plus cyclophosphamide.

It’s clear that innovations in conditioning regimens are spicing up allogeneic HCT. Print new menus!

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