Letermovir primary prophylaxis for cytomegalovirus reactivation in patients undergoing allogeneic hematopoietic stem cell transplantation -- first experience.

Introduction: Cytomegalovirus (CMV) reactivation remaining a common complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is associated with an increased risk of post-transplant morbidity and mortality. Primary prophylaxis with letermovir (LMV) significantly decreased the risk of CMV infection in allotransplanted patients if compared with placebo. Material and methods: We report on our first experience with LMV prophylaxis in 12 adult patients (7 males), median age of 47 years (range 28-69) undergoing allo-HSCT for hematologic malignancies in the recent year. These data were compared with historical group of 40 patients having the same CMV serological status (negative CMV IgG donor to positive CMV IgG recipient) and did not receive LMV prophylactically. Results: Median time to LMV post-transplant initiation was 14 days (range 5-21) and all patients received 240 mg a day due to concomitant ciclosporin administration. LMV was continued to day +100 or to the occurrence of CMV reactivation. LMV was found to have satisfying safety profile with exceptional tolerance. One patient was found to have CMV "blip" with 1600 copies/mL but LMV was continued. A repeated PCR assay was found to be negative. In total, only 1 patient (8%) reactivated CMV on day +83 post transplantation with repeated positive PCR assays and max. of 4200 copies/mL. He was treated successfully with valganciclovir. In the historical group, CMV reactivation was observed in 11 patients (35%) at median day of +27 post-transplantation (range 20-87). Median number of CMV copies was 11300/mL (range 900-36,000). All these patients received treatment with ganciclovir or valganciclovir with CMV eradication, but myelosuppressive effect was substantial. Conclusions: According to our early observations, LMV was found to be more effective than placebo and CMV replication occurred at later phase of a post-transplant period. More data are needed to conclude on polish patients. [ABSTRACT FROM AUTHOR]