Incidence of CMV Infection and Disease and Adverse Events Associated with Antiviral Therapy in a Retrospective Cohort of Allogeneic Hematopoietic Cell Transplant Recipients at an Academic Children's Hospital

Letermovir prophylaxis reduced cytomegalovirus reactivation and resistance post umbilical cord blood transplantation

To explore the impact of letermovir (LET) prophylaxis on cytomegalovirus (CMV) reactivation and resistance in both adult and paediatric umbilical cord blood transplantation (UCBT) patients, we retrospectively compared 43 UCBT patients who received LET as CMV prophylaxis with a historical cohort of 207 UCBT patients without LET usage. LET was administered from Day +1 to Day +100. The 180-day cumulative incidence of CMV reactivation (47.3% vs. 74.4%, p < 0.001) and the proportion of refractory CMV reactivation (15.0% vs. 42.9%, p = 0.016) were significantly lower than those in the control group. However, more frequent late CMV infection (31.0% vs. 4.3%, p = 0.002) and the 180-day cumulative incidence of Epstein-Barr virus (EBV) reactivation (9.3% vs. 3.4%, p = 0.087) were observed in UCBT patients with LET prophylaxis. Meanwhile, older age (>15 years old) and the occurrence of pre-engraftment syndrome were identified as the significant risk factors for CMV reactivation, and in patients at high risk, the incidence of CMV reactivation in the LET group was lower than that in the control group (46.7% vs. 86.5%, p < 0.001), while this decline was less pronounced among patients at low risk (47.8% vs. 62.1%, p = 0.120).

Case Report: Approaches for managing resistant cytomegalovirus in pediatric allogeneic hematopoietic cell transplantation recipients

The instructional case is a pediatric haploidentical TCRαβ+/CD19+ depleted allogeneic hematopoietic cell transplantation recipient who developed early onset CMV infection, which was complicated by resistant CMV (both UL97 and UL54) and successfully managed with maribavir and haploidentical CMV-specific T lymphocytes. Novel approaches to resistant CMV infection are reviewed and effective utilization of recent advances in diagnosis and management of resistant CMV in pediatric HCT are highlighted.

Optimization of Ganciclovir and Valganciclovir Starting Dose in Children by Machine Learning

BACKGROUND AND OBJECTIVES

Ganciclovir (GCV) and valganciclovir (VGCV) show large interindividual pharmacokinetic variability, particularly in children. The objectives of this study were (1) to develop machine learning (ML) algorithms trained on simulated pharmacokinetics profiles obtained by Monte Carlo simulations to estimate the best ganciclovir or valganciclovir starting dose in children and (2) to compare its performances on real-world profiles to previously published equation derived from literature population pharmacokinetic (POPPK) models achieving about 20% of profiles within the target.

MATERIALS AND METHODS

The pharmacokinetic parameters of four literature POPPK models in addition to the World Health Organization (WHO) growth curve for children were used in the mrgsolve R package to simulate 10,800 pharmacokinetic profiles. ML algorithms were developed and benchmarked to predict the probability to reach the steady-state, area-under-the-curve target (AUC0-24 within 40-60 mg × h/L) based on demographic characteristics only. The best ML algorithm was then used to calculate the starting dose maximizing the target attainment. Performances were evaluated for ML and literature formula in a test set and in an external set of 32 and 31 actual patients (GCV and VGCV, respectively).

RESULTS

A combination of Xgboost, neural network, and random forest algorithms yielded the best performances and highest target attainment in the test set (36.8% for GCV and 35.3% for the VGCV). In actual patients, the best GCV ML starting dose yielded the highest target attainment rate (25.8%) and performed equally for VGCV with the Franck model formula (35.3% for both).

CONCLUSION

The ML algorithms exhibit good performances in comparison with previously validated models and should be evaluated prospectively.

Disparities in Cytomegalovirus Infection Rates by Race and Ethnicity among Pediatric Allogeneic Hematopoietic Cell Transplantation Recipients at a Single Center

Previous literature has reported cytomegalovirus (CMV) infection rate disparities among racial/ethnic groups of hematopoietic cell transplantation (HCT) recipients. Because race and ethnicity categorizations are social constructs unlikely to affect biological systems, it is likely there are covariates on the pathway to CMV detection, known as mediators, that can explain the observed disparity. Recent developments in mediation analysis methods enable the analysis of time-to-event outcomes, allowing an investigation of these disparities to also consider the timing of CMV infection detection relative to HCT. This study aimed to explore whether racial and ethnic CMV infection disparities existed within a population of HCT recipients at our center, and whether clinical covariates explained any observed association. The study cohort included all recipients of allogeneic HCT performed at the Children's Hospital of Philadelphia between January 2004 and April 2017 who were CMV PCR-negative pretransplantation, had known donor/recipient CMV serology, and were under blood CMV PCR surveillance. Subjects were followed for 100 days post-HCT. Accelerated failure time models using subject's reported race/ethnicity, dichotomized into non-Hispanic White (NHW) and non-NHW, and exposure and time to CMV detection as outcomes examined whether selected clinical factors-donor/recipient CMV serostatus, recipient age, indication for HCT, hematopoietic cell source, match quality-mediated any identified exposure-outcome association. The analysis included 348 HCTs performed in 335 subjects, with 86 episodes (24.7%) in which CMV was detected via PCR analysis. The accelerated failure time model without mediators estimated that non-NHW subjects had fewer CMV-free survival days (time ratio, .21; 95% confidence interval, .10 to .44). Any hypothesized mediator mediated at most 5% of the total association between race/ethnicity and time to CMV detection. Non-NHW HCT recipients had fewer CMV-free survival days than NHW recipients; none of the clinical factors hypothesized to mediate this association accounted for a significant component of total association. Further research should focus on nonclinical factors influenced by systemic racism to better understand their effect on CMV infection among HCT recipients.

CMV hyperimmune globulin as salvage therapy for recurrent or refractory CMV infection in children undergoing hematopoietic stem cell transplantation

Cytomegalovirus (CMV) is a major cause of allogeneic hematopoietic stem cell transplant (HSCT)-related morbidity and mortality. Treatment failure continues to be a major issue in patients with CMV infection due to both drug resistance and intolerance. This single-center brief retrospective analysis of a case series aims to investigate the safety and efficacy of CMV-hyperimmune globulin as salvage therapy for CMV infection in children undergoing HSCT. Fifteen pediatric patients received human CMV-specific immunoglobulin (CMVIG) between July 2018 and December 2021 as a salvage therapy for refractory or recurrent CMV infection. At the time of CMVIG prescription, eight children presented with recurrent CMV infection and seven with refractory CMV infection. The overall response rate was 67% at 50 days from the CMVIG administration [95% confidence interval (CI): 44-88]. Overall survival (OS) from CMVIG administration at 100 days was 87% (95% CI: 56-96), and OS from HSCT at 1 year was 80% (95% CI: 50-93). Four patients died, three unrelated to CMV infection and one due to CMV pneumonia. CMVIG as salvage therapy was well tolerated, and no infusion-related adverse events were observed.

Evaluation of Platelet Parameters in Patients With Secondary Failure of Platelet Recovery and Cytomegalovirus Infection After Hematopoietic Stem Cell Transplantation

OBJECTIVE

To investigate the clinical significance of changes in platelet parameters in patients with secondary failure of platelet recovery (SFPR) and cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT).

METHODS

In this retrospective study, 79 patients who had undergone allogeneic HSCT (allo-HSCT), including 40 patients with SFPR and 39 patients without SFPR, were recruited. The evaluated parameters were platelet count (PLT), plateletcrit (PCT), platelet-large cell ratio (P-LCR), mean platelet volume (MPV), platelet distribution width (PDW), the incidence of CMV infection after allo-HSCT, and the correlation of SFPR and CMV infection in patients who had undergone allo-HSCT. The control group included 107 healthy donors.

RESULTS

The SFPR group had significantly lower megakaryocyte counts, PLT, and PCT and significantly higher P-LCR, MPV, and PDW than the healthy donor and non-SFPR groups. The incidence of CMV infection was higher in SFPR patients than in non-SFPR patients. Among the patients with SFPR, P-LCR, MPV, and PDW were lower in those with CMV DNA >8000 copies/mL than in those with CMV DNA <8000 copies/mL (P < .05 for all); the CMV viral load was slightly negatively correlated with MPV (P = .0297) and P-LCR (P = .0280).

CONCLUSION

We demonstrate for the first time that the level of platelet activation in SFPR patients, which was closely related to CMV infection, was higher than that in that in non-SFPR patients, and higher CMV load was associated with the inhibition of platelet activation.

Risk Factors for CMV Viremia and Treatment-Associated Adverse Events Among Pediatric Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV) causes substantial morbidity and mortality after hematopoietic stem cell transplantation (HSCT). There are limited data on risk factors for CMV viremia and the safety of antiviral medications used to treat CMV in children.

METHODS

We conducted a single-center retrospective study of children who underwent HSCT between 2000 and 2016. We used log-logistic regression to evaluate associations between clinical characteristics and CMV-free survival at 100 days after HSCT. We compared the incidences of laboratory-defined adverse events (AEs) during treatment with ganciclovir and foscarnet.

RESULTS

Among 969 children, the median (interquartile range) age was 6.5 (3.1-11.5) years, and 80% underwent allogeneic HSCT. Two hundred forty-four (25%) children developed CMV viremia. Older age (odds ratio [OR], 0.95; 95% CI, 0.92-0.98), male sex (OR, 0.71; 95% CI, 0.51-0.99), non-Black, non-White race (OR, 0.56; 95% CI, 0.36-0.87), umbilical cord blood donor source (OR, 0.28; 95% CI, 0.08-0.97), and CMV seropositivity (R-/D+: OR, 0.17; 95% CI, 0.07-0.41; R+/D-: OR, 0.14; 95% CI, 0.09-0.21; R+/D+: OR, 0.08; 95% CI, 0.04-0.15) were associated with lower odds of 100-day CMV-free survival. Compared with foscarnet, ganciclovir was associated with lower incidences of thrombocytopenia (incidence rate ratio [IRR], 0.38; 95% CI, 0.15-0.97), electrolyte AEs (IRR, 0.42; 95% CI, 0.24-0.75), endocrine AEs (IRR, 0.52; 95% CI, 0.34-0.79), and renal AEs (IRR, 0.36; 95% CI, 0.19-0.65).

CONCLUSIONS

CMV viremia occurred commonly among children after HSCT, and ganciclovir and foscarnet were associated with distinct toxicity profiles among children with CMV infection. These findings should be considered when developing CMV prevention and treatment strategies for children after HSCT.