Letermovir Prophylaxis for CMV Reactivation in Allogeneic Stem Cell Recipients: Α Retrospective Single Center Analysis

Background/Aim: Cytomegalovirus (CMV) reactivation is one of the most clinically significant complications in allogeneic stem cell recipients and a frequent cause for transplantation related mortality. Letermovir is a newly available and recently approved drug for CMV prophylaxis. In a retrospective single center analysis, we investigated the benefit of letermovir as CMV prophylaxis in allogeneic stem cell recipients. Patients and Methods: We included 48 CMV-seropositive transplant recipients from January 2017 to August 2020 from our department. We compared the rate of CMV reactivation in patients who received letermovir as prophylaxis from day 0 after allogeneic stem cell transplantation (alloSCT) with a control group that did not receive CMV prophylaxis. The primary endpoint was CMV reactivation and was defined as an increase of CMV copies over 1250 Ul/ml in the peripheral blood; secondary endpoints were overall survival (OS) up to 180 days, engraftment and all-cause mortality. Results: We included 21 patients in the control group and 27 patients in the letermovir group. Letermovir treatment led to a significantly reduced incidence of CMV reactivation after alloSCT (33.3% in the letermovir group versus 76.2% in the control group, p<0.001). The OS at day 180 was 80.9% in the control group versus 92.6% in the letermovir group (p<0.05). The median duration of letermovir prophylaxis was 192±104 days. Conclusion: Our results indicate that letermovir prophylaxis is associated with a significant lower risk of CMV reactivation and improved overall survival in CMV-seropositive stem cell recipients. Moreover, a prolonged use of letermovir prophylaxis might be a survival benefit.