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 10 patients (9 males, 1 female) with ablative allogeneic HSCT, who achieved second chronic phase (CP) by the use of imatinib after onset of BC between October 2003 and August 2006. Median patient age was 32 years (range, 17–46). Imatinib was given orally at daily doses ranging from 600 to 800mg according to patients tolerance for at least 2 months (range, 2–5) prior to HSCT Among them, 4 patients received HSCT from human leukocyte antigen mismatched haplo-identical family donors, the others underwent a transplant from HLA matched related (n=5) or unrelated (n=1) donors. At the time of transplantation, 5 patients were in complete hematologic response with 3 patients achieved a cytogenetic response, 5 patients were in partial hematologic response. After a median follow-up of 26 months (range, 10–44), 6 (60%) out of the 10 patients were alive with mean Karnofsky score reaching 80. Among them, 5 patients achieved a molecular remission. 1 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 3 of 6 patients who could be evaluated. Patients transplanted with haplo-identical donors had a high treatment-related modality, 3 out of 4 patients died. These results suggest that 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.