Tacrolimus as secondary intervention vs. cyclosporine continuation in patients at risk for chronic renal allograft failure

Does diabetes impact therapeutic immunomodulation therapy decisions for kidney transplant recipients? Data from the Folic Acid for Vascular Outcome Reduction in Transplant (FAVORIT) trial

Although survival has improved for kidney transplant recipients over the past several decades, long-term survival in diabetic cohorts still is significantly less than that of non-diabetic cohorts. We hypothesized that among stable kidney transplant recipients, there might be differences between subgroups with and without diabetes with respect to prevalence of prior cardiovascular events and post-transplant antihypertensive and immunosuppressive therapy. We performed a post hoc analysis of participants in the Folic Acid for Vascular Outcome Reduction in Transplant (FAVORIT) trial, a multicenter international trial of 4110 prevalent kidney transplant recipients enrolled from 2002 to 2007 evaluating the effect of homocysteine-lowering vitamin therapy on cardiovascular outcomes. There were 2447 participants without diabetes, 166 with type 1 diabetes, and 1447 with type 2 diabetes at study entry, which occurred on average 4 years post-transplant. Recipients with diabetes had a greater prevalence of prior cardiovascular events, were more likely to have required multiple medications to control hypertension, and were more likely to have received tacrolimus as opposed to cyclosporine than the non-diabetic transplant recipients (all p<0.001). The effect of differences in treatment of non-diabetic vs diabetic cohorts after stable renal transplantation upon outcomes has not yet been studied and could provide additional information that might lead to improved care.

A Systematic Literature Review Approach to Estimate the Therapeutic Index of Selected Immunosuppressant Drugs After Renal Transplantation

BACKGROUND

Drugs that exhibit close margins between therapeutic and toxic blood concentrations are considered to have a narrow therapeutic index (NTI). The Food and Drug Administration has proposed that NTI drugs should have more stringent bioequivalence standards for approval of generic formulations. However, many immunosuppressant drugs do not have a well-defined therapeutic index (TI).

METHODS

We sought to determine whether safety, efficacy, and pharmacokinetic data obtained from the medical literature through a comprehensive literature search could be used to estimate the TI of cyclosporine, tacrolimus, and sirolimus. In this analysis, we considered TI ≤2 as a criterion to define a drug as having an NTI.

RESULTS

Published literature indicates that cyclosporine has a TI of 2-3, which falls just short of our criteria to be classified as having an NTI. We found sirolimus and tacrolimus to have a therapeutic range of 5-12 ng/mL and of 5-20 ng/mL, respectively, but were unable to calculate the TI.

CONCLUSIONS

Although the current literature does not provide a clear indication that these drugs have an NTI, the routine use of therapeutic drug monitoring in clinical practice suggests that more stringent testing of their pharmacokinetic and pharmacodynamic properties should be performed before the approval of generic formulations.

Switching from calcineurin inhibitor-based regimens to a belatacept-based regimen in renal transplant recipients: a randomized phase II study

BACKGROUND AND OBJECTIVES

Prolonged use of calcineurin inhibitors (CNIs) in kidney transplant recipients is associated with renal and nonrenal toxicity and an increase in cardiovascular risk factors. Belatacept-based regimens may provide a treatment option for patients who switch from CNI-based maintenance immunosuppression.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a randomized, open-label Phase II trial in renal transplant patients with stable graft function and receiving a CNI-based regimen. Patients who were ≥6 months but ≤36 months after transplantation were randomized to either switch to belatacept or continue CNI treatment. All patients received background maintenance immunosuppression. The primary end point was the change in calculated GFR (cGFR) from baseline to month 12.

RESULTS

Patients were randomized either to switch to belatacept (n=84) or to remain on a CNI-based regimen (n=89). At month 12, the mean (SD) change from baseline in cGFR was higher in the belatacept group versus the CNI group. Six patients in the belatacept group had acute rejection episodes, all within the first 6 months; all resolved with no allograft loss. By month 12, one patient in the CNI group died with a functioning graft, whereas no patients in the belatacept group had graft loss. The overall safety profile was similar between groups.

CONCLUSIONS

The study identifies a potentially safe and feasible method for switching stable renal transplant patients from a cyclosporine- or tacrolimus-based regimen to a belatacept-based regimen, which may allow improved renal function in patients currently treated with CNIs.

Long-term assessment of plasma lipids in transplant recipients treated with tacrolimus in relation to fatty liver

Immunosuppression has improved graft and recipient survival in transplantation but is associated with possible adverse effects including cardiovascular diseases. The impact of tacrolimus on the lipidic profile has been debated for several years. Twenty-nine kidney transplant recipients on tacrolimus treatment were monitored for six years, and multiple laboratory parameters investigating the lipid asset, as well as glucose profile, were carried out. Tacrolimus has been responsible for significant changes in plasma lipid concentrations only for the first six months, but not for the remaining time of observation. Similarly, in the same periods, glycemic imbalance was highlighted. The liver enzyme activity showed a modest derangement during the tacrolimus treatment, suggesting the presence of lipid accumulation in the liver. Fatty liver reversed in the long term follow-up. Tacrolimus, although it is not a completely safe option in the first months of the immunosuppressive protocols in organ transplanted recipients, still retains a certain role in the long-term post-transplantation immunosuppressive approach with high cardiovascular risks.

Five-year study of tacrolimus as secondary intervention versus continuation of cyclosporine in renal transplant patients at risk for chronic renal allograft failure

BACKGROUND

Chronic allograft nephropathy is the most frequent cause of long-term kidney allograft loss. Studies are desperately needed to improve long-term survival. Tacrolimus has been associated with less rejection and better kidney function compared with cyclosporine in clinical trials. This study tested the hypothesis that conversion from cyclosporine to tacrolimus might improve long-term outcomes in patients with chronic allograft damage.

METHODS

In this multicenter Canadian clinical trial, cyclosporine-treated patients with biopsy-proven chronic allograft nephropathy and impaired renal function were randomly assigned (2:1) to convert to tacrolimus or continue on cyclosporine therapy. A total of 106 (70 tacrolimus and 36 cyclosporine treated) patients were followed-up for up to 5 years. The primary outcome was graft survival.

RESULTS

In an intention to treat analysis, subsequent graft (73% vs. 81%, P=0.2835, log-rank test) and patient survival (91% vs. 92%, P=0.8668, log-rank test) were not different between the tacrolimus and cyclosporine groups, respectively. Changes in Chronic Allograft Damage Index scores on protocol biopsies from baseline to 3 years were not different (+0.4+/-1.8 vs. +1.3+/-3.2, P=0.5910, cyclosporine vs. tacrolimus, respectively). There were no significant differences in biopsy-proven acute rejection (6 [8.6%] vs. 2 [5.6%], tacrolimus vs. cyclosporine, respectively, P=0.5906).

CONCLUSIONS

In this study, patients with chronic allograft damage converted from cyclosporine to tacrolimus demonstrated no apparent benefit.

Optimizing tacrolimus therapy in the maintenance of renal allografts: 12-month results

BACKGROUND

The determination of optimal tacrolimus (TAC) trough levels is needed to prevent adverse effects of calcineurin inhibitors.

METHODS

Stable transplant recipients currently receiving cyclosporine (CsA) were assigned randomly (1:1:1) to continue CsA (target trough level of 50-250 ng/mL); or convert to "reduced" TAC (target trough level 3.0-5.9 ng/mL) or "standard" TAC (target trough level 6.0-8.9 ng/mL).

RESULTS

At 12 months, there was a significant improvement in renal function in the reduced TAC versus CsA group with lower serum creatinine (P=0.004) and cystatin C (P<0.001), and higher estimated creatinine clearance (P=0.017). However, there were no statistically significant differences in any renal parameter in the standard TAC versus CsA group. Total and low-density lipoprotein cholesterol were significantly reduced in both TAC groups versus the CsA group (P<0.001). Patient and graft survival and episodes of biopsy-confirmed acute rejection were similar for all treatment groups, and no statistically significant differences were observed between groups in the incidence of new-onset diabetes or cardiac conditions, or in the prevalence of hyperglycemia, hypertension, or hyperlipidemia among patients who did not have these conditions at baseline. Alopecia developed more commonly among TAC-treated patients than CsA-treated patients (P<0.001).

CONCLUSIONS

Compared with CsA continuation, conversion to reduced TAC target trough concentrations resulted in significantly improved renal function without increasing the risk of rejection. Conversion to TAC, regardless of target concentration, resulted in improved serum lipid profiles in kidney transplant recipients at 12 months.

Early conversion from cyclosporine to tacrolimus increases renal graft function in chronic allograft nephropathy at BANFF stages I and II

Switching from cyclosporine to tacrolimus without steroid pulse was suggested as a therapeutic option in chronic allograft nephropathy (CAN). Thirty-one renal transplant recipients with CAN were prospectively converted from cyclosporine to tacrolimus (group A), in parallel 31 matched cyclosporin A (CsA) patients (group B) without CAN were followed up for 30 months. In six matching patients of groups A and B inulin and para-aminohippurate (PAH)-clearances and mycophenolate were measured over a span of 3 months. Transplant biopsies of group A were scored according to BANFF. While group A presented with transplant dysfunction compared with group B before switching (2.7 +/- 0.16 mg/dl vs. 1.7 +/- 0.09 mg/dl; P < 0.001), transplant function was equal 30 months later: it ameliorated in group A (2.0 +/- 0.18 mg/dl vs. 2.7 +/- 0.16 mg/dl; P < 0.001) and decreased in group B (1.9 +/- 0.13 mg/dl vs. 1.7 +/- 0.09 mg/dl, P < 0.05). Especially, patients with biopsy scores I and II according to BANFF benefited from tacrolimus. Within 3 months, mycophenolate acid (MPA) levels increased under tacrolimus (P < 0.05) whereas inulin and PAH-clearances remained unchanged. At switching, antihypertensive treatment was more intense in group B, but this difference evened out. Adverse side effects were more frequent under tacrolimus. Patients with mild to moderate CAN significantly benefited from switching to tacrolimus. Increased MPA-levels under tacrolimus might have contributed to this effect.

Conversion from cyclosporine to tacrolimus in patients at risk for chronic renal allograft failure: 60-month results of the CRAF Study

BACKGROUND

This study compared the long-term effects of switching from cyclosporine to tacrolimus on the incidence, progression, and severity of chronic renal allograft failure in patients with elevated serum creatinine levels.

METHODS

Patients were assigned randomly (2:1) to switch to tacrolimus or remain on cyclosporine. Tacrolimus was initiated at 1/50th of the cyclosporine dose or 0.15 mg/kg/day, whichever dose was lower, to maintain trough concentrations between 5 and 15 ng/mL. Cyclosporine doses were adjusted to achieve trough concentrations between 100 and 300 ng/mL.

RESULTS

At 60 months, the median change from baseline in serum creatinine was -0.2 mg/dL in the tacrolimus group and 0.3 mg/dL in the cyclosporine group (P=0.003). Median change in estimated creatinine clearance was 1.2 mL/min in the tacrolimus group and -4.1 mL/min in the cyclosporine group (P=0.019). The incidence of new-onset diabetes, hyperglycemia, hypertension, lymphoma, and malignancies was generally low and comparable between groups. Fewer patients in the tacrolimus group than in the cyclosporine group developed new cardiac conditions (11% vs. 28%, P=0.004), had low-density lipoprotein (LDL) cholesterol values more than 130 mg/dL (29% vs. 57%, P=0.002), or developed hyperlipidemia (24% vs. 67%, P=0.046) during the 60-month follow-up period. Despite these changes, patient and graft survival were similar for both groups.

CONCLUSION

Switching from cyclosporine to tacrolimus resulted in improved renal function and a reduction in the occurrence of new-onset cardiac conditions and hyperlipidemia, with no increase in the incidence of new-onset diabetes or new-onset hyperglycemia. However, after 5 years there was no impact on patient or graft survival.

Cardiovascular outcomes in the outpatient kidney transplant clinic: the Framingham risk score revisited

BACKGROUND AND OBJECTIVES

Cardiovascular disease is an important cause of morbidity and death in kidney transplant recipients. This study examines the Framingham risk score's ability to predict cardiac and stroke events. Because cyclosporine and tacrolimus have different cardiovascular risk profiles, these agents were also examined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective cohort evaluation of 540 patients were followed for a median of 4.7 yr in an outpatient kidney transplant clinic. Baseline Framingham risk scores were calculated and all cardiovascular outcomes were collected.

RESULTS

Rates per 100 patient-years were 1.79 for cardiac and 0.78 for stroke events. The ratio of observed-to-predicted cardiac events was 1.64-fold higher [95% confidence interval (CI) 1.19 to 2.94] for the cohort, 2.74-fold higher (95% CI 1.70 to 4.24) in patients age 45 to 60 with prior cardiac disease or diabetes mellitus, but not higher in other age subgroups. Stroke was not increased above predicted. Risk scores for cardiac (c = 0.65, P = 0.003) and stroke (c = 0.71, P = 0.004) events were modest predictors. 10-yr event scores for cardiac (9.3 versus 13.5%, P < 0.001) and stroke (7.1 versus 10.0%, P = 0.002) were lower for tacrolimus compared with cyclosporine-treated patients. However observed cardiac events were higher in tacrolimus recipients (2.50, 95% CI 1.09 to 5.90) in an adjusted Cox model.

CONCLUSIONS

Although risk scores are only modest predictors, patients with the highest event rates are easily identified. Treating high-risk patients with cardioprotective medications should remain a priority.

Predictors of renal function improvement following tacrolimus conversion in cyclosporine-treated kidney transplant recipients

The objective of this study was to evaluate the relationship between variability of cyclosporine (CsA) absorption and tacrolimus (TAC) conversion seeking factors that predict improvement in allograft function after TAC conversion. We performed a retrospective study of 44 adult kidney transplant recipients undergoing conversion from CsA to TAC-based immunosuppression. Before TAC conversion, patients had complete, consecutive, 6 monthly C2 levels and a follow-up duration beyond 6 months after TAC conversion. The patients were divided into 2 groups: one (n=23) with low variability of CsA absorption and one (n=21) with high variability of CsA absorption. At TAC conversion, the estimated glomerular filtration rate (eGFR) was similar in both patient groups. Six months after TAC conversion, eGFR improved in both groups. Stepwise regression analysis revealed the DeltaSCr6 (change in serum creatinine level at 6 months) to be independently associated with the preconversion serum creatinine (SCr; P<.0001) and the percent coefficient of variation (%CV) of SCr (P=.0034). DeltaSCr6 was inversely associated with posttransplantation years (P=.0033), and 6-month TAC blood levels (P=.0053). The DeltaSCr6 was not associated with variability of oral CsA absorption. The cutoff value of baseline SCr at TAC conversion differentiated an increase in or reduction of SCr to be about 1.0 mg/dL. Our study of CsA-treated kidney transplant recipients who underwent TAC conversion showed that a preconversion SCr>1.0 mg/dL, a high variability of SCr, and early TAC conversion predicted greater short-term benefit on graft function.

What we CAN do about chronic allograft nephropathy: Role of immunosuppressive modulations

Given the potency of modern immunosuppressive agents, kidney transplantation across alloantingen barriers is a routine phenomenon with excellent 1-year graft survival in most centers. However, the improvement in 1-year graft survival has not been matched by improvements in long-term graft function and chronic allograft nephropathy (CAN) remains the second commonest cause of graft attrition over time. Calcineurin inhibitors, namely cyclosporine A (CyA) and tacrolimus, have been implicated as causal agents in the development of the fibrotic processes that are the hallmarks of CAN. Many studies have, therefore, concentrated on the improvement of long term graft function through the modulation of immunosuppressive therapy. It is the purpose of this review to describe and appraise the available evidence for the prevention and management of CAN through modulation of immunosuppressive agents.