P1341: HAPLO-CORD VS HAPLOIDENTICAL TRANSPLANT IN 49 CHILDREN – A RETROSPECTIVE SINGLE CENTER ANALYSIS

Abstract

Background: Haplo-cord transplantation means that umbilical cord blood grafts from unrelated donors are infused together with CD34+-selected cells selected from Haploidentical relatives, which avoids the delayed implantation and long initial hospital stay caused by umbilical cord blood transplantation, and provides an effective alternative for patients without suitable donors. Some studies showed that haplo-cord transplantation could lead to faster neutrophil recovery and lower incidence of chronic GVHD compared with haplo transplantation. In order to make full use of the advantages of easy access to grafts and possibly reducing the incidence of chronic GVHD, we have adopted haplo-cord program to some children lacking suitable donors, and reported the outcome of haplo-cord transplantation, comparing Virus reactivation,the incidence rate of acute and chronic GVHD, and 3-year overall survival rate with haplo-SCT. Aims: To compare the outcome of haplo-cord transplantation program with haplo transplantation. Methods: 35 children with Haplo-cord transplantation and 14 children with Haplo-SCT in our hospital were followed up between May 2017 and May 2021, the engraftment, immune reconstitution,Virus reactivation, incidence of GVHD and 3-year overall survival rate were observed. Results: The median time of neutrophil recovery in both groups was 13 days, and the cumulative recovery rate of neutrophils on the 30th day was 100%. By day 15,85.7% of the haplo-cord recipients had recovered neutrophil counts vs 92.7% of haplo recipients (P= 0.8). The median time of platelet recovery in both groups was 17 days, and no primary graft failure was observed in all patients. Secondary graft failure was documented in 5 haplo-cord recipients and 2 haplo recipients. 17 patients developed CMV-DNAemia in haplo-cord transplant and 9 in haplo patients. 31 cases had EB-DNAemia in haplo-cord vs 10 in haplo patients.By day 100, the cumulative incidence of acute GVHD in Haplo-cord patients was 25.7% vs 28.5% in haplo patients (P=1), and the cumulative incidence of grade 3-4 acute GVHD by day 100 was 11.4% vs 21.4% respectively (P = 0.65). There were no acute GVHD related deaths. Chronic GVHD was significantly reduced in haplo-cord with a cumulative incidence of 5.7% vs 28.6% in haplo patients by 1 year (P =0.04), but no extensive chronic GVHD was observed. The 3-year overall survival rate was 84.5% in haplo-cord transplant vs 74.3% in haplo transplant(P=0.98). Summary/Conclusion: Haplo-cord transplantation has high implantation rate and good long-term prognosis, and the incidence of chronic GVHD is significantly reduced, which provides an alternative for patients lacking Human leukocyte antigen-matched sibling donor and HLA-matched unrelated donor.