Successful attainment of the third chronic phase by autologous peripheral blood stem cell transplantation and imatinib in a patient with chronic myeloid leukemia

Chronic myeloid leukemia in a 61-year-old man progressed into the accelerated phase 8 months after the initial evaluation (Ph chromosome [20/20], FISH 93.5%), although the major cytogenetic response (Ph chromosome [0/20], FISH 9.7%) had been achieved 6 months after the initiation of the treatment with interferon and hydroxyurea. The Peripheral blood stem cells (Ph chromosome [0/20], FISH 5.8%, PCR 2.7 x 10(2) copies/microgram RNA) were harvested simultaneously with the attempt to induce the second chronic phase using the mini-ICE (idarubicin, cytosine arabinoside and etoposide) therapy. However, 2 months later, the disease progressed into blast crisis with the additional chromosomal abnormalities, and did not respond to the re-induction therapy with idarubicin and cytosine arabinoside. Autologous stem cell transplantation was then performed using the preparatory regimen with busulfan and cyclophosphamide. The third chronic phase was successfully achieved, and has been well maintained with imatinib for more than 13 months (Ph chromosome [0/20], FISH 0.0%, PCR < 10(2) copies/microgram RNA). This may be a rare case in which normal hematopoietic stem cells could be enriched in the peripheral blood in the accelerated phase, and that cytogenetic remission was achieved using these cells in the blast crisis. Flexible use of peripheral blood stem cells and imatinib could be an additional strategy for the better treatment of chronic myeloid leukemia.