Background: Valganciclovir (ValG) is the most widely used drug for cytomegalovirus (CMV) prophylaxis in kidney transplant recipients (KTRs). However, it is associated with dose-limiting side effects and considerable costs. Some centers have identified valacyclovir (ValA) as an economically attractive alternative with a lower risk of bone marrow suppression. The comparative effectiveness of these two drugs is not well-established. This study aims to compare the efficacy and safety of ValA and ValG for CMV prophylaxis in KTRs.
Methods: Searches were conducted of the Medline, Cochrane, Web of Science, Embase, and Ovid databases. Endpoints encompassed the incidence of CMV disease, CMV viremia, acute rejection, leukopenia/neutropenia, and other infections, including BK polyomavirus and non-CMV herpesviruses (HVs). Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model.
Results: Six studies, comprising 888 patients (438 receiving ValA), were included. The groups were comparable in CMV viremia incidence (RR, 0.70; 95% CI, 0.31–1.57; P=0.4) and the development of CMV disease (RR, 0.74; 95% CI, 0.09–5.97; P=0.8). No significant differences in acute rejection rates were observed (RR, 0.97; 95% CI, 0.50–1.91; P=0.8). However, the rate of leukopenia/neutropenia was significantly lower in the ValA group (RR, 0.57; 95% CI, 0.42–0.77; P<0.01). No significant differences were noted for BK viremia (RR, 0.67; 95% CI, 0.24–1.87; P=0.4) or other HV infections (RR, 1.43; 95% CI, 0.61–3.38; P=0.4).
Conclusions: The drugs demonstrate comparable efficacy in preventing CMV infection following kidney transplantation. However, ValA may have a lower impact on bone marrow suppression.

Keywords: Kidney, Valganciclovir, Valacyclovir, Cytomegalovirus