1589. Long term hematopoietic cell transplant outcomes in patients at high risk for cytomegalovirus infections in the era of letermovir


 
 
 Letermovir (LTV) primary prophylaxis (PP) has reduced the incidence of clinically significant cytomegalovirus infection (CS-CMVi) in allogeneic hematopoietic cell transplant (allo-HCT) recipients. However, it is not clear if these are similar to low-risk recipients (seronegative donor [D-] and recipient [R-]). Prior studies have reported that D-/R- allo-HCT recipients have reduced relapse rates, graft versus host disease (GVHD), and overall mortality. We compared the clinical outcomes of R+ allo-HCT recipients with and without LTV PP to D-/R- allo-HCT recipients.
 
 
 
 This is a single-center study of allo-HCT recipients who underwent transplantation between March 2016 and December 2018. Data on baseline and transplant characteristics were collected. Outcomes included incidence of CS-CMVi, GVHD, all-cause mortality, relapse and NRM. Univariate analysis was performed to compare outcomes in R+ with and without LTV PP cohorts to D-/R- cohort. Categorical and continuous variables were compared using Fisher’s exact test and Wilcoxon rank sum respectively. Survival curves were compared with the log-rank test. Patients who relapsed after transplant were excluded from NRM analysis.
 
 
 
 A total of 616 patients underwent an allo-HCT; 124 R+ were on LTV PP, 415 were R+ on no LTV PP as well as the 77 who were CMV D-/R-. When compared to D-/R- group, R+ group who received or not LTV PP were more likely to have AML and ALL, and underwent myeloablative conditioning. The incidence of CS-CMVi was the lowest in the D-/R- group (4%), followed by the R+ on LTV PP (17%), and the highest in the R+ group on no LTV PP (53%) (table 2). Kaplan-Meier survival analysis for NRM 1 year after transplant showed trends towards lower survival in R+ allo-HCT recipients who did not receive LTV PP when compared to the D-/R- group at day 200 and day 360 (p=0.07 vs. p=0.08, respectively). In addition, R+ allo-HCT on LTV PP had similar NRM at day 360 compared to D-/R- (p=0.77) and lower NRM at day 360 compared to R+ allo-HCT on no LTV PP (p=0.0192).
 
 
 
 Our study showed a reduction in the rate of CS-CMVi within 48 weeks post HCT in high risk allo-HCT recipients on LTV. NRM was lower in R+ allo-HCT recipients on LTV PP when compared to those without LTV. No difference in NRM was seen between D-/R- allo-HCT and R+ allo-HCT on LTV PP.
 
 
 
 Terri Lynn Shigle, PharmD, BCOP, Takeda: Advisor/Consultant Gabriella Rondon, MD, Omeros: Advisor/Consultant Elizabeth Shpall, MD, Adaptimmune: Advisor/Consultant|Affimed: License agreement|Axio: Advisor/Consultant|Bayer Helathcare Pharmaceuticals: Honoraria|Fibroblasts and FibrioBiologics: Advisor/Consultant|Navan: Advisor/Consultant|NY Blood Center: Advisor/Consultant|Takeda: License agreement Ella J. Ariza Heredia, MD, Merck & Co. Inc: Grant/Research Support Roy F. Chemaly, MD/MPH, Karius: Advisor/Consultant|Karius: Grant/Research Support.
