A Randomized Controlled Trial Comparing the Tolerability and Efficacy of Maribavir vs. Valganciclovir for CMV Prophylaxis in High-Risk Kidney Transplant Recipients: Study Protocol (Maribavir IIR)

Abstract

Background: Cytomegalovirus (CMV) infection remains a significant problem in kidney transplantation despite advances in screening, monitoring, therapeutics, and management. Although universal prophylaxis with antiviral therapy has significantly reduced the risk of early CMV infection and disease, late-onset CMV is still common and can be difficult to clinically manage in high-risk patients. A recent systematic review showed that with antiviral prophylaxis, early CMV infection occurred in only 6% of kidney recipients and late infection occurred in more than one in six patients. ⁴ The two antiviral prophylaxis medications this study is comparing, valganciclovir (VGC) and maribavir, are highly effective at preventing CMV infection. In studies using valganciclovir, the reported occurrence of leukopenia is 20 - 40% and neutropenia is 10 - 30%^6-12. In studies using maribavir, the reported occurrence of neutropenia was 4 - 5% versus 15 - 18% in valganciclovir patients. With appropriate dosing, maribavir appears to have similar efficacy to valganciclovir in treating current and preventing future CMV infection with a significantly reduced rate of neutropenia. Methods: Maribavir IIR is a 12-month, single-center, open-label, randomized controlled trial enrolling 70 patients (35 in each arm) examining the difference in preventing CMV infection while specifically assessing the tolerability of the two antiviral prophylactic medications. The trial is currently in the follow-up phase, with the first patient enrolled in November 2023, and enrollment concluding in June 2024. Discussion: The primary objective of this study is to assess the tolerability of maribavir versus valganciclovir (VGC) prophylaxis in adult kidney transplant recipients at high-risk of CMV infection (D+/R- or thymo use if R+). This was done by assessing the incidence of leukopenia in the two arms, the occurrence of CMV infection despite prophylaxis, the impact of these medications on healthcare utilization and costs, and any outcome differences associated with race and sex. In this preliminary report, we describe the study design, methods, aims, and outcome measures that will be utilized in the ongoing Maribavir IIR clinical trial. Trial Registration: ClinicalTrials.gov NCT06034925: https://www.clinicaltrials.gov/study/NCT06034925