Antiviral medications for preventing cytomegalovirus disease in solid organ transplant recipients.

BACKGROUND: The risk of cytomegalovirus (CMV) infection in solid organ transplant recipients has resulted in the frequent use of prophylaxis to prevent the clinical syndrome associated with CMV infection. This is an update of a review first published in 2005 and updated in 2008 and 2013. OBJECTIVES: To determine the benefits and harms of antiviral medications to prevent CMV disease and all-cause death in solid organ transplant recipients. SEARCH METHODS: We contacted the information specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 5 February 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs comparing antiviral medications with placebo or no treatment, comparing different antiviral medications or different regimens of the same antiviral medications for CMV prophylaxis in recipients of any solid organ transplant. Studies examining pre-emptive therapy for CMV infection are studied in a separate review and were excluded from this review. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study eligibility, risk of bias and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: This 2024 update found four new studies, bringing the total number of included studies to 41 (5054 participants). The risk of bias was high or unclear across most studies, with a low risk of bias for sequence generation (12), allocation concealment (12), blinding (11) and selective outcome reporting (9) in fewer studies. There is high-certainty evidence that prophylaxis with aciclovir, ganciclovir or valaciclovir compared with placebo or no treatment is more effective in preventing CMV disease (19 studies: RR 0.42, 95% CI 0.34 to 0.52), all-cause death (17 studies: RR 0.63, 95% CI 0.43 to 0.92), and CMV infection (17 studies: RR 0.61, 95% CI 0.48 to 0.77). There is moderate-certainty evidence that prophylaxis probably reduces death from CMV disease (7 studies: RR 0.26, 95% CI 0.08 to 0.78). Prophylaxis reduces the risk of herpes simplex and herpes zoster disease, bacterial and protozoal infections but probably makes little to no difference to fungal infection, acute rejection or graft loss. No apparent differences in adverse events with aciclovir, ganciclovir or valaciclovir compared with placebo or no treatment were found. There is high certainty evidence that ganciclovir, when compared with aciclovir, is more effective in preventing CMV disease (7 studies: RR 0.37, 95% CI 0.23 to 0.60). There may be little to no difference in any outcome between valganciclovir and IV ganciclovir compared with oral ganciclovir (low certainty evidence). The efficacy and adverse effects of valganciclovir or ganciclovir were probably no different to valaciclovir in three studies (moderate certainty evidence). There is moderate certainty evidence that extended duration prophylaxis probably reduces the risk of CMV disease compared with three months of therapy (2 studies: RR 0.20, 95% CI 0.12 to 0.35), with probably little to no difference in rates of adverse events. Low certainty evidence suggests that 450 mg/day valganciclovir compared with 900 mg/day valganciclovir results in little to no difference in all-cause death, CMV infection, acute rejection, and graft loss (no information on adverse events). Maribavir may increase CMV infection compared with ganciclovir (1 study: RR 1.34, 95% CI: 1.10 to 1.65; moderate certainty evidence); however, little to no difference between the two treatments were found for CMV disease, all-cause death, acute rejection, and adverse events at six months (low certainty evidence). AUTHORS' CONCLUSIONS: Prophylaxis with antiviral medications reduces CMV disease and CMV-associated death, compared with placebo or no treatment, in solid organ transplant recipients. These data support the continued routine use of antiviral prophylaxis in CMV-positive recipients and CMV-negative recipients of CMV-positive organ transplants.

Congenital and Postnatal Cytomegalovirus: Case Series and State of the Science for Neonatal Providers.

Cytomegalovirus (CMV), a beta-herpes virus, is the most common viral infection in infants. Transmission may occur congenitally (cCMV) or postnatally (pCMV). Early detection and intervention are crucial in reducing morbidities, notable developmental delays, and sensorineural hearing loss. However, more than 90% of infants are asymptomatic at birth. Treatment involves intravenous ganciclovir or the oral prodrug, valganciclovir, drugs usually reserved for use with symptomatic infants because of the toxicity profile. Research currently supports standardized antenatal CMV screening and treatment of affected pregnant patients with hyperimmune globulin as well as vaccination against CMV in unaffected pregnant patients, although widespread adoption is lacking. Standardized postnatal CMV screening is a proven, cost-effective way to detect and diagnose CMV and optimize outcomes across the lifespan. This article presents a case series of cCMV and pCMV and a review of the state of science of CMV as well as promising scientific advances that are on the horizon.

Cytomegalovirus colitis as intestinal obstruction in an immunocompetent adolescent: a case report and literature review.

BACKGROUND: Cytomegalovirus infection manifests varying clinical characteristics and severity in diverse populations with different immune statuses. The signs and symptoms of gastrointestinal involvement are nonspecific. Here, we present a case of cytomegalovirus colitis in an immunocompetent adolescent, which manifested as intestinal pseud-obstruction. CASE PRESENTATION: A 15-year-old man who had contracted novel coronavirus infection one month earlier was admitted to our hospital with fever, abdominal pain, and hematochezia. His abdomen was distended, and laboratory evaluation revealed a decrease in the blood count, an increase in inflammatory indicators and hepatic impairment. Imaging shows bowel wall thickening and dilatation of the colon. A diagnosis of intestinal infection combined with acute intestinal pseud-obstruction was made. Diarrhea persisted despite conservative treatment with empirical antibiotics. A colonoscopy was performed. Pathology confirmed cytomegalovirus infection. Ganciclovir therapy was initiated, and subsequent review showed a good recovery. CONCLUSIONS: The case was diagnosed as cytomegalovirus colitis. We reviewed the reports of 9 cases of bowel obstruction, including our own, and found that the majority of the adult patients were elderly with underlying disease. Clinical and endoscopic manifestations are typically nonspecific, and imaging shows typical signs of intestinal obstruction. The final diagnosis was confirmed by pathology. Most of them have a good prognosis. We suggest that cytomegalovirus colitis can also lead to intestinal obstruction and that viral reactivation in immunocompetent individuals may be associated with inflammatory conditions and viral coinfection, particularly with the novel coronavirus.

Acute primary CMV infection complicated by pneumonitis and ITP in young immunocompetent woman in a regional Queensland Hospital.

We present the first published case of simultaneous pneumonitis and immune thrombocytopenic purpura secondary to primary cytomegalovirus (CMV) infection in an immunocompetent patient. Treatment with oral valganciclovir for 2 weeks successfully led to complete clinical recovery. CMV is traditionally associated with infection in immunocompromised patients and neonates; however, evidence of severe CMV infections in immunocompetent hosts is emerging. It is important to highlight the broad range of clinical presentations of CMV infections to prevent diagnostic delay and associated morbidity and expense.

The complete Kaposi sarcoma-associated herpesvirus genome induces early-onset, metastatic angiosarcoma in transgenic mice.

Kaposi sarcoma (KS) is the most common cancer in persons living with HIV. It is caused by KS-associated herpesvirus (KSHV). There exists no animal model for KS. Pronuclear injection of the 170,000-bp viral genome induces early-onset, aggressive angiosarcoma in transgenic mice. The tumors are histopathologically indistinguishable from human KS. As in human KS, all tumor cells express the viral latency-associated nuclear antigen (LANA). The tumors transcribe most viral genes, whereas endothelial cells in other organs only transcribe the viral latent genes. The tumor cells are of endothelial lineage and exhibit the same molecular pattern of pathway activation as KS, namely phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR, interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF). The KSHV-induced tumors are more aggressive than Ha-ras-induced angiosarcomas. Overall survival is increased by prophylactic ganciclovir. Thus, whole-virus KSHV-transgenic mice represent an accurate model for KS and open the door for the genetic dissection of KS pathogenesis and evaluation of therapies, including vaccines.

Combination of ganciclovir and trifluridine prevents drug-resistance emergence in HSV-1.

Ocular herpes simplex virus 1 (HSV-1) infections can lead to visual impairment. Long-term acyclovir (ACV) prophylaxis reduces the frequency of recurrences but is associated with drug resistance. Novel therapies are needed to treat drug-resistant HSV-1 infections. Here, we describe the effects of trifluridine (TFT) in combination with ACV or ganciclovir (GCV) on HSV-1 replication and drug-resistance emergence. Wild-type HSV-1 was grown under increasing doses of one antiviral (ACV, GCV, or TFT) or combinations thereof (ACV + TFT or GCV + TFT). Virus cultures were analyzed by Sanger sequencing and deep sequencing of the UL23 [thymidine kinase (TK)] and UL30 [DNA polymerase (DP)] genes. The phenotypes of novel mutations were determined by cytopathic effect reduction assays. TFT showed overall additive anti-HSV-1 activity with ACV and GCV. Five passages under ACV, GCV, or TFT drug pressure gave rise to resistance mutations, primarily in the TK. ACV + TFT and GCV + TFT combinatory pressure induced mutations in the TK and DP. The DP mutations were mainly located in terminal regions, outside segments that typically carry resistance mutations. TK mutations (R163H, A167T, and M231I) conferring resistance to all three nucleoside analogs (ACV, TFT, and GCV) emerged under ACV, TFT, ACV + TFT pressure and under GCV + TFT pressure initiated from suboptimal drug concentrations. However, higher doses of GCV and TFT prevented drug resistance in the resistance selection experiments. In summary, we identified novel mutations conferring resistance to nucleoside analogs, including TFT, and proposed that GCV + TFT combination therapy may be an effective strategy to prevent the development of drug resistance.

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.

Development and Validation of an HPLC-UV Method for the Quantification of Acyclovir and Ganciclovir in the Plasma of Pediatric Immunocompromised Patients.

Acyclovir and ganciclovir comprise the prophylaxis and treatment of herpesvirus and cytomegalovirus infections occurring in immunocompromised patients. Their therapeutic drug monitoring is fundamental because of interindividual variability leading to side effects and drug resistance and is performed through several techniques, such as liquid chromatography coupled with UV spectrophotometry (HPLC-UV) or mass spectrometry (LC-MS/MS). Therefore, we developed and validated a low-cost, non-time-consuming, and low-sample-consuming HPLC-UV method. Briefly, 100 µL of sample was used for sample preparation, mainly consisting of precipitation through organic solvent. In total, 20 µL was injected into the instrument. Chromatographic separation was obtained eluting mobile phases A (10 mM ammonium formiate 0.01% formic acid) and B (acetonitrile) on a Poroshell 120 SB-C8 2.1 × 150 mm, 2.7 µm for 12 min isocratically (97:3; A:B) at a flow rate of 0.2 mL/min. The linearity range (0.5-40 mg/L) of the method allowed us to quantify both the Cmin and Cmax of acyclovir and ganciclovir. Plasma concentrations measured on a small cohort of patients undergoing acyclovir (31) and ganciclovir (9) treatment by the proposed method and the LC-MS/MS methods, already in use, were significantly correlated. The proposed HPLC-UV method may be implemented in diagnostics as an alternative method in case of the unavailability of the LC-MS/MS system.

Folate-Targeted Nanocarriers Co-Deliver Ganciclovir and miR-34a-5p for Combined Anti-KSHV Therapy.

Kaposi's sarcoma-associated herpesvirus (KSHV) can cause a variety of malignancies. Ganciclovir (GCV) is one of the most efficient drugs against KSHV, but its non-specificity can cause other side effects in patients. Nucleic acid miR-34a-5p can inhibit the transcription of KSHV RNA and has great potential in anti-KSHV therapy, but there are still problems such as easy degradation and low delivery efficiency. Here, we constructed a co-loaded dual-drug nanocomplex (GCV@ZIF-8/PEI-FA+miR-34a-5p) that contains GCV internally and adsorbs miR-34a-5p externally. The folic acid (FA)-coupled polyethyleneimine (PEI) coating layer (PEI-FA) was shown to increase the cellular uptake of the nanocomplex, which is conducive to the enrichment of drugs at the KSHV infection site. GCV and miR-34a-5p are released at the site of the KSHV infection through the acid hydrolysis characteristics of ZIF-8 and the "proton sponge effect" of PEI. The co-loaded dual-drug nanocomplex not only inhibits the proliferation and migration of KSHV-positive cells but also decreases the mRNA expression level of KSHV lytic and latent genes. In conclusion, this co-loaded dual-drug nanocomplex may provide an attractive strategy for antiviral drug delivery and anti-KSHV therapy.

Valganciclovir in Infants with Hearing Loss and Clinically Inapparent Congenital Cytomegalovirus Infection: A Nonrandomized Controlled Trial.

OBJECTIVE: To assess the efficacy of valganciclovir in infants with hearing loss and clinically inapparent congenital cytomegalovirus infection (cCMV), as there is no consensus on treatment of this group. STUDY DESIGN: A nationwide, nonrandomized controlled trial, comparing 6 weeks of oral valganciclovir to no treatment in infants with cCMV, recruited after newborn hearing screening resulted in referral to an audiologist. The choice whether to treat was left to parents of subjects. Eligible subjects were full term infants aged <13 weeks with sensorineural hearing loss and diagnosed with cCMV through dried blood spot testing. The primary outcome, measured by linear and ordinal logistic regression, was change in best-ear hearing from baseline to follow-up at 18-22 months of age. RESULTS: Thirty-seven participants were included in the final analysis, of whom 25 were in the treatment group and 12 in the control group. The majority of subjects in both groups had neuroimaging abnormalities, which were mostly mild. Hearing deterioration was more likely in the control group compared with the treatment group (common OR 0.10, 95% CI 0.02-0.45, P = .003). Mean best-ear hearing deteriorated by 13.7 dB in the control group, compared with improvement of 3.3 dB in the treatment group (difference 17 dB, 95% CI 2.6 - 31.4, P = .02). CONCLUSIONS: We investigated treatment in children with hearing loss and clinically inapparent cCMV. Although our study was nonrandomized, it is the first prospective and controlled trial in this population. Valganciclovir-treated children with hearing loss and inapparent cCMV had less hearing deterioration at 18 through 22 months of age than control subjects. EUDRACT REGISTRY NUMBER: 2013-003068-30.

Resource Use and Financial Impact of Oral Step-Down Therapy for Resistant Cytomegalovirus in Solid Organ Transplant Recipients.

BACKGROUND: Cytomegalovirus (CMV) infections are common opportunistic infections in solid organ transplants (SOT) with increased health care resource USE and costs. Costs are further increased with ganciclovir-resistance (GR). This study aimed to evaluate the real-world impact of conversion to oral step-down therapy on duration of foscarnet and hospital length of stay (LOS) for treatment of GR-CMV infections in SOT. METHODS: This study included adult recipients of kidney or lung transplants who received foscarnet for genotypically documented GR-CMV while admitted at the University of Wisconsin Hospital from October 1, 2015, to January 31, 2022. Patients in the oral step-down group were converted from standard of care (SOC; foscarnet) to maribavir or letermovir; patients in the historical control group were treated with SOC. RESULTS: Twenty-six patients met the inclusion criteria: 5 in the intervention group and 21 in the SOC group. The median viral load at foscarnet initiation was 11,435 IU/mL. Patients who received oral step-down conversion had shorter mean foscarnet duration than those who received SOC (7 ± 4 vs 37 ± 25 days, P = .017). Mean hospital LOS in the oral step-down group (16 ± 3 days) was shorter than the SOC group (33 ± 21 days; P < .001). In the SOC group, 9 patients lost their graft, and 9 patients died; 2 deaths were attributed to CMV. There were 2 deaths in the oral step-down group, neither of which was attributed to CMV. CONCLUSION AND RELEVANCE: In this real-world case series of patients receiving treatment for GR-CMV infection, oral step-down conversion decreased foscarnet therapy duration and hospital LOS. Future studies are needed to evaluate better the effect of oral step-down in treating GR-CMV infection on treatment duration and cost-savings.

Cytomegalovirus Pneumonia in a Patient with Down Syndrome.

Down syndrome (DS) is a chromosomal disorder due to the presence of an additional chromosome 21 that causes intellectual deficit and physical anomalies and predisposes patients to develop infections throughout their lives. Pneumonias are more serious in patients with DS, requiring hospitalization, and they represent an important cause of mortality in this population. Cytomegalovirus (CMV) causes widespread and serious infections in immunocompromised individuals, affecting the respiratory tract and, when causing interstitial pneumonia, associated with a high mortality rate. However, CMV-induced pneumonia is not reported in DS patients. The prevalence and severity of CMV respiratory infections in subjects with DS is unknown. This case describes a 50-year-old female patient with DS who developed extensive bilateral pneumonia with severe respiratory failure which required hospitalization in intensive care, intubation, and mechanical ventilation after approximately 10 days of empiric antibiotic and anitimycotic therapy for fever, cough, and dyspnea. The patient was diagnosed with CMV pneumonia and recovered after treatment with ganciclovir. To the best of our knowledge, this is the first reported case of CMV pneumonia in a patient with DS. This case aims to highlight that CMV pneumonia in individuals with DS can be a life-threatening condition. It also clarifies the importance of early diagnosis of infections from opportunistic pathogens such as CMV to ensure timely and efficient treatment.

Evaluation of valganciclovir's neutropenia risk in pediatric solid organ transplant recipients utilizing two dosing regimens.

BACKGROUND: Valganciclovir is approved for cytomegalovirus prophylaxis in pediatrics using the Pescovitz algorithm. There are reports of valganciclovir overdoses in children with low body surface area and overestimated creatinine clearance utilizing this algorithm. This study compared the incidence of neutropenia and cytomegalovirus infection between the Pescovitz and weight-based dosing algorithms. METHODS: A single-center retrospective chart review from January 2010 to September 2018 was performed on pediatric heart, liver, and kidney transplant recipients, who received valganciclovir. Data were collected from the initiation of valganciclovir prophylaxis to 30 days after discontinuation. The primary objective was the incidence of neutropenia in patients receiving valganciclovir dosed by the Pescovitz versus weight-based dosing algorithms. RESULTS: This study included 187 pediatric transplant recipients who received valganciclovir dosed via the Pescovitz (62 recipients) or weight-based dosing algorithms (125 recipients). The incidence of neutropenia was higher in the Pescovitz (69.4%) compared to the weight-based dosing group (53.6%; p = .04) including moderate and severe neutropenia. Cytomegalovirus viremia was not significantly different between the two groups and occurred in 4.8% of the Pescovitz group compared to 2.4% of the weight-based group (p = .4). CONCLUSIONS: The incidence of neutropenia was greater in recipients receiving valganciclovir dosed via the Pescovitz algorithm compared to the weight-based dosing. There were no significant differences in regard to cytomegalovirus viremia or disease between the two groups.

Oral Valganciclovir Initiated Beyond 1 Month of Age as Treatment of Sensorineural Hearing Loss Caused by Congenital Cytomegalovirus Infection: A Randomized Clinical Trial.

OBJECTIVE: The objective of this study was to determine if valganciclovir initiated after 1 month of age improves congenital cytomegalovirus-associated sensorineural hearing loss. STUDY DESIGN: We conducted a randomized, double-blind, placebo-controlled phase 2 trial of 6 weeks of oral valganciclovir at US (n = 12) and UK (n = 9) sites. Patients of ages 1 month through 3 years with baseline sensorineural hearing loss were enrolled. The primary outcome was change in total ear hearing between baseline and study month 6. Secondary outcome measures included change in best ear hearing and reduction in cytomegalovirus viral load in blood, saliva, and urine. RESULTS: Of 54 participants enrolled, 35 were documented to have congenital cytomegalovirus infection and were randomized (active group: 17; placebo group: 18). Mean age at enrollment was 17.8 ± 15.8 months (valganciclovir) vs 19.5 ± 13.1 months (placebo). Twenty (76.9%) of the 26 ears from subjects in the active treatment group did not have worsening of hearing, compared with 27 (96.4%) of 28 ears from subjects in the placebo group (P = .09). All other comparisons of total ear or best ear hearing outcomes were also not statistically significant. Saliva and urine viral loads decreased significantly in the valganciclovir group but did not correlate with change in hearing outcome. CONCLUSIONS: In this randomized controlled trial, initiation of antiviral therapy beyond the first month of age did not improve hearing outcomes in children with congenital cytomegalovirus-associated sensorineural hearing loss. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01649869.

Low-Dose vs Standard-Dose Valganciclovir for Cytomegalovirus Prophylaxis After Kidney Transplantation: A Single-Center Retrospective Analysis.

BACKGROUND: Prophylactic administration of valganciclovir (VG) is an accepted method for the prevention of cytomegalovirus (CMV) infection after kidney transplantation (KTx). The standard dosage of oral VG is 900 mg/day, adjusted to renal function. There is growing evidence that low-dose 450 mg/day VG might be safe and effective. We compared low-dose vs standard-dose prophylaxis after KTx in a single-center follow-up study. METHODS: Data from 603 renal transplantations at a single center were retrospectively analyzed (2011-2014, 12-month follow-up). Recipients with donor IgG positive-recipient IgG positive (D+/R+), (D+/R-), and (D-/R+) CMV serostatus were routinely treated with 450 mg/day VG for 3 months. Based on the same prophylactic dose, patients could be categorized into two groups according to their postoperative renal function: those receiving standard-dose VG due to a lower estimated glomerular filtration rate (eGFR) (average eGFR<60 mL/min/1.73 m2) and those receiving low-dose VG due to higher eGFR (average eGFR>60 mL/min/1.73 m2). RESULTS: Estimated glomerular filtration rate-based VG serum alterations significantly affected the risk of CMV infection with a higher incidence in higher VG levels (standard-dose: 357 patients, CMV: 33 cases (9.2 %); low-dose: 246 patients, CMV: 10 cases (4.1%). The occurrence of known risk factors: serologic risk distribution and rate of induction therapy were not statistically different between the 2 groups. Treatment of an acute rejection episode influenced the infection rate significantly in the standard-dose group. As a side effect of prophylaxis, leucopenia (<3G/L) was 2.46 times higher in standard-dose vs low-dose group. CONCLUSION: Low-dose VG administration is safe and non-inferior to the standard dose in the prophylaxis of CMV infection after KTx.

Ganciclovir and maribavir cross-resistance revisited: Relative drug susceptibilities of canonical cytomegalovirus mutants.

Therapeutic use of maribavir for human cytomegalovirus infection has renewed attention to the extent of cross-resistance with ganciclovir as the existing standard therapy. Each drug selects in vivo for a characteristic set of resistance mutations in the viral UL97 kinase gene. To improve the calibration of relative susceptibilities to each drug, genetic variants at relevant UL97 codons were extensively phenotyped using the same baseline viral clone, cell culture conditions and growth readout. Ganciclovir-selected mutations at codons 460, 520, 592, 594, 595 and 603 conferred 2.8-fold (C603Y) to 12-fold (M460I) increases in ganciclovir 50% inhibitory concentrations (EC50) over wild type baseline, while conferring maribavir EC50 fold changes ranging from 0.21-fold (M460I) to 1.9-fold (A594V). Maribavir-selected mutations at codons 409, 411 and 480 conferred maribavir EC50 fold changes ranging from 17 (H411Y) to 210 (C480F), while conferring ganciclovir EC50 fold changes ranging from 0.7 (H411Y) to 2.3 (C480F). The P-loop substitution F342Y, selected by either drug, is confirmed to confer 4.7-fold and 6-fold increases in maribavir and ganciclovir EC50s respectively, and suggests this part of the ATP-binding domain of UL97 to be involved in moderate resistance to both drugs. The maribavir hypersensitivity of M460I and M460V may be advantageous.

Incidence of valganciclovir-related leukopenia and neutropenia in solid organ transplant recipients at high risk of cytomegalovirus disease.

BACKGROUND: Valganciclovir (VGCV) prophylaxis is associated with an increased risk of hematologic side effects. We analyzed the impact of VGCV prophylaxis on leukopenia and neutropenia rates and explored risk factors for its occurrence. METHODS: Retrospective cohort study of adult cytomegalovirus (CMV)-seronegative solid organ transplantation (SOT) recipients of either CMV-seropositive (CMV D+/R-) or CMV-seronegative (CMV D-/R-) donors between July 2005 and March 2019. CMV D+/R- SOT recipients received 3-12 months of VGCV prophylaxis whereas CMV D-/R- SOT recipients received no VGCV prophylaxis. Competing risk regression was used to calculate risk factors for significant neutropenia (neutrophil count < 1000/µL). RESULTS: A total of 430 CMV-seronegative SOT recipients (median age of 52.1 years, 76.5% males) were included, of which 203 (47.2%) were CMV D+/R- and 227 (52.8%) CMV D-/R-. The unadjusted incidence rate ratio of significant neutropenia attributable to VGCV exposure in the first year post-transplant was 13.50 (95% confidence interval 7.36-27.11). Acute rejection occurred more frequently in neutropenic patients at 32.5% compared to 19.1% in those without neutropenia (p = .033). On multivariate analysis, VGCV prophylaxis for 1-90 days and 91-180 days versus no VGCV were the strongest risk factors for significant neutropenia with a sub-distribution hazard ratio of 39.6 (95% CI, 8.57-182.6) and 13.2 (95% CI, 5.46-32.0), respectively. CONCLUSIONS: VGCV prophylaxis is limited by high rates of neutropenia. Future prospective studies are needed to assess alternative CMV prophylactic strategies in SOT recipients.

Cytomegalovirus related hospitalization costs among hematopoietic stem cell and solid organ transplant recipients treated with maribavir versus investigator-assigned therapy: A US-based study.

BACKGROUND: Cytomegalovirus (CMV) infections among hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients impose a significant health care resource utilization (HCRU)-related economic burden. Maribavir (MBV), a novel anti-viral therapy (AVT), approved by the United States Food and Drug Administration for post-transplant CMV infections refractory (with/without resistance) to conventional AVTs has demonstrated lower hospital length of stay (LOS) versus investigator-assigned therapy (IAT; valgancilovir, ganciclovir, foscarnet, or cidofovir) in a phase 3 trial (SOLSTICE). This study estimated the HCRU costs of MBV versus IAT. METHODS: An economic model was developed to estimate HCRU costs for patients treated with MBV or IAT. Mean per-patient-per-year (PPPY) HCRU costs were calculated using (i) annualized mean hospital LOS in SOLSTICE, and (ii) CMV-related direct costs from published literature. Probabilistic sensitivity analysis with Monte-Carlo simulations assessed model robustness. RESULTS: Of 352 randomized patients receiving MBV (n = 235) or IAT (n = 117) for 8 weeks in SOLSTICE, 40% had HSCT and 60% had SOT. Mean overall PPPY HCRU costs of overall hospital-LOS were $67,205 (95% confidence interval [CI]: $33,767, $231,275) versus $145,501 (95% CI: $62,064, $589,505) for MBV and IAT groups, respectively. Mean PPPY ICU and non-ICU stay costs were: $32,231 (95% CI: $5,248, $184,524) versus $45,307 (95% CI: $3,957, $481,740) for MBV and IAT groups, and $82,237 (95% CI: $40,397, $156,945) MBV versus $228,329 (95% CI: $94,442, $517,476) for MBV and IAT groups, respectively. MBV demonstrated cost savings in over 99.99% of simulations. CONCLUSIONS: This analysis suggests that Mean PPPY HCRU costs were 29%-64% lower with MBV versus other-AVTs.

Retinitis after haematopoietic stem cell transplantation with multiple intraocular viral infections (cytomegalovirus, Epstein‒Barr virus and herpes simplex virus)- a case report.

BACKGROUND: To report a case of retinitis with multiple intraocular viral infections after second haematopoietic stem cell transplantation. CASE PRESENTATION: A 39-year-old female patient developed retinitis after a second haematopoietic stem cell transplant. Right eye was tested for three viral infections- cytomegalovirus, Epstein‒Barr virus and herpes simplex virus, while left was infected with cytomegalovirus. The patient was subsequently treated with vitreous cavity ganciclovir injections, and 1 week later both eyes tested negative for aqueous humour viruses. DISCUSSION AND CONCLUSION: CMV, EBV and HSV belong to the herpes virus family. They are all commonly observed in the body and represent opportunity infectious viruses. The retinitis they cause have different characteristics. But simultaneous infection of the eye by multiple viruses is quite rare. In this case, three viruses were detected in the patient's eye, but whether the retina was caused by all three viruses at the same time could not be determined. A satisfactory outcome was achieved after treatment with vitreous cavity ganciclovir injection.