Everolimus-treated renal transplant recipients have a more robust CMV-specific CD8+ T-cell response compared with cyclosporine- or mycophenolate-treated patients. Transplantation. 2013;95:184-191. [PMID: 23222818 DOI: 10.1097/tp.0b013e318276a1ef]

Human cytomegalovirus-related gastrointestinal disease after kidney transplantation: A systematic review

BACKGROUND

Human-cytomegalovirus (hCMV) infection involving the gastrointestinal tract represents a leading cause of morbidity and mortality among kidney transplant (KT) recipients (KTRs). Signs and symptoms of the disease are extremely variable. Prompt anti-viral therapy administration and immunosuppression modification are key factors for optimizing management. However, complex work-up strategies are generally required to confirm the preliminary diagnosis. Unfortunately, solid evidence and guidelines on this specific topic are not available. We consequently aimed to summarize current knowledge on post-KT hCMV-related gastrointestinal disease (hCMV-GID).

METHODS

We conducted a systematic review (PROSPERO ID: CRD42023399363) about hCMV-GID in KTRs.

RESULTS

Our systematic review includes 52 case-reports and ten case-series, published between 1985 and 2022, collectively reporting 311 cases. The most frequently reported signs and symptoms of hCMV-GID were abdominal pain, diarrhea, epigastric pain, vomiting, fever, and GI bleeding. Esophagogastroduodenoscopy and colonoscopy were the primary diagnostic techniques. In most cases, the preliminary diagnosis was confirmed by histology. Information on anti-viral prophylaxis were extremely limited as much as data on induction or maintenance immunosuppression. Treatment included ganciclovir and/or valganciclovir administration. Immunosuppression modification mainly consisted of mycophenolate mofetil or calcineurin inhibitor minimization and withdrawal. In total, 21 deaths were recorded. Renal allograft-related outcomes were described for 26 patients only. Specifically, reported events were acute kidney injury (n = 17), transplant failure (n = 5), allograft rejection (n = 4), and irreversible allograft dysfunction (n = 3).

CONCLUSIONS

The development of local and national registries is strongly recommended to improve our understanding of hCMV-GID. Future clinical guidelines should consider the implementation of dedicated diagnostic and treatment strategies.

Anti-CMV therapy, what next? A systematic review

Human cytomegalovirus (HCMV) is one of the main causes of serious complications in immunocompromised patients and after congenital infection. There are currently drugs available to treat HCMV infection, targeting viral polymerase, whose use is complicated by toxicity and the emergence of resistance. Maribavir and letermovir are the latest antivirals to have been developed with other targets. The approval of letermovir represents an important innovation for CMV prevention in hematopoietic stem cell transplant recipients, whereas maribavir allowed improving the management of refractory or resistant infections in transplant recipients. However, in case of multidrug resistance or for the prevention and treatment of congenital CMV infection, finding new antivirals or molecules able to inhibit CMV replication with the lowest toxicity remains a critical need. This review presents a range of molecules known to be effective against HCMV. Molecules with a direct action against HCMV include brincidofovir, cyclopropavir and anti-terminase benzimidazole analogs. Artemisinin derivatives, quercetin and baicalein, and anti-cyclooxygenase-2 are derived from natural molecules and are generally used for different indications. Although they have demonstrated indirect anti-CMV activity, few clinical studies were performed with these compounds. Immunomodulating molecules such as leflunomide and everolimus have also demonstrated indirect antiviral activity against HCMV and could be an interesting complement to antiviral therapy. The efficacy of anti-CMV immunoglobulins are discussed in CMV congenital infection and in association with direct antiviral therapy in heart transplanted patients. All molecules are described, with their mode of action against HCMV, preclinical tests, clinical studies and possible resistance. All these molecules have shown anti-HCMV potential as monotherapy or in combination with others. These new approaches could be interesting to validate in clinical trials.

The Mycophenolate-based Immunosuppressive Regimen Is Associated With Increased Mortality in Kidney Transplant Patients With COVID-19

BACKGROUND

The chronic use of immunosuppressive drugs is a key risk factor of death because of coronavirus disease 2019 (COVID-19) in kidney transplant recipients (KTRs), although no evident association between the class of immunosuppressive and outcomes has been observed. Thus, we aimed to compare COVID-19-associated outcomes among KTRs receiving 3 different immunosuppressive maintenance regimes.

METHODS

This study included data from 1833 KTRs with COVID-19 diagnosed between March 20 and April 21 extracted from the national registry before immunization. All patients were taking calcineurin inhibitor associated with mycophenolate acid (MPA, n = 1258), azathioprine (AZA, n = 389), or mammalian targets of rapamycin inhibitors (mTORi, n = 186). Outcomes within 30 and 90 d were assessed.

RESULTS

Compared with patients receiving MPA, the 30-d (79.9% versus 87.9% versus 89.2%; P < 0.0001) and 90-d (75% versus 83.5% versus 88.2%; P < 0.0001) unadjusted patient survivals were higher in those receiving AZA or mTORi, respectively. Using adjusted multivariable Cox regression, compared with patients receiving AZA, the use of MPA was associated with a higher risk of death within 30 d (adjusted hazard ratio [aHR], 1.70; 95% confidence interval [CI], 1.21-2.40; P = 0.003), which was not observed in patients using mTORi (aHR, 0.78; 95% CI, 0.45-1.35; P = 0.365). At 90 d, although higher risk of death was confirmed in patients receiving MPA (aHR, 1.46; 95% CI, 1.09-1.98; P = 0.013), a reduced risk was observed in patients receiving mTORi (aHR, 0.59; 95% CI, 0.35-0.97; P = 0.04) compared with AZA.

CONCLUSIONS

This national cohort data suggest that, in KTRs receiving calcineurin inhibitor and diagnosed with COVID-19, the use of MPA was associated with higher risk of death, whereas mTORi use was associated with lower risk of death.

Recurrent Cytomegalovirus Infection Controlled by the Introduction of Everolimus in a Simultaneous Pancreas-Kidney Transplantation Recipient: A Case Report

In simultaneous pancreas-kidney transplantation (SPK) recipients, cytomegalovirus (CMV) infection is a major complication that has been associated with the use of tacrolimus (TAC)-based immunosuppression. As one of the immunosuppressive drug options, the use of mammalian target of rapamycin inhibitors (mTORi) results in reduced rates of CMV infection in the field of solid organ transplantation. However, little is known about mTORi usage in pancreas transplantation. We report a case of recurrent CMV infection that was controlled by the introduction of mTORi (everolimus) in addition to a TAC-based immunosuppression regimen in SPK. A 52-year-old man underwent SPK. Graft duodenal perforation occurred on the 13th day of surgery, and graft duodenal resection was performed after long-term abscess drainage treatment. After graft duodenal resection, he was diagnosed with CMV viremia, and valganciclovir was started. However, because of recurrent febrile neutropenia caused by cytopenia as a side effect of valganciclovir, there was a repeated need for granulocyte-colony stimulating factor treatment. Immunosuppressive drug taper adjustment was attempted to control recurrent CMV viremia, and everolimus was introduced with the aim of reducing the dose of TAC and mycophenolate mofetil. This resulted in a continuously negative CMV antigenemia test and a stable general condition. Understanding the characteristics of various immunosuppressive agents and appropriately controlling and managing infectious diseases is crucial for the good postoperative management of patients with SPK.

Incidence of cytomegalovirus infection in seropositive kidney transplant recipients treated with everolimus: A randomized, open-label, multicenter phase 4 trial

Cytomegalovirus (CMV) persists as the most frequent opportunistic infection among solid organ transplant recipients. This multicenter trial aimed to test whether treatment with everolimus (EVR) could decrease the incidence of CMV DNAemia and disease. We randomized 186 CMV seropositive kidney transplant recipients in a 1:1 ratio to receive EVR or mycophenolic acid (MPA) in association with basiliximab, cyclosporin, and steroids and 87 in each group were analyzed. No universal prophylaxis was administered to either group. The composite primary endpoint was the presence of CMV DNAemia, CMV treatment, graft loss, death, and discontinuation of the study at 6 months posttransplant. In the modified intent-to-treat analysis, 42 (48.3%) and 70 (80.5%) patients in the EVR and MPA groups reached the primary endpoint (OR = 0.21, 95% CI: 0.11-0.43, p < .0001). Fewer patients of the EVR group received treatment for CMV (21.8% vs. 47.1%, p = .0007). EVR was discontinued in 31 (35.6%) patients. Among the 56 patients with ongoing EVR treatment, only 7.4% received treatment for CMV. In conclusion, EVR prevents CMV DNAemia requiring treatment in seropositive recipients as long as it is tolerated and maintained.

Case Report: Management of a Multidrug-Resistant CMV-Strain in a Renal Transplant Recipient by High-Dose CMV-Specific Immunoglobulins, Modulation in Immunosuppression, and Induction of CMV-Specific Cellular Immunity

The management of multidrug-resistant strains of cytomegalovirus after solid organ transplantation is challenging. This case report demonstrates the successful treatment of a multidrug-resistant strain of cytomegalovirus that may represent a valuable option for problematic cases. This report illustrates the emergence of a multidrug-resistant cytomegalovirus (CMV) UL54 mutant strain in a renal transplant recipient with severe lymphopenia and thrombocytopenia. We show that the combined treatment with high-dose intravenous cytomegalovirus-specific immunoglobulins (CMV-IVIG) after the switch to a mammalian target of rapamycin (mTOR)-inhibitor and cyclosporine A was a successful treatment alternative to direct antiviral treatment with high-dose ganciclovir and foscarnet. This treatment was associated with a quantitative induction of CMV-specific CD4 and CD8 T cells that showed maturation in phenotype and functionality with decreasing viral load. Our case report illustrates that high-dose CMV-IVIG and conversion of immunosuppressive drugs to mTOR inhibitors and cyclosporine A can be a successful treatment in a situation where the use of direct antiviral drugs was considered insufficient.

Virus-specific T cells in pediatric renal transplantation

After pediatric kidney transplantation, immunosuppressive therapy causes an increased risk of severe viral complications, especially from cytomegalovirus (CMV), BK polyomavirus (BKPyV) or Epstein-Barr virus (EBV), and less frequent from adenovirus (ADV). However, suitable predictive markers for the individual outcome of viral infections are missing and the therapeutic management remains a challenge to the success of pediatric kidney transplantation. Virus-specific T cells are known for controlling viral replication and there is growing evidence that virus-specific T cells may serve as a prognostic marker to identify patients at risk for viral complications. This review provides an overview of the usability of virus-specific T cells for improving diagnostic and therapeutic management of viral infections with reference to the necessity of antiviral prophylaxis, timing of pre-emptive therapy, and dosing of immunosuppressive medication after pediatric kidney transplantation. Several studies demonstrated that high levels of virus-specific T cells are associated with decrease of virus load and favorable outcome, whereas lack of virus-specific T cells coincided with virus-induced complications. Accordingly, the additional monitoring of virus-specific T cells aims to personalize the management of antiviral therapy, identify overimmunosuppression, and avoid unnecessary therapeutic interventions. Prospective randomized trials in pediatric kidney recipients comparing standard antiviral and immunosuppressive regimens with T cell-guided therapeutic interventions are needed, before monitoring of virus-specific T cells is implemented in the routine care of pediatric kidney graft recipients.

Effect of everolimus-based drug regimens on CMV-specific T-cell functionality after renal transplantation: 12-month ATHENA subcohort-study results

Post-transplant cytomegalovirus (CMV) infections and increased viral replication are associated with CMV-specific T-cell anergy. In the ATHENA-study, de-novo everolimus (EVR) with reduced-exposure tacrolimus (TAC) or cyclosporine (CyA) showed significant benefit in preventing CMV infections in renal transplant recipients as compared to standard TAC + mycophenolic acid (MPA). However, immunomodulatory mechanisms for this effect remain largely unknown. Ninety patients from the ATHENA-study completing the 12-month visit on-treatment (EVR + TAC n = 28; EVR + CyA n = 19; MPA + TAC n = 43) were included in a posthoc analysis. Total lymphocyte subpopulations were quantified. CMV-specific CD4 T cells were determined after stimulation with CMV-antigen, and cytokine-profiles and various T-cell anergy markers were analyzed using flow cytometry. While 25.6% of MPA + TAC-treated patients had CMV-infections, no such events were reported in EVR-treated patients. Absolute numbers of lymphocyte subpopulations were comparable between arms, whereas the percentage of regulatory T cells was significantly higher with EVR + CyA versus MPA + TAC (p = 0.019). Despite similar percentages of CMV-specific T cells, their median expression of CTLA-4 and PD-1 was lower with EVR + TAC (p < 0.05 for both) or EVR + CyA (p = 0.045 for CTLA-4) compared with MPA + TAC. Moreover, mean percentages of multifunctional CMV-specific T cells were higher with EVR + TAC (27.2%) and EVR + CyA (29.4%) than with MPA + TAC (19.0%). In conclusion, EVR-treated patients retained CMV-specific T-cell functionality, which may contribute to enhanced protection against CMV infections.

High Dimensional Renal Profiling: Towards a Better Understanding or Renal Transplant Immune Suppression

PURPOSE OF REVIEW

The goal of this review is to discuss new approaches to avoid CNI/CCS toxicities with a focus on new biologics and new methods to understand transplant rejection at the single-cell level.

RECENT FINDINGS

Recently developed biologics hold significant promise as the next wave of therapeutics designed to promote CNI/CCS-free long-term allograft acceptance. Indeed, belatacept, soluble CTLA4-Ig, is largely devoid of CNI-like toxicities, although it is accompanied by an increased frequency of acute rejection. Besides belatacept, other biologics hold promise as CNI-free immune suppressive approaches. Finally, powerful new single cell approaches can enable characterization of cellular populations that drive rejection within the rejecting allograft.

SUMMARY

We propose that the incorporated single cell profiling into studies investigating new biologics in transplantation, could be tailored to each patient, correlated with potential biomarkers in the blood and urine, and provide a platform where therapeutic targets can be rationally defined, mechanistically-based, and exploited.

Cytomegalovirus in solid organ transplant recipients-Guidelines of the American Society of Transplantation Infectious Diseases Community of Practice

Cytomegalovirus (CMV) is one of the most common opportunistic infections that affect the outcome of solid organ transplantation. This updated guideline from the American Society of Transplantation Infectious Diseases Community of Practice provides evidence-based and expert recommendations for screening, diagnosis, prevention, and treatment of CMV in solid organ transplant recipients. CMV serology to detect immunoglobulin G remains as the standard method for pretransplant screening of donors and transplant candidates. Antiviral prophylaxis and preemptive therapy are the mainstays of CMV prevention. The lack of a widely applicable viral load threshold for diagnosis and preemptive therapy is highlighted, as a result of variability of CMV nucleic acid testing, even in the contemporary era when calibrators are standardized. Valganciclovir and intravenous ganciclovir remain as drugs of choice for CMV management. Strategies for managing drug-resistant CMV infection are presented. There is an increasing use of CMV-specific cell-mediated immune assays to stratify the risk of CMV infection after solid organ transplantation, but their role in optimizing CMV prevention and treatment efforts has yet to be demonstrated. Specific issues related to pediatric transplant recipients are discussed.

Everolimus delayed and suppressed cytomegalovirus DNA synthesis, spread of the infection, and alleviated cytomegalovirus infection

Everolimus is an inhibitor of mammalian target of rapamycin (mTOR) and reduces the risk of cytomegalovirus (CMV) infection in transplant recipients. Everolimus inhibits mTOR complex 1, which regulates factors involved in several crucial cellular functions and is required for CMV replication. However, it is not clear how everolimus regulates CMV replication and prevents and alleviates CMV infection. Effects of everolimus on CMV infection, spread, and DNA synthesis and release from infected cells were assessed by plaque formation, infectious centre assay, real-time PCR of infected cells, and culture supernatant in CMV-infected cultures with and without everolimus. Everolimus enhanced plaque formation by 3.6 times, but the size of the plaques was reduced to 36.4% of untreated cultures in the absence of a pretreatment period. Everolimus reduced viral adsorption but enhanced the replication efficiency of inoculated virus, resulting in an increase in plaque number in the early phase of infection. Preinfection treatment of cells with everolimus efficiently exhibited its antiviral efficacy, and everolimus delayed and suppressed viral DNA synthesis and release from infected cells. Everolimus had suppressed the spread of infection and reduced the number of total infected cells to 40% of untreated cells on day 9, indicating reduction of the size of CMV lesions to one-sixth in 2-3 replication cycles. Preinfection treatment of the cells with everolimus augmented its suppressive effect on CMV infection and replication. Everolimus reduced the total number of infected cells and limited the CMV lesions, and this reduction in the spread of CMV infection would alleviate CMV infection in transplant recipients.

The Role of mTOR Inhibitors in the Management of Viral Infections: A Review of Current Literature

Viruses are the leading cause of infections after solid organ transplant. The antiviral properties of mammalian target of rapamycin inhibitors (mTORis) have been ascribed to a variety of mechanisms and historical data have supported their use over other immunosuppressants for a myriad of viruses. Herein, we summarize the most current data to highlight the role of mTORis in the management of viral infections after solid organ transplant. The mTORis play a clear role in the management of cytomegalovirus, and have data supporting their potential use for BK virus and human herpesvirus 8-related Kaposi sarcoma. No data definitively supports mTORis for use in Epstein-Barr virus-mediated posttransplant lymphoproliferative disorder or hepatitis C virus viral replication. Although theoretically an advantageous therapy for hepatitis C virus-related liver allograft fibrosis and human immunodeficiency virus, mTORi use specifically for these indications is less attractive with modern treatments currently available. Data surrounding mTORi efficacy in preventing rejection, and their toxicity profile must be balanced with their potential antiviral effects in combination with patient-specific factors.

The impact of everolimus in reducing cytomegalovirus events in kidney transplant recipients on steroid-avoidance strategy: 3-year follow-up of a randomized clinical trial

There is no evidence of whether everolimus (EVR) reduces cytomegalovirus (CMV) events in patients receiving steroid-free regimens. Besides, studies evaluating a tacrolimus (TAC) and EVR regimen are limited to 1-year follow-up. In this single-center prospective randomized trial, the incidence of CMV and 3-year efficacy and safety outcomes of EVR were compared to those of mycophenolate sodium (MPS) in a steroid-free regimen based on low-exposure TAC. Both groups received rabbit anti-thymocyte globulin (r-ATG) induction (6 mg/kg) and the steroids were withdrawn at day 7. Maintenance immunosuppression consisted of TAC (4-7 ng/ml until month 3 and 2-4 ng/ml thereafter) plus EVR (3-8 ng/ml) in the EVR group (n = 59); and TAC (4-7 ng/ml during all follow-up) plus MPS (1440 mg) in the MPS group (n = 56). The EVR group presented with a lower incidence of CMV events (18.6% vs. 50%, P = 0.001). No differences were observed in biopsy-proven acute rejection (6.8% vs. 3.6%, P = 0.680),graft loss (0.0% vs. 1.8%, P = 0.487),death (6.8% vs. 1.8%, P = 0.365), or estimated glomerular filtration rate at 36 months (61.1 ± 25.4 vs. 66.3 ± 24 ml/min/1.73 m² , P = 0.369). A higher proportion of patients discontinued MPS treatment (8.5% vs. 26.8%, P = 0.013) for safety issues. In conclusion, EVR was associated with lower rates of CMV events in patients induced with standard dose r-ATG and a maintenance steroid-free regimen based on TAC. This regimen effectively prevented acute rejection and demonstrated a more favorable safety profile. (ClinicalTrials.gov:NCT02084446).

The effect of anti-thymocyte globulin and everolimus on the kinetics of cytomegalovirus viral load in seropositive kidney transplant recipients without prophylaxis

BACKGROUND

The use of mTOR inhibitors is associated with lower incidence of CMV infections but its effect on viral load has not been investigated.

AIMS, MATERIALS AND METHODS

This post-hoc analysis included data from 273 CMV seropositive kidney transplant recipients randomized to receive anti-thymocyte globulin and everolimus (rAGT/TAC/EVR, n = 81), basiliximab and everolimus (BAS/TAC/EVR, n = 97) or basiliximab and mycophenolate (BAS/TAC/MPS, n = 95). All patients received tacrolimus (TAC) and corticosteroids. Preemptive CMV therapy based on weekly pp65 antigenemia test was used during the first 6 months. Blinded weekly CMV DNAemia was compared among the groups.

RESULTS

The proportion of patients with undetectable CMV DNAemia (23.4% vs 56.7% vs 22.1%, P < .001) was higher in the BAS/TAC/EVR. The median number of study visits with positive CMV DNAemia (2.0 vs 0.0 vs 4.6, rATG/EVR vs BAS/MPS, P = .354; BAS/EVR vs BAS/MPS, P < .0001; rATG/EVR vs BAS/EVR, P < .001) were lower in the BAS/TAC/EVR. The proportion of patients with positive CMV DNAemia who were not treat for CMV infection/disease based on pp65 antigenemia was higher in rATG/TAC/EVR group (74.1% vs 36.1% vs 44.2%, P < .001) but mean CMV DNAemia was comparable to BAS/TAC/EVR and lower than BAS/TAC/MPS (8536 ± 15 899 vs 7975 ± 17 935 vs 16 965 ± 37 694 copies/mL, P < .05), respectively. The proportion of patients with CMV DNAemia below 5000 copies/mL was higher in patients receiving EVR (74.1% vs 83.5% vs 50.0%, P = .000), respectively.

DISCUSSION AND CONCLUSION

These data suggest that mTOR inhibitors reduce the incidence of CMV infection by limiting CMV viral replication.

ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors)

BACKGROUND

The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies.

AIMS

To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations.

SOURCES

Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family.

CONTENT

Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing).

IMPLICATIONS

Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the reviewed agents.

Sirolimus Associated with Tacrolimus at Low Doses in Elderly Kidney Transplant Patients: A Prospective Randomized Controlled Trial

OBJECTIVES

There is no consensus on the best immunosuppressive regimen for elderly renal transplant recipients. The objective of this study was to assess cytomegalovirus infection incidence and kidney transplant outcomes in elderly recipients treated with mammalian target of rapamycin inhibitors sirolimus/ tacrolimus at low doses compared with those receiving tacrolimus/mycophenolate sodium.

MATERIALS AND METHODS

In this single-center prospective randomized study (Trial Registration No. NCT02683291), kidney transplant recipients over 60 years of age were randomly allocated into 2 groups: tacrolimus-sirolimus (21 patients) and tacrolimus-mycophenolate (23 patients). Cytomegalovirus infection rate and patient survival, biopsy-proven acute rejection, and renal function at 12 months were assessed.

RESULTS

Cytomegalovirus infection rate was higher in the mycophenolate group (60.9%) than in the sirolimus group (16.7%; P = .004). The rates of biopsy-proven acute rejection, patient survival, graft survival, and estimated glomerular filtration rate over 12 months did not significantly differ between groups.

CONCLUSIONS

The incidence of cytomegalovirus infection was significantly lower in the sirolimus group. The use of tacrolimus combined with sirolimus in elderly kidney transplant recipients is safe.

Conversion from calcineurin inhibitors to mTOR inhibitors as primary immunosuppressive drugs in pediatric heart transplantation

There are only a few reports of successful use of mammalian target of rapamycin (mTORI) as primary immunosuppression in pediatric heart transplantation. Compared to calcineurin inhibitors, mTORI have less side effects, especially nephrotoxicity, infections, and malignancies. A retrospective study was conducted at our institution of all 170 heart transplants from 1995 to 2015. Nineteen patients were switched from tacrolimus (n=15) or cyclosporin (n=4) to everolimus (n=4) or sirolimus (n=15) due to nephrotoxicity (n=5), malignancy (n=8), EBV viremia/reactive plasmacytic changes (n=5), and immune hemolytic anemia (n=1). We monitored for rejection, infection, BUN, creatinine, hyperlipidemia, EBV and CMV copies, CBC, cardiac allograft vasculopathy (CAV), and death. Target trough levels of sirolimus and everolimus were 4-10. Four treatment failures included debilitating rash, bone marrow suppression, recurrent rejection, and renal transplantation. There were no deaths. One patient had recurrent rejection episodes, and tacrolimus was reinitiated. One patient with preexisting CAV underwent heart retransplantation. One patient, who was treated for PTLD, transformed to CD30+ Hodgkins disease, and was treated with brentuximab. There were three acute rejection episodes. Median creatinine preswitch was higher 0.82 than postswitch 0.78 (P=.016). Median eGFR was lower preswitch, 75.6, than postswitch, 91.2 (P=.0004). These results indicate that conversion to mTORI as primary immunosuppression may be safely accomplished in some pediatric heart transplant patients.

CMV and BKPyV Infections in Renal Transplant Recipients Receiving an mTOR Inhibitor-Based Regimen Versus a CNI-Based Regimen: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

BACKGROUND AND OBJECTIVES

The objective of this meta-analysis is to compare the incidences of cytomegalovirus and BK polyoma virus infections in renal transplant recipients receiving a mammalian target of rapamycin inhibitor (mTOR)-based regimen compared with a calcineurin inhibitor-based regimen.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a comprehensive search for randomized, controlled trials up to January of 2016 addressing our objective. Other outcomes included acute rejection, graft loss, serious adverse events, proteinuria, wound-healing complications, and eGFR. Two review authors selected eligible studies, abstracted data, and assessed risk of bias. We assessed quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology.

RESULTS

We included 28 randomized, controlled trials with 6211 participants classified into comparison 1: mTOR inhibitor versus calcineurin inhibitor and comparison 2: mTOR inhibitor plus reduced dose of calcineurin inhibitor versus regular dose of calcineurin inhibitor. Results showed decreased incidence of cytomegalovirus infection in mTOR inhibitor-based group in both comparison 1 (risk ratio, 0.54; 95% confidence interval, 0.41 to 0.72), with high quality of evidence, and comparison 2 (risk ratio, 0.43; 95% confidence interval, 0.24 to 0.80), with moderate quality of evidence. The available evidence neither confirmed nor ruled out a reduction of BK polyoma virus infection in mTOR inhibitor-based group in both comparisons. Secondary outcomes revealed more serious adverse events and acute rejections in mTOR inhibitor-based group in comparison 1 and no difference in comparison 2. There was no difference in graft loss in both comparisons. eGFR was higher in the mTOR inhibitor-based group in comparison 1 (mean difference =4.07 ml/min per 1.73 m2; 95% confidence interval, 1.34 to 6.80) and similar to the calcineurin inhibitor-based group in comparison 2. More proteinuria and wound-healing complications occurred in the mTOR inhibitor-based groups.

CONCLUSIONS

We found moderate- to high-quality evidence of reduced risk of cytomegalovirus infection in renal transplant recipients in the mTOR inhibitor-based compared with the calcineurin inhibitor-based regimen. Our review also suggested that a combination of a mTOR inhibitor and a reduced dose of calcineurin inhibitor may be associated with similar eGFR and rates of acute rejections and serious adverse events compared with a standard calcineurin inhibitor-based regimen at the expense of higher incidence of proteinuria and wound-healing complications.

Calcineurin inhibitor withdrawal or tapering for kidney transplant recipients

BACKGROUND

Calcineurin inhibitors (CNI) can reduce acute transplant rejection and immediate graft loss but are associated with significant adverse effects such as hypertension and nephrotoxicity which may contribute to chronic rejection. CNI toxicity has led to numerous studies investigating CNI withdrawal and tapering strategies. Despite this, uncertainty remains about minimisation or withdrawal of CNI.

OBJECTIVES

This review aimed to look at the benefits and harms of CNI tapering or withdrawal in terms of graft function and loss, incidence of acute rejection episodes, treatment-related side effects (hypertension, hyperlipidaemia) and death.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 11 October 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) where drug regimens containing CNI were compared to alternative drug regimens (CNI withdrawal, tapering or low dose) in the post-transplant period were included, without age or dosage restriction.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for eligibility, risk of bias, and extracted data. Results were expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 83 studies that involved 16,156 participants. Most were open-label studies; less than 30% of studies reported randomisation method and allocation concealment. Studies were analysed as intent-to-treat in 60% and all pre-specified outcomes were reported in 54 studies. The attrition and reporting bias were unclear in the remainder of the studies as factors used to judge bias were reported inconsistently. We also noted that 50% (47 studies) of studies were funded by the pharmaceutical industry.We classified studies into four groups: CNI withdrawal or avoidance with or without substitution with mammalian target of rapamycin inhibitors (mTOR-I); and low dose CNI with or without mTOR-I. The withdrawal groups were further stratified as avoidance and withdrawal subgroups for major outcomes.CNI withdrawal may lead to rejection (RR 2.54, 95% CI 1.56 to 4.12; moderate certainty evidence), may make little or no difference to death (RR 1.09, 95% CI 0.96 to 1.24; moderate certainty), and probably slightly reduces graft loss (RR 0.85, 95% CI 0.74 to 0.98; low quality evidence). Hypertension was probably reduced in the CNI withdrawal group (RR 0.82, 95% CI 0.71 to 0.95; low certainty), while CNI withdrawal may make little or no difference to malignancy (RR 1.10, 95% CI 0.93 to 1.30; low certainty), and probably makes little or no difference to cytomegalovirus (CMV) (RR 0.87, 95% CI 0.52 to 1.45; low certainty)CNI avoidance may result in increased acute rejection (RR 2.16, 95% CI 0.85 to 5.49; low certainty) but little or no difference in graft loss (RR 0.96, 95% CI 0.79 to 1.16; low certainty). Late CNI withdrawal increased acute rejection (RR 3.21, 95% CI 1.59 to 6.48; moderate certainty) but probably reduced graft loss (RR 0.84, 95% CI 0.72 to 0.97, low certainty).Results were similar when CNI avoidance or withdrawal was combined with the introduction of mTOR-I; acute rejection was probably increased (RR 1.43; 95% CI 1.15 to 1.78; moderate certainty) and there was probably little or no difference in death (RR 0.96; 95% CI 0.69 to 1.36, moderate certainty). mTOR-I substitution may make little or no difference to graft loss (RR 0.94, 95% CI 0.75 to 1.19; low certainty), probably makes little of no difference to hypertension (RR 0.86, 95% CI 0.64 to 1.15; moderate), and probably reduced the risk of cytomegalovirus (CMV) (RR 0.60, 95% CI 0.44 to 0.82; moderate certainty) and malignancy (RR 0.69, 95% CI 0.47 to 1.00; low certainty). Lymphoceles were increased with mTOR-I substitution (RR 1.45, 95% CI 0.95 to 2.21; low certainty).Low dose CNI combined with mTOR-I probably increased glomerular filtration rate (GFR) (MD 6.24 mL/min, 95% CI 3.28 to 9.119; moderate certainty), reduced graft loss (RR 0.75, 95% CI 0.55 to 1.02; moderate certainty), and made little or no difference to acute rejection (RR 1.13 ; 95% CI 0.91 to 1.40; moderate certainty). Hypertension was decreased (RR 0.98, 95% CI 0.80 to 1.20; low certainty) as was CMV (RR 0.41, 95% CI 0.16 to 1.06; low certainty). Low dose CNI plus mTOR-I makes probably makes little of no difference to malignancy (RR 1.22, 95% CI 0.42 to 3.53; low certainty) and may make little of no difference to death (RR 1.16, 95% CI 0.71 to 1.90; moderate certainty).

AUTHORS' CONCLUSIONS

CNI avoidance increased acute rejection and CNI withdrawal increases acute rejection but reduced graft loss at least over the short-term. Low dose CNI with induction regimens reduced acute rejection and graft loss with no major adverse events, also in the short-term. The use of mTOR-I reduced CMV infections but increased the risk of acute rejection. These conclusions must be tempered by the lack of long-term data in most of the studies, particularly with regards to chronic antibody-mediated rejection, and the suboptimal methodological quality of the included studies.

Role of mTOR inhibitors for the control of viral infection in solid organ transplant recipients

Appropriate post-transplant immunosuppressive regimens that avoid acute rejection, while reducing risk of viral reactivation, have been sought, but remain a chimera. Recent evidence suggesting potential regulatory and antiviral effects of mammalian target of rapamycin inhibitors (mTORi) is of great interest. Although the concept of an immunosuppressive drug with antiviral properties is not new, little effort has been made to put the evidence together to assess the management of immunosuppressive therapy in the presence of a viral infection. This review was developed to gather the evidence on antiviral activity of the mTORi against the viruses that most commonly reactivate in adult solid organ recipients: cytomegalovirus (CMV), polyomavirus, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), and hepatitis C virus (HCV). A rapid review methodology and evaluation of quality and consistency of evidence based on the GRADE system was used. The existing literature was variable in nature, although indicating a potential advantage of mTORi in CMV, polyomavirus, and HHV8 infection, and a most doubtful relation with EBV and HCV infection. Several recommendations about the management of these infections are presented that can change certain current patterns of immunosuppression and help to improve the prognosis of the direct and indirect effects of viral infection in solid organ recipients.

Infectious Diseases in Transplantation--Report of the 20th Nantes Actualités Transplantation Meeting

The 20th Nantes Actualités Transplantation (NAT) meeting was held on June 11, 2015, and June 12, 2015. This year, the local organizing committee selected an update on infectious diseases in solid organ and hematopoietic stem cell transplantation. With an attendance of close to 170 clinicians, researchers, students, engineers, technicians, invited speakers, and guests from North and South America, Germany, Switzerland, Netherlands, and France, the meeting was well attended. Invited speakers' expertise covered basic as well as translational microbiology, immunology, transplantation, and intensive care medicine. This report identifies a number of advances presented during the meeting in the care and management of infectious diseases in transplantation and immunocompromised patients. New antiviral immune responses and their modulation by pathogens in addition to novel antimicrobial therapeutic strategies, cell therapies, and genomic analysis were discussed.

Immunosuppressive potency of mechanistic target of rapamycin inhibitors in solid-organ transplantation

Mammalian target of rapamycin, also known as mechanistic target of rapamycin (mTOR) is a protein kinase that belongs to the PI3K/AKT/mTOR signaling pathway, which is involved in several fundamental cellular functions such as cell growth, proliferation, and survival. This protein and its associated pathway have been implicated in cancer development and the regulation of immune responses, including the rejection response generated following allograft transplantation. Inhibitors of mTOR (mTORi) such as rapamycin and its derivative everolimus are potent immunosuppressive drugs that both maintain similar rates of efficacy and could optimize the renal function and diminish the side effects compared with calcineurin inhibitors. These drugs are used in solid-organ transplantationtoinduceimmunosuppression while also promoting the expansion of CD4+CD25+FOXP3+ regulatory T-cells that could favor a scenery of immunological tolerance. In this review, we describe the mechanisms by which inhibitors of mTOR induce suppression by regulation of these pathways at different levels of the immune response. In addition, we particularly emphasize about the main methods that are used to assess the potency of immunosuppressive drugs, highlighting the studies carried out about immunosuppressive potency of inhibitors of mTOR.

A randomized trial of everolimus and low-dose cyclosporine in renal transplantation: with or without steroids?

This multicenter, randomized, prospective, controlled trial (EVIDENCE study) aimed to determine short-term effects of early steroid withdrawal in renal transplant patients initially treated with everolimus, low-dose cyclosporine (CsA), and steroids. Patients were randomized to standard triple therapy with CsA, everolimus twice daily and steroids (group A), steroid-free immunosuppression (group B), or triple therapy once daily (group C). However, since patient enrollment was slower than expected, group C randomization was prematurely discontinued. The primary end point was treatment failure rate (composite end point of death, graft loss, biopsy-proven acute rejection, and loss to follow-up) between randomization and month 12. Patients evaluable for the primary end point included 139 randomized patients. According to intention-to-treat analysis, 2.8% of patients in group A and 14.7% in group B experienced treatment failure (95% upper confidence limit 19.7%). As this was higher than the predefined noninferiority limit of 10%, noninferiority could not be proved. No conclusive statements can be made on noninferiority of the steroid withdrawal regimen vs the standard regimen in these patients. Additional studies with longer follow-up are required to determine the efficacy of steroid-free immunosuppression in renal transplant recipients receiving everolimus.

Prevention of carcinogen and inflammation-induced dermal cancer by oral rapamycin includes reducing genetic damage

Cancer prevention is a cost-effective alternative to treatment. In mice, the mTOR inhibitor rapamycin prevents distinct spontaneous, noninflammatory cancers, making it a candidate broad-spectrum cancer prevention agent. We now show that oral microencapsulated rapamycin (eRapa) prevents skin cancer in dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) carcinogen-induced, inflammation-driven carcinogenesis. eRapa given before DMBA/TPA exposure significantly increased tumor latency, reduced papilloma prevalence and numbers, and completely inhibited malignant degeneration into squamous cell carcinoma. Rapamycin is primarily an mTORC1-specific inhibitor, but eRapa did not reduce mTORC1 signaling in skin or papillomas, and did not reduce important proinflammatory factors in this model, including p-Stat3, IL17A, IL23, IL12, IL1β, IL6, or TNFα. In support of lack of mTORC1 inhibition, eRapa did not reduce numbers or proliferation of CD45(-)CD34(+)CD49f(mid) skin cancer initiating stem cells in vivo and marginally reduced epidermal hyperplasia. Interestingly, eRapa reduced DMBA/TPA-induced skin DNA damage and the hras codon 61 mutation that specifically drives carcinogenesis in this model, suggesting reduction of DNA damage as a cancer prevention mechanism. In support, cancer prevention and DNA damage reduction effects were lost when eRapa was given after DMBA-induced DNA damage in vivo. eRapa afforded picomolar concentrations of rapamycin in skin of DMBA/TPA-exposed mice, concentrations that also reduced DMBA-induced DNA damage in mouse and human fibroblasts in vitro. Thus, we have identified DNA damage reduction as a novel mechanism by which rapamycin can prevent cancer, which could lay the foundation for its use as a cancer prevention agent in selected human populations.

Beyond calcineurin inhibitors: emerging agents in kidney transplantation

PURPOSE OF REVIEW

Despite their effectiveness, calcineurin inhibitors (CNIs) represent a major obstacle in the improvement of long-term graft survival in transplantation. The identification of new agents to implement CNI-free regimens is the focus of current transplant research. The purpose of this review is to summarize the novel immunosuppressive agents, including details about their mechanisms of action, stages of development, potential benefits and challenges.

RECENT FINDINGS

Targeting costimulation with belatacept is now an option for controlling the alloimmune response and has proved to be more effective in preserving long-term allograft function than CNIs despite an increased rate of acute rejection in some studies. mTOR inhibitors are also promising with their remarkable antineoplastic properties, though frequent side-effects may limit their broader use. Other agents under development include JAK inhibitors, CD40 blockade and leukocyte adhesion blockers, with unique potential benefits and side-effects in transplantation.

SUMMARY

Novel immunosuppressive agents are now available for use in CNI-free regimens in solid organ transplantation. Timing of initiation as well as long-term efficacy and safety are questions that remain to be answered in future clinical trials.

New cell-signaling pathways for controlling cytomegalovirus replication

Cytomegalovirus (CMV) is increasingly recognized as an accomplished modulator of cell-signaling pathways, both directly via interaction between viral and cellular proteins, and indirectly by activating metabolic/energy states of infected cells. Viral genes, as well as captured cellular genes, enable CMV to modify these pathways upon binding to cellular receptors, up until generation of virus progeny. Deregulation of cell-signaling pathways appears to be a well-developed tightly balanced virus strategy to achieve the desired consequences in each infected cell type. Importantly and perhaps surprisingly, identification of new signaling pathways in cancer cells positioned CMV as a sophisticated user and abuser of many such pathways, creating opportunities to develop novel therapeutic strategies for inhibiting CMV replication (in addition to standard of care CMV DNA polymerase inhibitors). Advances in genomics and proteomics allow the identification of CMV products interacting with the cellular machinery. Ultimately, clinical implementation of candidate drugs capable of disrupting the delicate balance between CMV and cell-signaling will depend on the specificity and selectivity index of newly identified targets.

Conversion to mTOR-inhibitor-based immunosuppression: which patients and when?

Mammalian target of rapamycin (mTOR) inhibitors are currently considered an alternative immunosuppressive treatment that can prevent the nephrotoxicity, viral infections and malignancies that are associated with calcineurin inhibitor-based immunosuppressive regimens. However, the side effects of mTOR-inhibitor-based regimens lead to frequent treatment discontinuations, and not all patients seem to have the same benefits from conversion to mTOR inhibitors. This review focuses on long-term results of trials that have assessed early and late conversion to sirolimus or everolimus. The renal benefit of late conversion (≥1 year post transplantation) is limited, except in patients with good renal function and without proteinuria. Early conversion to mTOR inhibitors in the first 6 months, in combination with mycophenolate mofetil, could be an appropriate strategy for maintenance therapy in renal transplant recipients with a low immunological risk after careful screening at the time of conversion. Good renal function (glomerular filtration rate >40 ml/ minute), weak proteinuria (<1 g/day), an absence of previous acute rejection and subclinical rejection, and appearance of donor-specific anti-human leukocyte antigen antibodies appear to be the most important criteria in identifying patients for whom conversion to an mTOR inhibitor may improve renal function at 5 years.