The current role of maribavir for treatment of cytomegalovirus in transplant recipients

Cytomegalovirus (CMV) is one of the most common infections after solid organ or hematopoietic stem cell transplantation. Typically, ganciclovir or valganciclovir have been used for first-line therapy, with foscarnet and cidofovir being used for resistant or refractory infections. Maribavir was recently approved as a novel CMV therapeutic for transplant recipients. We examine published studies of maribavir for posttransplant cytomegalovirus infection and summarize the current understanding of its pharmacology, clinical efficacy, toxicity, and risk of treatment-emergent resistance. Maribavir is generally the preferred therapy for CMV infection that is resistant or refractory to valganciclovir/ganciclovir treatment or transplant recipients who are intolerant of first-line treatment. It is well-tolerated overall without significant myelosuppression or nephrotoxicity, a stark difference from traditional CMV antivirals. However, there are high rates of treatment-emergent maribavir resistance, particularly among patients with high baseline CMV viral loads. Some UL97 mutations impart resistance to both maribavir and ganciclovir, though high-grade cross-resistance is rare. Transplant recipients who receive maribavir require close monitoring as resistance can develop even after an initial therapeutic response. Maribavir is an effective and well-tolerated addition to the CMV armamentarium, though it has important caveats that require consideration by infectious disease and transplant practitioners.