Lower tacrolimus trough levels are associated with subsequently higher acute rejection risk during the first 12 months after kidney transplantation.

The premise that lower TAC trough levels are associated with subsequently higher first BPAR risk during the first 12 mo post-transplant was recently questioned. Using our prospectively followed cohort of 528 adult, primary kidney transplant recipients (pooled across four randomized trials) who received reduced TAC dosing plus an IMPDH inhibitor, TAC trough levels measured at seven time points, 7, 14 days, 1, 2, 3, 6 and 9 months post-transplant, were utilized along with Cox's model to determine the multivariable significance of TAC level(t) (a continuous time-dependent covariate equaling the most recently measured TAC level prior to time t) on the hazard rate of developing first BPAR during the first 12 months post-transplant. The percentage developing BPAR during the first 12 months post-transplant was 10.2% (54/528). In univariable analysis, lower TAC level(t) was associated with a significantly higher BPAR rate (P = 0.00006), and its significance was maintained even after controlling for 2 significant baseline predictors (African-American/Hispanic Recipient and Developed DGF) in Cox's model (multivariable P = 0.0003). Use of a cutpoint, TAC level(t) <4.0 vs. ≥4.0 ng/ml, yielded an even greater association with BPAR rate (univariable and multivariable P < 0.000001), with an estimated hazard ratio of 6.33. These results suggest that TAC levels <4.0 ng/ml should be avoided during the first 12 months post-transplant when TAC is used in combination with fixed-dose mycophenolate with or without corticosteroids and induction therapy.

Single-centre study of 628 adult, primary kidney transplant recipients showing no unfavourable effect of new-onset diabetes after transplant.

AIMS/HYPOTHESIS: To better understand the implications of new-onset diabetes after transplant (NODAT), we used our prospectively followed cohort of 628 adult primary kidney transplant recipients to determine the prognostic impact of pretransplant diabetes and NODAT. METHODS: The study cohort consisted of all participants in four randomised immunosuppression trials performed at our centre since May 2000. For each cause-specific hazard analysed, Cox stepwise regression was used to determine a multivariable model of significant baseline predictors; the multivariable influence of having pretransplant diabetes and NODAT (t) (the latter defined as a zero-one, time-dependent covariate) was subsequently tested. Similar analyses of estimated glomerular filtration rate (eGFR) at 36 and 60 months post transplant were performed using stepwise linear regression. Finally, a repeated measures analysis of mean HbA1c as a function of diabetes category (pretransplant diabetes vs NODAT) and randomised trial (first to fourth) was performed. RESULTS: Median follow-up was 56 months post transplant. Patients with pretransplant diabetes comprised 23.4% (147/628), and 22.5% (108/481) of the remaining patients developed NODAT. Pretransplant diabetes had no prognostic influence on first biopsy-proven acute rejection and death-censored graft failure hazard rates, nor on eGFR, but was associated with significantly higher rates of death with a functioning graft (DWFG) (p = 0.003), DWFG due to a cardiovascular event (p = 0.005) and infection that required hospitalisation (p = 0.03). NODAT (t) had no unfavourable impact on any of these hazard rates nor on eGFR, with actuarial freedom from DWFG remaining at over 90% among patients in pre- and post-NODAT states at 72 months post transplant/NODAT. Mean HbA1c for patients in the first to fourth randomised trials, averaged across diabetes category, decreased by trial (7.28%, 6.92%, 6.87% and 6.64% [56.1, 52.1, 51.6 and 49.1 mmol/mol], respectively; p = 0.02). CONCLUSIONS/INTERPRETATION: Less-than-expected post-NODAT risk for graft loss and death may exist in the current climate of tighter glucose monitoring post transplant.

Multivariable risk of developing new onset diabetes after transplant-results from a single-center study of 481 adult, primary kidney transplant recipients.

BACKGROUND: Understanding the relative contributions of baseline demographics and immunosuppressive therapy on NODAT risk may help in developing preventive strategies. METHODS: Using our prospectively followed cohort of 481 adult, primary kidney transplant recipients without pre-transplant diabetes, we determined the significant baseline predictors for the hazard rate of developing NODAT via Cox stepwise regression. The multivariable influence of first BPAR (defined as a time-dependent covariate) was also tested. RESULTS: Median follow-up was 57 mo post-transplant; the overall percentage who developed NODAT was 22.5% (108/481). Four baseline predictors of a greater NODAT hazard rate were found (by order of selection): higher BMI (p < 0.000001), planned maintenance with SRL (p = 0.0003), non-white recipient (p = 0.0004), and older recipient age (p = 0.0004). Approximately one-half of the 106 patients in the highest demographic risk category (BMI ≥25 kg/m(2) , non-white race, and age at transplant ≥40 yr) developed NODAT; actuarial NODAT risk ranged from 10% to 30% in the lower demographic risk categories. First BPAR was also associated with significantly higher NODAT in multivariable analysis (p = 0.02)-the highly elevated NODAT rate observed during the first few months post-transplant and following first BPAR appears to demonstrate the diabetogenic effect of using high-dose (intravenous) corticosteroids. CONCLUSIONS: The disturbingly high NODAT rate found among patients having multiple demographic risk factors is still an important problem that awaits a better solution.

Machine perfusion following static cold storage preservation in kidney transplantation: donor-matched pair analysis of the prognostic impact of longer pump time.

The impact of machine perfusion (MP) time on kidney transplant outcome is mixed in previous studies using multivariable analyses. In an analysis of 66 pairs of donor-matched adult, first transplant recipients (N = 132) with identical donor characteristics except for pump time, tests of association of shorter versus longer pump time (first versus second kidney removed) by delayed graft function(DGF), slow graft function(SGF), and biopsy proven acute rejection(BPAR) were performed using McNemar's test. Freedom-from-BPAR, graft and patient survival, and renal function were also compared. Mean ± SD pump times for paired recipients with first and second kidneys were 22.7 ± 7.3 h and 31.2 ± 7.9 h, respectively (mean difference: 8.5 ± 4.5 h, P < .000001). There was no significant impact of pump time on DGF or SGF, with discordant pairs favoring less SGF with longer pump time (N.S.). The incidence of BPAR during the first 12 months post-transplant yielded a borderline difference favoring longer pump time (P = .09), and freedom-from-BPAR during the first 12 months was significantly more favorable for longer pump times (95% vs. 84%, P = 0.04). No differences were observed in graft and patient survival, and renal function. While offering significantly favorable protection from BPAR, this analysis of donor-matched recipient pairs corroborates longer MP (pump) times having no unfavorable effect on other clinical outcomes.

Randomized trial of immunosuppressive regimens in renal transplantation.

The optimal long-term regimen for immunosuppression for kidney transplant recipients is unknown. We conducted a randomized trial involving 150 kidney transplant recipients to compare tacrolimus/sirolimus, tacrolimus/mycophenolate mofetil (MMF), and cyclosporine/sirolimus. All patients received daclizumab induction and maintenance corticosteroids. Median follow-up was 8 yr post-transplant. Acute rejection (AR) occurred significantly less often among those treated with tacrolimus/MMF (12%) than among those treated with tacrolimus/sirolimus (30%) or cyclosporine/sirolimus (28%). Mean estimated GFR was consistently higher in the tacrolimus/MMF arm, especially after controlling for donor age in a multivariable model during the first 36 mo (P ≤ 0.008). The rate of dying with a functioning graft was significantly higher among those treated with tacrolimus/sirolimus (26%) than among those treated with tacrolimus/MMF (12%) or cyclosporine/sirolimus (4%). We did not observe significant differences in actuarial graft survival at 8 yr post-transplant between the groups. Patient noncompliance seemed responsible for 45% (13/29) of observed graft failures, with 11 of these occurring after 36 mo. Significantly more viral infections, protocol violations, and need for antilipid therapy occurred among patients receiving sirolimus, but we did not observe differences between the groups with regard to infections requiring hospitalization or new-onset diabetes. Taken together, these results suggest that maintenance therapy with tacrolimus/MMF is more favorable than either tacrolimus/sirolimus or cyclosporine/sirolimus.

Randomized trial of mycophenolate mofetil versus enteric-coated mycophenolate sodium in primary renal transplant recipients given tacrolimus and daclizumab/thymoglobulin: one year follow-up.

BACKGROUND: It was of interest to compare enteric-coated mycophenolate sodium (EC-MPS) versus mycophenolate mofetil (MMF) among renal transplant recipients receiving a tacrolimus-based immunosuppressive regimen. METHODS: Between December 2004 and February 2006, a single-center, open-label randomized trial of MMF (group A, n=75) versus EC-MPS (group B, n=75) was performed in primary renal transplant recipients receiving combined thymoglobulin/daclizumab induction along with reduced tacrolimus dosing and elimination of corticosteroids 1 week postoperatively. The primary endpoint was the incidence rate of acute rejection (AR) during the first 12 months posttransplant; secondary aims were to compare graft and patient survival, renal function, drug dosing and monitoring, gastrointestinal side effects, and other adverse events at 12 months of follow-up. RESULTS: Patient/graft survival in groups A and B were 100%/96% versus 99%/96%, respectively (N.S.). At 12 months, a total of nine patients (6%) experienced biopsy-proven AR, 3% (2/75) vs. 9% (7/75) in the MMF and EC-MPS arms, respectively (N.S.). At 12 months, the geometric mean*/SE serum creatinine concentration and arithmetic mean+/-SE calculated glomerular filtration rate in groups A and B, respectively, were 1.30*/1.03 and 61.4+/-2.0 vs. 1.26*/1.03 and 66.0+/-2.1 (N.S.). Incidence of new onset diabetes mellitus (11% vs. 11%), infections requiring hospitalization (13% vs. 15%), and gastrointestinal side effects (36% vs. 32%) appeared equivalent (N.S.). CONCLUSIONS: Early efficacy and toxicity were equivalent between the two study arms. Optimizing either MMF or EC-MPS along with a combined thymoglobulin/daclizumab induction, low tacrolimus dosing and steroid avoidance resulted in a low AR rate and an acceptably high renal function at 12 months.

Randomized trial of rATg/Daclizumab vs. rATg/Alemtuzumab as dual induction therapy in renal transplantation: Results at 8years of follow-up.

Our goal in using dual induction therapy is to bring the kidney transplant recipient closer (through more effectively timed lymphodepletion) to an optimally immunosuppressed state. Here, we report long-term results of a prospective randomized trial comparing (Group I,N=100) rATG/Dac (3 rATG, 2 Dac doses) vs. (Group II,N=100) rATG/Alemtuzumab(C1H) (1 dose each), using reduced tacrolimus dosing, EC-MPS, and early corticosteroid withdrawal. Lower EC-MPS dosing was targeted in Group II to avoid severe leukopenia. Median follow-up was 96mo post-transplant. There were no differences in 1st BPAR (including borderline) rates: 10/100 vs. 9/100 in Groups I and II during the first 12mo(P=0.54), and 20/100 vs. 20/100 throughout the study(P=0.90). Equally favorable renal function was maintained in both treatment arms(N.S.). While not significant, more patients in Group II experienced graft loss, 25/100 vs. 18/100 in Group I(P=0.23). Actuarial patient/graft survival at 96mo was 92%/83% vs. 85%/73% in Groups I and II(N.S.). DWFG-due-to-infection(N.S.), EC-MPS withholding-due-to-leukopenia during the first 2mo(P=0.03), and incidence of viral infections(P=0.09) were higher in Group II, whereas EC-MPS withholding-due-to-GI symptoms was higher in Group I(P=0.009). No other adverse event differences were observed. While long-term anti-rejection and renal function efficacy were demonstrated in both treatment arms, slight over-immunosuppression of Group II patients occurred.

Randomized trial of three induction antibodies in kidney transplantation: long-term results.

BACKGROUND: In searching for an optimal induction regimen, we conducted two separate randomized trials of 38 living donor and 90 deceased donor adult, primary kidney transplant recipients comparing antithymocyte globulin (Thymoglobulin) (group A, N=43) versus alemtuzumab (group B, N=43) versus daclizumab (group C, N=42), using exactly the same three treatment arms in each trial. METHODS: For the purpose of maximizing statistical power, results from the two randomized trials were combined. Groups A and C received standard maintenance dosing with tacrolimus (TAC), mycophenolate mofetil (MMF), and corticosteroids. Because of intense lymphodepletion expected with alemtuzumab use (and hoped-for achievement of a truer immunoregulatory state), group B received lower TAC and MMF dosing and corticosteroid avoidance. Long-term target TAC trough level and MMF dosing were 5 to 7 ng/mL and 1,000 mg b.i.d. in groups A and C; 4 to 6 ng/mL and 500 mg b.i.d. in group B. RESULTS: With median follow-up of 95 months, biopsy-proven cute rejection incidence was similar in the three groups (8/43, 14/43, and 12/42, P=0.34), but biopsy-proven chronic allograft injury incidence was significantly higher in group B (19/43) in comparison with groups A (9/43) and C (7/42) combined (P=0.0008). Mean calculated creatinine clearance was significantly lower in group B versus the average of groups A and C means throughout 60 months posttransplant (62.9±4.2 vs. 83.6±6.9 and 79.8±5.9 at 60 months, P=0.01), and death-censored graft failure was significantly higher in group B (13/43) versus groups A (5/43) and C (5/42) combined (P=0.009). Total infection and new-onset diabetes after transplant rates were not significantly different. Ad hoc analysis suggested that the inferior results in group B were specifically a result of reduced dosing and greater withholding of TAC and MMF occurring in that group. CONCLUSIONS: Long-term results clearly indicate inferior clinical outcomes in group B.

Graft failure due to noncompliance among 628 kidney transplant recipients with long-term follow-up: a single-center observational study.

BACKGROUND: In adult kidney transplantation, there is no clear consensus on the incidence of graft failure-due-to noncompliance (GFNC), with some reporting it as relatively uncommon and others as a major cause of late graft failure. We suspected that GFNC was a major cause of late graft loss at our center but did not know the extent of this problem. METHODS: In our prospectively followed cohort of 628 adult, primary kidney-alone transplant recipients with long-term follow-up, GFNC and other graft loss causes were determined from our ongoing clinical evaluations. Using competing risks methodology, we determined the overall percentage of patients developing GFNC and the significant prognostic factors for its hazard rate and cumulative incidence (via Cox regression). RESULTS: Cumulative incidence estimates (± standard error) of GFNC (n=29), GF-with-compliance (n=46), receiving a never-functioning graft (n=7), and death-with-a-functioning-graft (n=53) at 101 months after transplant (last-observed-graft loss) were as follows: 9.8%± 2.4%, 10.9%± 1.7%, 1.1%± 0.4%, and 13.0%± 1.9%, respectively. Only three patients experienced GFNC during the first 24 months; GFNC represented 48.1% (26/54) of death-censored GFs beyond 24 months. Two baseline variables were jointly associated with a significantly higher GFNC hazard and cumulative incidence: younger recipient age (P<0.000001 each) and non-white recipient (P=0.004 and P=0.02). Estimated percentages of ever developing GFNC were 28.4%± 6.5% among 79 non-whites younger than 35 years versus 0.0% (0/144) among whites 50 years or older. Among 302 recipients younger than 50 years, 18.1%± 4.1% developed GFNC, representing 67.6% (25/37) of its death-censored graft failures observed beyond 24 months after transplant. CONCLUSIONS: GFNC is a major cause of late GF at our center, with younger and non-white recipients at a significantly greater GFNC risk. Interventional approaches to eliminate GFNC could dramatically improve long-term kidney graft survival.

A randomized pilot study of donor stem cell infusion in living-related kidney transplant recipients receiving alemtuzumab.

BACKGROUND: Transplant tolerance would remove the need for maintenance immunosuppression while improving survival and quality of life. METHODS: A prospective, randomized pilot study was undertaken to assess the safety and efficacy of donor stem cell infusion (DSCI) in living-related kidney transplant recipients treated with alemtuzumab (C1H) induction and tacrolimus and mycophenolate maintenance with switch to sirolimus and weaning over 2 years. RESULTS: Four patients received DSCI; five patients were controls. Graft failure occurred in two patients in the DSCI arm. Recurrence of glomerular disease occurred in two DSCI recipients, leading to graft loss in one. Biopsy-proven acute rejection episodes occurred in three patients (two in the DSCI vs. one in the control). One DSCI patient, with recurrence, subsequently developed antibody-mediated rejection leading to graft failure. In the remaining two DSCI patients, weaning was attempted but was not successful. All (4 of 4) DSCI patients had biopsy-proven chronic allograft injury and/or recurrence. CONCLUSION: DSCI with C1H induction and a steroid-free maintenance regimen in a small group of patients failed to induce tolerance, with suboptimal patient and graft survival. The results do not justify extension of this particular trial and underscore the importance of patient selection, specifically avoidance of patients with glomerulopathies whose recurrence may obscure potential benefit.

Prolonged lymphocyte depletion by single-dose rabbit anti-thymocyte globulin and alemtuzumab in kidney transplantation.

Although antibody induction has gained in popularity, two agents are rarely combined. We retrospectively analyzed peripheral lymphocyte phenotypes of renal transplant recipients who received induction therapy with a different antibody/combination: alemtuzumab(C1H), Thymoglobulin(rATG), daclizumab(Dac), rATG+C1H, and rATG+Dac. CD4+ T-cells were suppressed by C1H and rATG+C1H, as well as by rATG and rATG+Dac but to a lesser extent. The effect lasted for 3 years at around 40% of baseline values. CD8+ T-cells showed a similar trend but had a more rapid recovery to baseline. CD19+ B-cells were effectively suppressed for 2 months by C1H and rATG+C1H, and abruptly returned to baseline afterwards; suppression by rATG(7 doses) was modest but lasted longer. A higher proportion of CD56+CD16+ Natural Killer cells in C1H treated patients suggested a relatively spared effect of C1H on this cell type. Low CD25+ T-cells by 5-dose Dac returned to baseline around 6 months, whereas rATG+C1H and rATG+Dac showed persistent effect. CD4+CD25hi T-cells were suppressed by both rATG+C1H and rATG+Dac, but the initial proportion of CD4+CD25hi T-cells among CD4+ T-cells and CD4+CD25hi/CD4+CD25lo ratio were significantly higher in rATG+C1H. Overall, with extensive and persistent lymphocyte suppression by a simple administration of agents, single-dose rATG+C1H induction can be an alternative in renal transplantation.

Randomized trial of mycophenolate mofetil versus enteric-coated mycophenolate sodium in primary renal transplantation with tacrolimus and steroid avoidance: four-year analysis.

BACKGROUND: Our single-center, open-labeled randomized trial of 150 adult, primary kidney transplant recipients receiving 2 g mycophenolate mofetil (group A, n=75) versus 1.440 g enteric-coated mycophenolate sodium (group B, n=75), with reduced maintenance tacrolimus dosing, steroid elimination at 1 week, and combined rabbit antithymocyte globulin/daclizumab induction, previously showed at 1 year posttransplant low biopsy-proven acute rejection (BPAR), acceptably high renal function, and no differences in incidence of symptomatic gastrointestinal (GI) side effects between the two groups. This report includes 3 additional years of follow-up with similar endpoints as in the original study. METHODS: Rates of developing first BPAR, graft failure (death censored and uncensored), death, and adverse events (GI toxicity, infections requiring hospitalization, and new onset diabetes mellitus after transplantation) during the first 48 months posttransplant were compared between the two groups using an intent-to-treat approach. RESULTS: At 48 months posttransplant, patient/graft survival in groups A and B was 97%/90% vs. 96%/86%, respectively (not significant [NS]). Twenty-seven patients experienced BPAR (including borderline), with actuarial 19% (14/75) vs. 18% (13/75) in groups A and B, respectively (NS). Geometric mean*/standard error serum creatinine level and arithmetic mean calculated glomerular filtration rate (±standard error) at 48 months in groups A and B, respectively, were 1.25*/1.06 and 69.2±3.9 vs. 1.20*/1.05 and 71.2±3.2 (NS). Incidence of new onset diabetes mellitus after transplantation (22% vs. 15%), infections requiring hospitalization (31% vs. 39%), and GI side effects (45% vs. 52%) seemed equivalent. CONCLUSIONS: This is the first long-term, randomized trial comparing enteric-coated mycophenolate sodium versus mycophenolate mofetil along with reduced maintenance tacrolimus dosing and steroid avoidance, which resulted in similarly low-BPAR rates, acceptably high renal function at 48 months, and an equivalent side effect profile.

Randomized trial of dual antibody induction therapy with steroid avoidance in renal transplantation.

BACKGROUND: Given our previous experience using dual-induction therapy with antithymocyte globulin (ATG)/daclizumab (Dac) (each with fewer doses than if used alone), we chose to compare two distinct dual-induction strategies. METHODS: Single-center, open-label randomized trial of 200 primary kidney transplant recipients was performed: (group I, n=100) ATG/Dac (3 ATG, 2 Dac doses) versus (group II, n=100) ATG/alemtuzumab (1 dose each), with maintenance consisting of reduced tacrolimus dosing (rTd), enteric-coated mycophenolate sodium (EC-MPS), and early corticosteroid withdrawal. One half of standard EC-MPS dosing was targeted in group II to avoid severe leukopenia previously seen with alemtuzumab. The goal in both arms was to achieve rapid and effective lymphocyte depletion while simultaneously allowing reduced maintenance immunosuppression. Primary endpoint was the incidence of biopsy-proven acute rejection (BPAR). RESULTS: With median follow-up of 38 months, there were no differences in BPAR rates: 14 of 100 vs. 13 of 100 (including borderline) and 10 of 100 vs. 9 of 100 (excluding borderline) in groups I and II, respectively (nonsignificant). Actuarial patient/graft survival at 48 months was 96%/91% in group I vs. 92%/83% in group II (N.S.). Mean estimated glomerular filtration rate (±standard error) at 36 months was 72.1±3.3 vs. 67.5±3.3 in groups I and II (N.S.). Greater incidence of leukopenia occurred in group II at month 1 only (P=0.002). Percentages having EC-MPS withheld/discontinued due to leukopenia, gastrointestinal symptoms, and infection were 12 of 100, 7 of 100, and 0 of 100 in group I vs. 19 of 100, 0 of 100, and 2 of 100 in group II, respectively (P=0.01). Rates of new onset diabetes mellitus after transplantation and infections were equally low in both groups (no lymphoproliferative disorders were observed). CONCLUSIONS: These two distinct dual-induction therapies with rTd, EC-MPS, and planned early corticosteroid withdrawal resulted in favorable rates of BPAR and all secondary outcomes.

Favorable outcomes with machine perfusion and longer pump times in kidney transplantation: a single-center, observational study.

BACKGROUND: Hypothermic machine perfusion (MP) preservation is used for all deceased donor kidney transplants at our center. Kidneys are placed in cold storage at retrieval, then transferred to MP on arrival. Because a lack of consensus regarding optimal use of MP still exists, we evaluated the overall impact of using MP at our center and the prognostic value of MP (Pump) time. METHODS: We retrospectively analyzed 339 adult, primary deceased donor kidney transplant recipients who were pooled across three prospective, randomized immunosuppression trials (since 2000) at our center. In addition to providing overall results for delayed graft function (DGF) (requirement for dialysis in the first week), slow graft function (SGF), first biopsy-proven acute rejection (BPAR), and graft failure, stepwise logistic and Cox regression analyses were used to determine the prognostic value of pump time, particularly after controlling for other significant prognosticators. RESULTS: Mean cold storage and pump times were 6.6 and 26.7 hr, consistent across immunosuppression protocols. Overall DGF and SGF rates were 4.4% (15/339) and 12.1% (41/339). DGF was equally low for pump time less than 24 vs. more than or equal to 24 hr, 5.2% (6/116) vs. 4.0% (9/223) (P=0.63), with similar results after adjusting for known DGF predictors. A significantly lower first BPAR rate was observed for longer pump time (as a continuous variable) among more immunologically active recipients (those having more risk factors: DGF, age <50 yr, and non-white) (univariable P=0.005; multivariable P=0.009), with an estimated hazard ratio of 0.43 (P=0.006) favoring pump time more than or equal to 24 hr among those with more than or equal to two risk factors. CONCLUSIONS.: In this single-center, observational study, MP with prolonged pump times was associated with low DGF/SGF and first BPAR rates, supporting continued use of MP.