Cytomegalovirus (CMV) infection is arguably the most important infectious complication that negatively affects the outcome of solid organ transplantation. For decades, CMV management after transplantation has relied on antiviral drugs that inhibit viral DNA polymerase (ganciclovir, foscarnet, and cidofovir). However, their use has been complicated by myelosuppression, nephrotoxicity, and selection of drug-resistant viruses. During the past few years, the therapeutic armamentarium for the management of CMV in solid organ transplant recipients has expanded with the approval of letermovir for CMV prophylaxis in high-risk CMV D+/R- kidney recipients, and maribavir for the treatment of refractory and resistant CMV infection. Both drugs offer significant improvement when compared to standard anti-CMV therapies; letermovir was as efficacious for CMV prevention, whereas maribavir was more effective in treating refractory and resistant CMV infections. Both letermovir and maribavir have favorable safety profiles compared to CMV DNA polymerase inhibitors, without the risk of neutropenia and leukopenia associated with ganciclovir and renal toxicities associated with foscarnet and cidofovir. Moreover, letermovir and maribavir are orally bioavailable, which allows convenient outpatient treatment. However, letermovir and maribavir have a significant drug interaction potential in solid organ transplant recipients, resulting in higher levels of calcineurin inhibitors (cyclosporine and tacrolimus) and mTOR inhibitors (sirolimus and everolimus). Both letermovir and maribavir are CMV-specific and do not have clinical efficacy against other herpes viruses. Thus, there is a need for additional antiviral drugs to prevent herpes simplex and other herpes viruses when clinically indicated. This article provides a comprehensive review of the clinical data supporting the use of letermovir and maribavir in clinical practice. The author provides perspectives on the role of these newly approved drugs in the current management landscape of CMV infection in solid organ transplantation.

OBJECTIVE: Evaluate cytomegalovirus (CMV) post-prophylaxis surveillance in high-risk (D+/R-) kidney and liver transplant recipients.
METHODS: Adult D+/R- patients were included if transplanted between 6/1/15 and 11/30/22 and divided into a pre-CMV-stewardship-era (6/1/15-5/31/18), CMV-stewardship-era (6/1/18-6/30/20), and a surveillance-era (7/1/2020-11/30/2022) then followed through 12 months. The primary objective was to evaluate CMV-related outcomes. The secondary objective was to assess graft and patient survival by era.
RESULTS: There were 328 patients in the study period; 133 in the pre-stewardship-era, 103 in the stewardship-era, and 92 in the surveillance-era. Replication rates in the surveillance-era were significantly higher, as anticipated due to increased sampling (pre 38.4%, stewardship 33.0%, surveillance 52.2%, p = 0.02). Time from transplant to first replication was similar (pre 214.0 ± 79.0 days, stewardship 231.1 ± 65.5, surveillance 234.9 ± 61.4, p = 0.29). CMV viral load (VL) at first detection, maximum-VL, and incidence of VL > 100 000 IU/mL were numerically lower in the surveillance era, although not statistically significant. CMV end-organ disease (p < 0.0001) and ganciclovir-resistance (p = 0.002) were significantly lower in the surveillance era than in both previous eras. Rejection was not different between eras (p = 0.4). Graft (p = 0.0007) and patient survival (p = 0.008) were significantly improved in the surveillance era.
CONCLUSIONS: Post-prophylaxis surveillance significantly reduced CMV end-organ disease and resistance. Despite observing increased replication rates in the surveillance era, rejection was not significantly different and there was no graft loss or patient mortality at 12 months.

Cytomegalovirus (CMV) retinitis is a rare disease, and overlapping manifestations involving the anterior segment are extremely uncommon. We report a patient who initially presented with persistent corneal edema and was later diagnosed with CMV retinitis. A 72-year-old man with uncontrolled intraocular pressure (IOP) in his right eye visited a tertiary hospital. At initial presentation, the IOP was 36 mmHg and the fundus was not clear due to corneal edema. Spectral domain optical coherence tomography revealed paracentral acute middle maculopathy (PAMM). Panretinal obstructive vasculopathy was observed on ultra-widefield fluorescein angiography. Three weeks later, trabeculectomy was performed to resolve the persistently high IOP. Once corneal edema improved, a white patch-like peripheral lesion and silver wire-like retinal vasculature were observed. Polymerase chain reaction of the aqueous humor was positive for CMV. Oral valganciclovir and intravitreal ganciclovir were administered as antiviral therapies. Despite treatment for 4 months, the final visual acuity was no light perception, with persistent corneal edema and neovascularization of the iris. We describe a rare case of the simultaneous occurrence of hypertensive uveitis and CMV retinitis. The presence of PAMM could be an initial identifiable sign of CMV retinitis, even in the presence of media opacity.

Ganciclovir (GCV) and its prodrug valganciclovir (VGCV) are antiviral medications primarily used to treat infections caused by cytomegalovirus (CMV), particularly in immunocompromised individuals such as solid organ transplant (SOT) recipients. Therapy with GCV is associated with significant side effects, including bone marrow suppression. Therefore, therapeutic drug monitoring (TDM) is mandatory for an appropriate balance between subtherapeutic and toxic drug levels. This study aimed to develop and validate three novel methods based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for GCV determination in serum (reference methodology), dried serum spots (DSS), and VAMS-Mitra™ devices. The methods were optimized and validated in the 0.1-25 mg/L calibration range. The obtained results fulfilled the EMA acceptance criteria for bioanalytical method validation. Assessment of DSS and VAMS techniques extended GCV stability to serum for up to a minimum of 49 days (at room temperature, with desiccant). Developed methods were effectively evaluated using 80 clinical serum samples from pediatric renal transplant recipients. Obtained samples were used for DSS, and dried serum VAMS samples were manually generated in the laboratory. The results of GCV determination using serum-, DSS- and VAMS-LC-MS/MS methods were compared using regression analysis and bias evaluation. The conducted statistical analysis confirmed the interchangeability between developed assays. The DSS and VAMS samples are more accessible and stable during storage, transport and shipment than classic serum samples.

Intravenous ganciclovir and oral valganciclovir display significant variability in ganciclovir pharmacokinetics, particularly in children. Therapeutic drug monitoring currently relies on the area under the concentration-time (AUC). Machine-learning (ML) algorithms represent an interesting alternative to Maximum-a-Posteriori Bayesian-estimators for AUC estimation. The goal of our study was to develop and validate an ML-based limited sampling strategy (LSS) approach to determine ganciclovir AUC0-24 after administration of either intravenous ganciclovir or oral valganciclovir in children. Pharmacokinetic parameters from four published population pharmacokinetic models, in addition to the World Health Organization growth curve for children, were used in the mrgsolve R package to simulate 10,800 pharmacokinetic profiles of children. Different ML algorithms were trained to predict AUC0-24 based on different combinations of two or three samples. Performances were evaluated in a simulated test set and in an external data set of real patients. The best estimation performances in the test set were obtained with the Xgboost algorithm using a 2 and 6 hours post dose LSS for oral valganciclovir (relative mean prediction error [rMPE] = 0.4% and relative root mean square error [rRMSE] = 5.7%) and 0 and 2 hours post dose LSS for intravenous ganciclovir (rMPE = 0.9% and rRMSE = 12.4%). In the external data set, the performance based on these two sample LSS was acceptable: rMPE = 0.2% and rRMSE = 16.5% for valganciclovir and rMPE = -9.7% and rRMSE = 17.2% for intravenous ganciclovir. The Xgboost algorithm developed resulted in a clinically relevant individual estimation using only two blood samples. This will improve the implementation of AUC-targeted ganciclovir therapeutic drug monitoring in children.

The prevention and treatment of many herpesvirus associated diseases is based on the utilization of antiviral therapies, however therapeutic success is limited by the development of drug resistance. Currently no single database cataloguing resistance mutations exists, which hampers the use of sequence data for patient management. We therefore developed HerpesDRG, a drug resistance mutation database that incorporates all the known resistance genes and current treatment options, built from a systematic review of available genotype to phenotype literature. The database is released along with an R package that provides a simple approach to resistance variant annotation and clinical implication analysis from common sanger and next generation sequencing data. This represents the first openly available and community maintainable database of drug resistance mutations for the human herpesviruses (HHV), developed for the community of researchers and clinicians tackling HHV drug resistance.

Ganciclovir, a guanine analogue, is used intravenously (IV) first-line for the prophylaxis and treatment of cytomegalovirus (CMV) infection in solid organ transplant recipients. The pharmacokinetics (PK) of ganciclovir are highly variable, with myelosuppression occurring at high concentrations. Ganciclovir is primarily renally excreted as the parent compound, and clearance is significantly reduced in renal impairment. Acute kidney injury (AKI) is a common post-operative complication of cardiac transplantation, reducing the clearance of ganciclovir. In the intensive care unit (ICU), AKI is often managed by kidney replacement therapy (KRT). One form of KRT, prolonged intermittent kidney replacement therapy (PIKRT) is increasingly used for cost and flexibility advantages. Ganciclovir dosing recommendations are available for varying degrees of renal impairment and KRT, except for PIKRT. In this case of cardiac transplantation, complicated by anuric AKI, a ganciclovir dose of 2.0-2.5 mg/kg of adjusted body weight given after each PIKRT session was demonstrated to achieve PK targets.

OBJECTIVE: The mortality rate for alimentary tract hemorrhage remains high due to a variety of contributing factors. In this report, we present a case of post-severe trauma patient with life-threatening gastrointestinal bleeding caused by cytomegalovirus (CMV)-induced damage to the terminal ileum.
METHODS: A 76-year-old female with a history of hypertension and gastrointestinal bleeding developed CMV ileitis post-severe trauma. Despite negative CMV IgM antibodies, PCR testing confirmed CMV infection in the biopsy tissue. Histopathological examination revealed viral inclusion bodies, with immunohistochemistry confirming CMV presence.
RESULTS: Intravenous ganciclovir effectively managed symptoms and halted bleeding. CMV ileitis, typically seen in immunocompromised states, may occur sporadically in immunocompetent individuals, including post-orthopedic surgery patients. The exact mechanism remains unclear, possibly related to surgical stress. Diagnosis relies on histopathology and immunohistochemistry.
CONCLUSIONS: Early recognition and treatment are vital for optimal outcomes, emphasizing the need for awareness among orthopedic surgeons regarding CMV as a potential cause of postoperative complications.

UNASSIGNED: Patients with biliary atresia (BA) and ongoing cytomegalovirus (CMV) infection may have poorer outcomes after Kasai portoenterostomy than uninfected patients. Still, there is no consensus on the usefulness of viral testing and antiviral treatment (AVT). This study aims to explore the need for future research on AVT for CMV infection by assessing how CMV infection in BA patients is managed in different centers.
UNASSIGNED: An online questionnaire with 10 questions was offered to participants at an international congress on BA, organized in collaboration with the European Reference Network for rare liver diseases in 2022. Answers to questions were either dichotomic or multiple choices of different numeric intervals. Ongoing CMV infection was defined by detecting cytomegalovirus-immunoglobulin M (CMV-IgM) in serum or cytomegalovirus-deoxyribonucleic acid (CMV-DNA) by polymerase chain reaction in blood or urine.
UNASSIGNED: There were 43 respondents from 36 centers in 26 countries. The total number of BA patients per year was between 208 and 380 from centers with 0-5 to >20 BA patients yearly (median 6-10). CMV infection was tested in 27 centers (75%), of which 18 (67%) use AVT. The rate of CMV infection varied between 0%-5% and 40%-50% (median 5%-10%). Willingness to treat the infection did not differ between centers with low and high rates of CMV infection.
UNASSIGNED: Most centers test for CMV infection, and a considerable proportion use AVT despite the lack of evidence of its benefits. A future randomized study on treating CMV infection in BA patients is necessary and feasible.

Purpose: To assess the long-term safety and clinical outcomes of a ganciclovir intravitreal implant in patients with cytomegalovirus (CMV) retinitis. Methods: A retrospective study was performed of patients with CMV retinitis treated with a ganciclovir intravitreal implant. Results: The study included 13 patients (16 eyes) previously treated with a ganciclovir intravitreal implant. The mean time since the last implant placement was 21.3 years and the mean total duration of follow-up, 22.7 years. Visual acuity (VA) ranged from 20/25 to light perception, with 56% of eyes maintaining a VA of 20/60 or better at the most recent follow-up examination. Common ocular complications included epiretinal membrane (38%), macular fibrosis/scarring (25%), retinal detachment (RD) (25%), implant dislocation (25%), and immune reactivation uveitis (19%). Intraocular surgery was required in 10 eyes (63%), with the most frequent being cataract extraction (31%), pars plana vitrectomy (PPV) for implant removal (19%), and PPV for RD (13%). Conclusions: Results show the long-term safety of the ganciclovir intravitreal implant despite its residual inactive inert shell. Complication rates are consistent with those expected from infectious sequelae.