Prior studies suggest increased cytomegalovirus (CMV)
infection after haploidentical donor
transplantation with posttransplant
cyclophosphamide (HaploCy). The role of allograft source and posttransplant
cyclophosphamide (PTCy) in CMV
infection is unclear. We analyzed the effect of graft source and PTCy on incidence of CMV
infection, and effects of serostatus and CMV
infection on transplant outcomes. We examined patients reported to the Center for International Blood and Marrow
Transplantation Research between 2012 and 2017 who had received HaploCy (n = 757), matched related (Sib) with PTCy (SibCy, n = 403), or Sib with
calcineurin inhibitor-based prophylaxis (SibCNI, n = 1605). Cumulative incidences of CMV
infection by day 180 were 42%, 37%, and 23%, respectively (P < .001). CMV disease was statistically comparable. CMV
infection risk was highest for CMV-seropositive recipients (R+), but significantly higher in PTCy recipients regardless of donor (HaploCy [n = 545]: hazard ratio [HR], 50.3; SibCy [n = 279]: HR, 47.7; SibCNI [n = 1065]: HR, 24.4; P < .001). D+/R- patients also had increased risk for CMV
infection. Among R+ or those developing CMV
infection, HaploCy had worse overall survival and nonrelapse mortality. Relapse was unaffected by CMV
infection or serostatus. PTCy was associated with lower
chronic graft-versus-host disease (GVHD) overall, but CMV
infection in PTCy recipients was associated with higher chronic GVHD (P = .006). PTCy, regardless of donor, is associated with higher incidence of CMV
infection, augmenting the risk of seropositivity. Additionally, CMV
infection may negate the chronic GVHD protection of PTCy. This study supports aggressive prevention strategies in all receiving PTCy.