[Clinical research of HLA-haploidentical peripheral hematopoietic stem cell transplantation following reduced intensity conditioning regimen with hematological malignancy patients over 50 years old].

Objective: To analyze the efficacy of HLA-haploidentical peripheral hematopoietic stem cell transplantation (haplo-PBSCT) following reduced intensity conditioning (RIC) regimen to treat the patients with hematological malignancies who were older than 50 years old. Methods: Eighteen patients with hematological malignancies over 50 years were enrolled, including 8 male and 10 female patients. The median age of all patients was 52 (range: 50-66) years. Of them, 8 patients had acute myeloid leukemia (AML) , 2 chronic myelocytic leukemia (CML) , 5 myelodysplastic syndrome (MDS) , 2 acute lymphoblastic leukemia (ALL) , and 1 aggressive natural killer cell leukemia (ANKL) . All patients received fludarabine, cytarabine and melphalan with rabbit anti-human thymocyte globulin (FAB+rATG regimen) and transplanted with high dose non-T cell-depleted peripheral hematopoietic stem cells from donors. Enhanced graft versus host disease (GVHD) prophylaxis and infection prevention were administered. Results: Fifteen days after transplantation, 16 patients achieved complete donor chimerism. One of them rejected the donor graft completely at thirty days after transplantation, and the other 2 patients had mixed chimerism 15 days after transplantation and converted to complete recipient chimerism at 30 days after transplantation. The cumulative incidence of acute GVHD (aGVHD) was 61.1% (95%CI49.6%-72.6%) . The incidence of grade Ⅱ-Ⅳ aGVHD was 35.4% (95%CI 21.1%-49.7%) , whereas grade III-IV was 13.8% (95%CI 4.7%-22.9%) . The 2-year cumulative incidence of chronic GVHD (cGVHD) rate was estimated at 38.2% (95%CI 25.5%-50.9%) . Patients were followed-up for a median of 14.5 months (range, 3-44 months) . The Kaplan Meier estimates of 2-year overall survival (OS) and disease-free survival (DFS) was 72.6% (95%CI 60.1%-85.1%) and 63.7% (95%CI 49.2%-78.2%) , respectively. The 2-year cumulative incidence of relapse and non-relapse-mortality (NRM) was 31.2% (95%CI 16.5%-45.9%) and 12.5% (95%CI 4.2%-20.8%) , respectively. Conclusion: RIC-haplo-PBSCT protocol can achieve better results in patients with hematologic malignancies over 50 years old.