Valganciclovir for cytomegalovirus prevention in solid organ transplant patients: an evidence-based reassessment of safety and efficacy

Multicenter Analysis of Valganciclovir Prophylaxis in Pediatric Solid Organ Transplant Recipients

Background

Valganciclovir is the only approved antiviral for cytomegalovirus (CMV) prevention in pediatric solid organ transplantation (SOT). Additional approaches may be needed to improve outcomes.

Methods

A multicenter retrospective study from 2016 to 2019 was conducted of pediatric SOT recipients in whom at least 3 months of valganciclovir prophylaxis was planned. Episodes of CMV DNA in blood (DNAemia), CMV disease, drug-related toxicities, as well as other infections in the first year posttransplant and demographic and clinical data were collected. CMV DNAemia in the first year after prophylaxis or during prophylaxis (breakthrough) was analyzed by multivariate hazard models.

Results

Among the 749 patients enrolled, 131 (17.5%) had CMV DNAemia at any time in the first year; 85 (11.4%) had breakthrough DNAemia, and 46 (6.1%) had DNAemia after prophylaxis. CMV disease occurred in 30 (4%). In a multivariate model, liver transplantation compared to kidney or heart, intermediate or high risk based on donor/recipient serologies, neutropenia, and valganciclovir dose modifications attributed to toxicity were associated with increased risk of total and/or breakthrough DNAemia. Bacteremia was also associated with increased hazard ratio for CMV DNAemia. In a separate multivariate analysis, rejection occurred more often in those with breakthrough CMV DNAemia (P = .002); liver transplants, specifically, had increased rejection if CMV DNAemia occurred in the first year (P = .004). These associations may be bidirectional as rejection may contribute to infection risk.

Conclusions

CMV DNAemia in the first year posttransplantation occurs despite valganciclovir prophylaxis and is associated with medication toxicity, bacteremia, and rejection. Pediatric studies of newer antivirals, especially in higher-risk subpopulations, appear to be warranted.

Challenges for the improvement of valganciclovir prophylaxis in solid organ transplantation and the possible role of therapeutic drug monitoring in adults

Cytomegalovirus (CMV) infection frequently occurs after solid organ transplantation and is associated with an increased morbidity and mortality. Fortunately, the development of valganciclovir prophylaxis has lowered the incidence of CMV infection and its complications in immunosuppressed solid organ transplant recipients. However, breakthrough infections during valganciclovir prophylaxis and late CMV infection after cessation of valganciclovir prophylaxis still occur with the current prophylactic strategy. Additionally, valganciclovir resistance has emerged among CMV strains, which complicates the treatment of CMV infections. Furthermore, the use of valganciclovir is associated with myelotoxicity, which can lead to the premature withdrawal of prophylaxis. It is important to address these current issues in order to improve the standard care after solid organ transplantation. This paper will therefore discuss the clinical practice of valganciclovir prophylaxis, elaborate on its issues and suggest how to improve the current prophylactic strategy with a possible role for therapeutic drug monitoring.

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.

Approaches and Challenges in the Current Management of Cytomegalovirus in Transplant Recipients: Highlighting the Role of Advanced Practice Providers (Nurse Practitioners and Physician Assistants)

Cytomegalovirus (CMV) infection is associated with increased morbidity and mortality in hematopoietic cell transplant (HCT) and solid organ transplant (SOT) recipients, with traditional anti-CMV therapies limited by their associated toxicities and the development of resistance. Clinical providers are often faced with challenging and complicated CMV infections that require multiple courses of antiviral therapies. Increasingly, advanced practice providers (APPs) are playing an important role in the day-to-day management of transplant recipients with CMV infection, including resistant/refractory CMV and other complex CMV syndromes. Here, we provide an overview of current preventative and treatment strategies for CMV infection in HCT and SOT recipients, highlighting the challenging aspects of current management and the potential utility of newer antiviral agents. This article also focuses on how a multidisciplinary team, orchestrated by APPs, can improve CMV-associated patient outcomes. Protocols using antiviral agents for the prevention or treatment of CMV infections require carefully designed and meticulously implemented strategies to ensure the best clinical outcomes for patients. APPs, who have increasingly become the frontline providers of outpatient care for transplant recipients, are ideally positioned to design and carry out these protocols.

High burden of CMV infections after simultaneous pancreas-kidney transplantation-a nationwide cohort study

Cytomegalovirus (CMV) infections remain a common problem after solid-organ transplantation. We characterized the burden of CMV infections, and adverse events of CMV prophylaxis after simultaneous pancreas-kidney transplantation (SPK). We included all SPK patients (n = 236) since 2010 in our country. Immunosuppression was ATG, tacrolimus, mycophenolate, and steroids. Valganciclovir prophylaxis was given to all CMV D+/R- patients for six months, and to seropositive SPK patients for three months since February 2019. CMV DNAemia was monitored with quantitative PCR from plasma. Among D+/R- SPK recipients, post prophylaxis CMV infection was detected in 41/60 (68%) during follow-up. In seropositive SPK recipients with no prophylaxis, CMV infection was detected in 53/95 (56%), vs. 28/78 (36%) in those who received 3 months of prophylaxis (P = 0.01). CMV was symptomatic in 35 (15%) patients, of which 10 required hospitalization. Mean duration of viremia was 28 days (IQR 21-41). Leukopenia was detected in 63 (46%) of the 138 patients with valganciclovir prophylaxis. 7/122 (6%) of the CMV infections detected were defined as refractory to treatment, and three patients had confirmed ganciclovir resistance. SPK recipients experience a high burden of CMV infections despite CMV prophylaxis. Leukopenia is common during valganciclovir prophylaxis.

A new direction for cytomegalovirus prophylaxis among transplant recipients: Benefits and nonviral outcomes of letermovir use as primary CMV prophylaxis

PURPOSE OF REVIEW

Letermovir has changed the game of primary prophylaxis against cytomegalovirus (CMV) for hematopoietic stem cell transplant (HSCT) and more recently, solid organ transplant recipients. This is largely due to letermovir's similar efficacy in protecting against CMV reactivation and disease, along with its superior safety profile, notably reduced myelotoxicity, and lack of renal dose adjustment compared to standard agents like valganciclovir. This review will describe the potential benefits and clinical considerations of letermovir as prophylaxis among transplant recipients, with a focus on recent evidence describing nonviral outcomes of CMV.

RECENT FINDINGS

Recent evidence has demonstrated improved safety (e.g., less myelosuppression) and tolerability with no difference in rates of CMV infection or disease in kidney transplant recipients given letermovir compared to valganciclovir. Real-world studies and meta-analyses in HSCT populations have explored various nonviral outcomes with letermovir use. Letermovir prophylaxis was associated with reduced mortality, lower rates of graft versus host disease, delayed CMV immune reconstitution, improved tolerability with extended durations, and decreased healthcare utilization.

SUMMARY

Letermovir is an effective antiviral agent for CMV prevention and has demonstrated enhanced safety, which may allow for extended durations of primary prophylaxis among transplant recipients along with other improved clinical outcomes by mitigating the indirect effects of CMV.

Efficacy and safety of preemptive therapy for cytomegalovirus end-organ disease in people living with HIV: a systematic review and meta-analysis

INTRODUCTION

Cytomegalovirus end-organ-disease (CMV EOD) is still a major cause of debilitating illness in people living with HIV, especially in developing countries.

OBJECTIVE

To evaluate the efficacy and safety of preemptive therapy against CMV EOD in HIV-positive adults with CMV viremia.

METHODS

Systematic review of clinical trials by searching electronic databases and clinical trial registries, screening and selection of references, data extraction and assessment of risk of bias. The results were presented in a narrative synthesis. Aggregated analyzes for dichotomous outcomes were reported as odds ratios with 95 % Confidence Intervals.

RESULTS

Four RTC were included. A reduction in the risk of CMV EOD with preemptive therapy was found OR=0.49 (95 % CI 0.31‒0.76). We did not identify significant differences for all-cause mortality, adverse events, and withdrawal of the therapy secondary to adverse events.

CONCLUSIONS

Preemptive therapy could be a potential option for preventing CMV EOD in people living with HIV.

Pediatric intestinal transplantation

Advancements in donor management, organ preservation and operative techniques, as well as immunosuppressive therapies, have provided children with intestinal failure and its complications a chance not only for enteral autonomy but also long-term survival through intestinal transplantation (ITx). First described in the 1960's, experience has grown in managing these complex patients both pre- and post-transplant. The goals of this review are to provide a brief history of intestinal transplantation and intestinal rehabilitation in pediatric patients, followed by focused discussions of the indications for ITx, induction and maintenance immunosuppression therapies, common post-operative complications, and outcomes/quality of life post-transplant.

Immunoguided Discontinuation of Prophylaxis for Cytomegalovirus Disease in Kidney Transplant Recipients Treated with Antithymocyte Globulin: A Randomized Clinical Trial

BACKGROUND

Antiviral prophylaxis is recommended in cytomegalovirus (CMV)-seropositive kidney transplant (KT) recipients receiving antithymocyte globulin (ATG) as induction. An alternative strategy of premature discontinuation of prophylaxis after CMV-specific cell-mediated immunity (CMV-CMI) recovery (immunoguided prevention) has not been studied. The aim of this study was to evaluate whether it is effective and safe to discontinue prophylaxis when CMV-CMI is detected and to continue with preemptive therapy.

METHODS

In this open-label, non-inferiority clinical trial, patients were randomized 1:1 to follow immunoguided strategy, receiving prophylaxis (valganciclovir 900 mg daily) until CMV-CMI recovery or to receive fixed-duration prophylaxis until day +90. After prophylaxis, preemptive therapy (valganciclovir 900 mg twice daily) was indicated in both arms until month 6. The primary and secondary outcomes were incidence of CMV disease and replication, respectively, within the first 12 months. Desirability of outcome ranking (DOOR) assessed two deleterious events (CMV disease/replication and neutropenia).

RESULTS

A total of 150 CMV-seropositive KT recipients were randomly assigned. There was no difference in the incidence of CMV disease (0% vs. 2.7%; P = 0.149) and replication (17.1% vs. 13.5%; log-rank test, P = 0.422) between both arms. Incidence of neutropenia was lower in the immunoguided arm (9.2% vs. 37.8%; OR, 6.0; P < 0.001). A total of 66.1% of patients in the immunoguided arm showed a better DOOR, indicating a greater likelihood of a better outcome.

CONCLUSIONS

Prophylaxis can be prematurely discontinued in CMV-seropositive KT patients receiving ATG when CMV-CMI is recovered since no significant increase in the incidence of CMV replication or disease is observed.

Role of Virus-Specific T Cell Therapy for Cytomegalovirus and BK Infections in Kidney Transplant Recipients

Cytomegalovirus (CMV) and BK virus (BKV) are common viral infections after kidney transplant. Their negative effects on patient and graft outcomes have been well described. However, despite improvement in screening and prophylaxis strategies, CMV and BKV continue to negatively affect both short- and long-term graft survival. Adequate cell-mediated immunity is essential for the control and prevention of opportunistic viral infections, such as CMV and BKV. Therefore, immune reconstitution, in particular T cell recovery, is a key factor in antiviral control after kidney transplantation. Cell-based immunotherapy offers an attractive alternative approach to traditional interventions. Adoptive T cell transfer, via infusions of allogeneic virus-specific T lymphocytes is capable of restoring virus-specific T cell immunity, and are safe and effective in the treatment of viral infections after hematopoietic stem cell transplantation. In this article, we review the emerging role of virus-specific T cell therapy in the management of CMV and BKV after kidney transplantation. On the basis of the available data, virus-specific T cell therapy may be a promising addition to the antiviral treatment armamentarium after kidney transplantation. Future studies are needed to more clearly define the efficacy and risks of virus-specific T cell therapy in the kidney transplant population.

Cytomegalovirus retinitis in a patient of granulomatosis with polyangiitis on long-term immunosuppressants

A 69-year-old male patient presented to the retina clinic with a sudden decrease in vision in his right eye since 1 day. He was a known case of granulomatosis with polyangiitis and was on systemic immunosuppression for the past 3 years. The best-corrected visual acuity (BCVA) in his right eye was 20/60 and he has no perception of light in the left eye. Fundus examination revealed the presence of retinitis lesions in the right eye and total optic atrophy in the left eye. A vitreous biopsy was done and the PCR was found to be positive for cytomegalovirus (CMV). He was treated with intravitreal ganciclovir injections. Subsequently, the retinitis lesions regressed and BCVA in the right eye improved to 20/40.This case report elaborates on the risks of the development of opportunistic ocular infections in patients receiving long-term systemic immunosuppressants and the need for regular ocular examinations in such cases.

Evaluation of cytomegalovirus prophylaxis in low and intermediate risk kidney transplant recipients receiving lymphocyte-depleting induction

Cytomegalovirus (CMV) is a significant cause of morbidity in kidney transplant recipients (KTR). Historically at our institution, KTR with low and intermediate CMV risk received 6 months of valganciclovir if they received lymphocyte depleting induction therapy. This study evaluates choice and duration of CMV prophylaxis based on donor (D) and recipient (R) CMV serostatus and the incidence of post-transplant CMV viremia in low (D-/R-) and intermediate (R+) risk KTR receiving lymphocyte-depleting induction therapy. A protocol utilizing valacyclovir for 3 months for D-/R- and valganciclovir for 3 months for R+ was evaluated. Adult D-/R- and R+ KTR receiving anti-thymocyte globulin, rabbit or alemtuzumab induction from 8/20/2016 to 9/30/2018 were evaluated through 1 year post-transplant. Patients were excluded if their CMV serostatus was D+/R-, received a multi-organ transplant, or received basiliximab. Seventy-seven subjects met the inclusion criteria: 25 D-/R- (4 historic group, 21 experimental group) and 52 R+ (31 historic, 21 experimental). No D-/R- patients experienced CMV viremia. Among the R+ historic and experimental groups, there was no significant difference in viremia incidence (35.5% vs 52.4%; P = .573). Of these cases, the peak viral load was similar between the groups (median [IQR], 67 [<200-444] vs <50 [<50-217]; P = .711), and there was no difference in the incidence of CMV syndrome (16.1% vs 14.3%; P = 1.000) or CMV related hospitalization (12.9% vs 14.3%; P = 1.000). No patient experienced tissue invasive disease. These results suggest limiting valganciclovir exposure may be possible in low and intermediate risk KTR receiving lymphocyte-depleting induction therapy with no apparent impact on CMV-related outcomes.

CMV Prevention and Treatment in Transplantation: What's New in 2019

PURPOSE OF REVIEW

Transplant recipients are at risk for cytomegalovirus (CMV) infection and associated morbidity and mortality. We summarize recently introduced or currently investigated modalities for prevention and treatment of CMV infection in hematopoietic cell (HCT) and solid organ transplant (SOT) recipients.

RECENT FINDINGS

Letermovir was recently approved for CMV prevention in HCT recipients. Data from real world studies support its role to improve outcomes in this population. Letermovir is currently under investigation for broader patient populations and indications. Maribavir is in late stages of development for CMV treatment and may provide a safer alternative to currently available anti-CMV drugs. Promising CMV vaccine candidates and adoptive cell therapy approaches are under evaluation. CMV immune monitoring assays are predicted to play a more central role in our clinical decision making. In recent years, major advances have been made in CMV prevention and treatment in transplant recipients. Rigorous research is ongoing and is anticipated to further impact our ability to improve outcomes in this population.

High incidence of clinically significant cytomegalovirus infection in CMV D+/R+ lung transplant recipients receiving 3 months of antiviral prophylaxis

BACKGROUND

Universal antiviral prophylaxis is the preferred preventive strategy for lung transplant recipients (LTRs) at risk of CMV infection. We compared the risk of CMV infection between CMV D+/R + and D-/R + LTRs after 3 months of prophylaxis.

METHODS

This was a retrospective review of CMV R + LTRs transplanted between 2005 and 2013. Patients dying before completing 3 months, or receiving >180 days of prophylaxis were excluded. The primary outcome was proportion of LTRs who developed CMV infection and clinically significant CMV infection defined as CMV infection leading to preemptive therapy or CMV disease.

RESULTS

We analyzed 90 D+/R + and 72 D-/R + with a median follow up of 730 days. CMV infection and disease was more common in D+/R + compared to D-/R+ (CMV infection 66% vs 40%; P = 0.001; CMV disease 13% vs 4% P = 0.045). Fifty-nine patients developed at least one episode of clinically significant CMV infection (41/90 [46%] D+/R + and 18/72 [25%] D-/R + P=0.007) with recurrence occurring in 29 LTRs (49% of patients with previous CMV infection), of which 22 (76%) were CMV D+/R+. Thirty percent had side effects related to CMV therapy.

CONCLUSION

Three months prophylaxis in D+/R + LTRs was associated with high rates of clinically significant CMV infection and recurrences.

Topical Ganciclovir for Prophylaxis of Cytomegalovirus Endotheliitis in Endothelial Keratoplasty

PURPOSE

To describe the presentation and management of 2 cases of Descemet stripping automated endothelial keratoplasty (DSAEK) with failure secondary to cytomegalovirus (CMV) infection and prophylaxis with topical ganciclovir to prevent repeat failure of Descemet membrane endothelial keratoplasty (DMEK) regrafts.

METHODS

A retrospective chart review was conducted for 2 patients with DSAEK failure secondary to CMV infection.

RESULTS

A 70-year-old immunocompetent man (case 1) and a 53-year-old immunocompromised man (case 2) received DSAEK for presumed pseudophakic bullous keratopathy and endothelial decompensation secondary to recurrent uveitis, respectively. Case 1 had first graft failure at 10 months and case 2 at 21 months with inferior edema and keratic precipitates. Both failed to respond to topical steroid drops, and case 1 had 3 subsequent failed DSAEKs. Anterior chamber paracentesis confirmed CMV DNA. Neither had a clinical response to 6 weeks of oral valganciclovir. They were then administered topical ganciclovir (0.15% ophthalmic gel), and repeat endothelial transplant (DMEK) was performed for both patients. They were again administered topical ganciclovir 4 times daily after surgery because aqueous samples remained positive for CMV. Both remain free of inflammation or failure on topical ganciclovir for 21 months (case 1) and 29 months (case 2) with uncorrected visual acuities of 20/40 and 20/25, respectively.

CONCLUSIONS

Long-term topical ganciclovir use can prevent recurrence of CMV-associated graft failure even in immunocompromised hosts without side effects of systemic antivirals. DMEK may have advantages over DSEK in eyes with previous CMV infection and in eyes prone to inflammation.

A Native Human Monoclonal Antibody Targeting HCMV gB (AD-2 Site I)

Hyperimmune globulin (HIG) has shown efficacy against human cytomegalovirus (HCMV) for both transplant and congenital transmission indications. Replicating that activity with a monoclonal antibody (mAb) offers the potential for improved consistency in manufacturing, lower infusion volume, and improved pharmacokinetics, as well as reduced risk of off-target reactivity leading to toxicity. HCMV pathology is linked to its broad cell tropism. The glycoprotein B (gB) envelope protein is important for infections in all cell types. Within gB, the antigenic determinant (AD)-2 Site I is qualitatively more highly-conserved than any other region of the virus. TRL345, a high affinity (Kd = 50 pM) native human mAb to this site, has shown efficacy in neutralizing the infection of fibroblasts, endothelial and epithelial cells, as well as specialized placental cells including trophoblast progenitor cells. It has also been shown to block the infection of placental fragments grown ex vivo, and to reduce syncytial spread in fibroblasts in vitro. Manufacturing and toxicology preparation for filing an IND (investigational new drug) application with the US Food and Drug Administration (FDA) are expected to be completed in mid-2019.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Pediatric Intestinal Transplantation

Pediatric intestinal transplantation has moved from the theoretic to an actual therapy for children with irreversible intestinal failure who are suffering from complications of total parenteral nutrition. Owing to significant advancement in the management of intestinal failure and prevention of parenteral nutrition-related complications that have led to reduction in incidence of parenteral nutrition-associated liver disease and have improved intestinal adaptation, the indications for intestinal transplantation are evolving. Long-term outcomes have improved, but challenges in long-term graft function owing to chronic rejection and immunosuppressant-related complications remain the major opportunities for improvement.

Incidence and Risk Factors for Leukopenia in Kidney Transplant Recipients Receiving Valganciclovir for Cytomegalovirus Prophylaxis

Context:

Valganciclovir is used not only for cytomegalovirus prophylaxis after kidney transplantation but can also induce leukopenia, thereby making patients more susceptible to other infections. The epidemiology of leukopenia in patients on valganciclovir remains poorly understood.

Objective:

To determine the incidence and risk factors for leukopenia in patients receiving valganciclovir for cytomegalovirus prophylaxis after kidney transplantation.

Methods:

In this single-center, retrospective, cohort study, we included kidney recipients transplanted from January 1, 2003, to December 31, 2010, to determine the incidence and risk factors for leukopenia in patients who received valganciclovir for cytomegalovirus prophylaxis. The Kaplan-Meier product limit method was used to graphically assess time to leukopenia, and risk factors were assessed using Cox proportional hazards models.

Results:

A total of 542 kidney transplant recipients were included in the study cohort. The cumulative incidence of leukopenia at 6 months posttransplant was 39.3% (11.0% for neutropenia). Low baseline white blood cell count (hazard ratio [HR] 2.34 [95% confidence interval [CI], 1.37-4.00]) and high baseline body mass index (HR 1.05 [95% CI, 1.02-1.09]) were independently associated with an increased risk of leukopenia, while higher Cockcroft-Gault creatinine clearance (HR 0.87 [95% CI, 0.78-0.97]) was significantly associated with a decreased risk of leukopenia.

Conclusions:

These data suggest that recipient baseline white blood cell count, baseline body mass index, and kidney function are clinical predictors of new-onset leukopenia after kidney transplantation. Our results may inform the approach to cytomegalovirus prophylaxis to reduce the risk of valganciclovir-induced leukopenia in kidney transplant recipients.

Pharmacokinetics and Safety of Letermovir Coadministered With Cyclosporine A or Tacrolimus in Healthy Subjects

Letermovir is being developed for human cytomegalovirus infection treatment and prophylaxis. In patients receiving transplants, antivirals are coadministered with cyclosporine A (CsA) or tacrolimus (TAC) immunosuppressants. Therefore, we investigated the potential for letermovir-immunosuppressant interactions. In 2 phase 1 clinical trials either CsA 50 mg or TAC 5 mg was administered to healthy males. Following washout, letermovir 80 mg was dosed twice daily for 7 and 11 days in the CsA and TAC trials, respectively, with a second dose of immunosuppressant coadministered with letermovir at steady state. In addition, letermovir 40 mg twice daily was administered for 14 days, and either CsA 50 or 200 mg administered on days 7 and 14. Pharmacokinetics and tolerability were assessed. Letermovir increased CsA and TAC C_max by 37% and 70%, respectively, and exposure by 70% and 78%, respectively, compared with immunosuppressant alone; t_½ was also increased from 10.7 to 17.9 hours for CsA. CsA (50/200 mg) increased letermovir C_max,ss (109%/167%) and AUC_ss,τ (126%/237%) and decreased t_½ (4.33 to 3.68/3.04 hours) versus letermovir alone. TAC did not significantly affect letermovir pharmacokinetics. All treatments were well tolerated. Concomitant letermovir increased TAC and CsA exposure. CsA altered letermovir pharmacokinetics, whereas TAC did not.

Pediatric intestinal transplantation

The field of intestinal transplantation has experienced dramatic growth since the first reported cases 3 decades ago. Improvements in operative technique, donor assessment and immunosuppressive protocols have afforded children who suffer from life-threatening complications of intestinal failure a chance at long-term survival. As experience has grown, newer diseases, with more systemic manifestations have arisen as potential indications for transplant. After discussing the historical developments of intestinal transplant as a backdrop, this review focuses on the specific pre-operative indications for transplant as well as the great success that intestinal rehabilitation has witnessed over the past decade. A detailed discussion of evolution of immunosuppressive strategies is followed a general review of the common infectious complications experienced by children after intestinal transplant as well as the current long- and short-term results, including a section on new research on the quality of life in this challenging population of patients.

Late cytomegalovirus infection in children: High incidence of allograft rejection and hepatitis in donor negative and seropositive liver transplant recipients

The complications and outcome associated with late CMV infection and disease on the graft are poorly characterized in PLT recipients. We studied the overall incidence, risk factors, and outcome of late CMV infection and disease (infection 6 months after transplant) in 180 PLT recipients admitted between 2008 and 2011 at the King's College Hospital. Antiviral prophylaxis of intravenous ganciclovir was given only to the D+R- group starting at day 7 post-transplant. The remaining groups (D-R+, D+R+, and D-R-) received pre-emptive therapy when they have CMV viremia above cut-off value and treatment for symptomatic CMV infection. The overall incidence of late CMV infection and disease was 9.4% (19/180) and 14.5% (19/130) in D+R-, D-R+, D+R- groups. The D-R+ group had the highest incidence of hepatitis (37.5%) and significantly increased incidence of CMV disease, and single and multiple acute rejection episodes when compared to the D+R- group, which received prophylaxis. The late CMV infection and disease in pediatric LT recipients was comparable to adult LT recipients despite variable duration of antiviral prophylaxis. Our results show that D-R+ group had highest rate of hepatitis and rejection episodes, associated with high morbidity, and should be considered for antiviral prophylaxis.

Treatment of alpha and beta herpesvirus infections in solid organ transplant recipients

INTRODUCTION

Human herpesviruses frequently cause infections in solid organ transplant (SOT) recipients. Areas covered: We provide an overview of the clinical impact of alpha and beta herpesviruses and highlight the mechanisms of action, pharmacokinetics, clinical indications, and adverse effects of antiviral drugs for the management of herpes simplex virus, varicella zoster virus and cytomegalovirus. We comprehensively evaluated key clinical trials that led to drug approval, and served as the foundation for management guidelines. We further provide an update on investigational antiviral agents for alpha and beta herpesvirus infections after SOT. Expert commentary: The therapeutic armamentarium for herpes infections is limited by the emergence of drug resistance. There have been major efforts for discovery of new drugs against these viruses, but the results of early-phase clinical trials have been less than encouraging. We believe, however, that more antiviral drug options are needed given the adverse side effects associated with current antiviral agents, and the emergence of drug-resistant virus populations in SOT recipients. Likewise, optimized use and strategies are needed for existing and novel antiviral drugs against alpha and beta-herpesviruses in SOT recipients.

Treatment and prevention of cytomegalovirus infection in heart and lung transplantation: an update

INTRODUCTION

Heart and lung transplantation are standard therapeutic strategies to improve survival and quality of life in selected patients with end-stage heart or lung diseases. Cytomegalovirus (CMV) is one the most clinically relevant and frequent post-transplant infectious agents, which may cause direct acute syndromes, and chronic indirect graft-related injury. Despite effective antiviral drugs being available to prevent and treat CMV infection, due to the immunosuppression burden and the specific characteristics of thoracic grafts, CMV infection remains a major clinical problem in heart and lung transplant recipients.

AREAS COVERED

We performed an extensive literature search focused on studies specifically including heart or lung transplantation, when available, or kidney transplant recipients when data on thoracic transplants were not available. We discuss the pros and cons supporting the use of currently available drugs and strategies for CMV prevention and treatment, highlighting current unmet needs.

EXPERT OPINION

While (Val)Ganciclovir remains the cornerstone of anti-CMV therapy, prolonged universal prophylaxis may expose a large number of patients to an excess of drug toxicity. Additional drugs with lower toxicity may be available in the context of anti-CMV prophylaxis, and effective CMV-risk stratification, by means of novel immune monitoring assays, which may help to customize the therapeutic approach.

Risks and Epidemiology of Infections After Intestinal Transplantation

Intestinal transplantation has become a well-accepted and successful procedure to save the lives of patients suffering from intestinal failure and who have developed life-threatening complications of parenteral nutrition. Advances in all aspects of care, from the role of multidisciplinary intestinal rehabilitation services prior to transplant to the development strategies for early recognition of infectious sequelae and even the increasing availability of preventive strategies, have led to improved outcomes and a dramatic decline in infection-associated morbidity and mortality in children undergoing intestinal transplantation. Improvements in surgical techniques and immunosuppressive regimens have been essential components in these improvements, reducing risk of infection through reduction of technical complications and more optimal immunosuppression regimens. In addition, the development of molecular tools for early recognition of viral pathogens and an understanding of the timing and risks for infection have allowed for earlier and more successful treatments. Despite these improvements, infectious sequelae remain an important problem in this population, and additional efforts are needed to further minimize the risk of infectious sequelae in those children requiring this procedure.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

Severe neutropenia in children after renal transplantation: incidence, course, and treatment with granulocyte colony-stimulating factor

BACKGROUND

Infections are an important cause of morbidity and mortality in solid organ transplant recipients. Neutrophils play a crucial role in the initial host defense against bacterial pathogens. Neutropenia is not uncommon after renal transplantation in adults; however, there are scarce published data in children. We conducted a historical cohort study to evaluate the incidence, clinical course, and management of severe neutropenia after renal transplantation in children.

METHODS

In a single-center study, we collected clinical and laboratory data on all children (<20 years) who underwent renal transplantation from January 2005 to March 2014. All post-transplantation blood counts were reviewed; the lowest absolute neutrophil count was recorded and correlated with clinical information and other laboratory findings.

RESULTS

Of the 72 patients studied, 46 (64%) had at least one episode of neutropenia [absolute neutrophil count (ANC) <1500/μl] during the study period, 16 of whom (22%) had severe neutropenia (ANC < 500/μl), 2-11 months (median, 3.5) after renal transplantation. Work-up for viral infection or malignancy was performed. Initial management included dose decrease and subsequent discontinuation of antimetabolite, stopping co-trimoxazole and valganciclovir. Bone marrow aspiration in four children revealed normal marrow cellularity in all cases, with myelocyte maturational arrest in two. Eight children (11%) were treated with granulocyte colony-stimulating factor (G-CSF) (5 mcg/kg/day) 1-4 doses (median, 2), with excellent response in all and no adverse effects. Eight children presented with fever during severe neutropenia, and were treated with empiric antibiotics. Mycophenolate/azathioprine were resumed in all patients unless contraindicated (pre-existing BK viremia -1, PTLD -1). Recurrence of neutropenia was seen in five patients, only one of whom required further treatment with G-CSF. Graft function was preserved during and after resolution of neutropenia. Post-transplant neutropenia in children is common, and mostly occurs in the first few months. Its etiology is probably primarily a result of the combination of immunosuppressive agents and prophylactic treatment of infections in the early post-transplant period.

CONCLUSIONS

Decreasing immunosuppressive or antimicrobial medications carries the risk of acute rejection or infection. Off-label treatment with G-CSF may present a safe and effective alternative.

Intravenous immunoglobulins in liver transplant patients: Perspectives of clinical immune modulation

Shortage of appropriate donor grafts is the foremost current problem in organ transplantation. As a logical consequence, waiting times have extended and pretransplant mortality rates were significantly increasing. The implementation of a priority-based liver allocation system using the model of end-stage liver disease (MELD) score helped to reduce waiting list mortality in liver transplantation (LT). However, due to an escalating organ scarcity, pre-LT MELD scores have significantly increased and liver recipients became more complex in recent years. This has finally led to posttransplant decreasing survival rates, attributed mainly to elevated rates of infectious and immunologic complications. To meet this challenging development, an increasing number of extended criteria donor grafts are currently accepted, which may, however, aggravate the patients’ infectious and immunologic risk profiles. The administration of intravenous immunoglobulins (IVIg) is an established treatment in patients with immune deficiencies and other antibody-mediated diseases. In addition, IVIg was shown to be useful in treatment of several disorders caused by deterioration of the cellular immune system. It proved to be effective in preventing hyperacute rejection in highly sensitized kidney and heart transplants. In the liver transplant setting, the administration of specific Ig against hepatitis B virus is current standard in post-LT antiviral prophylaxis. The mechanisms of action of IVIg are complex and not fully understood. However, there is increasing experimental and clinical evidence that IVIg has an immuno-balancing impact by a combination of immuno-supporting and immuno-suppressive properties. It may be suggested that, especially in the context of a worsening organ shortage with all resulting clinical implications, liver transplant patients should benefit from immuno-regulatory capabilities of IVIg. In this review, perspectives of immune modulation by IVIg and impact on outcome in liver transplant patients are described.

Oral Valganciclovir as a Preemptive Treatment for Cytomegalovirus (CMV) Infection in CMV-Seropositive Liver Transplant Recipients

Objectives

Cytomegalovirus (CMV) infections in liver transplant recipients are common and result in significant morbidity and mortality. Intravenous ganciclovir or oral valganciclovir are the standard treatment for CMV infection. The present study investigates the efficacy of oral valganciclovir in CMV infection as a preemptive treatment after liver transplantation.

Methods

Between 2012 and 2013, 161 patients underwent liver transplantation at Samsung Medical Center. All patients received tacrolimus, steroids, and mycophenolate mofetil. Patients with CMV infection were administered oral valganciclovir (VGCV) 900mg/day daily or intravenous ganciclovir (GCV) 5mg/kg twice daily as preemptive treatment. Stable liver transplant recipients received VGCV.

Results

Eighty-three patients (51.6%) received antiviral therapy as a preemptive treatment because of CMV infection. The model for end-stage liver disease (MELD) score and the proportions of Child-Pugh class C, hepatorenal syndrome, and deceased donor liver transplantation in the CMV infection group were higher than in the no CMV infection group. Sixty-one patients received GCV and 22 patients received VGCV. The MELD scores in the GCV group were higher than in the VGCV group, but there were no statistical differences in the pretransplant variables between the two groups. AST, ALT, and total bilirubin levels in the GCV group were higher than in the VGCV group when CMV infection occurred. The incidences of recurrent CMV infection in the GCV and VGCV groups were 14.8% and 4.5%, respectively (P=0.277).

Conclusion

Oral valganciclovir is feasible as a preemptive treatment for CMV infection in liver transplant recipients with stable graft function.

Valganciclovir for the prevention of complications of late cytomegalovirus infection after allogeneic hematopoietic cell transplantation: a randomized trial

BACKGROUND

Optimal prevention of late cytomegalovirus (CMV) disease is poorly defined.

OBJECTIVE

To compare valganciclovir prophylaxis with polymerase chain reaction-guided preemptive therapy.

DESIGN

Randomized, double-blind trial. (ClinicalTrials.gov: NCT00016068).

SETTING

Multicenter trial.

PATIENTS

184 recipients of hematopoietic cell transplantation (HCT) who were at high risk for late CMV disease (95 patients received valganciclovir and 89 received placebo).

INTERVENTION

6 months of valganciclovir (900 mg/d) or placebo. Patients with polymerase chain reaction positivity at 1000 copies/mL or greater or a 5-fold increase over baseline were treated with ganciclovir or valganciclovir (5 mg/kg or 900 mg twice daily, respectively).

MEASUREMENTS

The composite primary end point was death, CMV disease, or other invasive infections by 270 days after HCT. Secondary end points were CMV disease, CMV DNAemia, death, other infections, resource utilization, ganciclovir resistance, quality of life, immune reconstitution, and safety.

RESULTS

The primary composite outcome occurred in 20% of valganciclovir recipients versus 21% of placebo-preemptive therapy recipients (treatment difference, -0.01 [95% CI, -0.13 to 0.10]; P = 0.86). There was no difference in the primary end point or its components 640 days after HCT. The incidence of a CMV DNAemia level of 1000 copies/mL or greater or a 5-fold increase over baseline was reduced in the valganciclovir group (11% vs. 36%; P < 0.001). Neutropenia was not significantly different at the absolute neutrophil count of less than 0.5 × 109 cells/L (P = 0.57); however, more patients received hematopoietic growth factors in the valganciclovir group (25.3% vs. 12.4%; P = 0.026). No significant differences were seen in other secondary outcomes.

LIMITATION

Some high-risk patients were not included.

CONCLUSION

Valganciclovir prophylaxis was not superior in reducing the composite end point of CMV disease, invasive bacterial or fungal disease, or death when compared with polymerase chain reaction-guided preemptive therapy. Both strategies performed similarly with regard to most clinical outcomes.

PRIMARY FUNDING SOURCE

Roche Laboratories.

A high-affinity native human antibody neutralizes human cytomegalovirus infection of diverse cell types

Human cytomegalovirus (HCMV) is the most common infection causing poor outcomes among transplant recipients. Maternal infection and transplacental transmission are major causes of permanent birth defects. Although no active vaccines to prevent HCMV infection have been approved, passive immunization with HCMV-specific immunoglobulin has shown promise in the treatment of both transplant and congenital indications. Antibodies targeting the viral glycoprotein B (gB) surface protein are known to neutralize HCMV infectivity, with high-affinity binding being a desirable trait, both to compete with low-affinity antibodies that promote the transmission of virus across the placenta and to displace nonneutralizing antibodies binding nearby epitopes. Using a miniaturized screening technology to characterize secreted IgG from single human B lymphocytes, 30 antibodies directed against gB were previously cloned. The most potent clone, TRL345, is described here. Its measured affinity was 1 pM for the highly conserved site I of the AD-2 epitope of gB. Strain-independent neutralization was confirmed for 15 primary HCMV clinical isolates. TRL345 prevented HCMV infection of placental fibroblasts, smooth muscle cells, endothelial cells, and epithelial cells, and it inhibited postinfection HCMV spread in epithelial cells. The potential utility for preventing congenital transmission is supported by the blockage of HCMV infection of placental cell types central to virus transmission to the fetus, including differentiating cytotrophoblasts, trophoblast progenitor cells, and placental fibroblasts. Further, TRL345 was effective at controlling an ex vivo infection of human placental anchoring villi. TRL345 has been utilized on a commercial scale and is a candidate for clinical evaluation.

Efficacy of valganciclovir and ganciclovir for cytomegalovirus disease in solid organ transplants: A meta-analysis

BACKGROUND

Cytomegalovirus (CMV), a problematic virus in solid organ transplant recipients (SOTR) such as liver, can worsen overall mortality and transplant outcome, so its prevention and treatment is a key of success in such patients. This study is aimed to compare the efficacy of ganciclovir (GCV) and valganciclovir (VGC) for prevention and treatment of infection with CMV.

MATERIALS AND METHODS

After sensitive and systematic search in PubMed, EMBASE, Cochrane and other available databases, both prospective and retrospective studies on effect of VGC and GCV in prevention and treatment of CMV disease among SOTR, which had our study criteria, were included. The pooled risk estimates were calculated using random-effects models.

RESULTS

Among 1324 title, 19 studies were included. In 11 prophylactic studies (2368 patients), the pooled risk of CMV disease (VGC relative to GCV) was 1.16, 95% confidence interval (CI): 0.91-1.49 and in studies of liver transplant recipients, 1.53, 95% CI: 0.86-2.70. Rate of viremia eradication in VGC to GCV was 1.05, 95% CI: 0.97-1.13. In 3 treatment studies (422 patients), rate of successful treatment in VGC to GCV was 0.98, 95% CI: 0.91-1.06 and viremia eradication 0.95, CI 95% 0.77-1.16. All these values did not show statistically significantly differences between GCV and VGC.

CONCLUSION

It can be concluded that VGC as an alternative to GCV can be used with equal efficacy in prevention and treatment of CMV disease in SOTR.

Randomized trial of valganciclovir versus valacyclovir prophylaxis for prevention of cytomegalovirus in renal transplantation

BACKGROUND AND OBJECTIVES

Both valganciclovir and high-dose valacyclovir are recommended for cytomegalovirus prophylaxis after renal transplantation. A head-to-head comparison of both regimens is lacking. The objective of the study was to compare valacyclovir prophylaxis with valganciclovir, which constituted the control group.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

In a randomized, open-label, single-center trial, recipients of renal transplants (recipient or donor cytomegalovirus-seropositive) were randomly allocated (1:1) to 3-month prophylaxis with valacyclovir (2 g four times daily) or valganciclovir (900 mg daily). Enrollment occurred from November of 2007 to April of 2012. The primary end points were cytomegalovirus DNAemia and biopsy-proven acute rejection at 12 months. Analysis was by intention to treat.

RESULTS

In total, 119 patients were assigned to valacyclovir (n=59) or valganciclovir prophylaxis (n=60). Cytomegalovirus DNAemia developed in 24 (43%) of 59 patients in the valacyclovir group and 18 (31%) of 60 patients in the valganciclovir group (adjusted hazard ratio, 1.35; 95% confidence interval, 0.71 to 2.54; P=0.36). The incidence of cytomegalovirus disease was 2% with valacyclovir and 5% with valganciclovir prophylaxis (adjusted hazard ratio, 0.21; 95% confidence interval, 0.01 to 5.90; P=0.36). Significantly more patients with valacyclovir prophylaxis developed biopsy-proven acute rejection (18 of 59 [31%] versus 10 of 60 [17%]; adjusted hazard ratio, 2.49; 95% confidence interval, 1.09 to 5.65; P=0.03). The incidence of polyomavirus viremia was higher in the valganciclovir group (18% versus 36%; adjusted hazard ratio, 0.43; 95% confidence interval, 0.19 to 0.96; P=0.04).

CONCLUSIONS

Valganciclovir shows no superior efficacy in cytomegalovirus DNAemia prevention compared with valacyclovir prophylaxis. However, the risk of biopsy-proven acute rejection is higher with valacyclovir.

The efficacy and cost-effectiveness of valacyclovir in cytomegalovirus prevention in solid organ transplantation

Prevention of cytomegalovirus infection using antiviral prophylaxis or the pre-emptive therapy approach is an integral part of management of patients after solid organ transplantation. Regarding renal transplantation, valacyclovir is currently the only antiviral agent recommended for prophylaxis as an alternative to valganciclovir. This review article discusses studies documenting the efficacy and safety of valacyclovir prophylaxis as well as those comparing valacyclovir with other prophylactic regimens or with pre-emptive therapy. Also addressed are the economic aspects supporting the cost-effectiveness of valacyclovir prophylaxis and demonstrating lower costs compared with other cytomegalovirus preventive strategies.

High risk of cytomegalovirus infection following solid organ transplantation despite prophylactic therapy

Cytomegalovirus infection (CMV) in solid organ transplant recipients is a major clinical problem. The aim of this study was to evaluate the incidence of CMV infection and its association with mortality during the first year after transplantation in a large solid organ transplant cohort at the Royal Infirmary of Edinburgh between January 2006 and April 2009. Data including the use of CMV prophylaxis, nature of CMV disease, treatment and deceased date (when appropriate) was collected retrospectively using hospital databases and patient notes for all transplanted patients with detectable CMV viraemia. The outcomes between recipients of kidney and liver transplants in the four CMV donor/recipient serostatus categories (D+R+, D-R-, D+R-, D-R+) were compared. A total of 428 individuals were included. Despite the administration of valganciclovir prophylaxis, CMV disease (syndrome or end-organ involvement) was diagnosed within the year of transplantation in the D+R--group in 31.3% of liver and 19.2% of kidney recipients. All D+R- transplant recipients that received CMV-prophylaxis presented with late-onset CMV disease. Furthermore, the rate of CMV disease in the D+R+-group was markedly higher in renal graft recipients compared to liver recipients (22% vs. 5%). The highest mortality was observed among the D+R+ liver and kidney graft recipients with CMV infection. The high incidence of late-onset CMV disease in D+R- transplant recipients receiving CMV prophylaxis demonstrates that CMV disease remains an important problem after organ transplantation. Furthermore, the surprisingly high mortality in the D+R+-transplant patients with CMV viraemia highlights the need for proactive monitoring of this group.

Preemptive therapy prevents cytomegalovirus end-organ disease in treatment-naïve patients with advanced HIV-1 infection in the HAART era

BACKGROUND

The efficacy of preemptive therapy against cytomegalovirus (CMV) infection remains unknown in treatment-naïve patients with advanced HIV-1 infection in the HAART era.

METHODS

The subjects of this single-center observation study were 126 treatment-naïve HIV-1 infected patients with positive CMV viremia between January 1, 2000 and December 31, 2006. Inclusion criteria were age more than 17 years, CD4 count less than 100/μl, plasma CMV DNA positive, never having received antiretroviral therapy (ART) and no CMV end-organ disease (EOD) at first visit. The incidence of CMV-EOD was compared in patients with and without preemptive therapy against CMV-EOD. The effects of the CMV preemptive therapy were estimated in uni- and multivariate Cox hazards models.

RESULTS

CMV-EOD was diagnosed in 30 of the 96 patients of the non-preemptive therapy group (31%, 230.3 per 1000 person-years), compared with 3 of the 30 patients of the preemptive therapy group (10%, 60.9 per 1000 person-years). Univariate (HR = 0.286; 95%CI, 0.087-0.939; p = 0.039) and multivariate (adjusted HR = 0.170; 95%CI, 0.049-0.602; p = 0.005) analyses confirmed that CMV-EOD is significantly prevented by CMV preemptive therapy. Multivariate analysis showed that plasma CMV DNA level correlated significantly with CMV-EOD (per log10/ml, adjusted HR = 1.941; 95%CI, 1.266-2.975; p = 0.002). Among the 30 patients on preemptive therapy, 7 (23.3%) developed grade 3-4 leukopenia. The mortality rate was not significantly different between the two groups (p = 0.193, Log-rank test).

CONCLUSIONS

The results indicate that preemptive therapy lowers the incidence of CMV-EOD by almost 25%. Preemptive therapy for treatment-naïve patients with CMV viremia is effective, although monitoring of potential treatment-related side effects is required.

Evaluation of clinical outcomes of prophylactic versus preemptive cytomegalovirus strategy in liver transplant recipients

Cytomegalovirus (CMV) is a major cause of morbidity and mortality following solid organ transplantation (SOT). Two strategies, prophylactic, and preemptive have emerged for the prevention of CMV infection and disease after SOT. This retrospective chart review of two liver transplant cohorts: prophylactic and preemptive, compares the clinical impact of transitioning from prophylactic to preemptive strategy. The primary outcome is the incidence of CMV viremia at 3-and 6-months post-transplant. Secondary outcomes include: incidence of CMV tissue-invasive disease, acute cellular rejection, leukopenia and neutropenia, opportunistic infection rates, hospital readmission rates, and mortality at 3-and 6-months post-transplant. A total of 109 patients were included in the analysis. The incidence of CMV viremia was 4.9% and 50.0% (P < 0.001) in the prophylactic versus preemptive cohort, respectively, at 3 months post-transplant. The incidence of CMV viremia was 24.6% and 8.3% (P = 0.026) in the prophylactic versus preemptive cohort, respectively, at 6 months post-transplant. There were no statistical significant differences in the secondary outcomes between both cohorts. In conclusion, there is a statistical significant difference in time to onset of CMV viremia; however, the use of either prophylactic or preemptive strategy was not associated with significant negative clinical outcomes of CMV.

Valganciclovir dosing using area under the curve calculations in pediatric solid organ transplant recipients

Pediatric valganciclovir dosing recommendations have not been extensively validated for prevention or treatment for CMV infection. As such, we performed a pharmacokinetic study to compare different valganciclovir dosing regimens and the potential benefits of individualized dose adjustments in children following organ transplantation. Ganciclovir AUCs were calculated from four plasma drug levels in pediatric SOT recipients aged six months through three yr receiving valganciclovir suspension by mouth. Of the 28 ganciclovir AUC calculations performed, 11 (39%) were outside the therapeutic target range of 40-60 mcg h/L leading to a valganciclovir dose adjustment. Current manufacturer-recommended dosing based on BSA and CrCl was estimated to result in therapeutic AUCs in fewer patients than the simple weight-based formula used in our institution (4 vs. 13; p = 0.017). An AUC calculation using only the two- and five-h measurements was strongly correlated with the AUC using all four time measurements (R(2) = 0.846; p < 0.001). A simple weight-based dosing approach gives a higher probability for therapeutic AUCs compared to the manufacturer-recommended dosing in pediatric transplant patients aged six months through three yr with normal renal function. An AUC calculated using two sample times might allow for fewer blood draws in the future.

Risk of cytomegalovirus disease in high-risk liver transplant recipients on valganciclovir prophylaxis: a systematic review and meta-analysis

Valganciclovir (VGC) was approved by the Food and Drug Administration in 2004 as cytomegalovirus (CMV) prophylaxis except for liver transplant recipients because of their high incidence of CMV disease with this drug. However, surveys have shown its common off-label use for CMV prophylaxis in liver transplant recipients. We aimed to evaluate the risk of CMV disease with VGC prophylaxis in liver transplant recipients. All studies that evaluated liver transplant recipients and used VGC (900 or 450 mg daily) for the prevention of CMV disease were included. Five controlled studies (n = 483) were pooled with a random effects model; five single-arm studies (n = 380) were pooled for the prevalence rate of CMV disease. The risk of CMV disease with VGC versus ganciclovir was 1.81 [95% confidence interval (CI) = 1.00-3.29, P = 0.05, I(2) = 0%]. For high-risk (donor-positive/recipient-negative) patients, the risk of CMV disease was 1.96 (95% CI = 1.05-3.67, P = 0.035, I(2) = 0%). The risk of CMV disease remained significant with 900 mg of VGC daily (P = 0.04) but not with 450 mg of VGC daily (P = 0.76). The risk of leukopenia with VGC was 1.87 (95% CI = 1.03-3.37, P = 0.04, I(2) = 0%). In single-arm trials, the overall CMV disease rate was 12% (95% CI = 9%-16%, P < 0.001), and the rate for high-risk patients was 20% (95% CI = 10%-38%, P = 0.002). In conclusion, 900 mg of VGC daily may not be safe as CMV prophylaxis in high-risk liver transplant recipients because of the significant 2-fold increase in the risk of CMV disease and the 1.9-fold increase in the risk of leukopenia. Alternative CMV prophylaxis should be used for liver transplant recipients.

Advances in cytomegalovirus-preventive strategies in solid organ transplantation: defending pre-emptive therapy

Prevention of cytomegalovirus (CMV) infection is an important part of clinical care provided to patients after solid organ transplantation. While the optimal preventive strategy has not been defined, most centers rely on universal prophylaxis or pre-emptive therapy. This article comments on recent studies designed to identify strategies that effectively reduce the incidence of late-onset CMV disease as the main problem associated with prophylaxis, and on recent data regarding the development of CMV-specific immunity depending on the CMV-preventive regimen used. Despite an apparent trend to prefer prophylaxis in clinical practice, this approach does not seem to be based on robust evidence.

[Prophylaxis of cytomegalovirus infection in liver transplantation]

CMV prevention strategies in liver transplant recipients should be stratified according to serological status. In donor (D)-/recipient (R)- combinations, no prophylaxis or preemptive therapy is recommended. In the remaining combinations, the most widely used strategies are universal prophylaxis and preemptive therapy. Both strategies are effective compared with placebo but have not been compared with each other in well-designed clinical trials. Preemptive therapy is the preferred strategy in low-risk patients while prophylaxis is the most widely used option in those at high-risk. Delayed CMV disease is an adverse consequence of universal prophylaxis. Prolongation of prophylaxis from 100 to 200 days does not reduce the incidence of CMV disease. CMV-specific cell mediated immunity, facilitated by preemptive therapy and delayed by prophylaxis, has a therapeutic effect by reducing CMV replication. The drug of choice in both strategies is valganciclovir but the duration and dose differ. When preemptive therapy is used, viremia monitoring is required for the first 4 months. The technique of choice is quantitative polymerase chain reaction. Given the lack of conclusive data, the choice of one or other strategy in these patients should be individualized in each patient and center according to the available resources and possibilities of follow-up.

Incidence, risk factors, and outcomes associated with cytomegalovirus disease in small bowel transplant recipients

Despite improved prophylaxis, monitoring, and more efficient immunosuppression, CMV infection remains a common opportunistic infection in transplant recipients. We assessed the incidence of CMV disease in pediatric SBT recipients, the timing of CMV disease after transplantation, and its impact on patient outcome. The medical records of 98 SBT recipients were reviewed. We performed descriptive analysis, regression analysis, and Kaplan-Meier curves to determine the time-to-event after transplantation. Fifty-three percent patients were male and 47% female, with a mean age of 38.3 months. Thirty-five percent of patients received prophylactic VGC, 55% GCV, 10% a combination of GCV/VGC, and 99% CMV immunoglobulins. A total of 24.5% recipients were CMV D+/R- (CMV serostatus donor positive/recipient negative). Seven (c. 7%) patients developed CMV disease. CMV disease was associated with 2.5 times (0.52-12.1; p = 0.25) higher rate of CMV mismatch and 11.1 times (1.3-95.9; p = 0.03) higher risk of death. CMV prophylaxis increased time-to-death (p = 0.074). Time-to-CMV disease was shorter in patients with enteritis (p < 0.0001), and CMV disease was associated with shorter time-to-death after transplantation (p = 0.001). CMV disease in SBT recipients was associated with an 11-fold mortality increase and a fourfold faster time-to-death. Time-to-death was significantly shorter with CMV enteritis.