Allogeneic hematopoietic stem cell transplantation for patients with chronic myeloid leukemia in second chronic phase attained by imatinib after onset of blast crisis

The prognosis for patients with chronic myeloid leukemia (CML) in blast crisis (BC) remains dismal even with the availability of the BCR-ABL tyrosine kinase inhibitor imatinib, since it only offers short-term benefit in most cases. Allogeneic hematopoietic stem cell transplantation (HSCT) seems to be a viable option for BC-CML patients who attained remission. We treated ten patients with ablative allogeneic HSCT, who achieved second chronic phase (CP) by the use of imatinib after onset of BC. Median patient age was 32 years (range 17–46). Among them, four patients received HSCT from human leukocyte antigen mismatched haplo-identical family donors. After a median follow-up of 24 months (range 8–42), six out of the ten patients were alive in durable complete cytogenetic remission, one patient died in relapse 4 months after transplantation, the others died of severe acute graft-versus-host disease and associated infections. No unusual organ toxicities and engraftment difficulties were observed. Extensive chronic GVHD developed in three of six patients who could be evaluated. Patients transplanted with haplo-identical donors had a high treatment-related modality. Allogeneic HSCT may represent a feasible treatment for patients with CML in second CP attained by imatinib after onset of BC especially when a suitable donor is available.