Maribavir for Refractory Cytomegalovirus Infection in Transplant Recipients: A Single-Center Real-World Case Series with Tailored Therapeutic Management

Background: Refractory cytomegalovirus (CMV) infection remains a major challenge after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT). Maribavir has demonstrated efficacy and a favorable safety profile in clinical trials, but real-world data on virological endpoints, treatment duration, and recurrence remain limited. Methods: We retrospectively reviewed all consecutive transplant recipients treated with maribavir for refractory CMV infection/disease at a tertiary referral center in Naples, Italy. Clinical and laboratory information were extracted from medical records. Results: Six patients were included: five SOT recipients and one autologous HSCT recipient. Maribavir was administered at 400 mg twice daily for a median of 43.5 days (IQR 23–56 days). At the end of treatment, five patients had detectable CMV DNA < 1000 IU/mL without confirmed clearance. Patient 6 was the only patient to achieve confirmed clearance (<LLOQ on two consecutive tests) and experienced virological and clinical rebound 18 days after discontinuation. Overall, 3/6 patients rebounded within 15–21 days. Adverse events were mild, and no patient discontinued therapy because of toxicity. Conclusions: In this small real-world series, maribavir was well tolerated and was associated with marked reductions in CMV DNA. However, three patients experienced early post-treatment rebound, including the only patient who achieved confirmed clearance. These observations are hypothesis-generating and do not establish a stopping threshold for low-level DNAemia or a validated post-treatment monitoring interval. Larger studies incorporating longitudinal viral kinetics, immune recovery, and resistance testing are needed.