Effectivity of a T-Cell-Adapted Induction Therapy With Anti-Thymocyte Globulin (Sangstat)

European flow cytometry quality assurance guidelines for the diagnosis of primary immune deficiencies and assessment of immune reconstitution following B cell depletion therapies and transplantation

Over the last 15 years activity of diagnostic flow cytometry services have evolved from monitoring of CD4 T cell subsets in HIV-1 infection to screening for primary and secondary immune deficiencies syndromes and assessment of immune constitution following B cell depleting therapy and transplantation. Changes in laboratory activity in high income countries have been driven by initiation of anti-retroviral therapy (ART) in HIV-1 regardless of CD4 T cell counts, increasing recognition of primary immune deficiency syndromes and the wider application of B cell depleting therapy and transplantation in clinical practice. Laboratories should use their experience in standardization and quality assurance of CD4 T cell counting in HIV-1 infection to provide immune monitoring services to patients with primary and secondary immune deficiencies. Assessment of immune reconstitution post B cell depleting agents and transplantation can also draw on the expertise acquired by flow cytometry laboratories for detection of CD34 stem cell and assessment of MRD in hematological malignancies. This guideline provides recommendations for clinical laboratories on providing flow cytometry services in screening for immune deficiencies and its emerging role immune reconstitution after B cell targeting therapies and transplantation.

Retrospective Evaluation of Rabbit Antithymocyte Globulin Induction in Heart Transplant Patients

The dosing intensity of antithymocyte globulin as induction therapy in heart transplantation remains controversial. We sought to evaluate the efficacy and safety of rabbit antithymocyte globulin at a total dose of 4.5 mg/kg compared with <4.5 mg/kg.

Malignancy among adult heart transplant recipients following patient-tailored dosing of anti-thymocyte globulin: a retrospective, nested case-control study of individualized dosing

Post-transplant malignancy is diagnosed in approximately 18% of heart transplant patients and is a leading cause of death post-transplant. One modifiable risk factor is the type and amount of immunosuppression received. Contemporary rabbit anti-thymocyte globulin (rATG) dosing strategy using T-cell-guided dosing, and its effect on malignancy in heart transplant patients is unclear. This was a single-center, retrospective chart review of heart transplant recipients receiving rATG for induction. Patients diagnosed with malignancy post-transplant were matched 1:2 to controls using a nested case-control design. The primary endpoint was to determine the relative risk of rATG exposure with the actual incidence of malignancy post-transplant. The secondary endpoint was the impact of maintenance immunosuppression on malignancy risk. Of the 126 patients included in the study, 25 developed malignancy and were matched to 50 control patients. The median cumulative rATG dose in milligrams (mg) between groups was 365 mg in malignancy cases and 480 mg in controls (OR 0.90, 95% CI 0.75-1.08, P = 0.28). In both the univariate and multivariable analysis, there was no statistically significant difference in malignancy risk found with any maintenance immunosuppressant. The results of this study showed that patient-tailored rATG dosing strategies may not be associated with malignancy development as previously thought.

Pharmacodynamic monitoring using biomarkers to individualize pharmacotherapy

Drug doses are often titrated upon their clinical effects (e.g., blood pressure). Unfortunately, for many drugs there is no direct, clinical read-out to estimate dose adequateness. Alternatively, drug dosing is based on the maximum tolerated dose approach or therapeutic drug monitoring. However, the concentration-response curves may be flattened or bell-shaped as suggested for some ‘biologicals’. Together, these aspects raise the question why drug dosing is not individualized by pharmacodynamic monitoring. Evaluating the effects of drugs at their pharmacological target or meaningful biomarkers might indicate nonresponders, objectively quantify the maximum molecular effect and thus restrict overdose and underdosing. This review outlines the theory and biological or technical prerequisites for biomarker-based pharmacodynamic monitoring, and highlights selected examples from different fields of clinical medicine.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

Analysis of malignancies in patients after heart transplantation with subsequent immunosuppressive therapy

Objective

The aim of this study was to analyze the distribution of malignancies in patients after heart transplantation (HTX) and to evaluate the risk factors including immunosuppressive therapy with regard to the development of malignancies and survival. Special emphasis was placed on the effects of a mammalian target of rapamycin (mTOR) containing immunosuppressive regimen.

Methods

A total of 381 patients (age ≥18 years) receiving HTX were included in the present analysis. All patients were followed-up at the University of Heidelberg Heart Center, Heidelberg, Germany. Data were retrieved from the Heidelberg Registry for Heart Transplantation being collected between 1989 and 2014. According to center standard, all patients received induction therapy with anti-thymocyte globulin guided by T-cell monitoring since 1994. The initial immunosuppressive regimen consisting of cyclosporine A (CsA) and azathioprine (AZA) was replaced by CsA and mycophenolate mofetil (MMF) in 2001 and by tacrolimus (TAC) and MMF in 2006. Additionally, mTOR inhibitors (everolimus/sirolimus) were applied since 2003.

Results

Mean recipient age at HTX was 51.2±10.5 years and the mean follow-up period after HTX was 9.7±5.9 years. During follow-up, 130 patients developed a neoplasm (34.1% of total). Subgroup analysis revealed 58 patients with cutaneous malignancy only (15.2%), 56 patients with noncutaneous malignancy only (14.7%), and 16 patients with both cutaneous and noncutaneous malignancy (4.2%). Statistically significant risk factors associated with an increased risk of malignancy after HTX were older age (P<0.0001), male recipients (P=0.0008), dyslipidemia (P=0.0263), diabetes mellitus (P=0.0003), renal insufficiency (P=0.0247), and >1 treated rejection episode (TRE) in the first year after HTX (P=0.0091). Administration of CsA (P=0.0195), AZA (P=0.0008), or steroids (P=0.0018) for >1 year after HTX was associated with increased development of malignancy, whereas administration of MMF (P<0.0001) or mTOR inhibitors (P<0.0001) was associated with a lower risk for development of malignancy. Additionally, 5-year follow-up of cutaneous malignancy recurrence (P=0.0065) and noncutaneous malignancy mortality (P=0.0011) was significantly lower in patients receiving an mTOR inhibitor containing therapy after the development of a malignancy.

Conclusion

This study highlights the complexity of risk factors including immunosuppression with regard to the development of malignancies after HTX. mTOR-inhibitor-based immunosuppression is associated with a better outcome after HTX, particularly in cases with noncutaneous malignancy.

Immunosuppressive T-cell antibody induction for heart transplant recipients

BACKGROUND

Heart transplantation has become a valuable and well-accepted treatment option for end-stage heart failure. Rejection of the transplanted heart by the recipient's body is a risk to the success of the procedure, and life-long immunosuppression is necessary to avoid this. Clear evidence is required to identify the best, safest and most effective immunosuppressive treatment strategy for heart transplant recipients. To date, there is no consensus on the use of immunosuppressive antibodies against T-cells for induction after heart transplantation.

OBJECTIVES

To review the benefits, harms, feasibility and tolerability of immunosuppressive T-cell antibody induction versus placebo, or no antibody induction, or another kind of antibody induction for heart transplant recipients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2012), MEDLINE (Ovid) (1946 to November Week 1 2012), EMBASE (Ovid) (1946 to 2012 Week 45), ISI Web of Science (14 November 2012); we also searched two clinical trial registers and checked reference lists in November 2012.

SELECTION CRITERIA

We included all randomised clinical trials (RCTs) assessing immunosuppressive T-cell antibody induction for heart transplant recipients. Within individual trials, we required all participants to receive the same maintenance immunosuppressive therapy.

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently. RevMan analysis was used for statistical analysis of dichotomous data with risk ratio (RR), and of continuous data with mean difference (MD), both with 95% confidence intervals (CI). Methodological components were used to assess risks of systematic errors (bias). Trial sequential analysis was used to assess the risks of random errors (play of chance). We assessed mortality, acute rejection, infection, Cytomegalovirus (CMV) infection, post-transplantation lymphoproliferative disorder, cancer, adverse events, chronic allograft vasculopathy, renal function, hypertension, diabetes mellitus, and hyperlipidaemia.

MAIN RESULTS

In this review, we included 22 RCTs that investigated the use of T-cell antibody induction, with a total of 1427 heart-transplant recipients. All trials were judged to be at a high risk of bias. Five trials, with a total of 606 participants, compared any kind of T-cell antibody induction versus no antibody induction; four trials, with a total of 576 participants, compared interleukin-2 receptor antagonist (IL-2 RA) versus no induction; one trial, with 30 participants, compared monoclonal antibody (other than IL-2 RA) versus no antibody induction; two trials, with a total of 159 participants, compared IL-2 RA versus monoclonal antibody (other than IL-2 RA) induction; four trials, with a total of 185 participants, compared IL-2 RA versus polyclonal antibody induction; seven trials, with a total of 315 participants, compared monoclonal antibody (other than IL-2 RA) versus polyclonal antibody induction; and four trials, with a total of 162 participants, compared polyclonal antibody induction versus another kind, or dose of polyclonal antibodies.No significant differences were found for any of the comparisons for the outcomes of mortality, infection, CMV infection, post-transplantation lymphoproliferative disorder, cancer, adverse events, chronic allograft vasculopathy, renal function, hypertension, diabetes mellitus, or hyperlipidaemia. Acute rejection occurred significantly less frequently when IL-2 RA induction was compared with no induction (93/284 (33%) versus 132/292 (45%); RR 0.73; 95% CI 0.59 to 0.90; I(2) 57%) applying the fixed-effect model. No significant difference was found when the random-effects model was applied (RR 0.73; 95% CI 0.46 to 1.17; I(2) 57%). In addition, acute rejection occurred more often statistically when IL-2 RA induction was compared with polyclonal antibody induction (24/90 (27%) versus 10/95 (11%); RR 2.43; 95% CI 1.01 to 5.86; I(2) 28%). For all of these differences in acute rejection, trial sequential alpha-spending boundaries were not crossed and the required information sizes were not reached when trial sequential analysis was performed, indicating that we cannot exclude random errors.We observed some occasional significant differences in adverse events in some of the comparisons, however definitions of adverse events varied between trials, and numbers of participants and events in these outcomes were too small to allow definitive conclusions to be drawn.

AUTHORS' CONCLUSIONS

This review shows that acute rejection might be reduced by IL-2 RA compared with no induction, and by polyclonal antibody induction compared with IL-2 RA, though trial sequential analyses cannot exclude random errors, and the significance of our observations depended on the statistical model used. Furthermore, this review does not show other clear benefits or harms associated with the use of any kind of T-cell antibody induction compared with no induction, or when one type of T-cell antibody is compared with another type of antibody. The number of trials investigating the use of antibodies against T-cells for induction after heart transplantation is small, and the number of participants and outcomes in these RCTs is limited. Furthermore, the included trials are at a high risk of bias. Hence, more RCTs are needed to assess the benefits and harms of T-cell antibody induction for heart-transplant recipients. Such trials ought to be conducted with low risks of systematic and random error.

Effects of vildagliptin (Galvus®) therapy in patients with type 2 diabetes mellitus after heart transplantation

Background

Type 2 Diabetes mellitus (T2DM) is a common comorbidity in patients after heart transplantation (HTx) and is associated with adverse long-term outcomes.

Methods

The retrospective study reported here analyzed the effects of vildagliptin therapy in stable patients post-HTx with T2DM and compared these with control patients for matched-pairs analysis. A total of 30 stable patients post-HTx with T2DM were included in the study. Fifteen patients (mean age 58.6 ± 6.0 years, mean time post-HTx 4.9 ± 5.3 years, twelve male and three female) were included in the vildagliptin group (VG) and 15 patients were included in the control group (CG) (mean age 61.2 ± 8.3 years, mean time post-HTx 7.2 ± 6.6 years, all male).

Results

Mean glycated hemoglobin (HbA_1c) in the VG was 7.4% ± 0.7% before versus 6.8% ± 0.8% after 8 months of vildagliptin therapy (P = 0.002 vs baseline). In the CG, HbA_1c was 7.0% ± 0.7% versus 7.3% ± 1.2% at follow-up (P = 0.21). Additionally, there was a significant reduction in mean blood glucose in the VG, from 165.0 ± 18.8 mg/dL to 147.9 ± 22.7 mg/dL (P = 0.002 vs baseline), whereas mean blood glucose increased slightly in the CG from 154.7 ± 19.7 mg/dL to 162.6 ± 35.0 mg/dL (P = 0.21). No statistically significant changes in body weight (from 83.3 ± 10.8 kg to 82.0 ± 10.9 kg, P = 0.20), total cholesterol (1.5%, P = 0.68), or triglyceride levels (8.0%, P = 0.65) were seen in the VG. No significant changes in immunosuppressive drug levels or dosages were observed in either group.

Conclusion

Vildagliptin therapy significantly reduced HbA_1c and mean blood glucose levels in post-HTx patients in this study with T2DM and did not have any negative effects on lipid profile or body weight. Thus, vildagliptin therapy presented an interesting therapeutic approach for this selected patient cohort.

Effects of oral valganciclovir prophylaxis for cytomegalovirus infection in heart transplant patients

BACKGROUND

Cytomegalovirus (CMV) infection is a serious complication following heart transplantation. This study (June 2003-January 2010) retrospectively assessed the effects of oral valganciclovir prophylaxis in adult heart transplant recipients during the first year after transplantation.

METHODS

In patients with normal renal function, 900 mg of oral valganciclovir was administered twice daily for 14 days after heart transplant followed by 900 mg per day for following 6 months. In the event of renal insufficiency, valganciclovir was adjusted according to the manufacturer's recommendations. Antigenemia testing for pp65 antigen and simultaneous polymerase chain reaction (PCR) were used to document exposure to CMV. From 2003 to 2010, 146 patients (74.0% men) of mean age 50.7 ± 10.3 years at the time of heart transplant were included.

RESULTS

A total of 16 patients (11.0% of total, 75.0% male) had a positive pp65 and PCR result (ie, CMV infection) during the year following heart transplant; three of these patients had discontinued valganciclovir prophylaxis within the first 6 months following transplant because of leukopenia, including one patient developed CMV colitis. Two further patients developed CMV pneumonia during prophylactic valganciclovir therapy. Eight patients had positive pp65 and PCR tests in the 6-12 months after heart transplant following cessation of routine prophylaxis. One of these patients developed CMV pneumonia and another developed CMV colitis and CMV pneumonia. Thirty-seven of the 146 (25.3%) patients were CMV donor-seropositive/recipient-seronegative, and seven (18.9% of this subgroup) had a positive CMV test. In patients who were CMV donor-seropositive/recipient-seronegative, the risk of a positive CMV test (ie, CMV infection) was significantly elevated (P = 0.023).

CONCLUSION

CMV prophylaxis with oral valganciclovir for 6 months following heart transplant is clinically feasible. In line with previous studies, CMV donor-seropositive/recipient-seronegative patients have a significantly elevated risk of CMV infection. In patients who prematurely discontinue valganciclovir, close monitoring of CMV antigenemia appears warranted. No significantly elevated rate of CMV infection was observed after 6 months of valganciclovir prophylaxis.

Malignancies after heart transplantation: incidence, risk factors, and effects of calcineurin inhibitor withdrawal

The objectives of the present study were to evaluate the incidence of malignancies and to describe the effects of immunosuppression on survival and recurrence of malignancies after heart transplantation (HTX). Data were analyzed in 211 cardiac allograft recipients, in whom HTX was performed between 1989 and 2005. All of these patients survived for more than 2 years after HTX and received induction therapy with antithymocyte globulin (RATG) guided by T-cell monitoring since 1994. An immunosuppressive regimen consisting of cyclosporine A (CsA) combined with azathioprine was followed by CsA and mycophenolate mofetil (MMF) in 2001; mammalian target of rapamycin (mTOR) inhibitors (everolimus/sirolimus) were used since 2003. Mean patient age at HTX was 51.4 ± 10.5 years; mean follow-up time after HTX 9.2 ± 4.7 years. Overall incidence of neoplasias was 30.8%. Individual risk factors associated with a higher risk of malignancy after HTX were higher age at transplantation (P = .003), male gender (P = .005) and ischemic cardiomyopathy before HTX (P = .04). Administration of azathioprine (P < .0001) or a calcineurin inhibitor (CNI) (P = .02) for more than 1 year was associated with development of malignancy, whereas significantly fewer malignancies were noticed in patients receiving an mTOR-inhibitor (P < .0001). Kaplan-Meier analysis demonstrated a strong statistical trend toward an improved survival in patients with a noncutaneous neoplasia switched to a CNI-free protocol (P = .05). This study demonstrated the impact of a variety of individual risk factors and immunosuppressive drugs on development of malignancy after HTX. Markedly fewer patients with noncutaneous malignancies died after switch to a CNI-free regimen, not quite reaching statistical significance by Kaplan-Meier analysis, however.

Epstein-Barr virus load in whole blood is associated with immunosuppression, but not with post-transplant lymphoproliferative disease in stable adult heart transplant patients

Development of Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) is a serious complication following heart transplantation (HTX). This study investigates EBV DNA load in adult heart transplant recipients, its association with immunosuppression, and its potential as a marker for development of PTLD. EBV DNA load was measured prospectively by quantitative real-time polymerase chain reaction (PCR) in 172 stable HTX patients. Sixty-seven patients (39.0% of total) had a positive EBV PCR at initial examination [median 4.9 (range 1.1-16.9) years post-HTX]. In follow-up testing of 67 positive patients 6 months later, 36 patients continued to have a positive EBV PCR. Overall incidence of EBV DNA was significantly associated with calcineurin inihibitors, azathioprine medication, and with the absence of mycophenolate mofetil (MMF) treatment. In patients with positive EBV DNA levels at initial examination and negative levels at retesting, cyclosporine A levels were found to be significantly higher at initial examination (148.4 +/- 70.2 vs. 119.6 +/- 53.5 ng/ml, P < 0.05). Three patients (1.7%, 3/172) were diagnosed with PTLD during the course of the study (mean follow up 4.0 years). EBV DNA viral load determination does not appear to be useful for risk prediction or early diagnosis of PTLD in adults after HTX, but an association of EBV DNA load with qualitative and quantitative immunosuppression is demonstrated.

Interstitial leukocytes in right ventricular endomyocardial biopsies after heart transplantation in patients with complicated versus uneventful postoperative course

BACKGROUND

Infections and rejections play key roles in morbidity and mortality in the early postoperative period after orthotopic heart transplantation (HTX). The aim of this study was to evaluate whether qualitative and quantitative analyses of various interstitial leukocytes in endomyocardial biopsies during the first 2 weeks after HTX provided early information on these complications.

PATIENTS AND METHODS

During and after HTX, endomyocardial biopsies were obtained in 51 patients. By immunohistochemistry we determined the CD3-, CD4-, CD8-, CD15-, CD20-, CD57-, and CD68-positive cell numbers projected to planimetrically measured areas. To compare morbidity in the postoperative course, the patients were subdivided into complicated versus uncomplicated after 3 months.

RESULTS

In the uncomplicated group, the cell counts of CD3-, CD8-, CD57-, and CD68-positive cells were significantly lower than in the complicated group. CD3-, CD4-, and CD8-positive cell numbers showed a significant decrease in the first week among the uncomplicated group. In the complicated group, the cell counts increased significantly in the second week. The numbers of CD57-positive cells were significantly lower during the first and second weeks among the uncomplicated group.

CONCLUSIONS

Increased T lymphocytes, natural killer cells, and macrophages observed in the second week after HTX indicated increased morbidity. A reduction in CD3-positive cells in the first week indicated a low morbidity risk; an increase indicated a higher risk.

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.