High dose valaciclovir to prevent cytomegalovirus infection in allogeneic haematopoietic stem cell transplant recipients

Cytomegalovirus (CMV) infection causes morbidity and mortality after allogeneic haematopoietic stem cell transplantation (HSCT). We investigated whether prophylaxis with high dose valaciclovir is effective at reducing the incidence of clinically significant CMV infection (csCMVi) within six months of allogeneic HSCT. Consecutive allogeneic HSCT recipients who received 2g valaciclovir orally four times daily from transplant until day 100 (prophylaxis group) were compared to subsequent patients who received no CMV prophylaxis (control group). Forty-nine patients in the prophylaxis group and 59 in the control group were included. The cumulative incidence of csCMVi at 6 months was 20% (95% confidence interval (CI): 9%-27%) in the prophylaxis group and 39% (95% CI: 26%-47%) in the control group (P = .009). There was no CMV disease in the prophylaxis group and three cases in the control group. There was no difference in time to neutrophil or platelet recovery nor graft failure between groups. On multivariable analysis, lack of high dose valaciclovir prophylaxis, positive recipient CMV IgG and age were associated with greater likelihood of csCMVi. There was no significant difference in acute graft versus host disease, non-relapse mortality or overall survival between groups. In this retrospective cohort study, high dose valaciclovir prophylaxis resulted in a lower incidence of csCMVi within six months of HSCT.