Comparison between valganciclovir and aciclovir/valaciclovir for CMV prophylaxis in pediatric renal transplantation

Diagnosis of Human Cytomegalovirus Drug Resistance Mutations in Solid Organ Transplant Recipients-A Review

Human cytomegalovirus (HCMV) infection may be asymptomatic in healthy individuals but can cause severe complications in immunocompromised patients, including transplant recipients. Breakthrough and drug-resistant HCMV infections in such patients are major concerns. Clinicians are first challenged to accurately diagnose HCMV infection and then to identify the most effective antiviral drug and determine when to initiate therapy, alter drug dosage, or switch medication. This review critically examines HCMV diagnostics approaches, particularly for immunocompromised patients, and the development of genotypic techniques to rapidly diagnose drug resistance mutations. The current standard method to identify prevalent and well-known resistance mutations involves polymerase chain reaction amplification of UL97, UL54, and UL56 gene regions, followed by Sanger sequencing. This method can confirm clinical suspicion of drug resistance as well as determine the level of drug resistance and range of cross-resistance with other drugs. Despite the effectiveness of this approach, there remains an urgent need for more rapid and point-of-care HCMV diagnosis, allowing for timely lifesaving intervention.

Personalized application of antimicrobial drugs in pediatric patients with augmented renal clearance: a review of literature

The effect of renal functional status on drug metabolism is a crucial consideration for clinicians when determining the appropriate dosage of medications to administer. In critically ill patients, there is often a significant increase in renal function, which leads to enhanced drug metabolism and potentially inadequate drug exposure. This phenomenon, known as augmented renal clearance (ARC), is commonly observed in pediatric critical care settings. The findings of the current study underscore the significant impact of ARC on the pharmacokinetics and pharmacodynamics of antimicrobial drugs in critically ill pediatric patients. Moreover, the study reveals a negative correlation between increased creatinine clearance and blood concentrations of antimicrobial drugs. The article provides a comprehensive review of ARC screening in pediatric patients, including its definition, risk factors, and clinical outcomes. Furthermore, it summarizes the dosages and dosing regimens of commonly used antibacterial and antiviral drugs for pediatric patients with ARC, and recommendations are made for dose and infusion considerations and the role of therapeutic drug monitoring.

CONCLUSION

 ARC impacts antimicrobial drugs in pediatric patients.

WHAT IS KNOWN

• ARC is inextricably linked to the failure of antimicrobial therapy, recurrence of infection, and subtherapeutic concentrations of drugs.

WHAT IS NEW

• This study provides an updated overview of the influence of ARC on medication use and clinical outcomes in pediatric patients. • In this context, there are several recommendations for using antibiotics in pediatric patients with ARC: 1) increase the dose administered; 2) prolonged or continuous infusion administration; 3) use of TDM; and 4) use alternative drugs that do not undergo renal elimination.

Population Pharmacokinetics of Intravenous and Oral Acyclovir and Oral Valacyclovir in Pediatric Population To Optimize Dosing Regimens

Acyclovir is an antiviral currently used for the prevention and treatment of herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. This study aimed to characterize the pharmacokinetics (PK) of acyclovir and its oral prodrug valacyclovir to optimize dosing in children. Children receiving acyclovir or valacyclovir were included in this study. PK were described using nonlinear mixed-effect modeling. Dosing simulations were used to obtain trough concentrations above a 50% inhibitory concentration for HSV or VZV (0.56 mg/liter and 1.125 mg/liter, respectively) and maximal peak concentrations below 25 mg/liter. A total of 79 children (212 concentration-time observations) were included: 50 were taking intravenous (i.v.) acyclovir, 22 were taking oral acyclovir, and 7 were taking both i.v. and oral acyclovir, 57 for preventive and 22 for curative purposes. A one-compartment model with first-order elimination best described the data. An allometric model was used to describe body weight effect, and the estimated glomerular filtration rate (eGFR) was significantly associated with acyclovir elimination. To obtain target maximal and trough concentrations, the more suitable initial acyclovir i.v. dose was 10 mg/kg of body weight/6 h for children with normal renal function (eGFR ≤ 250 ml/min/1.73 m²) and 15 to 20 mg/kg/6 h for children with augmented renal clearance (ARC) (eGFR > 250 ml/min/1.73 m²). The 20-mg/kg/8 h dose for oral acyclovir and valacyclovir produced effective concentrations in more than 75% of children; however, a 15-mg/kg/6 h dose, if possible, is preferred. These doses should be prospectively confirmed, and therapeutic drug monitoring could be used to refine them individually. (This study has been registered at ClinicalTrials.gov under identifier NCT02539407.).

GCV/VCVG prophylaxis against CMV DNAemia in pediatric renal transplant patients: A systematic review and meta-analysis

CMV disease continues to stand as a significant threat to the longevity of renal transplants in children. More pediatric recipients are CMV-negative with CMV-positive donor serologies resulting in a HR mismatch. The length of prophylaxis with GCV or VGCV required to optimally prevent recurrence of CMVDNAemia remains unknown. This study is a meta-analysis comparing GCV/VGCV prophylaxis regimens provided for <6 months, from 6 to <12 months, and ≥12 months after transplant in order to prevent CMVDNAemia. The search conducted involved PubMed, EMBASE, ISI Web of Science, and Cochrane Central Register from inception through December 2017. Search terms Kidney Transplantation, CMV, GCV, and VGCV provided 204 studies for abstract review. Studies excluded were those which did not itemize pediatric data separately, single case reports, and duplicate studies. Pooled analysis of five retrospective studies and one prospective study identified that there is no statistically significant difference in the incidence of CMV DNAemia when comparing <6 months of prophylaxis and >12 months of prophylaxis (23% and 15%, respectively, P = 0.23). Regardless of the length of prophylaxis, there was no statistical difference in the incidence of CMV DNAemia in the HR patients (6 to <12 months vs <6 months, P = 0.62; 6 to <12 months vs ≥12 months, P = 0.78; ≥12 months vs <6 months, P = 0.83). This study identifies no optimal length of prophylaxis for HR mismatch pediatric renal transplant patients as many develop CMV DNAemia.

Infection-related hospitalizations after kidney transplantation in children: incidence, risk factors, and cost

BACKGROUND

Infection is the leading cause of death and hospitalization in renal transplant recipients. We describe posttransplant infections requiring hospitalization, their risk factors and cost in a national pediatric kidney transplantation cohort.

METHODS

Data on renal transplant recipients <20 years were extracted from the French National Medicoadministrative Hospital Discharge database between 2008 and 2013 and matched with the Renal Transplant Database. We used Cox regression to study risk factors of hospitalization and calculated the instantaneous risk of hospitalization per month for all infections and by infection type.

RESULTS

Five hundred and ninety-three patients were included, and 660 infection-related hospitalizations were identified in 260 patients. The leading cause of hospitalization was urinary tract infection (UTI), followed by viral infection (16.6 and 15.6 per 100 person-years, respectively). Risk factors were younger age at transplantation, high number of HLA mismatches, and use cyclosporine rather than tacrolimus as first anticalcineurin treatment. Risk factors varied by infection type. Female gender, uropathy, cold ischemia time, and cyclosporine were associated with increased risk of UTI, while only age at transplantation inversely correlated with virus-related hospitalizations. Instantaneous risk of all infections decreased with time, except for cytomegalovirus (CMV) infection that displayed a peak at 6 months posttransplantation after prophylaxis withdrawal. Total cost of infection-related hospitalizations was 1600 kilo-euro (k€) (933 €/person-years).

CONCLUSIONS

This study highlights the high burden of infection in transplanted pediatric patients, especially the youngest. This should be considered both for pretransplantation information and designing procedures aiming to decrease hospitalization rate and duration.