[Clinical Efficacy of Modified BU/CY as Conditioning Regimen Combined with Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation in Young Acute Myeloid Leukemia Patients with Low or Intermediate Risk].

OBJECTIVE

To investigate the safety and efficacy of autologous peripheral blood hematopoietic stem cell transplantation (auto-PBHSCT) using modified BU/CY conditioning regimen for young AML patients of low and middle risk in the first complete remission (CR1).

METHODS

Ten young AML patients of low and middle risk who did not want to accept allogeneic hematopoietic stem cell transplantation（allo-HSCT）and underwent auto-PBHSCT in CR1 during May 2013 to December 2016 were retrospectively analyzed. From 3 months after auto-PBHSCT, the maintenance therapy with interleukin-2 (IL-2) or IL-2 combined with histamine dihydrochloride was performed for these patients in the next 18 months. The side effects of the conditioning regimen, hematopoietic recovery time, transplant-related mortality (TRM) within 100 days and 1 year after auto-PBHSCT, relapse rate, leukemia-free survival (LFS) rate at 2 years and 3 years, overall survival (OS) were evaluated at 3 years and 4 years.

RESULTS

Gastrointestinal side effects were the major non-hematologic toxicity reaction, among which, 7 cases relatively mild and 3 cases displayed moderate, just one case suffered from severe reaction. In 4 cases, the mild liver damage occurred, but no hemorrhagic cystitis occurred. All the patients experienced different kinds of infection, including 5 cases of bloodstream infection, 2 cases of gastrointestinal infection, 3 cases of crissum infection and 2 cases of oral infection. The myeloablative effect occurred in all ten patients. The median times for absolute neutrophil count (ANC)<0.5×10/L and for platelet count <20.0×10/L were 1.5 (0-3) days and 3 (2-5) days after transplantation, respectively. The patients achieved ANC>0.5×10/L at 10 to 19 days, median was 13 days after auto-PBHSCT. The patients achieved platelet count >20×10/L at 10 to 72 days; median was 32 days after auto-PBHSCT. The TRM within 100 days and 1 year after transplantation was 0. The relapse occurred in 2 cases at 6 and 14 months after auto-PBHSCT raspectively. The median follow-up time was 48.1 months, and the median survival time was 54.7 months after transplantation. The 2-year and 3-year LFS were 100% (10 cases) and 80% (8 cases), respectively. The 3-year and 4-year OS were 80% (8 cases) and 70% (7 cases), respectively.

CONCLUSION

Modified BU/CY as conditioning regimen for auto-PBHSCT can achieve the myeloablative effect without raising TRM and obtain good LFS and OS. As for young AML patients without high risk, it is a valuable therapeutic option, especially for those lacking the chance of allo-HSCT.