OBJECTIVESTo assess bone marrow morphologic changes in Philadelphia-chromosome positive chronic myeloid leukemia (Ph(+)-CML) patients treated with Imatinib, and to evaluate the correlation of the morphologic changes with hematological or cytogenetic responses.

METHODSOne hundred and seventeen patients with Ph(+) CML: 54 in chronic phase but failed to interferon-alpha treatment, 41 in accelerated phase, 22 in blastic phase received oral administration of Imatinib 400 or 600 mg once daily for more than 18 months.

RESULTSAll of the patients responded to the treatment, including complete hematological response, bone marrow response and return to chronic phase, bone marrow cellularity and myeloblast count reduced significantly to non-CML picture. Myeloid/erythroid ratio and megkaryocyte count were decreased significantly in most patients in chronic and accelerated phases (P < 0.05). Bone marrow hypoplasia or aplasia was associated with lower cytogenetic response rates in patients in chronic phase (58.8% vs 86.5%, P = 0.035), lower complete hematological response in patients in accelerated phase (26.3% vs 75.0%, P = 0.004), and 6-month overall survival in patients in blastic phase (77.8% vs 16.7%, P = 0.009). Patients in advanced stage obtained non-CML marrow picture in 1 month of treatment had better prognosis. 18-month disease progression rates were lower (25% vs 75%, P = 0.028) and overall survival rates higher (75.0% vs 11.8%, P = 0.004) in patients obtained non-CML picture marrows than in those with CML marrows picture in accelerated phase. Hematological response rate and overall survival of more than 6 months were higher in patients with non-CML marrows picture than those with CML marrows picture (100.0% vs 40.0%, P = 0.017 and 83.3% vs 26.7%, P = 0.046 respectively) in blastic phase.

CONCLUSIONSNormal marrow appearance can be sustained under continuous treatment of Imatinib in CML patients who achieved hematological responses.