Antiviral Toxicity

This is a research study to test the tolerability and clinical effectiveness of the study drug, Letermovir (LET), when used as secondary prophylaxis following treatment of Cytomegalovirus (CMV) infection and disease in a solid organ transplant recipient. This study is an open label trial in which Letermovir will be prescribed to prevent the recurrence of CMV infection and disease in a solid organ transplant recipient following treatment of CMV infection or disease.