An Observation On Clinical Outcomes of HLA-Haplotype Hematopoietic Stem Cell Transplantation with High-Dose and Post-Transplantation Cyclophosphamide for Children Malignancies Hematopathy

Abstract 4547

We retrospectively analyzed early clinical outcomes of HLA-haploidentical HSCT with high-dose post-transplantation cyclophosphamide (Cy). Between June 2009 and June 2012, 20 patients with high-risk acute lymphoblastic leukemias (ALL, n = 10, CR1=5, CR>1=2, NR=3), acute myeloid leukemia (AML, n=7, CR1=3, CR>1=1£¬NR=3), chronic myeloid leukemia (CML) (n=1, CR), and lymphoma (n=2, CR) received HLA-haploidentical HSCT. All patients were HLA-mismatched equal to and more than HLA (at antigen level). All patients received conditioning therapy consisted of Busulfan, Cytarabine, Cy, VP-16 (or CCNU, or TT), and/or TBI. GVHD prophylaxis consisted of Cy 50mg/kg (for first 10 cases) or 40mg/kg (for second10 cases) on day 3 and 4, FK506 and MMF. The median follow-up time was 507 days. Donor chimerism was ¡Ý80% on day +60 but there were one patient with bone marrow failure (BMF) and two without platelet engraftment after day 60. The median time to neutrophil and platelet engraftment were 23 days and 25 days respectively, and no significant deference was found out between first 10 cases and second 10 cases. No II-IV acute GVHD was observed. However, the cumulative incidences of grade I and above GVHD were 60% (garde 1–2 acute GVHD was 40%; garde 3–4 acute GVHD was 15%), and chronic GVHD was 20% after DLI because of relapse. The cumulative incidences of relapse and non-relapse mortality (NRM) were 30% and 40% respectively. Cytopenia occurred in most patients within 6 months after transplant. Three-year overall survival and event-free survival are 35% and 30% respectively. Thirteen patients have died. The causes of death included relapse (n=5), infection (n=3), cGVHD (n=1), BMF (n=1), hemorrhagic cystitis (n=1).