Autologous Stem Cell Transplantation with PCR-Negative Graft Would Be Associated with a Favorable Outcome in Core-Binding Factor Acute Myeloid Leukemia

Although core-binding factor acute myeloid leukemia (CBF-AML) is generally considered to be a low-risk form of AML, the survival rate is still 50% to 60%. To evaluate the effectiveness of autologous stem cell transplantation (ASCT) with a PCR-negative graft we analyzed a series of consecutive CBF-AML patients. Between 1997 and 2006, 18 patients aged <60 years were referred under a diagnosis of CBF-AML. Peripheral blood stem cells (PBSC) were collected after a second or further course of postremission therapy. When >2.0 × 106/kg CD34-positive cells with minimal residual disease (MRD) undetectable by nested polymerase chain reaction (PCR) had been collected, ASCT was performed with busulfan, etoposide, and cytarabine combined with granulocyte colony-stimulating factor. Event-free survival (EFS) and complications of ASCT were then assessed. Fourteen of the 18 patients received ASCT. The median observation period was 4.4 years. The 5-year EFS was 93% for ASCT patients, despite the presence of adverse factors. In 8 of 10 patients who had detectable MRD in the bone marrow before ASCT, MRD became undetectable after ASCT. Neutrophils recovered promptly within 2 weeks, but platelets recovered relatively slowly. Half of the patients suffered from varicella zoster virus infection. Although 1 case of myelodysplastic syndrome occurred, there was no case of relapse. ASCT with a PCR-negative graft was associated with excellent EFS. For patients with CBF-AML, especially with adverse factors or remnant MRD in the bone marrow, this strategy is the treatment of choice.