Impact of GVHD prophylaxis on CMV reactivation and disease after HLA-matched peripheral blood stem cell transplantation.

The kinetics of early and late CMV reactivation after hematopoietic cell transplantation using various methods of graft-versus-host-disease (GVHD) prophylaxis are poorly defined. We retrospectively compared CMV reactivation and disease among 780 seropositive patients given HLA-matched peripheral blood stem cell (PBSC) grafts and calcineurin-inhibitor plus post-transplantation cyclophosphamide (PTCy; n=44), mycophenolate mofetil (MMF; n=414) or methotrexate (MTX; n=322). Transplantation occurred between 2007-2018; CMV-monitoring/management followed uniform standard practice. Hazards of CMV reactivation at various thresholds were compared. Spline curves were fit over average daily viral load, and areas under the curve (AUC) within one-year were calculated. PTCy and MMF were associated with an increased risk of early (day 100) CMV reactivation ≥250 IU/mL after multivariable adjustment (PTCy vs. MTX: HR=1.64; 95% CI: 1.03-2.61; p=0.039; MMF vs. MTX: HR=1.50; 95% CI: 0.97-2.32; p=0.067). The viral load AUC at one-year was highest with MMF (mean difference 0.125 units vs. MTX; 95% CI 0.061-0.189; p<.001) and similar between PTCy vs. MTX (mean difference 0.016 units vs. MTX group; 95% CI, -0.126-0.158, p=0.827). CMV disease risk was similar across groups. There was no interaction between GVHD prophylaxis and CMV reactivation on chronic GVHD risk. Despite PTCy-associated increased risk of early CMV reactivation, the CMV disease risk by 1 year was low in HLA-matched PBSC transplant recipients. In contrast, MMF was associated with higher overall CMV viral burden in the 1-year posttransplant. While different mechanisms of immunosuppressive agents may impact CMV reactivation risk, effective prevention of GVHD may reduce corticosteroid exposure and mitigate infection risk over time.