Three decades of transplantation for chronic myeloid leukemia: what have we learned?

Last year marked 30 years of hematopoietic stem cell transplantation as a curative treatment of chronic myeloid leukemia (CML). Initially studies used stem cells from identical twins but techniques rapidly developed to use cells first from HLA-identical siblings and later unrelated donors. During the 1990s CML became the most frequent indication for allogeneic transplantation worldwide. This, together with the relative biologic homogeneity of CML in chronic phase, its responsiveness to graft-versus-leukemia effect and the ability to monitor low level residual disease placed CML at the forefront of research into different strategies of stem cell transplantation. The introduction of BCR-ABL1 tyrosine kinase inhibitors during the last decade resulted in long-term disease control in the majority of patients with CML. In those who fail to respond and/or develop intolerance to these agents, transplantation remains an effective therapeutic solution. The combination of tyrosine kinase inhibitors with transplantation is an exciting new strategy and it provides inspiration for similar approaches in other malignancies.