Imatinib Mesylate Versus Allogeneic Hematopoietic Stem Cell Transplantation For Patients With Chronic Myeloid Leukemia In Chronic Phase

Following the introduction of the tyrosine kinase inhibitor (TKI) imatinib in treatment of chronic myeloid leukemia (CML) patients, the allogeneic hematopoietic stem cell transplantation (allo-HSCT) scene in CML has changed dramatically. This retrospective cohort study was designed to compare medical outcomes of Imatinib mesylate and allo-HSCT for patients with CML in chronic phase.

From February 2002 to February 2012, 198 patients treated consecutively at the Nanfang Hospital,Southern Medical University were assigned to two groups according to treatment with imatinib or allo-HSCT. One hundred fifteen cases of imatinib group were given imatinib at an initial dose of 400mg daily and the dose was then adjusted according to the patient´s blood and therapy response. All the patients were evaluated for hematologic, cytogenetic and molecular response every 1-3months. Eighty-three cases of allo-HSCT group received myeloablative preconditioning regimen, and methotrexate (MTX) and cyclosporine A (CsA) were used for graft-versus-host disease(GVHD), parts combined with mycophenolate mofetil (MMF) and antihuman thymocyte globulin(ATG). The primary end points of the study were complete cytogenetic response (CCyR), relapse rate, overall survival (OS) and progression-free survival (PFS) after therapy.

In total, 59 (68.9%) patients treated over 12 months achieved a CCyR after 12 months in imatinib group, while 67 (95.7%) patients in allo-HSCT group. The relapse rates were 14.8% (n=17) in imatinib group and 10.8% (n=9) in allo-HSCT group (P=0.456). Ten-year cumulative OS rates were 93.9% in imatinib group and 77.1% in allo-HSCT group(P=0.015) and ten- year cumulative PFS rates of two groups were 86.1% vs.88.0%(P=0.508). For Sokal rating stratified analysis, the ten-year OS rates of two groups were 96.4% vs.68.0% (P = 0.049) for high-risk patients,92.6% vs. 57.1% (P = 0.019) for intermediate-risk patients , while the ten-year PFS rates of two groups were 89.3% vs. 88.0% for high-risk patients (P = 0.942), 70.4% vs. 85.7% for intermediate-risk patients (P = 0.405).The ten-year OS rates and PFS rates were not significant difference for low-risk patients. The cumulative OS rates of two groups were 94.7% vs. 73.5%(P=0.019)for the patients who were not less than 30 years old,and the cumulative PFS rates of two groups were 84.2% vs. 94.1% respectively (P=0.147).

Imatinib mesylate treatment is superior to allogeneic hematopoietic stem cell transplantation for patients with chronic myeloid leukemia in chronic phase.

No relevant conflicts of interest to declare.