Tacrolimus with mycophenolate mofetil (MMF) or sirolimus vs. cyclosporine with MMF in cardiac transplant patients: 1-year report

Two-Dose Daclizumab, Tacrolimus, Mycophenolate Mofetil, and Steroid-Free Regimen in De Novo Cardiac Transplant Recipients: Early Experience

BACKGROUND

Tacrolimus (TAC) with mycophenolate mofetil (MMF) and a steroid-free regimen seems to have good efficacy in preventing acute rejection in cardiac transplant recipients, although concern exists about nephrotoxicity. Induction therapy with Daclizumab seems to give protection without side effects. Data are lacking about the outcome of 2-dose Daclizumab+TAC+MMF and a steroid-free regimen.

MATERIALS AND METHODS

We retrospectively reviewed 28 consecutive de novo heart transplantations performed at a single center between January 2001 and June 2006. Patients received induction therapy with 2-dose Daclizumab. Maintenance immunosuppression included TAC, MMF, and prednisone during the first 6 months. The endpoints were the incidence of acute rejection, patient and graft survival, and clinical tolerability.

RESULTS

Among 28 patients of mean age 57 +/- 9 years, 2 subjects (7%) died in the perioperative period due to infections. The mean follow-up was 2.8 +/- 1.5 years. There were no late deaths. Six patients experienced acute rejection (International Society of Heart and Lung Transplantation [ISHLT] >or=3A) that required treatment during the first 3 months. At follow-up, only 3 patients (>or=3A) required treatment. Mean creatinine level increased from 1.08 +/- 0.37 at baseline to 1.08 +/- 0.41 at 1 year (n = 23; P = not significant [NS]) to 1.39 +/- 0.68 (n = 13; P < .05) at 4 years, 1.65 +/- 0.51 (n = 8; P < .05) at 5 years. No patient required replacement therapy.

CONCLUSIONS

A steroid-free protocol with 2-dose Daclizumab induction therapy and maintenance with TAC and MMF seemed to be safe to prevent acute rejection. Creatinine levels were slightly but significantly increased.

Proliferation signal inhibitors in cardiac transplantation

PURPOSE OF REVIEW

Standard immunosuppression after cardiac transplantation includes a calcineurin inhibitor in combination with mycophenolate mofetil or azathioprine and corticosteroids. These agents have led to excellent outcomes but have shortcomings in terms of efficacy and toxicity. A new class of immunosuppressants, proliferation signal inhibitors, may meet some of these shortcomings.

RECENT FINDINGS

The efficacy of the available proliferation signal inhibitors - sirolimus and its derivative everolimus - has been compared with azathioprine in three randomized clinical trials. Sirolimus or everolimus use was associated with lower rates of acute rejection and reduced development of chronic allograft vasculopathy. Sirolimus was not found to be superior to mycophenolate mofetil in a randomized trial. Proliferation signal inhibitors have been reported to be effective in refractory recurrent acute rejection. Nonrandomized studies have demonstrated that proliferation signal inhibitor-based immunosuppression enables recovery from renal dysfunction secondary to calcineurin inhibitor treatment. Proliferation signal inhibitor-based treatment is associated with a lower risk of malignancy than calcineurin inhibitor-based regimens. Proliferation signal inhibitors have significant adverse effects that may limit widespread use.

SUMMARY

Proliferation signal inhibitors are important new immunosuppressive agents that have added considerably to the armamentarium allowing further tailored immunosuppression to individualize patient care after heart transplantation.

Sirolimus-based graft-versus-host disease prophylaxis protects against cytomegalovirus reactivation after allogeneic hematopoietic stem cell transplantation: a cohort analysis

Sirolimus-based immunosuppressive regimens in organ transplantation have been associated with a lower than expected incidence of cytomegalovirus (CMV) disease. Whether sirolimus has a similar effect on CMV reactivation after allogeneic hematopoietic stem cell transplantation (HSCT) is not known. We evaluated 606 patients who underwent HSCT between April 2000 and June 2004 to identify risk factors for CMV reactivation 100 days after transplantation. The cohort included 252 patients who received sirolimus-tacrolimus for graft-versus-host disease (GVHD) prophylaxis; the rest received non-sirolimus-based regimens. An initial positive CMV DNA hybrid capture assay was observed in 225 patients (37.1%) at a median 39 days after HSCT for an incidence rate of 0.50 cases/100 patient-days (95% confidence interval [CI], 0.44-0.57). Multivariable Cox modeling adjusting for CMV donor-recipient serostatus pairs, incident acute GVHD, as well as other important covariates, confirmed a significant reduction in CMV reactivation associated with sirolimus-tacrolimus-based GVHD prophylaxis, with an adjusted HR of 0.46 (95% CI, 0.27-0.78; P = .004). The adjusted HR was 0.22 (95% CI, 0.09-0.55; P = .001) when persistent CMV viremia was modeled. Tacrolimus use without sirolimus was not significantly protective in either model (adjusted HR, 0.66; P = .14 and P = .35, respectively). The protective effect of sirolimus-containing GVHD prophylaxis regimens on CMV reactivation should be confirmed in randomized trials.

Lower Risk of Infectious Deaths in Cardiac Transplant Patients Receiving Basiliximab Versus Anti-thymocyte Globulin as Induction Therapy

BACKGROUND

Conventional antibody induction therapy is currently used in heart transplantation despite safety concerns. This 6-month, prospective, randomized, multicenter, open-label study examined whether basiliximab offers a tolerability benefit compared with anti-thymocyte globulin (ATG) while maintaining similar efficacy in de novo heart transplant recipients.

METHODS

Adult heart transplant recipients were randomized to receive basiliximab (20 mg on Day 0 and Day 4) or ATG (2.5 mg/kg/day for 3 to 5 days) with cyclosporine, mycophenolate mofetil and steroids. The primary safety end-point was a composite of serum sickness, fever, cutaneous rash, anaphylaxis, infection, thrombocytopenia, leukopenia and post-transplant proliferative disease. Efficacy was assessed by a composite end-point of death, graft loss, acute rejection Grade > 1B, acute rejection associated with hemodynamic compromise or treated with antibody therapy, or loss to follow-up, whichever occurred first.

RESULTS

Eighty patients were randomized and analyzed. By Month 6, the incidence of the composite safety end-point was significantly lower with basiliximab than with ATG (50.0% vs 78.6%, p = 0.01), and infectious death was less frequent in the basiliximab group (0 of 38 vs 6 of 42, p = 0.027). The composite efficacy end-point occurred in 24 patients (63.2%) in the basiliximab arm vs 28 patients (66.7%, p = not significant [NS]) receiving ATG. Acute rejection episodes of Grade > or = 1B were reported with similar frequency (50% with basiliximab vs 45.2% with ATG, p = NS); 7 patients (18.4%) in the basiliximab group and 3 (7.1%) in the ATG group had rejection Grade > or = 3A.

CONCLUSIONS

These results suggest that basiliximab offers improved tolerability with similar efficacy compared with current polyclonal antibody induction therapy in de novo heart transplant patients.

Clinical utilities of peripheral blood gene expression profiling in the management of cardiac transplant patients

Cardiac allografts induce host immune responses that lead to endomyocardial tissue injury and progressive graft dysfunction. Inflammatory cell infiltration and myocyte damage characterize acute cellular rejection (ACR) that presents episodically in either a subclinical or symptom-associated manner. Sampling of the endomyocardium by transvenous biopsy enables pathologic grading using light microscopic criteria to distinguish severity based on the focality or diffuseness of inflammation and associated myocyte injury. Monitoring for ACR utilizes endomyocardial biopsy in conjunction with history and physical examination and assessment of allograft function by echocardiography. However, procedural and interpretive issues limit the diagnostic certainty provided by endomyocardial biopsy. The dynamic profiling of genes expressed by peripheral blood mononuclear cells (PBMCs) enables quantitative assessments of intracellular mRNA whose levels fluctuate during systemic alloimmune responses. Gene expression profiling of PBMCs using a multi-gene ACR classifier enables the AlloMap molecular expression test to distinguish moderate to severe ACR (p = 0.0018) in heart transplant patients. The AlloMap test provides molecular insights into a patient's risk for ACR by distilling the aggregate expression levels of its informative genes into a single score on a scale of 0 to 40. The selection of a score as a threshold value for clinical decision-making is based on its associated negative predictive value (NPV), which ranges from 98 to 99% for values in three post-transplant periods: > 2 to < or =6 months, > 6 to < or = 12 months, and > 12 months. Scores below the threshold value rule out ACR, while those above suggest increased ACR risk. Incorporating the AlloMap test into immunomonitoring protocols provides an opportunity for clinicians to enhance patient care and to define its role in immunodiagnostic strategies to optimize the clinical outcomes of heart transplant recipients. This summary highlights the concepts presented in an invited presentation at a conference focused on Immunodiagnostics and Immunomonitoring: From Research to Clinic, in San Diego, CA on November 7, 2006.

Two Years Postconversion From a Prograf-Based Regimen to a Once-Daily Tacrolimus Extended-Release Formulation in Stable Kidney Transplant Recipients

Tacrolimus extended-release (XL) is a once-daily formulation recently developed to reduce the frequency of dosing for patients currently using the twice-a-day formulation of tacrolimus (TAC). As reported previously, 67 kidney transplant recipients were safely converted (1:1 mg basis, total daily dose) from TAC twice-a-day to XL once-daily in the morning and were maintained on an am dosing regimen of XL using the same therapeutic monitoring and patient care techniques currently employed with TAC. The 2-year postconversion patient (100%) and graft (98.5%) survival, incidence of biopsy-confirmed acute rejection (6.0%), incidence of multiple rejections (1.5%), and safety profile (posttransplant diabetes, hyperlipidemia, hypertension, infections, renal dysfunction, hepatic dysfunction, and malignancies) were consistent with or more favorable than those previously reported for TAC twice-a-day.

Once-Daily Tacrolimus Extended Release Formulation: Experience at 2 Years Postconversion From a Prograf-Based Regimen in Stable Liver Transplant Recipients

Compliance with complex immunosuppressant drug therapies in transplant recipients might be improved with regimens that require less frequent dosing. A once-daily extended release (XL) formulation of tacrolimus has been developed that allows a 1:1 conversion from the twice-a-day tacrolimus (TAC) formulation and has a good exposure to trough concentration correlation. In an open-label, multicenter study, stable liver transplant recipients (n=69) were converted from twice-a-day TAC to XL once-daily in the morning, and were maintained for at least 2 years postconversion using the same therapeutic monitoring and patient care techniques employed with TAC. Two years after conversion, the incidence of biopsy-confirmed acute rejection was 5.8% (4 of 69); patient and graft survival was 98.6% (68 of 69). The safety profile of XL was consistent with that previously reported for TAC. Liver transplant recipients can be converted from twice-a-day TAC to once-daily XL and maintained for at least 2 years postconversion with neither unique efficacy nor safety concerns.

Low-dose Tacrolimus/Sirolimus and Steroid Withdrawal in Heart Recipients Is Highly Efficacious

Heart transplant recipients treated with long-term calcineurin inhibitors (CNIs) experience significant nephrotoxicity and transplant vasculopathy. Signal proliferation inhibitors might prevent the development of transplant vasculopathy. In an open, prospective pilot study, 33 primary heart transplant recipients received tacrolimus (Tac) and sirolimus (rapamycin, Rapa) with steroids. To reduce both nephrotoxicity and transplant vasculopathy at the same time, both Tac and Rapa exposure was kept low (6 to 8 ng/ml). Steroids were withdrawn successfully from all patients within 6 months. Just one acute rejection occurred at 54 days post-transplant, resulting in 0.03 acute rejection episode per patient at 1-year (primary end-point) and 2-year follow-up. Transplant vasculopathy assessed by angiogram was absent at 2 years. Graft and patient survival were 100% at 1 and 2 years. Accordingly, the survival estimate for freedom from first acute rejection, transplant vasculopathy, graft loss or death was 0.97 at 1 and 2 years. The regimen was well tolerated with only 3 patients requiring a change of study medication. Mean serum creatinine increased during the first year but returned to baseline at 2 years.

Unsuspected rejection episodes on routine surveillance endomyocardial biopsy post-heart transplant in paediatric patients

The use of routine endomyocardial biopsies post-heart transplant in children remains controversial. It is generally accepted as the gold standard for detecting rejection, but details of the surveillance protocol, such as number and timing of biopsies, remain uncertain, with suggestions that recent advances in immunosuppressant therapy have obviated the need to perform surveillance biopsies. We retrospectively analysed results of endomyocardial biopsies performed in our unit since the introduction of a policy of three routine biopsies in the first six months post-transplantation. We specifically examined only routine surveillance biopsies in order to determine whether clinically unsuspected cases of rejection were identified. Between January 2002 and April 2006, 63 children completed three biopsies in the first six months post-transplant. Of 189 surveillance endomyocardial biopsies, 19 (10%) patients showed significant, grade III or above, rejection. One patient had two episodes of rejection. In only one case the child was haemodynamically unstable, four cases were mildly unwell, and 14 of 19 (74%) cases demonstrated no cardiac symptoms. Four of eight cases treated with sirolimus for some part of their post-transplant course had an episode of rejection and of 54 tacrolimus-treated patients, 13 had an episode of asymptomatic rejection detected. One of the seven infants had significant episode of rejection. Asymptomatic, clinically significant rejection is detected in about 10% of biopsies overall using a three-biopsy protocol in the first six months after paediatric heart transplantation, and occurs in 24% of tacrolimus-treated patients. More frequent surveillance appears needed in children treated with sirolimus, but less frequent surveillance may be possible in infants.

[Heart failure in 2006]

This article are summarizes the most relevant articles in the field of heart failure including epidemiology, diagnostic and therapeutic issues. Therapy includes drugs, cardiac resinchronization therapy, automatic implantable defibrillator, heart transplantation and cell therapy. Stem cell therapy is feasible and short term data indicates it is safe. However there are unresolved concerns on arrhythmias, restenosis and efficacy. At this point experts recommend that medium-sized randomized controlled trials, using surrogate endpoints, should be carried out to establish the efficacy and safety of this form of treatment.

Everolimus interferes with healing of experimental intestinal anastomoses

BACKGROUND

Although clinical data suggest its existence, little is known about the effect of rapamycin derivatives on wound repair. This study aims to delineate the influence of the mammalian target of rapamycin inhibitor everolimus on wound healing in the rat intestine.

METHODS

Four groups of 26 male Wistar rats received everolimus in daily oral dosages of 0 (controls), 0.5 (group E-0.5), 1.0 (group E-1), and 3.0 (group E-3) mg/kg every 24 hours, respectively, starting four hours before the operation until killing. After resection of 1-cm segments of colon and ileum, intestinal anastomoses were constructed. The animals were killed at days three or seven after operation. Wound healing was assessed by mechanical (bursting pressure, breaking strength), biochemical (collagen content, gelatinase activity), and histologic parameters.

RESULTS

No differences between groups were recorded for any of the parameters on day three. On day seven, a dose-dependent reduction in breaking strength (P<0.05) was measured. The largest effects were found in group E-3 in which the breaking strength was reduced by 56% and 73% in colonic and ileal anastomoses, respectively. A similar pattern was observed with the bursting pressure. Loss of strength was accompanied by a reduction in hydroxyproline content and by a lessened collagen deposition in the wound area but not by an increased gelatinase activity. No further histologic abnormalities were found.

CONCLUSION

Everolimus causes a massive reduction in anastomotic strength such as normally observed in the proliferative phase of repair. The data suggest this to be caused by an impaired deposition of collagen in the anastomotic area.

Tacrolimus: in heart transplant recipients

Tacrolimus is a calcineurin inhibitor recently approved in the US and throughout the EU for the prevention of allograft rejection in heart transplant recipients. It is commonly administered orally for long-term immunosuppression. The incidence of mild to severe acute rejection in the first 6 months following heart transplantation was significantly lower in tacrolimus recipients than in ciclosporin recipients (54% vs 66%) in a large, phase III trial conducted in Europe. A large, phase III trial conducted in the US did not show a significant difference between tacrolimus and ciclosporin in the incidence of severe rejection or haemodynamic compromise rejection requiring treatment within the first 6 months post-transplant (22% vs 32%), but did show a significant difference in the incidence at 1 year (23% vs 37%). In phase III trials, 1-year patient survival was similar between tacrolimus and ciclosporin recipients in the EU (93% vs 92%) and the US (95% vs 90%). Tacrolimus was shown to be effective in the prevention of rejection in paediatric and African American heart transplant recipients. The tolerability profile of tacrolimus in heart transplant recipients was broadly similar to that of ciclosporin, although tacrolimus was usually associated with lower incidences of post-transplant hypertension and dyslipidaemia.

New advances in antirejection therapy

PURPOSE OF REVIEW

The prevention and treatment of rejection have been the major focus of clinical and research studies since the inception of heart transplantation. Recent improvement in survival after transplant has been in large part due to continued advancement in antirejection therapies.

RECENT FINDINGS

The combination of steroids/cyclosporine/azathioprine has been widely used since the early 1980s. The last decade has seen the increasing use of the drugs mycophenolate mofetil and tacrolimus. Newer agents such as target of rapamycin protein inhibitors and anti-interleukin-2 inhibitors have come under intense research recently, and may play a significant role in heart transplantation. Further study is required for agents such as rituximab. With the recent introduction of a new grading of cardiac allograft rejection, controversy remains over when rejection should be treated and which agents should be used.

SUMMARY

Use of newer proven antirejection drugs has reduced rejection and improved survival after heart transplantation. Rejection and side effects from these drugs are still major problems, however; therefore continued research in this area is required.

Renal protective strategies in heart transplant patients

PURPOSE OF REVIEW

Chronic renal failure associated with long-term calcineurin inhibitor immunosuppression is a substantial clinical problem in the heart transplant population, compounded by difficulties in identifying patients likely to develop renal dysfunction. Several approaches, however, have been developed or are being investigated to preserve renal function in heart transplant patients.

RECENT FINDINGS

Approaches to identify patients with an increased risk of developing renal dysfunction are being refined, and improved calcineurin inhibitor monitoring strategies are being investigated. Novel immunosuppressive regimens including mycophenolate mofetil and/or rapamycin that lack nephrotoxicity promise new therapeutic strategies with the efficacy of calcineurin inhibitor-based combinations. Temporary ('holiday') or permanent ('retirement') calcineurin inhibitor replacement with interleukin-2 receptor monoclonal antibodies has the potential to halt progressive renal dysfunction. Finally, emerging data on the renal protection afforded by angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, either singly or in combination, provide another avenue of investigation.

SUMMARY

Several strategies have demonstrated their potential to preserve or improve renal function in heart transplant patients in small studies. Large randomized controlled trials are necessary to determine the optimal strategies to prevent rejection while preserving renal function in the long-term management of heart transplant patients.

Immunosuppression on the Horizon

Many novel immunosuppressive agents are under active clinical investigation. In addition, creative approaches are being developed for the use of established immunosuppressive agents, with the goal of minimizing immunosuppression as early as possible posttransplantation. The hope is that these approaches will minimize the toxicity of these agents without sacrificing efficacy. Evidence suggests that the nephrotoxicity of calcineurin inhibitors can be reduced using these approaches. The introduction of newer immunosuppressive agents, including the proliferation signal inhibitors, raises the possibility that some of the long-term scourges of cardiac transplantation, including cardiac allograft vasculopathy and malignancy, can be ameliorated. Finally, costimulatory pathway inhibitors and other new immunosuppressive agents offer hope that all these goals can be accomplished with very low long-term maintenance immunosuppression.

Induction Therapy in Cardiac Transplantation: When and Why?

Induction therapy has continued to be a subject of controversy in heart transplantation for more than 20 years. It is an example of a therapy that is logical, and ought to be better than "doing without." However, a careful review of the evidence suggests otherwise. Except for patients where the benefits clearly outweigh the short and long-term risks, the use of induction therapy should be avoided. In immunosuppression, as in life, there is no "free lunch." Clinicians need to be certain they fully understand what they are ordering when asking for induction therapy to be administered to their patients.

Contemporary Concepts in Noncellular Rejection

Acute rejection is the major cause of morbidity and mortality in the first year after cardiac transplantation. Cellular rejection is the most common form of rejection observed; however, noncellular rejection is being seen more often. This noncellular rejection is mostly a result of less well-characterized antibody-mediated mechanisms. Antibody-mediated rejection is associated more commonly with hemodynamic compromise, increased graft loss, cardiac allograft vasculopathy, and increased mortality. Histologic, immunofluorescence, and immunoperoxidase studies of endomyocardial biopsies from such patients often reveal intravascular macrophages and immunoglobulin and complement deposition in capillaries, in the absence of lymphoid infiltrates. Severely ill patients require intense therapy, which includes high-dose corticosteroids, cytolytic agents, intravenous heparin, intravenous gamma globulin, plasmapheresis, and/or antiproliferative agents. Further understanding of noncellular rejection will lead to more effective therapy.

Tacrolimus in Heart Transplant Recipients

The development of cyclosporine was pivotal in allowing cardiac transplantation to become an accepted treatment for patients with end-stage heart disease. More recently, tacrolimus has become available as a useful alternative to cyclosporine, and has been successfully combined with either azathioprine or the newer anti-proliferative agents, mycophenolate mofetil or sirolimus. Numerous randomized clinical trials have demonstrated that tacrolimus is comparable to cyclosporine in terms of overall patient survival and at least equally effective in preventing acute rejection. In addition, tacrolimus has been particularly effective as a rescue treatment in cases where recurrent rejection has occurred with cyclosporine. The adverse effects of tacrolimus differ from those of cyclosporine, and the drug particularly shows an improved profile with respect to hypertension, dyslipidemia, and long-term renal function. These data have recently led to the regulatory approval of tacrolimus for primary immunosuppression in patients undergoing cardiac transplantation in the US.

Heart and lung transplantation in children

During the past two decades, several advances have resulted in marked improvement in medium-term survival for infants and children undergoing heart transplantation. Unfortunately, progress has been less dramatic in the field of lung and heart-lung transplantation, where there is little evidence of improved outcomes. The procedures remain palliative and all transplant recipients are at risk for the adverse effects of non-specific immunosuppression, including infections, lymphoproliferative disorders, and non-lymphoid malignancies. In addition, current immunosuppressive agents have narrow therapeutic windows and exhibit a wide array of organ toxicities, posing special challenges for the young patient who must endure life-long immunosuppression. New immunosuppressive regimens have lowered the rates of acute rejection but appear to have had relatively little impact on the incidence of chronic rejection, the principal cause of late graft loss. The ultimate goal is to induce a state of donor-specific tolerance, wherein the recipient will accept the allograft indefinitely without the need for long-term immunosuppression. This quest is currently being realised in animal models of solid organ transplantation, and offers great hope for children undergoing heart and lung transplantation in the future.