[Bone marrow morphologic features in patients treated with imatinib for Philadelphia chromosome positive chronic myeloid leukemia].

Objectives: To 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.

Methods: One 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.

Results: All 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.

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