Ten years of sirolimus therapy for human renal transplantation: the University of Texas at Houston experience

Human papillomavirus infection in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the American Society of Transplantation Infectious Diseases Community of Practice update the epidemiology and management of human papillomavirus (HPV) infections in organ transplant recipients. HPV is one of the most common sexually transmitted infections and is associated with cancers of the anogenital region. Increasing evidence suggests an association with head and neck cancers as well. Solid organ transplant recipients have a higher risk of HPV infection than the general population. Infection manifests as premalignant lesions, warts, or cancer of the cervix, penis, vulva, scrotum, and anal canal. Most are asymptomatic initially, so diagnosis can be difficult without screening. A vaccine is available though not effective in preventing all cancer-causing strains. Organ transplant recipients should be screened for HPV-associated cancers and appropriate therapy initiated in a timely manner. Further studies are warranted to delineate the most effective screening methods and therapeutic modalities, including whether changes in immunosuppression are effective in attenuating disease.

Renal association clinical practice guideline on Anaemia of Chronic Kidney Disease

Anaemia is a commonly diagnosed complication among patients suffering with chronic kidney disease. If left untreated, it may affect patient quality of life. There are several causes for anaemia in this patient population. As the kidney function deteriorates, together with medications and dietary restrictions, patients may develop iron deficiency, resulting in reduction of iron supply to the bone marrow (which is the body organ responsible for the production of different blood elements). Chronic kidney disease patients may not be able to utilise their own body's iron stores effectively and hence, many patients, particularly those receiving haemodialysis, may require additional iron treatment, usually provided by infusion.With further weakening of kidney function, patients with chronic kidney disease may need additional treatment with a substance called erythropoietin which drives the bone marrow to produce its own blood. This substance, which is naturally produced by the kidneys, becomes relatively deficient in patients with chronic kidney disease. Any patients will eventually require treatment with erythropoietin or similar products that are given by injection.Over the last few years, several iron and erythropoietin products have been licensed for treating anaemia in chronic kidney disease patients. In addition, several publications discussed the benefits of each treatment and possible risks associated with long term treatment. The current guidelines provide advice to health care professionals on how to screen chronic kidney disease patients for anaemia, which patients to investigate for other causes of anaemia, when and how to treat patients with different medications, how to ensure safe prescribing of treatment and how to diagnose and manage complications associated with anaemia and the drugs used for its treatment.

Association of Baseline Viral Serology and Sirolimus Regimens With Kidney Transplant Outcomes: A 14-Year Registry-Based Cohort Study in the United States

BACKGROUND

The risks for transplant outcomes associated with baseline viral serostatus in kidney transplant recipients (KTR) on sirolimus have not been widely studied.

METHODS

We performed a cohort-study of 61 590 adult KTR in 2000 to 2013. We used Cox regression models to determine the adjusted hazard ratio (aHR) of patient death, death-censored graft loss and posttransplant malignancy associated with the baseline serostatus (+ or -: hepatitis B core [HBc], hepatitis C virus [HCV], Epstein-Barr virus [EBV], or cytomegalovirus [CMV]) in KTR on sirolimus (SRL) + mycophenolate (MPA) or SRL + tacrolimus (Tac), relative to the control-regimen: Tac + MPA.

RESULTS

Compared with Tac + MPA, SRL + MPA, and SRL + Tac were associated with higher risks of 5-year mortality (aHR, 1.41; 95% CI, 1.23-1.60 and aHR, 1.59; 95% CI, 1.38-1.83, respectively) and death-censored graft loss (aHR, 1.41; 95% CI, 1.24-1.60 and aHR, 1.38; 95% CI, 1.21-1.57, respectively). In KTR with negative pretransplant EBV, CMV, HBc, or HCV serostatus, SRL + MPA not SRL + Tac was associated with a lower risk of posttransplant malignancy compared with control (aHR, 0.27; 95% CI, 0.10-0.72; aHR, 0.61; 95% CI, 0.43-0.88; aHR, 0.79; 95% CI, 0.64-0.97; and aHR, 0.80; 95% CI, 0.65-0.98, respectively, for SRL + MPA and aHR, 0.98: 95% CI, 0.52-1.80; aHR, 0.69; 95% CI, 0.46-1.06; aHR, 0.83; 95% CI, 0.66-1.06 and aHR, 0.85; 95% CI, 0.67-1.07, respectively, for SRL + Tac). In KTR with positive serostatus to any of the above viruses, SRL + MPA or SRL + Tac was not associated with a different malignancy risk compared with control.

CONCLUSIONS

Compared with Tac + MPA, SRL regimens were associated with higher risks for patient death and graft loss, although SRL + MPA was associated with a lower risk for posttransplant malignancy in kidney allograft recipients with negative pretransplant HBc, HCV, EBV, or CMV serology.

Chronic Allograft Nephropathy: Pathogenesis and Management of an Important Posttransplant Complication

Chronic allograft nephropathy is a devastating complication of kidney transplantation that is responsible for a significant proportion of graft loss. This complication is characterized by a progressive decline in kidney function, which is not attributable to a specific cause. Many risk factors exist for the development of chronic allograft nephropathy, including donor-, recipient-, and transplant-related factors (eg, use of calcineurin inhibitors and acute rejection episodes), as well as comorbid conditions such as hypertension and hyperlipidemia. There is no definitive treatment for this complication; management has focused on minimization or withdrawal of calcineurin inhibitors in conjunction with addition of sirolimus or mycophenolate mofetil. Alterations in the immunosuppressive regimen must be done cautiously, as precipitating acute rejection will cause further damage to the allograft. Optimal control of blood pressure, particularly with the use of agents such as angiotensin II receptor blockers, in conjunction with management of dyslipidemia may be effective concurrent therapies in patients with chronic allograft nephropathy.

New perspectives on mTOR inhibitors (rapamycin, rapalogs and TORKinibs) in transplantation

The macrolide rapamycin and its analogues (rapalogs) constitute the first generation of mammalian target of rapamycin (mTOR) inhibitors. Since the introduction of rapamycin as an immunosuppressant, there has been extensive progress in understanding its complex mechanisms of action. New insights into the function of mTOR in different immune cell types, vascular endothelial cells and neoplastic cells have opened new opportunities and challenges regarding mTOR as a pharmacological target. Currently, the two known mTOR complexes, mTOR complex (mTORC) 1 and mTORC2, are the subject of intense investigation, and the introduction of second-generation dual mTORC kinase inhibitors (TORKinibs) and gene knockout mice is helping to uncover the distinct roles of these complexes in different cell types. While the pharmacological profiling of rapalogs is advanced, much less is known about the properties of TORKinibs. A potential benefit of mTOR inhibition in transplantation is improved protection against transplant-associated viral infections compared with standard calcineurin inhibitor-based immunosuppression. Preclinical and clinical data also underscore the potentially favourable antitumour effects of mTOR inhibitors in regard to transplant-associated malignancies and as a novel treatment option for various other cancers. Many aspects of the mechanisms of action of mTOR inhibitors and their clinical implications remain unknown. In this brief review we discuss new findings and perspectives of mTOR inhibitors in transplantation.

Safety of mTOR inhibitors in adult solid organ transplantation

INTRODUCTION

Mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) are a class of immunosuppressive drugs approved for solid organ transplantation (SOT). By inhibiting the ubiquitous mTOR pathway, they present a peculiar safety profile. The increased incidence of serious adverse events in early studies halted the enthusiasm as a kidney sparing alternative to calcineurin inhibitors (CNI).

AREAS COVERED

Herein we review mTOR inhibitors safety profile for adult organ transplantation, ranging from acute side effects, such as lymphoceles, delayed wound healing, or cytopenias, to long-term ones which increase morbidity and mortality, such as cancer risk and metabolic profile. Infection, proteinuria, and cutaneous safety profiles are also addressed.

EXPERT OPINION

In the authors' opinion, mTOR inhibitors are a safe alternative to standard immunosuppression therapy with CNI and mycophenolate/azathioprine. Mild adverse events can be easily managed with an increased awareness and close monitoring of trough levels. Most serious side effects are dose- and organ-dependent. In kidney and heart transplantation mTOR inhibitors may be safely used as either low-dose de novo or through early-conversion. In the liver, conversion 4 weeks post-transplantation may reduce long-term chronic kidney disease secondary to calcineurin nephrotoxicity, without increasing hepatic artery/portal vein thrombosis.

Optimal management of skin cancer in immunosuppressed patients

Skin cancer is the most common malignancy in humans with basal cell carcinoma representing the majority of cases in the general population. The prevalence of skin cancer is increased amongst immunosuppressed patients such as those with lymphoproliferative disorders including non-Hodgkin lymphoma and chronic lymphocytic leukemia or those with iatrogenic immunosuppression following organ transplantation. In addition, these patients experience greater morbidity and mortality associated with skin cancers. The most common skin cancer in immunosuppressed patients is squamous cell carcinoma, which often presents with more aggressive features and has a greater rate of metastasis. This article reviews the risk factors, etiology, clinical presentation, and prevalence of skin cancer amongst immunosuppressed patients, including organ transplant, lymphoproliferative disorders, autoimmune disorders, and human immunodeficiency virus. We also provide a comprehensive review of treatment guidelines for immunosuppressed patients with cutaneous malignancy. Surgical therapy is the cornerstone of treatment; however, we also discuss pharmacologic treatment options, lifestyle modifications, and revision of immunosuppressive regimens.

An evaluation of sirolimus in renal transplantation

INTRODUCTION

Sirolimus is a powerful antiproliferative immunosuppressive drug approved for the prevention of kidney allograft rejection. By its unique mechanism of action, sirolimus provides a multitude of clinical potential and has been used effectively in different drug combinations. Extensive experience has been gained regarding the best timing of its application, side effect profile and potential benefits and limitations compared with other immunosuppressive drugs.

AREAS COVERED

The authors evaluate the recent experience with sirolimus in kidney transplantation. Pivotal randomized controlled trials were used to provide an overview with special attention to pharmacokinetic and dynamic aspects of sirolimus, its current clinical use as well as perspectives for its future role.

EXPERT OPINION

Sirolimus enriches the possibilities of immunosuppressive therapies after renal transplantation. Beneficial effects toward kidney function by allowing CNI sparing, lower incidence of malignancies and less viral infections have been suggested. Sirolimus should be used cautiously in de novo patients for reasons of wound healing. An early conversion to a sirolimus-based CNI-free regimen has shown promising results, whereas late conversion is more challenging. Finally, sirolimus-associated side effects are causing tolerability concerns and frequent discontinuations. Future research should aim to better define the therapeutic window and those patients most likely to benefit.

Managing post-transplant lymphoproliferative disorders in solid-organ transplant recipients: a review of immunosuppressant regimens

Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous group of potentially life-threatening complications that occur after solid organ and bone marrow transplantation. Risk factors for acquiring PTLD are type of organ transplanted, age, intensity of immunosuppression, viral infections such as Epstein-Barr virus (EBV) and time after transplantation. Due to a dearth of well designed prospective trials, treatment for PTLD is often empirical, with reduction in immunosuppression accepted as the first step. Rituximab, a monoclonal antibody directed against the CD20 antigen of immature B cells, is often used as monotherapy after reduction in immunosuppression, although this is associated with a high risk of relapse if patients have at least one of the following risk factors: age greater than 60 years, elevated lactate dehydrogenase levels and Eastern Cooperative Oncology Group Score between 2 and 4. For such patients, rituximab should be considered in combination with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone), particularly if high-grade PTLD is present. Although widely prescribed, the use of ganciclovir for PTLD remains controversial as EBV-transformed cells lack the thymidine kinase necessary for ganciclovir activation. Newer antivirals that combine ganciclovir with activators of cellular thymidine kinase have shown promising results in preclinical studies. In the absence of controlled trials, surgery may be indicated for localized disease and radiotherapy for patients with impending spinal cord compression or disease localized to the central nervous system or orbit. Future interventions may include adoptive immunotherapy, intravenous immunoglobulin, mammalian target of rapamycin inhibitors, monoclonal antibodies to interleukin-6 and galectin-1, and even EBV vaccination. Although several trials are in progress, it is necessary to wait for the long-term outcome of these studies on risk of PTLD relapse.

Long-term maintenance therapy with calcineurin inhibitors: an update

Combination therapy with mammalian target of rapamycin (mTOR)-inhibitors and calcineurin inhibitors (CNIs) provides significant immunosuppressive efficacy. If the combination of these agents is not properly optimized, however, important risks for synergistic toxicity and long-term complications may result. The combination of a CNI and an mTOR-inhibitor is a potent immunosuppressive therapy that effectively prevents the incidence of acute rejection, although the potential nephrotoxic impact must be considered in the longer term. The trend has therefore been to use a low-dose CNI in combination with the mTOR-inhibitor sirolimus in order to reduce the risk of nephrotoxicity. Recent studies show that an mTOR-inhibitor/low-dose CNI combination is effective in the short term following transplantation, and over time, consideration should be given to the elimination of the CNI in order to preserve renal function. In the medium to long term, it is also possible to consider the elimination of steroids from such a protocol. Considering CNI dose minimization or elimination is an essential component of this approach, as is the optimal dose and level of both drugs when used in combination.

Lymphoproliferative disorders after solid organ transplantation-classification, incidence, risk factors, early detection and treatment options

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous disease group of benign and malignant entities. The new World Health Organisation classification introduced in 2008 distinguishes early lesions, polymorphic, monomorphic and classical Hodgkin lymphoma-type PTLD. Based on the time of appearance, early and late forms can be identified.PTLDs are the second most frequent posttransplantation tumors in adulthood, and the most frequent ones in childhood. The incidence varies with the transplanted organ-from 1%-2% following kidney transplantation to as high as 10% following thoracic organ transplantation-due to different intensities in immunosuppression. Immunocompromised state and Epstein-Barr virus (EBV) infection are the two major risk factors.In Europe and the US approximately 85% of PTLDs are of B-cell origin, and the majority are EBV-associated. Symptoms are often unspecific; extranodal, organ manifestations and central nervous system involvement is common. Early lesions respond well to a decrease in immunosuppression. Malignant entities are treated with rituximab, chemotherapy, radiotherapy and surgical therapy. Adoptive T-cell transfer represents a promising therapeutic approach. The prognosis is favorable in early PTLD, and poor in late PTLD. Five-year survival is 30% for high-grade lymphomas. The prognosis of EBV-negative lymphomas is worse.Lowering the risk of PTLD may be achieved by low dose maintenance immunosuppression, immunosuppressive drugs inhibiting cell proliferation, and special immunotherapy (e.g. interleukin-2 inhibitors). Early detection is especially important for high risk-e.g. EBV-negative-patients, where the appearance of EBV-DNA and the increase in its titer may help.

Noninfectious pneumonitis after everolimus therapy for advanced renal cell carcinoma

RATIONALE

Noninfectious pneumonitis is a known class effect of mammalian target of rapamycin (mTOR) inhibitors.

OBJECTIVES

To assess the incidence, radiographic patterns, management, and outcome of pneumonitis in patients with advanced renal cell carcinoma receiving everolimus.

METHODS

Clinical study data from 416 patients, randomized to receive everolimus versus placebo, were analyzed for adverse events of pneumonitis. Radiographic studies performed every 8 weeks were subject to a prospective, independent, blinded central review for the presence of findings indicative of pneumonitis.

MEASUREMENTS AND MAIN RESULTS

Of 274 patients receiving everolimus, clinical pneumonitis was suspected for 37 patients (13.5%) (none with placebo). Nine cases (3.3%) were grade 1 (asymptomatic), 18 (6.6%) were grade 2 (not interfering with daily living), and 10 (3.6%) were grade 3 (interfering with daily living or oxygen indicated). No grade 4 (life-threatening) pneumonitis was observed. Of the 10 patients with grade 3 pneumonitis, 5 had baseline radiological evidence of pneumonitis before everolimus therapy. Twenty of the 37 cases (54.0%) were reversible within the follow-up period; resolution followed dose reduction for 20 patients and treatment discontinuation in 10 patients. Corticosteroid therapy was initiated in 16 cases. Dedicated radiological review of available serial radiographic studies (245 patients receiving everolimus and 132 receiving placebo) found a higher percentage of new radiographic findings even in patients without a diagnosis of clinical pneumonitis who were receiving everolimus versus placebo (38.9 vs. 15.2%).

CONCLUSIONS

Early recognition, prompt intervention, and a conservative approach are important in managing the risk associated with noninfectious pneumonitis in association with everolimus. Clinical trial registered with www.clinicaltrials.gov (NCT 00410124).

Randomized phase II study comparing two schedules of everolimus in patients with recurrent/metastatic breast cancer: NCIC Clinical Trials Group IND.163

PURPOSE

To evaluate the safety and efficacy of oral everolimus, a mammalian target of rapamycin (mTOR) inhibitor, in two different schedules in minimally pretreated patients with metastatic breast cancer and to explore for possible biologic correlates of response.

PATIENTS AND METHODS

Patients who received no or one prior chemotherapy regimen for metastatic breast cancer were entered onto this multicenter, noncomparative, randomized phase II study of everolimus 10 mg daily versus 70 mg weekly; the multinomial end points of response and progression were evaluated at 8 weeks. A two-stage accrual design was used, with 15 evaluable patients in each schedule in stage 1. Only daily therapy met criteria for continuing, and another 15 patients were added. pAKT, PTEN, carbonic anhydrase 9, estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2 (HER2) were evaluated for possible correlation with response.

RESULTS

The most common drug-related toxicities were fatigue, rash, anorexia, diarrhea, stomatitis, cough, and pneumonitis. Pneumonitis occurred at higher than expected rates and seemed to be schedule dependent, with the highest incidence on the daily schedule. Response rate with daily therapy was 12% (95% CI, 3.4% to 28.2%) compared with 0% (95% CI, 0.0% to 20.6%) for weekly therapy. Twenty-seven percent of patients on daily therapy discontinued treatment compared with 13% on weekly therapy (16% v 6% with pneumonitis, respectively). No biologic correlates of response could be identified, although there were trends favoring benefit in ER-positive and HER2-negative metastatic breast cancer.

CONCLUSION

Oral everolimus has activity in metastatic breast cancer that is schedule dependent. Daily therapy with 10 mg is worthy of further study in this patient population.

Fifteen years of clinical studies and clinical practice in renal transplantation: reviewing outcomes with de novo use of sirolimus in combination with cyclosporine

Over the course of 15 years the use of sirolimus, a macrocyclic lactone, has evolved from an adjunct to calcineurin inhibitors (CNI) to the foundation of therapy due to the drug's unique properties: First, it displays synergistic pharmacodynamic interactions with CNI. Even among high immunologic risk patients, this regimen attenuates the risk of acute allograft rejection episodes when used in combination with cyclosporine or tacrolimus. Indeed >80% reduction in CNI exposure de novo yields better long-term renal function than full cyclosporine (CsA) doses, a useful tradeoff, despite the augmented occurrence of lymphoceles and impaired wound healing. Second, by inhibiting mammalian target of rapamycin (mTOR), it exerts profound anti-neoplastic effects reducing the incidence and mediating the regression of tumors displaying PTEN-deletions and/or Akt-activations in transplant and non-transplant patients. Third, it is relatively non-nephrotoxic although it may exacerbate that property of CNI agents. Fourth, it allows prompt withdrawal of steroid therapy. Fifth, it displays reduced rates of cytomegalovirus, and BK virus infections. The major adverse reactions can generally be controlled with countermeasure therapy. Myelosuppressive effects, which tend to be transient (unless sirolimus is combined with mycophenolic acid), are readily amenable to treatment with granulocyte colony stimulating factor for leukopenia, interleukin 11 for thrombocytopenia and erythropoietin for anemia. Combinations of statins and fibrates represent effective countermeasure therapy for hypercholesterolemia and hypertriglyceridemia, respectively. Idiosyncratic reactions include hypoxemic pulmonary toxicity, refractory edema and diarrhea. Thus, sirolimus represents the vanguard of a new class of maintenance agents for immunosuppression.

Sirolimus does not absolutely abolish the occurrence/recurrence of urothelial carcinoma in renal transplant recipients

OBJECTIVE

Sirolimus (SRL), an immunosuppressant shown to possess anti-proliferative properties, was hypothesized to mitigate the occurrence of posttransplantation malignancy. We examined its effect on posttransplantation urothelial carcinoma (UC).

METHODS

This retrospective case analysis included renal allograft recipients with UC treated with SRL in a single institute.

RESULTS

Among 90 renal recipients treated with SRL, 6 had previous/new-onset UC in the native kidney/ureter or bladder: at a mean period of 28 months (range, 7-49) of administering SRL for these recipients, UC occurred/recurred in 4 of the 6 patients. Individual cases are presented in detail.

CONCLUSION

SRL does not absolutely abolish the occurrence/recurrence of UC among renal transplant recipients. Its potency as an anti-cancerous immunosuppressant for transplant recipients with UC deserves to be further defined in larger studies, probably by controlling SRL blood levels at lower or much higher ranges than used herein.

Sirolimus in combination with cyclosporine or tacrolimus plus methotrexate for prevention of graft-versus-host disease following hematopoietic cell transplantation from unrelated donors

In 2 consecutive prospective clinical trials, we evaluated the efficacy of sirolimus together with a calcineurin inhibitor (cyclosporine or tacrolimus) and low-dose methotrexate for prevention of graft-versus-host disease (GVHD) after unrelated hematopoietic cell transplantation (HCT). Nine patients received sirolimus with cyclosporine, and 17 received sirolimus with tacrolimus. The incidence of grade II-IV GVHD was 77%, with the median onset at day 7 after HCT. Because of toxicity, administration of sirolimus was discontinued earlier than planned in 11 patients, but after the onset of GVHD. Three patients developed renal failure requiring hemodialysis. Accrual in both studies was terminated because of lack of efficacy. In these studies, the addition of sirolimus to regimens containing a calcineurin inhibitor and methotrexate appeared to cause toxicity and provided no detectable improvement in preventing GVHD.

Cancer after renal transplantation

PURPOSE OF REVIEW

Prolonged waiting times for renal transplantation, an increase in the average age of recipients, decreased acute rejection rates due to use of newer potent immunosuppressives and improving long-term transplant survival have raised concerns in the transplant community regarding posttransplant cancer. In view of the fact that transplant recipients are living longer, it is of paramount importance that we continue to translate discoveries at the bench to the bedside and document cancers in the posttransplant recipient registries. Analysis of data will help in optimizing patient management.

RECENT FINDINGS

Recent evidence indicates that sirolimus is associated with a decreased incidence of posttransplant de-novo cancer and remission of Kaposi's sarcoma and nonmelanoma skin cancer. Mycophenolate mofetil has been shown to have an antiproliferative activity against leukemia and lymphoma and an anti-tumor effect against colon and prostate cancer. Clinically it has been shown to be associated with a reduced incidence of cancers like posttransplant lymphoproliferative disorder.

SUMMARY

Appropriate selection of transplant candidates, pretransplant and posttransplant cancer surveillance and judicious evidence-based use of newer immunosuppressants may help reduce the incidence and improve the outcome of posttransplant cancer.

Reduction of immunosuppression for transplant-associated skin cancer: thresholds and risks

BACKGROUND

Although evidence supports the efficacy of reducing immunosuppression for transplant-associated skin cancer, clinical thresholds for and risks associated with reduction are not well defined.

OBJECTIVES

In this study, experienced transplant physicians were surveyed regarding appropriate thresholds for consideration of reduction of immunosuppression and the likelihood of rejection and allograft compromise associated with various levels of reduction.

PATIENTS AND METHODS

Fifty-two transplant physicians reviewed 13 hypothetical patient scenarios with graduated morbidity and mortality risk and provided opinions on the degree of reduction of immunosuppression that was warranted and the risks associated with various degrees of reduction.

RESULTS

Renal, liver and cardiac transplant physicians generally concurred on the level of reduction of immunosuppression warranted by various degrees of skin cancer. As morbidity and mortality from skin cancer increased, physicians were more likely to accept risk to allograft function from more aggressive reduction.

CONCLUSIONS

Reduction of immunosuppression is considered a reasonable adjuvant strategy in recipients of solid organ transplants who have substantial morbidity and mortality risk from skin cancer. Physicians are willing to accept an increased risk of allograft compromise when confronted by severe or extensive skin cancer. Further research is needed to define the precise correlation among levels of reduction of immunosuppression, therapeutic efficacy, and concomitant risks.

Emerging approaches in hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is predicted to continue to increase over the next 30 years. Surgical intervention, including resection and orthotopic liver transplantation (OLT) is offered to a limited number of patients. Novel approaches to the treatment of patients with HCC are needed. This article aims to review emerging approaches in the care of the HCC patient including systemic treatment, selection of appropriate candidates for OLT, improved imaging to follow treatment response, and management pre-OLT and post-OLT.

Can mTOR inhibitors reduce the risk of late kidney allograft failure?

The most frequent causes of late kidney allograft failure are chronic rejection, nonalloimmune injury and death, all of which may depend on the characteristics of the donor and recipient, but may also be influenced by the type of immunosuppression. Combining calcineurin inhibitors (CNIs) and corticosteroids offers potent immunosuppression, but may also cause side effects leading to progressive graft dysfunction or an increased risk of death. New immunosuppressive strategies may come from the availability of inhibitors of mTOR, a downstream effector of phosphatidylinositol-3 kinase that provides the signal for cell proliferation by phosphorylating a cascade of kinases. Recent trials have shown that it is possible to minimize the dose or withdraw CNIs a few weeks after transplantation when they are combined with mTOR inhibitors and their combination may also make it possible to minimize or avoid the use of corticosteroids. Moreover, by inhibiting the signal for cell proliferation, mTOR inhibitors may reduce the replication of cytomegalovirus inside host cells, prevent transplant vasculopathy, and exert anti-oncogenic activity. All of these characteristics offer a ray of hope for reducing the risk of long-term allograft failure.

Use of sirolimus in solid organ transplantation

Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor that inhibits cell cycle progression and has proven to be a potent immunosuppressive agent for use in solid organ transplant recipients. The drug was initially studied as an adjunct to ciclosporin (cyclosporine) to prevent acute rejection in kidney transplant recipients. Subsequent studies have shown efficacy when combined with a variety of other immunosuppressive agents. The most common adverse effects of sirolimus are hyperlipidaemia and myelosuppression. The drug has unique antiatherogenic and antineoplastic properties, and may promote immunological tolerance and reduce the incidence of chronic allograft nephropathy. Although sirolimus is relatively non-nephrotoxic when administered as monotherapy, it pharmacodynamically enhances the toxicity of calcineurin inhibitors. Ironically, the drug has been used to facilitate calcineurin inhibitor-free protocols designed to preserve renal function after solid organ transplantation. Whether sirolimus can be used safely over the long term with low doses of calcineurin inhibitors requires further study. The use of sirolimus as a corticosteroid-sparing agent also remains to be proven in controlled trials. Postmarketing studies have revealed a number of unforeseen adverse effects including impaired wound healing and possibly proteinuria, oedema, pneumonitis and thrombotic microangiopathy. Overall, sirolimus is a powerful agent when used judiciously with other available immunosuppressants. As is true for all immunosuppressive drugs available for treatment of solid organ transplant recipients, the efficacy of the drug must be balanced against its considerable adverse effects.

The role and value of sirolimus administration in kidney and liver transplantation

Enormous advancements in visceral transplantation have led to significant improvements in the quality of life of patients. However, despite these developments, the average graft half-life after transplantation has remained almost unchanged and chronic rejection is still considered a major problem. In this regard, more concerns have shifted to factors influencing long-term graft survival, patient survival, and quality of life. To achieve this goal, detrimental effects of immunosuppressive (IS) agents, which have deleterious influence on the quality of life and/or patient survival, should be reduced. In the course of recent years, the transplant community has worked on reducing these side effects by developing new ISs, employing new combination regimens, or finding and adjusting optimal dosages and blood level concentrations. Among the IS agents, the antifungal, antitumoral and IS activity of mammalian target of rapamycin (mTOR) inhibitors without nephrotoxicity, have received special attention regarding this new class of IS. Sirolimus (SRL), as the first member of mTOR inhibitors, has been utilized in many clinical trials with respect to its benefit-risk assessment. In our review, the clinical evolution of SRL, as well as the evidence-based clinical benefits of SRL in kidney and liver transplantation (KTx, LTx), are summarized. Various studies of SRL in KTx and LTx have shown that combination therapy with SRL will enrich the variety of IS modalities. It also can be regarded as a safe base therapy to which other necessary drugs can be added. In addition to the enhanced acute rejection prophylaxis, and in contrast to the calcineurin inhibitors (CNI) and steroids, this drug solely does not have common side effects such as nephrotoxicity, neurotoxicity, diabetes mellitus and hypertension. Moreover, this agent might diminish vasculopathic processes that mediate chronic allograft nephropathy (CAN). Therefore, by reducing the likelihood of CAN it can decrease the rate of long-term organ failure. One possibly desirable characteristic of SRL is its antiproliferative effect, which could provoke antitumoral or antiatherogenic activity following transplantation. Despite all promising impacts of SRL in organ transplantation, there are some concerns regarding the adverse effects of this drug, for instance dyslipidemia, pneumonitis and wound healing problems. However, the majority of these side effects can be reduced or ceased by careful dose adjustments and correct timing of use. In conclusion, after a decade of both in vivo and in vitro studies on SRL, it can be advocated that SRL is a promising, potent and effective IS agent as it reduces the rate of acute rejection episodes in de novo transplants. It could improve the quality of life, graft and patient survival rate, and achieve excellent outcomes with few adverse effects when wisely used in combination with other immunosuppressants.

Malignancies after renal transplantation during 33 years at a single center

This study provides an analysis of incidence and characteristics of malignant tumors of 2535 patients who underwent renal transplantation between 1973 and 2007 at the Transplantation Center in Budapest. One hundred ninety-three malignant diseases were found in 188 patients (7.6%). The incidence of thyroid-, renal- hepatic-, skin- and gastric cancers as well as of Kaposi sarcoma and lymphomas increased in our transplant patient cohort compared to the figures of the general population based on the data of our Cancer Registry. On the other hand, colorectal-, oralprostate and lung cancers were underrepresented in our patient cohort. The mean time of diagnosis of malignancies following kidney transplantation was 58.5+/-44.8 months. One fifth of the tumors were detected within the first year. Patients with malignancies were distributed into four groups based on the immunosuppressive regimen: group I (8.5%), azathioprine + prednisone; group II (59.0%), cyclosporine + prednisone; group III (26.6%), cyclosporine + mycophenolate mofetil + prednisone; group IV (5.9%), tacrolimus + mycophenolate mofetil + prednisone. The mean age of patients was 47.3, 53.5, 55.5 and 58.1 years in group I, II, III and IV, respectively. Oncologic and immunosuppressive therapy was decided individually. Immunosuppression was switched to rapamycin-containing regimens in 63 cases. We lost 92 patients (48.9%) with a mean survival time of 25.8+/-39.4 months. Cumulative 1- and 5-year survivals were 69.5% and 52%, respectively. The increasing number of cancers seen early after transplantation and the increased risk of developing a cancer due to the older age of recipients draw attention to the importance of regular oncologic screening in patients on the waiting list and after transplantation.

Rapamycin retards growth and causes marked alterations in the growth plate of young rats

Rapamycin is a potent immunosuppressant with antitumoral properties widely used in the field of renal transplantation. To test the hypothesis that the antiproliferative and antiangiogenic activity of rapamycin interferes with the normal structure and function of growth plate and impairs longitudinal growth, 4-week-old male rats (n = 10/group) receiving 2 mg/kg per day of intraperitoneal rapamycin (RAPA) or vehicle (C) for 14 days were compared. Rapamycin markedly decreased bone longitudinal growth rate (94 +/- 3 vs. 182 +/- 3 microm/day), body weight gain (60.2 +/- 1.4 vs. 113.6 +/- 1.9 g), food intake (227.8 +/- 2.6 vs. 287.5 +/- 3.4 g), and food efficiency (0.26 +/- 0.00 vs. 0.40 +/- 0.01 g/g). Signs of altered cartilage formation such as reduced chondrocyte proliferation (bromodeoxiuridine-labeled cells 32.9 +/- 1.4 vs. 45.2 +/- 1.1%), disturbed maturation and hypertrophy (height of terminal chondrocytes 26 +/- 0 vs. 29 +/- 0 microm), and decreased cartilage resorption (18.7 +/- 0.5 vs. 31.0 +/- 0.8 tartrate-resistant phosphatase alkaline reactive cells per 100 terminal chondrocytes), together with morphological evidence of altered vascular invasion, were seen in the growth plate of RAPA animals. This study indicates that rapamycin can severely impair body growth in fast-growing rats and distort growth-plate structure and dynamics. These undesirable effects must be kept in mind when rapamycin is administered to children.

Immunosuppression in pediatric solid organ transplantation: opportunities, risks, and management

The pediatric transplant community stands at a time of unprecedented choice of immunosuppressive agents - and with a legacy of morbidity from those agents used in the previous two decades. This review considers the clinical utility and side-effect profiles of immunosuppressants used widely in current practice (e.g., glucocorticoids, azathioprine, ciclosporin, tacrolimus, mycophenolate, and sirolimus) and those agents which are in increasing use or in evaluation (e.g., IL-2 receptor antibodies, everolimus, FTY720, LEA29Y, and deoxyspergualin). Further consideration is given to the wider drug interactions likely during the use of new immunosuppressant regimens and to our growing awareness of the influences of genetic heterogeneity on drug efficacy and handling. Finally, we consider the new demands being placed on the use of drug monitoring to regulate dosage of this new repertoire of immunosuppressants.

Malignancy in pediatric transplant recipients

Malignancy is a well defined complication of chronic immunosuppression. Post transplant malignancies appear to be related to cumulative doses of immunosuppression, and in pediatric patients, acute infection of previously naive patients. The most commonly encountered malignancy in this age population is Post Transplant Lymphoproliferative Disorder (PTLD). PTLD is not a single entity but rather represents a continuum of disease. Treatment of PTLD should be initiated with immunosuppression reduction. Standard dose chemotherapy leads to significant morbidity. With the introduction of anti-CD20 antibody treatment with rituximab, chemotherapy has become second line therapy. The occurrence of solid malignancy appears to be associated with chronic immunosuppression. These cancers include those of skin, gynecologic organs, and the rectum, all of which appear to have the strongest association with viral mediators. Several strategies have been postulated to minimize the occurrence of malignancy. These include ganciclovir prophylaxis for the prevention of PTLD and the use of mychophenolic acid and TOR inhibitor maintenance to diminish the incidence of PTLD and solid malignancies. This leaves transplant physicians with several new and novel immunosuppressive agents with uncertain oncologic potentials that will need to be examined over the next decade.

Reduction of immunosuppression for transplant-associated skin cancer: expert consensus survey

BACKGROUND

Reduction of immunosuppression is considered a reasonable adjuvant therapeutic strategy in solid-organ transplant recipients experiencing multiple or high-risk skin cancers. However, the literature provides no guidance about what threshold of cancer development would warrant initiation of reduction of immunosuppression.

OBJECTIVES

To develop expert consensus guidelines for initiation of reduction of transplant-associated immunosuppression for solid-organ transplant recipients with severe skin cancer.

METHODS

An expert consensus panel was convened by the International Transplant Skin Cancer Collaborative and Skin Care for Organ Transplant Patients Europe Reduction of Immunosuppression Task Force. Thirteen hypothetical patient scenarios with graduated morbidity and mortality risks were presented and mean and mode expert opinions about appropriate level of reduction of systemic immunosuppression (mild, moderate, severe) were generated.

RESULTS

Mild reduction of transplant-associated immunosuppression was considered warranted once multiple skin cancers per year developed or with individual high-risk skin cancers. Moderate reduction was considered appropriate when patients experienced > 25 skin cancers per year or for skin cancers with a 10% 3-year risk of mortality. Severe reduction was considered warranted only for life-threatening skin cancers.

CONCLUSIONS

Reduction of immunosuppression is considered a reasonable adjuvant management strategy for transplant recipients with numerous or life-threatening skin cancers. Proposed guidelines are presented for the graduated reduction of immunosuppression coincident with the increasing skin cancer risks.

Long-term outcomes of single paediatric vs. ideal adult renal allograft transplants in adult recipients

AIM

To compare the outcomes of single paediatric vs. adult kidneys transplanted into adult recipients.

METHODS

A retrospective single-centre review of 38 single cadaver kidney transplants from donors less than five yr of age to wait-listed patients of low body mass index (BMI). Survival of grafts and quality of renal function were compared with 121 similarly low BMI recipients of grafts from donors 18-45 yr of age that were transplanted during the same period. Immunosuppression consisted of sirolimus, minimal-dose cyclosporine and prednisone. The mean age of the paediatric vs. adult donors was 2.8+/-1.0 and 31.1+/-9.2 yr, respectively (p<0.01) and of the recipients, 42.0+/-12.4 and 45.7+/-14.8 yr, respectively (p=NS). The mean BMI of paediatric vs. adult donor kidney recipients was 21.8+/-2.9 and 22.4+/-2.0 kg/m2 (p=NS). Sixty-six per cent of paediatric donor recipients were women compared with 44% of adult donor recipients (p=0.03).

RESULTS

Death censored actuarial graft survivals at one and five yr for recipients of paediatric vs. adult donor grafts were 93 and 84% compared with 93 and 85% (p=NS). There were no graft losses because of technical complications in the paediatric kidney donor group. At one and five yr post-transplantation, the mean estimated creatinine clearances of the paediatric donor graft recipients were 52.9+/-19.6 and 54.0+/-17.8 mL/min, respectively, compared with 56.4+/-19.8 and 49.1+/-21.7 mL/min for recipients of adult donor grafts at the same times (p=NS).

CONCLUSION

Transplantation of single paediatric donor kidneys into low BMI adult recipients provided equivalent outcomes to those of grafts from adult donors between the ages of 18 and 45 yr.

Pancreas transplantation utilizing thymoglobulin, sirolimus, and cyclosporine

BACKGROUND

This study aims to determine the impact of thymoglobulin-sirolimus-cyclosporine immunosuppression on the alloimune response of pancreas-kidney transplant recipients.

METHODS

Thirty-six pancreas transplant recipients received an induction protocol of thymoglobulin, sirolimus, reduced-dose cyclosporine, and corticosteroids. Ten recipients were also enrolled in a study to measure immune responsiveness. Flow PRA determined HLA antibody, donor-specific flow cytometry crossmatching (FCXM), T-cell subset, and suppressor cell assays were performed during the first posttransplant year.

RESULTS

One-year patient, kidney, and pancreas graft survivals were 97%, 94%, and 92%, respectively. There was one death and three graft losses. There were no acute rejection episodes. Recipients in the immune-monitoring study (n=10) displayed>80% depression of CD3, CD4, and CD8 (+) cell counts up to 3 months posttransplant. At transplantation 9/10 patients displayed<10% class I and no class II HLA antibody. By 3 months, 7/10 monitored recipients showed a transient elevation in class I HLA antibodies, including 2 patients who expressed>80% Flow PRA. One patient was pretransplant FCXM positive, whereas by 3 months posttransplant 2/10 patients demonstrated a positive FCXM. There were no clinical consequences of the presence of HLA antibody or the positive FCXMs. By 6 months, 7/9 patients demonstrated immunoregulatory suppressor cells.

CONCLUSIONS

The absence of acute rejection events was likely due to inhibition of donor-specific immunity by the immunosuppressive regimen. Seventy percent of patients demonstrated an early, non-donor-directed HLA antibody response that had no adverse effect on graft function and 78% of the monitored patients displayed immunoregulatory cells probably contributing to the successful outcomes.

Conversion to sirolimus from cyclosporine may induce nephrotic proteinuria and progressive deterioration of renal function in chronic allograft nephropathy patients

Antiproliferative and non-nephrotoxic properties of sirolimus have been exploited for treatment of patients with chronic graft dysfunction. In this paper we point to the possible association of nephrotic syndrome and renal impairment with rapid conversion from cyclosporine (CsA) to sirolimus in patients with chronic nephropathy. Five male patients, ages 34 to 56 years, with chronic renal failure in the course of glomerulonephritis, were transplanted between 1997 and 1999. For the first 49 to 65 months, the immunosuppressive regimen consisted of CsA, azathioprine (AZA), and prednisone. Thereafter, due to chronic nephropathy evidenced by biopsy, conversion to sirolimus was performed with sharp withdrawal of CsA. The serum creatinine level prior to conversion was 1.9 +/- 0.3 mg/dL. Trace to 86 mg/dL proteinuria was found in 3 patients, while 2 patients had about 200 mg/dL. After 2 to 4 months of sirolimus treatment the proteinuria progressed (558 +/- 183 mg/dL); edema, hypoproteinemia, hypoalbuminemia, and hyperlipidemia developed; and the serum creatinine increased to 3.5 +/- 0.8 mg/dL. Biopsies performed in three patients revealed new pathologic changes. After 4 to 5 months, we performed reconversion to calcineurin inhibitor. Proteinuria decreased to 0 to 150 mg/dL; nevertheless the serum creatinine was continuously rising. Six to 15 months after the conversion, 3 patients returned to dialysis. The fourth patient, who was earlier reconverted, has a serum creatinine level of 2.0 mg/dL after 15 months. In conclusion, conversion from CsA to sirolimus may induce nephrotic syndrome with progressive deterioration of renal function. Converted patients require careful monitoring of proteinuria and renal function. Early reconversion to calcineurin inhibitor may prevent progressive deterioration of graft function.

Individualization of Immunosuppressive Therapy. II. Sirolimus as a Less Nephrotoxic Alternative to Calcineurin Inhibitors

The nephrotoxic effects of chronic administration of calcineurin inhibitors have created a demand for a potent immunosuppressive drug free of this side effect. Sirolimus (SRL) clearly displays fewer and a lesser degree of adverse effects on renal function by itself. However, in combination with calcineurin antagonists, it tends to augment the nephrotoxicity due, at least in part, to a pharmacokinetic interaction. The use of SRL for de novo immunosuppression (even with adjunctive mycophenolate mofetil) is probably not sufficient to avert alloimmune reactions. A useful combination with SRL can be achieved by reducing calcineurin inhibitor exposure by 80% for immediately functioning kidneys or by delaying its inception until renal graft recovery. SRL proffers additional benefits as an inhibitor of endothelial and smooth muscle cell proliferation, serving as the foundation of chronic immunosuppressive therapy.

Relationship of cyclosporin and sirolimus blood concentrations regarding the incidence and severity of hyperlipidemia after kidney transplantation

The influence of drug concentrations on the development of persistent posttransplant hyperlipidemia was investigated in 82 patients who received cyclosporin A (CsA) and prednisone plus sirolimus (SRL) (52) or azathioprine (AZA) (30) during the first year after transplantation. Blood levels of CsA and SRL, daily doses of AZA and prednisone, and cholesterol, triglyceride, and glucose concentrations were determined during each visit (pretransplant and 30, 60, 90, 120, 180, and 360 days posttransplant). Persistent hyperlipidemia was defined as one-year average steady-state cholesterol (CavCHOL) or triglyceride (CavTG) concentrations above 240 and 200 mg/dL, respectively. Mean cholesterol and triglyceride concentrations increased after transplantation (P < 0.01) and were higher in patients receiving SRL compared to AZA (P < 0.001). Patients receiving SRL showed a significantly higher number of cholesterol (> 229 or > 274 mg/dL) and triglyceride (> 198 or > 282 mg/dL) determinations in the upper interquartile ranges. CsA and SRL interquartile ranges correlated with cholesterol concentrations (P = 0.001) whereas only SRL interquartile ranges correlated with triglyceride concentrations (P < 0.0001). Only pretransplant cholesterol concentration > 205 mg/dL was independently associated with development of persistent hypercholesterolemia (CavCHOL > 240 mg/dL, relative risk (RR) = 20, CI 3.8-104.6, P = 0.0004) whereas pretransplant triglyceride concentration > 150 mg/dL (RR = 7.2, CI 1.6-32.4, P = 0.01) or > 211 mg/dL (RR = 19.8, CI 3.6-107.9, P = 0.0006) and use of SRL (RR = 3, CI 1.0-8.8, P = 0.0049) were independently associated with development of persistent hypertriglyceridemia (CavTG > 200 mg/dL). Persistent hypercholesterolemia was more frequent among patients with higher pretransplant cholesterol concentrations and was dependent on both CsA and SRL concentrations. Persistent hypertriglyceridemia was more frequent among patients with higher pretransplant triglyceride concentrations and was dependent on SRL concentrations.

Malignancy after transplantation

As newer immunosuppressive regimens have steadily reduced the incidence of acute rejection and have extended the life expectancy of allograft recipients, posttransplant malignancy has become an important cause of mortality. In fact, it is expected that cancer will surpass cardiovascular complications as the leading cause of death in transplant patients within the next 2 decades. An understanding of the underlying pathobiology and how to minimize cancer risks in transplant recipients are essential. The etiology of posttransplant malignancy is believed to be multifactorial and likely involves impaired immunosurveillance of neoplastic cells as well as depressed antiviral immune activity with a number of common posttransplant malignancies being viral-related. Although calcineurin inhibitors and azathioprine have been linked with posttransplant malignancies, newer agents such as mycophenolate mofetil and sirolimus have not and indeed may have antitumor properties. Long-term data are needed to determine if the use of these agents will ultimately lower the mortality due to malignancy for transplant recipients.