Pitfalls in Valganciclovir Prophylaxis Dose Adjustment Based on Renal Function in Kidney Transplant Recipients.

Valganciclovir (VGC) is administered as prophylaxis to kidney transplant recipients (KTR) CMV donor (D)+/recipient (R)- and CMV R+ after thymoglobulin-induction (R+/TG). Although VGC dose adjustments based on renal function are recommended, there is paucity of real-life data on VGC dosing and associations with clinical outcomes. This is a retrospective Swiss Transplant Cohort Study-embedded observational study, including all adult D+/R- and R+/TG KTR between 2010 and 2020, who received prophylaxis with VGC. The primary objective was to describe the proportion of inappropriately (under- or over-) dosed VGC week-entries. Secondary objectives included breakthrough clinically significant CMV infection (csCMVi) and potential associations between breakthrough-csCMVi and cytopenias with VGC dosing. Among 178 KTR, 131 (73.6%) patients had ≥2 week-entries for the longitudinal data of interest and were included in the outcome analysis, with 1,032 VGC dose week-entries. Overall, 460/1,032 (44.6%) were appropriately dosed, while 234/1,032 (22.7%) and 338/1,032 (32.8%) were under- and over-dosed, respectively. Nineteen (14.5%) patients had a breakthrough-csCMVi, without any associations identified with VCG dosing (p = 0.44). Unlike other cytopenias, a significant association between VGC overdosing and lymphopenia (OR 5.27, 95% CI 1.71-16.22, p = 0.004) was shown. VGC prophylaxis in KTR is frequently inappropriately dosed, albeit without meaningful clinical associations, neither in terms of efficacy nor safety.

Valacyclovir or valganciclovir for cytomegalovirus prophylaxis: A randomized controlled trial in adult and pediatric kidney transplant recipients.

BACKGROUND: Valganciclovir (valG), a cytomegalovirus (CMV) prophylactic agent, has dose-limiting side effects. The tolerability and effectiveness of valacyclovir (valA) as CMV prophylaxis is unknown. METHODS: We conducted a randomized, open-label, single-center trial of valA versus valG for all posttransplant CMV prophylaxis in adult and pediatric kidney recipients. Participants were randomly assigned to receive valA or valG. Primary endpoints were the incidence of CMV viremia and side-effect related drug reduction with secondary assessment of incidence of EBV viremia. RESULTS: Of the 137 sequential kidney transplant recipients enrolled, 26 % were positive and negative for CMV antibody in donor and recipient respectively. The incidence of CMV viremia (4 of 71 [6 %]; 8 of 67 [12 %] P = 0.23), time to viremia (P = 0.16) and area under CMV viral load time curve (P = 0.19) were not significantly different. ValG participants were significantly more likely to require side-effect related dose reduction (15/71 [21 %] versus 1/66 [2 %] P = 0.0003). Leukopenia was the most common reason for valG dose reduction and granulocyte-colony stimulating factor was utilized for leukopenia recovery more frequently (25 % in valG vs 5 % in valA: P = 0.0007). Incidence of EBV viremia was not significantly different. CONCLUSIONS: ValA has significantly less dose-limiting side effects than valG. In our study population, a significant increase in CMV viremia was not observed, in adults and children after kidney transplant, compared to valG. TRIAL REGISTRATION NUMBER: NCT01329185.

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.

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.

The Yield of Targeted Examination for the Detection of Symptomatic Congenital Cytomegalovirus Infection.

BACKGROUND: The incidence of congenital cytomegalovirus (CMV) infection in Israel is 0.7%. Only 10-15% are symptomatic. Valganciclovir has been shown to improve hearing and neurodevelopmental outcomes in neonates with symptomatic congenital CMV infection. Targeted examination of infants who fail routine neonatal hearing screening or have clinical or laboratory findings suggestive of symptomatic congenital CMV infection may be a cost-effective approach. OBJECTIVES: To assess the possibility of targeted examination for the detection of newborns with symptomatic congenital CMV infection. METHODS: A prospective observational study was conducted in 2014-2015 at two medical centers in northern Israel. Included were all newborns who were tested in the first 3 days of life by polymerase chain reaction (PCR) for urine CMV DNA (n=692), either for failure the hearing screening (n=539, 78%), clinical or laboratory findings suggestive of symptomatic congenital CMV infection, or primary CMV infection during pregnancy (n=153, 22%). RESULTS: During the study period 15,433 newborns were born. The predicted rate of infection was 10-15% (symptomatic) of 0.7% of newborns, namely 0.07-0.105% or 10-15 infants. In fact, 15 infants (0.11%, 95% confidence interval 0.066-0.175) were diagnosed with symptomatic congenital CMV infection, 2/539 (0.37%) in the failed hearing group and 13/153 (8%) in the clinical/laboratory findings group. The incidence of symptomatic congenital CMV infection was within the predicted range. CONCLUSIONS: Targeted examination of only 4.5% (n=692) of newborns detected the predicted number of infants with symptomatic congenital CMV infection in whom valganciclovir therapy is recommended.

Concomitant congenital CMV infection and inherited liver diseases.

Inherited liver diseases may present in infancy as cholestatic jaundice progressing to severe hepatic dysfunction. Congenital cytomegalovirus (cCMV) infection may initially involve the liver, yet in otherwise healthy hosts rarely leads to long-term hepatic disease. We report a series of three patients, diagnosed with hereditary liver diseases: progressive familial intrahepatic cholestasis (PFIC) type IV, alpha 1 anti-trypsin deficiency (A1ATD) and Alagille syndrome (ALGS), who were also diagnosed with cCMV infection. All patients were treated with valgancilovir for symptomatic cCMV infection (6-12 months), followed by suppressive dosing in the 2 patients with PFIC and A1ATD. Following 15-24 months of follow-up - the patients with PFIC and A1ATD developed severe liver failure, and the third had ongoing cholestatic disease with stable synthetic function. We propose a significant contribution of cCMV infection to the course of the inherited primary disease, possibly leading to further compromise of the liver. We recommend screening patients with inherited liver disease for cCMV, and considering anti-viral treatment with valganciclovir to delay hepatic disease progression.

Immunoglobulin fetal therapy and neonatal therapy with antiviral drugs improve neurological outcome of infants with symptomatic congenital cytomegalovirus infection.

Infants with symptomatic congenital cytomegalovirus infection (cCMV) suffer from long-term sequelae. This study aimed at evaluating the efficacy of combining immunoglobulin (Ig) fetal therapy (FT) and neonatal therapy (NT) with antiviral drugs to improve neurological outcomes of affected infants. Women whose fetuses had symptomatic cCMV received Ig injection into the fetal peritoneal cavity and/or maternal blood as FT, while affected newborns received oral valganciclovir or intravenous ganciclovir as NT. We compared the neurological outcomes at ≥18 months old between infants receiving FT with or without NT (FT group) and those receiving NT only (NT group). From 2009-2019, 15 women whose fetuses had symptomatic cCMV received FT, while 19 newborns received NT only. In FT group, two newborns died, and two were <18 months old. Neurological outcomes of the remaining 11 infants in FT group were as follows: normal 45.5 %, mild impairments 36.4 %, and severe impairments 18.2 %. In NT group, one newborn died, one's parents refused the follow-up, one was <18 months old, and two had only chorioretinitis as symptoms. Neurological outcomes of the remaining 14 infants in NT group were as follows: normal 21.4 %, mild impairments 14.3 %, and severe impairments 64.3 %. The proportion of infants with severe impairments in FT group was significantly lower than that in NT group (18.2 % vs 64.3 %, p < 0.05). This is the first trial demonstrating that the combination of Ig FT and NT with antiviral drugs may be more effective in improving neurological outcomes of newborns with symptomatic cCMV as compared to NT only.

Valganciclovir prophylaxis for cytomegalovirus infection in pediatric kidney transplant recipients: a single-center experience.

BACKGROUND: There are two approaches for treating cytomegalovirus (CMV) infection occurring after kidney transplantation (KTx). One is preemptive therapy in which treatment is started after confirming positive CMV antigenemia using periodic antigenemia assay. The other approach is prophylactic therapy in which oral valganciclovir (VGCV) is started within 10 days after KTx and continued for 200 days. The Transplantation Society guidelines recommend prophylactic therapy for high-risk (donor's CMV-IgG antibody positive and recipient's negative) pediatric recipients. However, the adequate dose and side effects of VGCV are not clear in children, and there is no sufficient information about prophylaxis for Japanese pediatric recipients. METHODS: A single-center retrospective analysis was conducted on case series of high-risk pediatric patients who underwent KTx and received oral VGCV prophylaxis at the Department of Pediatric Nephrology, Tokyo Women's Medical University, between August 2018 and March 2019. Data were collected using medical records. RESULTS: The dose of administration was 450 mg in all the study patients (n = 5). Reduction or discontinuation was required in four of five patients due to adverse events, which included neutropenia in one patient, anemia in two patients, and neutropenia and digestive symptoms in one patient. Late-onset CMV disease occurred in all patients. No seroconversion was observed during prophylaxis. CONCLUSIONS: Our preliminary study suggests that the dosage endorsed by The Transplantation Society may be an overdose for Japanese pediatric recipients. Further studies are required to examine the safety and efficacy of VGCV prophylaxis in Japanese pediatric recipients.

Population Pharmacokinetics and Bayesian Estimation of the Area Under the Concentration-Time Curve for Ganciclovir in Adult Chinese Renal Allograft Recipients After Valganciclovir Administration.

Valganciclovir (VGCV) is the prodrug of ganciclovir (GCV). The objective of this study was to establish a population pharmacokinetic model (PPK) of GCV to investigate the PK characteristics of GCV after administration of VGCV in adult Chinese renal allograft recipients. Seventy Chinese renal allograft recipients were given 450 mg (n = 41) or 900 mg (n = 29) VGCV daily. Blood samples were drawn 0-24 hours after 5 days' therapy, and GCV plasma levels were determined. The PPK model was constructed using nonlinear mixed-effects modeling, and the Bayesian estimation of AUC0-24h was constructed for an individual patient based on limited plasma samples. The PK of GCV was best described by a 2-compartment model with a first-order absorption process. The CL/F, V2 /F, Q/F, V3 /F, Ka , and lag time of GCV were 15.8 ± 0.71 L/h, 10.9 ± 2.38 L, 3.98 ± 0.40 L/h, 167 ± 44.0 L, 0.23 ± 0.0078 1/h, and 0.93 ± 0.017 hours, respectively. Clearance of creatinine was found to have a significant impact on the CL/F of GCV (P < .01). Sampling strategies consisted of plasma concentrations 0 and 2 and 0, 2, and 4 hours after VGCV administration were shown to be suitable for the estimation of the GCV AUC0-24h . The PPK model was acceptable and can describe the PK of GCV in Chinese renal transplant patients administered VGCV. The AUC0-24h of GCV in Chinese renal transplant patients can be calculated by a limited sampling strategy method.

Optimization of Ganciclovir use in allogeneic hematopoietic cell transplant recipients - the role of therapeutic drug monitoring.

Introduction: Cytomegalovirus (CMV) is an opportunistic infectious complication that can occur after allogeneic hematopoietic cell transplantation (HCT). The mainstay of treatment and prevention of this infection is ganciclovir and its ester prodrug valganciclovir. There is conflicting evidence on the clinical utility of routine ganciclovir therapeutic drug monitoring (TDM) as a means to optimize treatment.Areas covered: This review aims to describe the current knowledge of the pharmacokinetic and pharmacodynamic characteristics of ganciclovir and valganciclovir, and to explore the evidence and challenges surrounding ganciclovir TDM within the allogeneic HCT cohort.Expert opinion: Ganciclovir TDM is important to optimize efficacy in selected patient groups where there are variable pharmacokinetic factors or inadequate response to treatment. However, defined pharmacokinetic exposures which correlate with treatment efficacy and toxicity remain elusive. Prospective clinical studies in specific patient groups are required to clarify this issue. Alternative TDM targets such as the intracellular ganciclovir triphosphate should be explored as they may prove to have better correlation with clinical outcomes and adverse effects. With recent advances in CMV immune monitoring, novel approaches integrating TDM with specific CMV immune phenotyping in a predictive model will be advantageous in optimizing ganciclovir dosing by combining TDM with a risk stratification approach.

Treating HIV-associated cytomegalovirus retinitis with oral valganciclovir and intra-ocular ganciclovir by primary HIV clinicians in southern Myanmar: a retrospective analysis of routinely collected data.

BACKGROUND: Cytomegalovirus retinitis (CMVR) is an opportunistic infection in HIV-infected people. Intraocular or intravenous ganciclovir was gold standard for treatment; however, oral valganciclovir replaced this in high-income countries. Low- and middle-income countries (LMIC) frequently use intraocular injection of ganciclovir (IOG) alone because of cost. METHODS: Retrospective review of all HIV-positive patients with CMVR from February 2013 to April 2017 at a Médecins Sans Frontièrs HIV clinic in Myanmar. Treatment was classified as local (IOG) or systemic (valganciclovir, or valganciclovir and IOG). The primary outcome was change in visual acuity (VA) post-treatment. Mortality was a secondary outcome. RESULTS: Fifty-three patients were included. Baseline VA was available for 103 (97%) patient eyes. Active CMVR was present in 72 (68%) eyes. Post-treatment, seven (13%) patients had improvement in VA, 30 (57%) had no change, and three (6%) deteriorated. Among patients receiving systemic therapy, four (12.5%) died, compared with five (24%) receiving local therapy (p = 0.19). CONCLUSIONS: Our results from the first introduction of valganciclovir for CMVR in LMIC show encouraging effectiveness and safety in patients with advanced HIV. We urge HIV programmes to include valganciclovir as an essential medicine, and to include CMVR screening and treatment in the package of advanced HIV care.

Pseudotumor asociado a citomegalovirus simulando un carcinoma de ciego en un paciente inmunocompetente / Cytomegalovirus-associated pseudotumor mimicking ceccum carcinoma in a non inmunocompromised patient

No disponible

Valganciclovir in an HIV-infected patient with Castleman's disease / Valganciclovir en un paciente infectado por VIH con enfermedad de Castleman

No disponible

One Year of Preemptive Valganciclovir Administration in Children After Liver Transplantation.

OBJECTIVES: Valganciclovir (VGCV) is used as prophylaxis against cytomegalovirus (CMV) infection after pediatric living donor liver transplantation (LDLT). The purpose of this study was to examine the efficacy of 1 year of preemptive VGCV administration compared with a shorter administration after pediatric LDLT. METHODS: VGCV was administered to 56 children who underwent LDLT. CMV and Epstein-Barr virus (EBV) antibody status, pp65 antigenemia, and other laboratory data were assessed at 1 year after LDLT. Patients were divided into the 1-year group (n = 32) (patients who had 1 year of VGCV administration) and the <1-year group (n = 24) (patients who had less than 1 year of VGCV administration). RESULTS: Study participants consisted of 34 females and 22 males, with a mean age of 4.2 years at transplant. Regarding pretransplant donor (D)/recipient (R) CMV antibody status, 13 were D positive (+)/R negative (-), 27 were D+/R+, 8 were D-/R+, and 8 were D-/R-. For EBV, 22 were D+/R+, 32 were D+/R-, and 2 were D-/R-. In the 1-year group, only 2 patients (6.5%) developed CMV infection, whereas 8 patients (33.3%) developed CMV infection in the <1-year group. The CMV pp65 antigenemia assay was positive in 2 patients. CMV IgM was positive in 7 patients. One year of preemptive VGCV administration was associated with a lower incidence of CMV infection (P = .008), but not EBV infection. No adverse effects were observed. CONCLUSIONS: One year of preemptive VGCV administration after LDLT is safe and suppresses CMV infection. It was useful after pediatric LDLT.

Impact of cytomegalovirus serologic status on heart transplantation.

BACKGROUND: Cytomegalovirus (CMV) infection has been associated with increased risk of mortality, cardiac allograft vasculopathy, and de novo malignancy following heart transplantation in prior institutional reports. This study examines the impact of the recipient and donor CMV status on heart recipients in the United States. METHODS: Adult heart transplant recipients were identified in the OPTN registry between 2005-2016. Recipients were stratified based on the recipient (R) and donor (D) CMV serologic status (+/-). The primary endpoint was survival 5-years after transplantation. The secondary endpoint was cardiac allograft vasculopathy 5-years after transplantation. Separate Cox proportional hazards regression models were developed to evaluate independent associations between CMV status and each of the study endpoints. RESULTS: A total of 21 878 recipients met the inclusion criteria. The breakdown of study arms by CMV serologic status was R-/D- = 3412, R+/D- = 4939; R-/D+ = 5230, and R+/D+ = 8,297. Five-year survival estimates were similar across groups (77-79%). CMV status was associated with increased mortality at 5-years (23%-41% increased risk) which was most evident in the first 3 months. The use of valganciclovir was associated with decreased risk of mortality (HR 0.56; 95% CI, 0.52-0.60). The cumulative incidence of cardiac allograft vasculopathy (R-/D- = 31%, R+/D- = 30%, R-/D+ = 31%, and R+/D+ = 30%) was similar across groups. CONCLUSIONS: CMV seropositivity at the time of transplantation is associated with increased long-term risk of mortality. Chemoprophylaxis with antivirals seems to mitigate this risk. There was no association with an increased risk of allograft vasculopathy.

Valganciclovir as Add-on to Standard Therapy in Glioblastoma Patients.

PURPOSE: Several groups have reported a prevalence of human cytomegalovirus (CMV) in glioblastoma close to 100%. Previously, we reported that treatment with the antiviral drug valganciclovir as an add-on to standard therapy significantly prolonged survival in 50 patients with glioblastoma. Here, we present an updated retrospective analysis that includes an additional 52 patients. EXPERIMENTAL DESIGN: From December 2006 to November 2019, 102 patients with newly diagnosed glioblastoma received valganciclovir as an add-on to standard therapy. No additional toxicity was observed. Contemporary controls were 231 patients with glioblastoma who received similar baseline therapy. RESULTS: Patients with newly diagnosed glioblastoma receiving valganciclovir had longer median overall survival (OS 24.1 vs. 13.3 months, P < 0.0001) and a 2-year survival rate (49.8% vs. 17.3%) than controls. Median time-to-tumor progression was also longer than in controls; 9.9 (0.7-67.5 months) versus 7.3 (1.2-49 months), P = 0.0003. Valganciclovir improved survival in patients with radical or partial resection and an unmethylated or methylated MGMT promoter gene. CONCLUSIONS: Valganciclovir prolonged median OS of patients with newly diagnosed glioblastoma (with methylated or unmethylated MGMT promoter gene) and was safe to use.

A cohort study of the universal neonatal urine screening for congenital cytomegalovirus infection.

OBJECTIVES: This prospective cohort study aimed to evaluate the efficacy of the universal neonatal urine screening, followed by diagnosis, workup and antiviral therapy for symptomatic congenital cytomegalovirus (CMV) infection to reduce neurological impairments and sequelae. METHODS: Neonates born in three facilities underwent the universal urine screening of PCR analyses for CMV-DNA. Neonates with symptomatic congenital CMV infection (cCMV) received oral valganciclovir (VGCV) of 32 mg/kg/day for six weeks or six months, and were evaluated for neurological outcomes including developmental quotient (DQ) and hearing function at around 18 months of corrected age. RESULTS: cCMV was diagnosed in 56 (0.48%) of 11,736 neonates, consisting of 23 neonates with symptomatic and 33 with asymptomatic cCMV. The incidence of cCMV in the general perinatal medical center (0.69%) was higher than that in the primary maternity hospital (0.23%, p<0.01%). Twenty of the 23 infants with symptomatic cCMV received VGCV therapy, and 19 underwent neurological assessment. Eight neonates (42%) had severe sequelae of DQ < 70, bilateral hearing dysfunction, and/or epilepsy. Four neonates (21%) had mild sequelae of DQ 70-79 or unilateral hearing dysfunction only, and seven (37%) showed normal development without any impairment. CONCLUSIONS: This study on a large scale demonstrated that a series of universal neonatal urine screening, diagnosis, workup, and VGCV therapy for neonates with symptomatic cCMV may decrease neurological impairments, because 58% of the treated infants had normal development or mild sequelae. The universal urine screening likely identifies subclinical symptomatic cCMV. Mothers with fetuses of cCMV seem to be selectively transferred to perinatal medical centers before deliveries.

Extending cytomegalovirus prophylaxis in high-risk (D+/R-) lung transplant recipients from 6 to 9 months reduces cytomegalovirus disease: A retrospective study.

RATIONALE: Cytomegalovirus (CMV)-seronegative recipients receiving a seropositive allograft (D+/R-) are at a high risk of developing CMV disease. Our program increased the duration of CMV prophylaxis from 6 to 9 months in May 2013. Here, we present the impact on the incidence of CMV infection, disease, side effects, rejection, and other factors. METHODS: Retrospective cohort of 241 CMV (D+/R-) patients transplanted between January 1, 2008, and December 31, 2017. Blood CMV testing was done according to protocol. All patients received ganciclovir/valganciclovir as prophylaxis. We compared the incidence and timing of CMV infection and disease up to 6 months after cessation of prophylaxis between patients who received 9 months (May 2013 onwards) and a historical control group who received 6 months of prophylaxis (prior to May 2013). CMV infection was defined as detectable CMV viremia in the absence of symptoms. CMV disease was defined as CMV syndrome or tissue-invasive disease. Side effects of prophylaxis and CMV resistance were recorded. RESULTS: A total of 116 patients were included in the 6-month group and 125 in the 9-month group. The extended 9-month CMV prophylaxis delayed the onset of CMV infection (median time to CMV infection after lung transplantation 295 vs 353 days, P < .01) but did not significantly reduce the incidence of CMV infection (65% vs 64%, P = .06, log-rank). The 9-month prophylaxis delayed the onset and decreased the incidence of CMV disease from 50% in the 6-month group to 42% (P = .02 log-rank). There was no difference in the rate of adverse effects (leukopenia in 32% in both groups, P = .53) or development of CMV resistance between the two groups (4 cases in both groups, P = .92). There were no significant differences in overall survival or the rate of chronic lung allograft dysfunction between the groups. CONCLUSIONS: Extending duration of CMV prophylaxis from 6 to 9 months resulted in a delayed and decreased incidence of CMV disease in our lung transplant population. The absolute risk reduction achieved by extended CMV prophylaxis was 8%. The incidence of CMV infection, and ganciclovir resistance and side effects were similar between the two groups. Our results suggest that extending CMV prophylaxis in the highest risk CMV D+/R- group is effective in reducing CMV disease.