Efficacy of haploidentical hematopoietic stem cell transplantation compared to HLA-matched transplantation for primary refractory acute myeloid leukemia

Newly diagnosed acute myeloid leukemia (AML) failed to achieve complete remission after two courses of intensive chemotherapy. This was considered as primary refractory AML (PRR-AML), and still has a dismal prognosis. Allogeneic hematopoietic stem cell transplantation could be the only cure for these patients. However, the role of haploidentical hematopoietic stem cell transplantation (HID-HCT) for PRR-AML is still undetermined. We retrospectively analyzed the outcomes of 45 adult patients with PRR-AML who underwent HID-HCT, and compared it with the result of 53 patients who received HLA-matched related or unrelated donor transplantation (MD-HCT) during the same treatment period. The 3-year overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and non-relapse mortality (NRM) rates in the HID-HCT group were 19.0, 16.5, 70.0, and 35.2%, respectively, but showed no significant differences from the results of MD-HCT. Multivariate analysis showed that complex karyotype with del(7) and time > 6 months from diagnosis to transplantation were associated with lower OS and LFS, and chronic GVHD demonstrated better OS and LFS in the entire cohort. Complex karyotype with del(7) was related with higher CIR and chronic GVHD with lower CIR. In conclusion, HID-HCT could be an alternative treatment strategy to improve the long-term survival in PRR-AML adult patients who have no HLA-matched donors.