Letermovir for CMV Prevention After Lung Transplantation

Inclusion Criteria: * Age ≥18 years on day of signing informed consent * Listed for lung transplantation (single or double) due to a diagnosis of IPF or receipt of a lung transplant (single or double) for IPF in the 72 hours prior to enrollment * Have a documented positive serostatus for CMV (CMV IgG seropositive, R+) * Have a documented negative serostatus for CMV (CMV IgG seronegative, R-) and anticipate receiving or having received a lung allograft from a CMV IgG positive donor, D+). Only participants who are R+ or who are CMV D+/R- will receive intervention. Participants who are CMV D-/R- will be considered screen failures * Able to travel to UPMC for routine post-transplant visits for a minimum of 15 months after transplantation * Able to provide informed consent * Be willing to use a contraceptive method while receiving LET and for at least 90 days following last dose of LET Exclusion Criteria: * Receipt of a previous solid organ transplant or hematopoietic stem cell transplant * Multi-organ transplant recipient, i.e., heart-lung or lung-liver * HIV seropositive * HCV antibody or HCV RNA positive * Donor HCV NAT positive * Anticipated need for use of ganciclovir, valganciclovir, foscarnet, or cidofovir at the time of transplant * Known or suspected hypersensitivity to LET or acyclovir * CrCl \< 10 ml/min or dialysis on day of transplant * Child-Pugh Class C severe hepatic insufficiency * Pregnancy or expected to conceive while on LET and through at least 90 days following cessation of LET