Cytomegalovirus Prophylaxis With Letermovir in Heart Transplant Recipients

CMV infection is the most prevalent infection after heart transplantation (HTX), occurring in up to 40-60% of the recipients. It most frequently occurs within the first 6 months after transplantation and commonly presents as an asymptomatic viral replication. Viral syndrome or tissue-invasive disease (gastroenteritis, pneumonitis, myocarditis or meningitis) are much less common. Even though CMV infection is generally treatable with virostatic therapy and/or CMV-specific immunoglobulins, direct effects of CMV infection (viral syndrome and tissue-invasive disease) and general and transplant-specific indirect effects of CMV infection have been associated with significant morbidity and mortality in HTX patient population, mainly due to graft loss, development of malignancies, or opportunistic infections. According to the latest consensus paper on CMV prophylaxis and treatment in solid organ transplant recipients, valgancyclovir (or its active form gancyclovir) represents a virostatic therapy of choice for CMV prophylaxis and treatment after HTX. However, valgancyclovir has an array of side effects including hematological (leukopenia, neutropenia, anemia, thrombocytopenia), neurologic (headache, insomnia), gastrointestinal (decreased appetite, diarrhea, vomiting and dyspepsia) and psychiatric (depression) disorders. These can either expose HTX patients to additional complications (e.g. leukopenia and/or neutropenia can result in systemic fungal infections), decrease patients' quality of life, or mandate a decrease in valgancyclovir dose, which exposes patients to an increased risk for CMV reactivation. Recently, letermovir (a novel CMV viral terminase inhibitor), was approved for CMV prophylaxis in allogeneic bone marrow transplant recipients as the placebo-controlled study showed that significantly less patients, treated with letermovir, developed CMV disease (37% vs. 60%; P\<0.001) and there was also a trend towards lower all-cause mortality. Data on bone marrow transp