Efficacy and safety of low-dose ganciclovir preemptive therapy in allogeneic haematopoietic stem cell transplant recipients compared with conventional-dose ganciclovir: a prospective observational study.

OBJECTIVES We performed a prospective observational study comparing the efficacy and safety of low-dose ganciclovir (5 mg/kg/day) as initial preemptive therapy in allogeneic haematopoietic stem cell transplantation (HSCT) recipients with conventional-dose ganciclovir (10 mg/kg/day). METHODS All adult patients undergoing allogeneic HSCT were enrolled at a transplant centre over a 24 month period. The decision to use low-dose or conventional-dose ganciclovir was at the discretion of each attending haematologist. A logistic regression model with inverse probability of treatment weighting (IPTW) using propensity scores was performed to reduce the effect of the selection bias in assignment for ganciclovir preemptive therapy. RESULTS Of the 252 HSCT recipients, 97 (38%) received preemptive ganciclovir therapy. Of these, 53 (55%) and 44 (45%) received low-dose and conventional-dose ganciclovir, respectively. The viral clearance rate was higher in the low-dose ganciclovir group [98% (52/53)] than in the conventional-dose ganciclovir group [86% (38/44), P = 0.04], while the low-dose ganciclovir group exhibited a longer viral clearance time (median 21.0 days) than the conventional-dose ganciclovir group (median 14.0 days, P = 0.05). The rate of discontinuation of therapy due to neutropenia or nephrotoxicity was similar in the two groups, although conventional-dose ganciclovir was changed to another regimen more frequently than low-dose ganciclovir. There were three cases of cytomegalovirus (CMV) disease in each group after the initial preemptive therapy. The logistic regression models using propensity scores also revealed that there were no significant differences in viral clearance, secondary episodes of CMV infection, CMV disease and overall mortality between the two groups. CONCLUSIONS Low-dose ganciclovir appears to be safe, and to be at least as effective as conventional-dose ganciclovir for CMV viraemia in allogeneic HSCT recipients.