Real-World Outcomes Associated With Letermovir Use for Cytomegalovirus Primary Prophylaxis in Allogeneic Hematopoietic Cell Transplant Recipients: A Systematic Review and Meta-analysis of Observational Studies

BACKGROUND: A systematic review and meta-analysis of real-world observational studies was conducted to summarize the impact of letermovir cytomegalovirus (CMV) primary prophylaxis (PP) among adult allogeneic hematopoietic cell transplant (allo-HCT) recipients. METHODS: Systematic searches in Medline/PubMed, Embase, and conferences (from database inception to October 2021) were conducted to identify studies for inclusion. Random-effects models were used to derive pooled estimates on the relative effectiveness of letermovir PP compared to controls. RESULTS: Forty-eight unique studies (N = 7104 patients) were included, most of which were comparative, single-center, and conducted in the United States. Letermovir PP was associated with statistically significant reduction in odds of CMV reactivation (pooled odds ratio [pOR], 0.13 and 0.24; P < .05), clinically significant CMV infection (pOR, 0.09 and 0.19; P < .05), and CMV disease (pOR, 0.31 and 0.35; P < .05) by day +100 and day +200 after allo-HCT, respectively. Letermovir PP was associated with significantly lower odds of all-cause (pOR, 0.73; P < .01) and nonrelapse mortality (pOR, 0.65; P = .01) beyond day 200 after allo-HCT. CONCLUSIONS: Letermovir for CMV PP was effective in reducing the risk of CMV-related complications overall and mortality beyond day 200 among adult allo-HCT recipients.