Efficacy of letermovir in HLA-haploidentical hematopoietic transplantation with posttransplant cyclophosphamide.

ABSTRACT

BACKGROUND: Cytomegalovirus reactivation (CMV-R) is a significant complication of allogeneic hematopoietic stem cell transplantation (allo-HCT), especially in human leukocyte antigen-haploidentical transplantation (haplo-HCT) with posttransplant cyclophosphamide (PTCy). Prophylactic letermovir (LTV) prevents CMV-R in patients undergoing allo-HCT. However, evidence regarding its use in haplo-HCTs with PTCy is limited. Therefore, we aimed to investigate the efficacy of prophylactic LTV in haplo-HCT with PTCy. METHODS: We retrospectively analyzed 52 patients seropositive for CMV who underwent haplo-HCT with PTCy at our institution between January 2015 and June 2021 and compared patients who received LTV prophylaxis (LTV group n = 29) with those who did not receive prophylaxis for CMV (control group n = 23). The primary endpoint was the 100-day cumulative CMV-R incidence. We used Gray's test and the Fine and Gray test to compare the two groups. RESULTS: The 100-day cumulative CMV-R incidence was lower in the LTV group than in the control group (17.2% vs 81.8%, p < 0.001). Multivariate analysis revealed that prophylactic LTV reduced the 100-day cumulative CMV-R incidence (hazard ratio 0.17, 95% confidence interval 0.06-0.44, p < 0.001). CONCLUSIONS: Prophylactic LTV effectively prevents CMV-R in patients undergoing haplo-HCT for PTCy.