Use of Letermovir for CMV Prophylaxis or Treatment in Thoracic Organ Transplant Recipients

Purpose CMV infection is common among transplant recipients and may result in increased morbidity and mortality. Valganciclovir and ganciclovir are frequently used for viral prophylaxis or treatment. However, these agents can be difficult to tolerate due to myelosuppression. Letermovir, an anti-viral drug which inhibits CMV-terminase complex, has been demonstrated to reduce the risk of CMV infection in hematopoetic-cell transplantation. We sought to assess the utility of letermovir in thoracic organ recipients in whom valganciclovir and ganciclovir were not well tolerated or were ineffective due to resistance. Methods We examined our institutional experience with the use of letermovir for either CMV prophylaxis or treatment in heart and lung transplant recipients from February to September 2018. Results Nine total patients received letermovir during the study period (8 lung, 1 heart). Letermovir was administered for CMV prophylaxis in 8 instances and for treatment of CMV viremia in 2 instances (see Table). One patient received letermovir for both prophylaxis and treatment on temporally separate occasions. 3 of 8 (37.5%) of patients receiving letermovir for CMV prophylaxis developed viremia while on treatment. One patient treated for ganciclovir resistant CMV disease with letermovir had overt clinical failure with a sharp rise in serum CMV PCR. The other patient treated for low grade CMV viremia initially cleared but then relapsed with low grade viremia (CMV PCR 214). No major side effects were reported. 2 patients experienced minor side effects (1 edema, 1 fatigue). Conclusion Letermovir was well tolerated with only minor side effects reported in a population intolerant or resistant to conventional CMV prophylaxis and treatment. However, efficacy was poor, with a high rate of CMV viremia on therapy (50%). Further study of letermovir for CMV prophylaxis or treatment in thoracic organ transplant recipients is nonetheless warranted to better characterize its potential role in this high risk population.