Valacyclovir or valganciclovir for cytomegalovirus prophylaxis: A randomized controlled trial in adult and pediatric kidney transplant recipients

Background: Valganciclovir (valG), a cytomegalovirus (CMV) prophylactic agent, has dose-limiting side effects. The tolerability and effectiveness of valacyclovir (valA) as CMV prophylaxis is unknown. Methods: We conducted a randomized, open-label, single-center trial of valA versus valG for all posttransplant CMV prophylaxis in adult and pediatric kidney recipients. Participants were randomly assigned to receive valA or valG. Primary endpoints were the incidence of CMV viremia and side-effect related drug reduction with secondary assessment of incidence of EBV viremia. Results: Of the 137 sequential kidney transplant recipients enrolled, 26 % were positive and negative for CMV antibody in donor and recipient respectively. The incidence of CMV viremia (4 of 71 [6 %]; 8 of 67 [12 %] P = 0.23), time to viremia (P = 0.16) and area under CMV viral load time curve (P = 0.19) were not significantly different. ValG participants were significantly more likely to require side-effect related dose reduction (15/71 [21 %] versus 1/66 [2 %] P = 0.0003). Leukopenia was the most common reason for valG dose reduction and granulocyte-colony stimulating factor was utilized for leukopenia recovery more frequently (25 % in valG vs 5 % in valA: P = 0.0007). Incidence of EBV viremia was not significantly different. Conclusions: ValA has significantly less dose-limiting side effects than valG. In our study population, a significant increase in CMV viremia was not observed, in adults and children after kidney transplant, compared to valG.