Hematopoietic stem cell transplantation in the era of tyrosine kinase inhibitors

Until the 1990s, the treatment of chronic myeloid leukemia (CML) recognized hematopoietic stem cell transplantation as the best treatment for those patients with an available donor. With the advent of imatinib in 2001, this paradigm changed dramatically as this drug provided outstanding and durable rates of hematologic, cytogenetic, and molecular responses. As a consequence it became the gold standard first-line treatment for most patients. However, after almost a decade of its use, it is clear that although very effective, imatinib cannot cure CML as transplantation has already proven so. Furthermore, the new non-myeloablative regimens and the improvements in survival after allogeneic transplant, especially in the field of unrelated transplants, offer this option to a broader population of patients with CML. This adds to the old question of whom to transplant, when and how to proceed with the allograft. This article reviews the current role of transplantation in the era of tyrosine kinase inhibitors and will try to elucidate its role in the frontline setting as well as after first- and second-line kinase inhibitors failure.