Comparison of Infectious Complications in Patients Receiving High-Dose Cyclophosphamide as GvHD After Transplantation From A 9/10 HLA-Matched Unrelated Donor with Standard GvHD Prophylaxis After Transplant From A Full Matching Donor

Background: The aim of this study was to evaluate whether cyclophosphamide administered after allogeneic stem cell transplantation (ASCT) from 9/10 HLA-Matched Unrelated Donors (MMUD) increases the rates of bloodstream infections (BSI) (fungal, viral (CMV, BK, hepatitis), bacterial), infectious complications (hemorrhagic cystitis(HC)) and infection-related mortality compared to allogeneic stem cell transplantation from matched related donors (MRD). Metods: This is a retrospective multicenter study. 45 MMUD ASCT patients who received posttransplant cyclophosphamide + methotrexate + calcineurin inhibitor compared with 45 MRD ASCT patients who received methotrexate + calcineurin inhibitor. Results: Although there was a statistically significant prolongation of neutrophil engraftment time in the PTCy arm, there was no statistically significant difference in bacterial BSI frequencies between the groups (PTCy; 9(20%), control;8 (17.8%), p=0.778). The distribution of CMV infection in the first 100 days was similar (p=0.827) but the distribution of CMV infection rate between the 100th and 365th days, was observed more frequently in the control group (p=0.005). HC rates and their grades were similar in both groups (PTCy; 4 (8.8%), control;6 (13.3%) p=0.502). The rates of VZV infection and invasive aspergillosis were similar in the PTCy and control groups (13.3% in the PTCy, and 17.8% in the control group p=0.561). IRM rate was statistically similar in both groups (13.3% in the PTCy arm and 17.8% in the control arm) Conclusions: The addition of PTCy to standard GvHD prophylaxis in MMUD ASCT does not lead to an increase in CMV reactivation, bacterial BSI, invasive fungal infection, viral hemorrhagic cystitis or infection-related mortality.