Letermovir for difficult to treat cytomegalovirus infection in lung transplant recipients.

Background. Cytomegalovirus (CMV)-infection remains a major cause of morbidity and mortality after lung transplantation. Treatment with currently available drugs poses treatment difficulties in some patients due to drug resistance or intolerability. Methods. We report a series of 4 lung transplant recipients with CMV-infection and treatment failure upon standard care due to antiviral drug resistance and treatment-limiting side effects. As rescue therapy letermovir recently approved for the prophylaxis of CMV-infection in patients after hematopoietic stem cell transplantation was initiated. Patients received 480 mg/day for a follow up of 36.1 +/- 12.9 weeks. Efficacy and tolerability were assessed retrospectively. Results. Mild nausea, vomiting, and diarrhea were the only side effects of letermovir reported by a single patient. A small adjustment of the tacrolimus dose was mandatory upon treatment initiation with letermovir. CMV viral load could be decreased and cleared subsequently in all patients. CMV clearance was observed after 17.7 +/- 12.6 weeks despite lack of CMV-immunity. Conclusions. CMV-infection and -disease were successfully managed with letermovir. Letermovir was well tolerated and effective in treating CMV-infections in lung transplant recipients failing on currently available antiviral agents.