Late autologous transplantation in chronic myelogenous leukemia with peripheral blood progenitor cells mobilized by G-CSF and interferon-α

In chronic myelogenous leukemia (CML), autologous stem cell transplantation could be a promising new approach for patients with no cytogenetic response after interferon- alpha (IFN-alpha) therapy. We report data on 28 CML patients autotransplanted in chronic phase with peripheral blood progenitor cells mobilized with GCSF (5 mug/kg/day x 5 days) given subcutaneously while continuing IFN-alpha therapy. At mobilization, 23 patients (82%) were in complete hematological remission (CHR), 16 (57%) achieved a minor cytogenetic response (mcr). We obtained, after stimulation, a median of 37.4x10(9)/l (6.9-108) white blood cells, 7.2x10(8)/kg (2.2-16.6) mononuclear cells, 39x10(4)/kg (4.8-403.5) CFU-GM and 4.2x10(6)/kg (0-58.6) CD34(+) cells. Six patients received GM-CSF after transplantation. All patients engrafted, with no significant influence stemming from the Sokal index score and pretransplantation IFN-alpha therapy duration. The first cytogenetic evaluation after transplantation showed 11 (39%) major cytogenetic response (Mcr), and nine (32%) mcr with no significant correlation between these responses, the Sokal index score, and pretransplantation IFN-alpha therapy duration, although there was a significant impact from GM-CSF administration (P=0.01). After transplantation, 26 patients received IFN-alpha alone or associated with hydroxyurea. The median follow-up was 12 months after transplantation and 57 months after diagnosis. At the time of follow-up, nine patients were in CHR, six remained stable in chronic phase, three presented an mcr and one remained in Mcr. At the last follow-up, 22 patients were alive. We conclude that the results of this strategy are encouraging in poor IFN-alpha responders but that other prospective studies that try to maintain the cytogenetic responses obtained immediately after transplantation are needed.