Alemtuzumab induction and steroid-free maintenance immunosuppression in pancreas transplantation

A comprehensive update of the metabolic and toxicological considerations for immunosuppressive drugs used during pancreas transplantation

INTRODUCTION

Despite significant advancements in immunosuppressive regimens and surgical techniques, the prevalence of adverse events related to immunosuppression remains a major challenge affecting the long-term survival rates of pancreas and kidney allografts.

AREAS COVERED

This article presents a comprehensive review of the literature and knowledge (Jan/2012-Feb/2023) concerning glucose metabolism disorders and nephrotoxicity associated with tacrolimus and mammalian target of rapamycin inhibitors (mTORi). Novel signaling pathways potentially implicated in these adverse events are discussed. Furthermore, we extensively examine the findings from clinical trials evaluating the efficacy and safety of tacrolimus, mTORi, and steroid minimization.

EXPERT OPINION

Tacrolimus-based regimens continue to be the standard treatment following pancreas transplants. However, prolonged use of tacrolimus and mTORi may lead to hyperglycemia and nephrotoxicity. Understanding and interpreting experimental data, particularly concerning novel signaling pathways beyond calcineurin-NFAT and mTOR pathways, can offer valuable insights for therapeutic interventions to mitigate hyperglycemia and nephrotoxicity. Additionally, critically analyzing clinical trial results can identify opportunities for personalized safety-based approaches to minimize side effects. It is imperative to conduct randomized-controlled studies to assess the impact of mTORi use and steroid-free protocols on pancreatic allograft survival. Such studies will aid in tailoring treatment strategies for improved transplant outcomes.

First World Consensus Conference on pancreas transplantation: Part II - recommendations

The First World Consensus Conference on Pancreas Transplantation provided 49 jury deliberations regarding the impact of pancreas transplantation on the treatment of diabetic patients, and 110 experts' recommendations for the practice of pancreas transplantation. The main message from this consensus conference is that both simultaneous pancreas-kidney transplantation (SPK) and pancreas transplantation alone can improve long-term patient survival, and all types of pancreas transplantation dramatically improve the quality of life of recipients. Pancreas transplantation may also improve the course of chronic complications of diabetes, depending on their severity. Therefore, the advantages of pancreas transplantation appear to clearly surpass potential disadvantages. Pancreas after kidney transplantation increases the risk of mortality only in the early period after transplantation, but is associated with improved life expectancy thereafter. Additionally, preemptive SPK, when compared to SPK performed in patients undergoing dialysis, appears to be associated with improved outcomes. Time on dialysis has negative prognostic implications in SPK recipients. Increased long-term survival, improvement in the course of diabetic complications, and amelioration of quality of life justify preferential allocation of kidney grafts to SPK recipients. Audience discussions and live voting are available online at the following URL address: http://mediaeventi.unipi.it/category/1st-world-consensus-conference-of-pancreas-transplantation/246.

Working towards an ERAS Protocol for Pancreatic Transplantation: A Narrative Review

Enhanced recovery after surgery (ERAS) initially started in the early 2000s as a series of protocols to improve the perioperative care of surgical patients. They aimed to increase patient satisfaction while reducing postoperative complications and postoperative length of stay. Despite these protocols being widely adopted in many fields of surgery, they are yet to be adopted in pancreatic transplantation: a high-risk surgery with often prolonged length of postoperative stay and high rate of complications. We have analysed the literature in pancreatic and transplantation surgery to identify the necessary preoperative, intra-operative and postoperative components of an ERAS pathway in pancreas transplantation.

Early protocol computer tomography and endovascular interventions in pancreas transplantation

BACKGROUND

Early vascular complications following pancreatic transplantation are not uncommon (3%-8%). Typically, cross-sectional imaging is requested in response to clinical change. We instituted a change in protocol to request imaging pre-emptively to identify patients with thrombotic complications.

METHODS

In 2013, protocol computer tomography angiography (CTA) at days 3-5 and day 10 following pancreas transplantation was introduced. A retrospective analysis of all pancreas transplants performed at our institution from January 2001 to May 2019 was undertaken.

RESULTS

A total of 115 patients received pancreas transplants during this time period. A total of 78 received pancreas transplant without routine CTA and 37 patients with the new protocol. Following the change in protocol, we detected a high number of subclinical thromboses (41.7%). There was a significant decrease in invasive intervention for thrombosis (78.6% before vs 30.8% after, p = .02), and graft survival was significantly higher (61.5% before vs 86.1% after, p = .04). There was also a significant reduction in the number of graft failures (all-cause) where thrombosis was present (23.4% before vs 5.6% after, p = .02). Patient survival was unaffected (p = .48).

CONCLUSIONS

Implementation of early protocol CTA identifies a large number of patients with subclinical graft thromboses that are more amenable to conservative management and significantly reduces the requirement for invasive intervention.

Anticoagulation in simultaneous pancreas kidney transplantation - On what basis?

BACKGROUND

Despite technical refinements, early pancreas graft loss due to thrombosis continues to occur. Conventional coagulation tests (CCT) do not detect hypercoagulability and hence the hypercoagulable state due to diabetes is left untreated. Thromboelastogram (TEG) is an in-vitro diagnostic test which is used in liver transplantation, and in various intensive care settings to guide anticoagulation. TEG is better than CCT because it is dynamic and provides a global hemostatic profile including fibrinolysis.

AIM

To compare the outcomes between TEG and CCT (prothrombin time, activated partial thromboplastin time and international normalized ratio) directed anticoagulation in simultaneous pancreas and kidney (SPK) transplant recipients.

METHODS

A single center retrospective analysis comparing the outcomes between TEG and CCT-directed anticoagulation in SPK recipients, who were matched for donor age and graft type (donors after brainstem death and donors after circulatory death). Anticoagulation consisted of intravenous (IV) heparin titrated up to a maximum of 500 IU/h based on CCT in conjunction with various clinical parameters or directed by TEG results. Graft loss due to thrombosis, anticoagulation related bleeding, radiological incidence of partial thrombi in the pancreas graft, thrombus resolution rate after anticoagulation dose escalation, length of the hospital stays and, 1-year pancreas and kidney graft survival between the two groups were compared.

RESULTS

Seventeen patients who received TEG-directed anticoagulation were compared against 51 contemporaneous SPK recipients (ratio of 1: 3) who were anticoagulated based on CCT. No graft losses occurred in the TEG group, whereas 11 grafts (7 pancreases and 4 kidneys) were lost due to thrombosis in the CCT group (P = 0.06, Fisher’s exact test). The overall incidence of anticoagulation related bleeding (hematoma/ gastrointestinal bleeding/ hematuria/ nose bleeding/ re-exploration for bleeding/ post-operative blood transfusion) was 17.65% in the TEG group and 45.10% in the CCT group (P = 0.05, Fisher’s exact test). The incidence of radiologically confirmed partial thrombus in pancreas allograft was 41.18% in the TEG and 25.50% in the CCT group (P = 0.23, Fisher’s exact test). All recipients with partial thrombi detected in computed tomography (CT) scan had an anticoagulation dose escalation. The thrombus resolution rates in subsequent scan were 85.71% and 63.64% in the TEG group vs the CCT group (P = 0.59, Fisher’s exact test). The TEG group had reduced blood product usage {10 packed red blood cell (PRBC) and 2 fresh frozen plasma (FFP)} compared to the CCT group (71 PRBC/ 10 FFP/ 2 cryoprecipitate and 2 platelets). The proportion of patients requiring transfusion in the TEG group was 17.65% vs 39.25% in the CCT group (P = 0.14, Fisher’s exact test). The median length of hospital stay was 18 days in the TEG group vs 31 days in the CCT group (P = 0.03, Mann Whitney test). The 1-year pancreas graft survival was 100% in the TEG group vs 82.35% in the CCT group (P = 0.07, log rank test) and, the 1-year kidney graft survival was 100% in the TEG group vs 92.15% in the CCT group (P = 0.23, log tank test).

CONCLUSION

TEG is a promising tool in guiding judicious use of anticoagulation with concomitant prevention of graft loss due to thrombosis, and reduces the length of hospital stay.

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

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

Immunosuppressive therapy for kidney transplantation in adults: a systematic review and economic model

BACKGROUND

End-stage renal disease is a long-term irreversible decline in kidney function requiring renal replacement therapy: kidney transplantation, haemodialysis or peritoneal dialysis. The preferred option is kidney transplantation, followed by immunosuppressive therapy (induction and maintenance therapy) to reduce the risk of kidney rejection and prolong graft survival.

OBJECTIVES

To review and update the evidence for the clinical effectiveness and cost-effectiveness of basiliximab (BAS) (Simulect(®), Novartis Pharmaceuticals UK Ltd) and rabbit anti-human thymocyte immunoglobulin (rATG) (Thymoglobulin(®), Sanofi) as induction therapy, and immediate-release tacrolimus (TAC) (Adoport(®), Sandoz; Capexion(®), Mylan; Modigraf(®), Astellas Pharma; Perixis(®), Accord Healthcare; Prograf(®), Astellas Pharma; Tacni(®), Teva; Vivadex(®), Dexcel Pharma), prolonged-release tacrolimus (Advagraf(®) Astellas Pharma), belatacept (BEL) (Nulojix(®), Bristol-Myers Squibb), mycophenolate mofetil (MMF) (Arzip(®), Zentiva; CellCept(®), Roche Products; Myfenax(®), Teva), mycophenolate sodium (MPS) (Myfortic(®), Novartis Pharmaceuticals UK Ltd), sirolimus (SRL) (Rapamune(®), Pfizer) and everolimus (EVL) (Certican(®), Novartis) as maintenance therapy in adult renal transplantation.

METHODS

Clinical effectiveness searches were conducted until 18 November 2014 in MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Central Register of Controlled Trials (via Wiley Online Library) and Web of Science (via ISI), Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and Health Technology Assessment (The Cochrane Library via Wiley Online Library) and Health Management Information Consortium (via Ovid). Cost-effectiveness searches were conducted until 18 November 2014 using a costs or economic literature search filter in MEDLINE (via Ovid), EMBASE (via Ovid), NHS Economic Evaluation Database (via Wiley Online Library), Web of Science (via ISI), Health Economic Evaluations Database (via Wiley Online Library) and the American Economic Association's electronic bibliography (via EconLit, EBSCOhost). Included studies were selected according to predefined methods and criteria. A random-effects model was used to analyse clinical effectiveness data (odds ratios for binary data and mean differences for continuous data). Network meta-analyses were undertaken within a Bayesian framework. A new discrete time-state transition economic model (semi-Markov) was developed, with acute rejection, graft function (GRF) and new-onset diabetes mellitus used to extrapolate graft survival. Recipients were assumed to be in one of three health states: functioning graft, graft loss or death.

RESULTS

Eighty-nine randomised controlled trials (RCTs), of variable quality, were included. For induction therapy, no treatment appeared more effective than another in reducing graft loss or mortality. Compared with placebo/no induction, rATG and BAS appeared more effective in reducing biopsy-proven acute rejection (BPAR) and BAS appeared more effective at improving GRF. For maintenance therapy, no treatment was better for all outcomes and no treatment appeared most effective at reducing graft loss. BEL + MMF appeared more effective than TAC + MMF and SRL + MMF at reducing mortality. MMF + CSA (ciclosporin), TAC + MMF, SRL + TAC, TAC + AZA (azathioprine) and EVL + CSA appeared more effective than CSA + AZA and EVL + MPS at reducing BPAR. SRL + AZA, TAC + AZA, TAC + MMF and BEL + MMF appeared to improve GRF compared with CSA + AZA and MMF + CSA. In the base-case deterministic and probabilistic analyses, BAS, MMF and TAC were predicted to be cost-effective at £20,000 and £30,000 per quality-adjusted life-year (QALY). When comparing all regimens, only BAS + TAC + MMF was cost-effective at £20,000 and £30,000 per QALY.

LIMITATIONS

For included trials, there was substantial methodological heterogeneity, few trials reported follow-up beyond 1 year, and there were insufficient data to perform subgroup analysis. Treatment discontinuation and switching were not modelled.

FUTURE WORK

High-quality, better-reported, longer-term RCTs are needed. Ideally, these would be sufficiently powered for subgroup analysis and include health-related quality of life as an outcome.

CONCLUSION

Only a regimen of BAS induction followed by maintenance with TAC and MMF is likely to be cost-effective at £20,000-30,000 per QALY.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013189.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Anesthesia and Perioperative Care in Reconstructive Transplantation

Reconstructive transplantation of vascularized composite allografts (VCAs), such as upper extremity, craniofacial, abdominal, lower extremity, or genitourinary transplants, has emerged as a cutting-edge specialty, with more than 50 programs in the United States and 30 programs across the world performing these procedures. Most VCAs involve complicated technical planning and preparation, protracted surgery, and complex immunosuppressive or immunomodulatory protocols, each associated with unique anesthesiology challenges. This article outlines key procedural, patient, and protocol-related aspects of VCA relevant to anesthesiology management with the goal of ensuring patient safety and optimizing surgical, immunologic, and functional outcomes.

Comparing Outcomes between Antibody Induction Therapies in Kidney Transplantation

Kidney transplant recipients often receive antibody induction. Previous studies of induction therapy were often limited by short follow-up and/or absence of information about complications. After linking Organ Procurement and Transplantation Network data with Medicare claims, we compared outcomes between three induction therapies for kidney recipients. Using novel matching techniques developed on the basis of 15 clinical and demographic characteristics, we generated 1:1 pairs of alemtuzumab-rabbit antithymocyte globulin (rATG) (5330 pairs) and basiliximab-rATG (9378 pairs) recipients. We used paired Cox regression to analyze the primary outcomes of death and death or allograft failure. Secondary outcomes included death or sepsis, death or lymphoma, death or melanoma, and healthcare resource utilization within 1 year. Compared with rATG recipients, alemtuzumab recipients had higher risk of death (hazard ratio [HR], 1.14; 95% confidence interval [95% CI], 1.03 to 1.26; P<0.01) and death or allograft failure (HR, 1.18; 95% CI, 1.09 to 1.28; P<0.001). Results for death as well as death or allograft failure were generally consistent among elderly and nonelderly subgroups and among pairs receiving oral prednisone. Compared with rATG recipients, basiliximab recipients had higher risk of death (HR, 1.08; 95% CI, 1.01 to 1.16; P=0.03) and death or lymphoma (HR, 1.12; 95% CI, 1.01 to 1.23; P=0.03), although these differences were not confirmed in subgroup analyses. One-year resource utilization was slightly lower among alemtuzumab recipients than among rATG recipients, but did not differ between basiliximab and rATG recipients. This observational evidence indicates that, compared with alemtuzumab and basiliximab, rATG associates with lower risk of adverse outcomes, including mortality.

Alemtuzumab Induction and Delayed Acute Rejection in Steroid-Free Simultaneous Pancreas-Kidney Transplant Recipients

Supplemental digital content is available in the text.

Background

The optimal immunosuppressive regimen in simultaneous pancreas-kidney transplant (SPKT) recipients that prevents acute rejection episodes (AREs) and allows optimal outcome remains elusive.

Methods

This cohort study assessed incidence and time to AREs in 73 consecutive SPKT recipients receiving alemtuzumab induction and steroid-free maintenance with tacrolimus and mycophenolate mofetil. A cohort with single high-dose antithymocyte globulin (ATG; n = 85) and triple therapy served as controls. In addition, we provided mechanistic insights in AREs after alemtuzumab depletion, including composition and alloreactivity of lymphocytes (flow cytometry and mixed lymphocyte reaction) plasma alemtuzumab levels (enzyme-linked immunosorbent assay), and maintenance drug exposure.

Results

Overall number of AREs at 3 years was significantly lower with alemtuzumab versus ATG induction (26.0% vs 43.5%; adjusted hazard ratio, 0.38; P = 0.029). Most AREs (94.6%) with ATG occurred within the first month, whereas 84.2% of AREs with alemtuzumab occurred beyond 3 months. Patients with and without an ARE in the steroid-free alemtuzumab group showed no differences in composition of lymphocytes, or in alemtuzumab levels. Of note, more than two thirds of these AREs were preceded by empiric tacrolimus and/or mycophenolate mofetil dose adjustments due to viral infections, leukopenia, or gastrointestinal symptoms.

Conclusions

Alemtuzumab induction resulted in a significant lower incidence of AREs. Empiric dose adjustments beyond 3 months in the absence of steroids carry a significant risk for subsequent rejection in SPKT recipients.

Successful Combined Pancreas Fourth-Kidney Third and Pancreas Third-Kidney Second Transplantation: A Case Report

Extremely few reports have been published on experience with multiple combined pancreas-kidney re-transplantation including long-term results. We here analyze our experience with two patients following successful combined pancreas fourth-kidney third and pancreas third-kidney second transplantation.

METHODS

Patient and graft survival as well as graft function and major complications were recorded. Patient 1 (women, 47 years) underwent combined pancreas fourth-kidney third transplantation after previous removal of the first and second renal and the second pancreatic grafts. Patient 2 (men, 51 years) underwent combined pancreas third-kidney second transplantation after nephrectomy of the first renal graft. Immunosuppression consisted of induction with alemtuzumab and maintenance with tacrolimus, mycophenolate mofetil/mycophenolic acid and steroids.

RESULTS

After a follow-up of 44 and 49 months, respectively, both patients are doing well with stable graft function. Leukopenia, thrombocytopenia, bacterial sepsis, and chronic hepatitis C as major complications were controllable.

CONCLUSIONS

Multiple pancreas-retransplantations combined with simultaneous renal transplantation are feasible. Meticulous immunosuppression, careful monitoring, and excellent patient adherence are of crucial importance.

[Modern immunosuppression after solid organ transplantation]

The one common factor in solid organ transplantation is the need for lifelong maintenance immunosuppression. Drug regimens after organ transplantation typically comprise a combination of different immunosuppressive drugs. In most cases a triple drug regimen with different mechanisms of action is used. The aim is to improve both patient and graft survival while minimizing potential side effects of immunosuppressive medication. The basis of most immunosuppressive regimens is calcineurin inhibitors in combination with mycophenolic acid. There are various stages of immunosuppression after solid organ transplantation involving induction therapy, initial and long-term maintenance therapy. In each phase an individual combination of immunosuppressants is set up depending on the risk profile of the individual patient to prevent transplant rejection and organ loss. Based on these considerations, concepts of calcineurin inhibitor or steroid reduction have been established in transplant medicine in recent years. The key role in terms of development of new immunosuppressive strategies is taken by kidney transplantation, the most common solid organ transplantation performed.

Immunosuppression for pancreas transplantation with an emphasis on antibody induction strategies: review and perspective

A review of recent literature was performed to identify trends and evaluate outcomes with respect to immunosuppression in pancreas transplantation (PTX). In the past decade, the majority of PTXs were performed with depleting antibody induction, particularly in the setting of either calcineurin inhibitor minimization, corticosteroid withdrawal or both. Maintenance immunosuppression consisted of predominantly tacrolimus (TAC)/mycophenolatemofetil, TAC/mycophenolic acid or TAC/sirolimus with or without corticosteroids. Depending on PTX category, donor and recipient risk factors, case mix and immunosuppressive regimen, the 1-year incidence of acute rejection has decreased to 5-20%. Current 1-year rates of immunological pancreas graft loss range between 1.8 and 6%. Depleting antibody induction and either TAC/mycophenolatemofetil or TAC/sirolimus maintenance therapy with early steroid withdrawal have become the mainstay of immunosuppression in PTX. However, the development of non-nephrotoxic, nondiabetogenic, and nongastrointestinal toxic regimens is highly desirable to improve quality of life in all solid organ transplant recipients.

Alemtuzumab induction in simultaneous pancreas and kidney transplantation

BACKGROUND

Alemtuzumab (AZ) is a monoclonal anti-CD52 antibody used as an induction agent in organ transplantation. Few studies have analyzed this agent in the context of simultaneous kidney-pancreas transplantation (SPKT).

METHODS

We examined US registry data of SPKT recipient outcomes from January 2002 to October 2009 stratified by induction agent including AZ, other T-cell-depleting agents combined (T cell), IL2 receptor blockade (IL-2RAb), and no induction (none).

RESULTS

Of 6860 SPKT recipients, induction therapy was AZ in 10%, T cell in 49%, IL-2RAb in 18%, and none in 22%. On multivariate analysis, there were no significant differences in overall patient survival, pancreas or renal allograft survival, or delayed renal graft function for the three induction groups compared with no induction. Rehospitalization within six months of transplantation occurred more often with AZ (51%) T cell (52%), and IL-2RAB (45%) compared with none (41%; p < 0.0001). On multivariate analysis, there was a significant higher odds of six-month rehospitalization with AZ (aOR 1.40, 95%CI 1.14-1.71), IL-2RAb (aOR 1.20, 95%CI 1.01-1.42-1.20), and other T-cell-depleting agents (aOR 1.50, 95%CI 1.31-1.73) compared with none. Median length of stay was significantly shorter in the AZ (8 d) compared with the IL-2RAb (9 d), T cell (10 d), and none (10 d) groups (p < 0.0001).

CONCLUSIONS

There are no differences in patient, pancreas or renal allograft survival using AZ induction. AZ may confer an advantage in the perioperative period as evidenced by a decreased hospital length of stay. However, this benefit may be lost due to more frequent rehospitalizations.

Extended pancreas donor program - the EXPAND study rationale and study protocol

BACKGROUND

Simultaneous pancreas kidney transplantation (SPK), pancreas transplantation alone (PTA) or pancreas transplantation after kidney (PAK) are the only curative treatment options for patients with type 1 (juvenile) diabetes mellitus with or without impaired renal function. Unfortunately, transplant waiting lists for this indication are increasing because the current organ acceptability criteria are restrictive; morbidity and mortality significantly increase with time on the waitlist. Currently, only pancreas organs from donors younger than 50 years of age and with a body mass index (BMI) less than 30 are allocated for transplantation in the Eurotransplant (ET) area. To address this issue we designed a study to increase the available donor pool for these patients.

METHODS/DESIGN

This study is a prospective, multicenter (20 German centers), single blinded, non-randomized, two armed trial comparing outcome after SPK, PTA or PAK between organs with the currently allowed donor criteria versus selected organs from donors with extended criteria. Extended donor criteria are defined as organs procured from donors with a BMI of 30 to 34 or a donor age between 50 and 60 years. Immunosuppression is generally standardized using induction therapy with Myfortic, tacrolimus and low dose steroids. In principle, all patients on the waitlist for primary SPK, PTA or PAK are eligible for the clinical trial when they consent to possibly receiving an extended donor criteria organ. Patients receiving an organ meeting the current standard criteria for pancreas allocation (control arm) are compared to those receiving extended criteria organ (study arm); patients are blinded for a follow-up period of one year. The combined primary endpoint is survival of the pancreas allograft and pancreas allograft function after three months, as an early relevant outcome parameter for pancreas transplantation.

DISCUSSION

The EXPAND Study has been initiated to investigate the hypothesis that locally allocated extended criteria organs can be transplanted with similar results compared to the currently allowed standard ET organ allocation. If our study shows a favorable comparison to standard organ allocation criteria, the morbidity and mortality for patients waiting for transplantation could be reduced in the future.

TRIAL REGISTRATION

Trial registered at: NCT01384006.

[Role of simultaneous pancreas-kidney transplantation in the treatment of diabetes mellitus]

The life expectancy of patients with type 1 diabetes mellitus is inferior to that of patients with some malignancies. Simultaneous pancreas-kidney transplantation is the procedure providing the best survival results among all options of renal replacement therapy. The operative techniques and immunosuppresion have been standardized in the last decade. Although the number of transplantable organs falls behind the need, simultaneous pancreas-kidney transplantation is the method of choice for the eligible patients. The results of the two Hungarian simultaneous pancreas-kidney transplantation programs are in accordance with data published in the international literature.

Trends in immunosuppression after pancreas transplantation: what is in the pipeline?

PURPOSE OF REVIEW

To provide an overview of currently available immunosuppressive strategies and novel therapeutic developments in pancreas transplantation.

RECENT FINDINGS

From 1966 through 2012 more than 30 000 pancreas transplantations have been performed around the world with excellent patient and graft survival. However, drug-related side effects and toxicities remain to negatively affect long-term outcomes. At present, more than 90% of pancreas transplant recipients receive induction therapy with depleting or nondepleting antibodies. The most widely used maintenance protocols are based on tacrolimus and mycophenolate mofetil with early or delayed corticosteroid withdrawal. In case of documented side effects related to this standard protocol, several regimens are actively pursued to switch to mammalian target of rapamycin inhibitors as well as to attempt initial calcineurin inhibitor avoidance and immunosuppression minimization. In addition, the recent documented negative impact of donor-specific antibodies on pancreas transplantation outcome has resulted in new treatment protocols for antibody-mediated rejection including intravenous immunoglobulins, anti-CD20 antibodies and protease inhibitors.

SUMMARY

Implementation of novel therapeutic strategies and combination protocols to reduce or avoid drug toxicities and immune-related complications that are evaluated in prospective and randomized trials is requested to improve outcomes after pancreas transplantation.

Single dose of alemtuzumab induction with steroid-free maintenance immunosuppression in pancreas transplantation

BACKGROUND

The use of alemtuzumab (humanized anti-CD52 monoclonal antibody) has been primarily studied in renal transplantation, and the experience of alemtuzumab induction in pancreas transplantation is still limited. The objective of this study is to analyze the outcome of pancreas transplantation by using a single dose of 30 mg alemtuzumab induction with steroid-free maintenance immunosuppression.

METHODS

We performed a total 28 pancreas transplants (17 simultaneous kidney-pancreas transplantation [SPK], 5 pancreas after kidney transplantation [PAK], and 6 pancreas transplant alone [PTA]) between November 2006 and April 2010. Median follow-up was 25 months (range, 8-49 months). Maintenance immunosuppression consists of tacrolimus and mycophenolate. We analyzed patient/graft survival, graft function, and complications.

RESULTS

One-year actuarial patient/graft survival was 100%/100% in SPK, PAK, and PTA. Three-year actuarial patient/pancreas graft survival rates for SPK, PAK, and PTA were 100%/100%, 100%/100%, and 100%/83%, respectively. Excellent pancreas and kidney graft functions were observed. Acute cellular rejection occurred in 42% of patients. Most of the rejection episode occurred approximately 1 or 6 months after transplant. Absolute lymphocyte count remained below preoperative level for 1 year posttransplant and WBC counts were significantly lower for 3 years after transplant compared with pretransplant level. Cytomegalovirus infection and bacterial infection occurred in 28% and 36% of patients, respectively. Eleven percent of patients developed donor-specific antibodies and 7% of patients experienced antibody-mediated rejection.

CONCLUSION

A single dose of 30 mg alemtuzumab induction with steroid-free maintenance immunosuppression achieved excellent mid-term patient and graft survival for pancreas transplantation with acceptable complication rate.

Current concepts in the simultaneous transplantation of kidney and pancreas

Diabetes mellitus (DM) represents an enormous health care concern for the United States and other countries. According to the American Diabetes Association in 2007, there were more than 23 million Americans living with diabetes. This is a 13.5% increase from 2005, likely representing increases in Type II DM (DMII). Diabetes mellitus results when the beta cells of the pancreas are unable to produce sufficient insulin to prevent hyperglycemia. Simultaneous pancreas and kidney transplantation, or SPK, may be indicated for patients that have experienced renal failure as a complication of DM (either type I or type II). Until recently, technical failure represented a significant impediment to the success of pancreas transplantation. At the turn of the century, however, both renal and pancreatic graft survival dramatically improved. Immunologic and nonimmunologic causes of graft failure continue to challenge inpatient and outpatient management. With vigilance in the ICU postoperatively and in the clinic, SPK can provide significant benefit both in patient survival and quality of life.

2011 update on pancreas transplantation: comprehensive trend analysis of 25,000 cases followed up over the course of twenty-four years at the International Pancreas Transplant Registry (IPTR)

AIM

This study aimed to analyze the outcome of pancreas and pancreas-kidney transplantations based on the comprehensive follow-up data reported to the International Pancreas Transplant Registry (IPTR).

METHODS

As of December 2010, more than 35,000 pancreas transplantations have been reported to the IPTR: more than 24,000 transplantations in the US and more than 12,000 outside the US. Cases with follow-up information until March 2011 were included in the analysis.

RESULTS

Pancreas transplantations in diabetic patients were divided into 3 categories: those performed simultaneously with a kidney (SPK) (75%), those given after a previous kidney transplantation (PAK) (18%), and pancreas transplantation alone (PTA) (7%). The total number of pancreas transplantations steadily increased until 2004 but has since declined. The largest decrease was seen in PAK, which decreased by 50% from 2004 through 2010. Comparatively, the number of SPK decreased by 7% during this time. Era analysis of US transplantations between 1987 and 2010 showed changes in recipient and donor characteristics. Recipient age at transplantation increased significantly as well as transplantations in type 2 diabetes patients. The trend over time was towards tighter donor criteria. There was a concentration on younger donors, preferable trauma victims, with short preservation time. Surgical techniques for the drainage of the pancreatic duct changed over time, too. Now enteric drainage is the predominantly used technique in combination with systemic drainage of the venous effluent of the pancreas graft. Immunosuppressive protocols developed towards antibody induction therapy with tacrolimus and MMF as maintenance therapy. The rate of transplantations with steroid avoidance increased over time in all 3 categories. These changes have led to improved patient and graft survival. Patient survival now reaches over 95% at one year post-transplant and over 83% after 5 years. The best graft survival was found in SPK with 86% pancreas and 93% kidney graft function at one year. PAK pancreas graft function reached 80%, and PTA pancreas graft function reached 78% at one year. In all 3 categories, early technical graft loss rates decreased significantly to 8-9%. Likewise, the 1-year immunological graft loss rate also decreased: in SPK, the immunological 1-year graft loss rate was 1.8%, in PAK 3.7%, and in PTA 6.0%.

CONCLUSIONS

Patient survival and graft function improved significantly over the course of 24 years of pancreas transplantation in all 3 categories. With further reduction in surgical complications and improvements in immunosuppressive protocols, pancreas transplantation offers excellent outcomes for patients with labile diabetes.

Alemtuzumab in solid organ transplantation and in composite tissue allotransplantation

Alemtuzumab (Campath®, Genzyme Corporation, MA, USA) is a potent monoclonal antilymphocyte, anti-CD52 antibody. Since the 1980s, alemtuzumab has been used extensively in organ transplantation as an induction agent – also with the aim of avoiding or reducing maintenance immunosuppression. We herein review the literature on alemtuzumab in solid organ and composite tissue allotransplantation with an emphasis on clinical and mechanistic aspects of alemtuzumab. In summary, the use of alemtuzumab in solid organ and composite tissue allotransplantation shows excellent early results and holds potential for wider use in conjunction with immunosuppression minimization protocols.

Immunosuppression in simultaneous pancreas-kidney transplantation: progress to date

Simultaneous pancreas-kidney transplantation (SPKT) is the treatment of choice for patients with end-stage renal failure due to type 1 diabetes mellitus. With advances in surgical techniques and immunosuppression management, outcomes have improved, with current 1- and 10-year pancreas graft survival rates of 86% and 53%, respectively. Induction therapy with either alemtuzumab or rabbit antithymocyte globulin (rATG) in combination with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) or sirolimus appears to be safe and effective in the setting of rapid steroid withdrawal (RSW), with excellent graft survival and low rejection rates. There are no large randomized trials between alemtuzumab and rATG to determine whether one is better than the other. Anti-interleukin (IL)-2 receptor antibody induction and no induction in combination with a CNI, MMF or sirolimus, and prednisone have demonstrated excellent graft survival rates but are associated with a higher incidence of acute rejection. The efficacy of anti-IL-2 receptor antibodies or no induction in the setting of RSW is unproven. Both of the CNIs, ciclosporin and tacrolimus, are effective in preventing acute rejection in SPKT recipients; however, pancreas allograft survival may be better with tacrolimus. MMF is more effective than azathioprine in preventing acute rejection. Sirolimus appears to be effective in preventing acute rejection, but the combination of sirolimus with a CNI may accentuate the nephrotoxicity of the CNI. RSW with induction therapy is safe and effective in SPKT recipients, but longer follow-up data on outcomes are needed. Recent analysis of registry data shows that most transplant centres are using an induction agent followed by a combination of tacrolimus, MMF and corticosteroids in SPKT recipients.

Defining the risks for cytomegalovirus infection and disease after solid organ transplantation

Cytomegalovirus continues to be one of the most clinically significant infections after solid organ transplantation. Classic definitions of patients at high risk for infection and tissue-invasive disease are focused on recipient-donor serostatus, type of organ transplanted, and overall level of immunosuppression. However, recent trends in clinical practice call for a reevaluation of cytomegalovirus infection risks after solid organ transplantation. Indeed, whereas early-onset cytomegalovirus infection is usually controlled by antiviral prophylaxis with ganciclovir and derivatives, delayed- and late-onset cytomegalovirus infection can develop after the completion of a course of preventive therapy. In addition, indirect effects of cytomegalovirus infection may occur as a result of persistent low-level viremia. Suboptimal dosing of antiviral drugs due to specific drug toxicities may result in the development of ganciclovir-resistant cytomegalovirus disease. The relationship between organ allograft rejection and cytomegalovirus infection and disease has been recognized for some time. Transplantation of increasing numbers of extended-criteria donor organs increases the risk of delayed graft function and acute rejection, prompting the use of more intensive immunosuppression. In addition, the trend to spare long-term exposure to calcineurin inhibitors has contributed to a resurgence in the use of polyclonal T-cell induction immunosuppressive agents, which may reduce host anticytomegalovirus immunity. We discuss the current trends in solid organ transplantation that provide a foundation for defining risks for cytomegalovirus infection and disease, including identification of patients who would benefit from more aggressive cytomegalovirus monitoring and prevention strategies.

Isolated left-sided pulmonary edema caused by alemtuzumab (Campath) during kidney transplantation

Alemtuzumab is a novel anti-CD-52 monoclonal antibody for immunosuppression. Although cost effective and efficacious, alemtuzumab is not without risk. Interestingly, intraoperative complications caused by alemtuzumab have rarely been reported. We describe a case of intraoperative pulmonary edema following administration of alemtuzumab. A 22-year-old man underwent kidney transplantation and received alemtuzumab intraoperatively. To provide better surgical exposure for transplantation, the operation table was tilted to the right. At the end of 3.5-h uneventful procedure, a sudden oxygen desaturation was noted after the bed was flattened. The postoperative chest X-ray showed opacification of the entire left lung field. After 4 days of bi-level positive airway pressure treatment, the lung field was cleared. This case is unique in that pulmonary edema developed during surgery after administration of alemtuzumab, and that the edema developed only in the nondependent lung. Transplant anesthesiologists should be aware of the risk of this complication with these novel anti-CD-52 monoclonal antibodies.

Pancreas transplantation in the United States: a review

PURPOSE OF REVIEW

The goal of pancreas transplantation is to restore normoglycemia in patients with labile diabetes. The results of this procedure improved over the years, but, although pancreas transplantation is not considered experimental anymore, there is often reluctance to recommend this procedure because of the complexity, especially for solitary pancreas transplants. This article reviews the current status of pancreas transplantation.

RECENT FINDINGS

Many improvements have been made in the surgical techniques and immunosuppressive regimens. The overall rate of technical problems decreased, yet immunologic graft loss is still a problem in solitary pancreas transplants. Careful donor selection significantly decreased the risk of graft failure and therefore improved patient survival.

SUMMARY

With modern immunosuppressive protocols and careful donor selection, patient survival rates and pancreas transplant graft function can be further improved in all three pancreas transplant categories.

Alemtuzumab induction prior to cardiac transplantation with lower intensity maintenance immunosuppression: one-year outcomes

Induction therapy with alemtuzumab (C-1H) prior to cardiac transplantation (CTX) may allow for lower intensity maintenance immunosuppression. This is a retrospective study of patients who underwent CTX at a single institution from January 2001 until April 2009 and received no induction versus induction with C-1H on a background of tacrolimus and mycophenolate. Those with C-1H received dose-reduced calcineurin inhibitor and no steroids. A total of 220 patients were included, 110 received C-1H and 110 received no induction. Recipient baseline characteristics, donor age and gender were not different between the two groups. Mean tacrolimus levels (ng/mL) for C-1H versus no induction: months 1-3 (8.5 vs. 12.9), month 4-6 (10.2 vs. 13.0), month 7-9 (10.2 vs. 11.9) and month 10-12 (9.9 vs. 11.3) were all significantly lower for the C-1H group, p < 0.001. There were no differences between the C-1H and no induction groups at 12 months for overall survival 85.1% versus 93.6% p = 0.09, but freedom from significant rejection was significantly higher for the C-1H group, 84.5% versus 51.6%, p < 0.0001. In conclusion, induction therapy after CTX with C-1H results in a similar 12 month survival, but a greater freedom from rejection despite lower calcineurin levels and without the use of steroids.