Calcineurin-inhibitors in renal transplantation. Too precious to be abandoned

Conversion From Cyclosporine to Once-Daily Tacrolimus on 50:1 mg Basis: A Short-Term Pilot Study

OBJECTIVES

In addition to graft dysfunction, renal transplant recipients on cyclosporine may be switched to tacrolimus to reduce its drug-related secondary clinical effects and undesirable cosmetic side effects. However, the dose level of once-daily tacrolimus for these patients has yet to be established. The objective of this prospective study was to confirm the safety of converting stable renal transplant recipients on cyclosporine to once-daily tacrolimus at a 50:1 mg ratio.

MATERIALS AND METHODS

Our study enrolled 17 patients receiving cyclosporine who were observed for 3 months. Graft biopsies did not reveal any acute rejection, and the conversion ratio to once-daily tacrolimus was 50:1 mg. Dose adjustments were made to achieve a target tacrolimus trough concentration of 3 to 5 ng/mL at 2 weeks, and graft biopsies were taken after the 3-month observation period.

RESULTS

Dose adjustment was required in 7 recipients (41.2%) within 3 months of conversion. None of the recipients had acute cellular rejection or C4d deposition, and the mean estimated glomerular filtration rate of 38.7 ± 11.0 mL/min/1.73 m2 at baseline was significantly improved to 42.0 ± 10.0 mL/min/1.73 m2 at month 3.

CONCLUSIONS

Although recipients of renal transplant can be forced to discontinue cyclosporine administration due to undesirable adverse effects, our study showed that a once-daily dose of tacrolimus may be safe when administered at a conversion ratio of 50:1.

Tacrolimus confers lower acute rejection rates and better renal allograft survival compared to cyclosporine

AIM

To compare the impact of tacrolimus (FK) and cyclosporine (CYA) on acute rejection and graft survival and to assess the predominant causes of graft loss between patients receiving these two calcineurin inhibitors (CNIs).

METHODS

Retrospective review of 1835 patients who received a kidney transplant (KTX) between 1999-2012. Patients were grouped based on initial CNI utilized: 1195 in FK group, 640 in CYA group. Data on baseline characteristics, clinical outcomes, and causes of graft loss in both groups were analyzed.

RESULTS

Cumulative acute rejection rates were 14% in the FK vs 24% in the CYA group. Despite more marginal donor characteristics in the FK group, these patients had better graft survival rates compared to the CYA group. Three and five year graft survival rates were 88% and 84% respectively in the FK group compared to 79% and 70% respectively in the CYA group (P < 0.001). After multivariate analysis, which controlled for confounders, FK use was a strong predictor for lower acute rejection rates [odds ratio (OR) 0.60, 95%CI: 0.45-0.79] and better renal allograft survival (OR 0.740, 95%CI: 0.58-0.94). Death with a functioning graft was the most common cause of graft loss in both groups. Common causes of death included cardiovascular disease, infections, and malignancies. Chronic allograft nephropathy was also found to be an important cause of graft loss, being more prevalent in the CYA group.

CONCLUSION

The use of FK-based maintenance immunosuppression therapy is associated with a significantly lower rate of acute rejection and better graft survival compared to CYA-based regimen. Individualizing immunosuppression through risk-stratified CNI choice may lead to improved outcomes across all spectra of KTX patients.

Everolimus with very low-exposure cyclosporine a in de novo kidney transplantation: a multicenter, randomized, controlled trial

BACKGROUND

In combination with everolimus (EVL), cyclosporine A (CsA) may be used at low exposure, so reducing the risk of renal dysfunction in renal transplant recipients (RTR). We evaluated whether higher exposure of EVL could allow a further reduction of CsA.

METHODS

De novo RTR were randomized to standard exposure EVL (C0 3-8 ng/mL) with low-concentration CsA (C2 maintenance levels 350-500 ng/mL, group A) or higher EVL exposure (C0 8-12 ng/mL) with very low-concentration CsA (C2 maintenance levels 150-300 ng/mL, group B). The primary endpoints were 6-month creatinine clearance (CrCl) and biopsy-proven acute rejection (BPAR) rate. After 6 months, patients were followed up (observational extension) to 12 months.

RESULTS

Two hundred eighty-five RTR (97% from deceased donors) were enrolled. Two patients per group died (1.4%). The 6-month death-censored graft survival was 90.2% in group A and 97.9% in group B and was unchanged at 12 months (P=0.007). There was no significant difference between groups at 6 months in CrCl (59.9 vs. 57.8 mL/min) and BPAR rates (14.7% vs. 11.9%) and also at 12 months (CrCl 62.5+/-20.7 vs. 61.3+/-22.0 mL/min, BPAR 14.7% vs. 14.1%). No significant differences were seen in treated acute rejections, steroid-resistant acute rejections, treatment failures, or delayed graft function, although there was a trend to better results in group B.

CONCLUSIONS

EVL given at higher exposure for 6 months plus very low CsA concentration may obtain low acute rejection rate and good graft survival in De novo renal transplantation. However, there was no difference between groups in CrCl.

Skin allograft survival and analysis of renal parameters after FTY720 + tacrolimus treatment in mice

Calcineurin inhibitors such as cyclosporine (CsA) and tacrolimus (FK506) show similar efficacy to prevent rejection within the first year after organ transplantation. However, their use is limited by side effects, such as kidney damage, hypertension, new-onset diabetes, and hyperlipidemia. The consensus opinion suggests that compared with CsA, FK506 has fewer negative effects on blood pressure, serum lipids, and renal function. Nevertheless, FK506 use is associated with a higher incidence of posttransplantation diabetes mellitus. FTY720 is a new compound that has shown beneficial effects in animal models of rejection in transplantation, ischemia/reperfusion injury, autoimmune diseases, and tumor development. Our aim was to investigate whether FTY720 + tacrolimus association could provide additional immunosuppression without causing renal toxicity. FTY720 as a monotherapy or in association with FK506 was administered to C57BL/6 mice for 21 days to prevent skin graft rejection and to evaluate renal function and structure. Increased skin allograft survival in the FTY720 + FK506 group was associated with decreased cell numbers in the spleen, blood, and axillary lymph nodes. Changes in major histocompatibility complex (MHC) class II and intercellular adhesion molecule-1 (ICAM-1) expressions in splenocytes were also found in this group. The major effects already described for FK506 (diabetes) or FTY720 (lymphopenia) were observed after 21 days administration even when the drugs were associated. FTY720 associated with FK506 caused fewer changes in kidney structure, and blood glucose levels were lower than in FK506 monotherapy.

Efficacy and safety of tacrolimus compared with cyclosporin A microemulsion in renal transplantation: 2 year follow-up results

BACKGROUND

Comparison studies of calcineurin inhibitors as cornerstone immunosuppressants in renal transplantation have demonstrated that tacrolimus consistently reduces acute rejection rates and, in some studies, also improves long-term renal outcome in comparison to cyclosporin A (CsA). The aim of the present 2 year follow-up of the European Tacrolimus vs Cyclosporin A Microemulsion Renal Transplantation Study was to investigate long-term clinical outcome in terms of rate of acute rejection, graft and patient survival and graft function.

METHODS

The European Tacrolimus vs Cyclosporin A Microemulsion Renal Transplantation Study was a randomized, comparative 6 month trial of the calcineurin inhibitors tacrolimus and CsA in combination with both azathioprine and steroids. The intent-to-treat population (ITT) consisted of 286 patients in the tacrolimus arm and 271 in the CsA microemulsion (CsA-ME) arm. Whereas whole blood level targets were 10-20 and 5-15 ng/ml for tacrolimus and 100-400 and 100-200 ng/ml for CsA during months 0-3 and 4-6, respectively, during the investigator-driven follow-up after termination of the main study (months 7-24) no specific calcineurin inhibitor target levels were required. Follow-up data were collected at 2 years post-transplantation from 237 (82.9% of the ITT population) patients who received tacrolimus and 222 (81.9% of the ITT population) patients who received CsA-ME.

RESULTS

Calculated on ITT populations, mortality (2.0% vs 3.3%; P<0.05 in Kaplan-Meier analysis) was lower, but rate of graft loss (9.3% vs 11.2%; P = 0.12 in Kaplan-Meier analysis) was not significantly different after 2 years with tacrolimus- vs CsA-ME-based immunosuppression. Biopsy-proven acute rejection was significantly lower (19.6%) with tacrolimus than with CsA-ME (37.3%) during months 0-6 (P<0.0001), but was not significantly different during months 7-12 and 13-24 of follow-up (1.7% and 0.8% with tacrolimus and 4.7% and 0.9% with CsA-ME, respectively). A composite endpoint consisting of graft loss, patient death and biopsy-proven acute rejection occurred significantly more frequently in CsA-ME patients than in tacrolimus patients (42.8% vs 25.9%; P<0.001) during 24 months follow-up. Renal function 2 years post-transplant, measured by serum creatinine concentrations, was significantly better in tacrolimus-based compared with CsA-ME-based immunosuppression (136.9 vs 161.6 micromol/l; P<0.01). Cornerstone immunosuppression remained unchanged in 82.5% and 66.2% of patients treated with tacrolimus and CsA-ME, respectively. At 2 years, more patients in the tacrolimus arm were off steroids and received calcineurin inhibitor monotherapy, and fewer tacrolimus patients remained on a triple immunosuppressive regimen. The cardiovascular risk profile was affected favourably in the tacrolimus arm, with lower cholesterol and triglyceride concentrations (despite less use of cholesterol-lowering drugs); no significant difference in requirement for antidiabetic medication was noted.

CONCLUSIONS

The 2 year study results confirm that tacrolimus is a highly efficacious cornerstone immunosuppressant in kidney transplantation. Tacrolimus-based immunosuppression may induce long-term benefits with regard to graft function and graft survival. The overall side-effect profile is considered to be favourable.

Cyclosporine: advantages versus disadvantages vis-à-vis tacrolimus

Despite a different molecular structure and biochemical properties, cyclosporine and tacrolimus--by inhibiting calcineurin activity--have been shown in the previous two decades of solid organ transplantation to be well tolerated and effective immunosuppressants. Initial randomized clinical trials showed a lower incidence of acute rejection in tacrolimus than in cyclosporine-treated patients, in combination with steroids and azathioprine. But in conjunction with mycophenolate mofetil, the difference in the incidence of acute rejection episodes is less clear. In general, short- and medium-term outcome variables (1-year serum creatinine, graft and patient survival) with cyclosporine and tacrolimus are excellent, and (almost) identical, with both substances having the same intrinsic nephrotoxic potential. On the other hand, cyclosporine and tacrolimus have a different impact on cardiovascular risk factors with tacrolimus having a better profile on arterial tension and lipid metabolism and cyclosporine on glucose metabolism. However, at present no data are available to discern that these differences in risk profile alter patient or graft survival or long-term cardiovascular morbidity/mortality. Therefore, prospective long-term trials are needed to study the quantitative impact of different immunosuppressive agents and concomitant cardiovascular risk factors on long-term patient and graft survival, before evidence-based (patient, graft, or cardiovascular) risk reduction can be firmly claimed by tailoring calcineurin inhibitors.

Cardiovascular risk factors and estimated risk for CAD in a randomized trial comparing calcineurin inhibitors in renal transplantation

Cardiovascular morbidity and mortality is high in patients following renal transplantation. The present analysis assessed major cardiovascular risk factors and estimated the risk of coronary artery disease in the largest present-day comparative trial of tacrolimus vs. microemulsified cyclosporine A. In this 6-month study, 557 patients were randomly allocated to therapy with tacrolimus (n = 286) or cyclosporine A (n = 271) concomitantly with azathioprine and corticosteroids. The primary endpoint was the incidence of and time to acute rejection. Blood pressure, serum cholesterol, HDL cholesterol, triglycerides, and blood glucose were measured at baseline, and at months 1, 3, and 6. Ten-year risk of coronary heart disease was estimated according to the Framingham risk algorithm. Tacrolimus resulted in significantly lower summary measures (time-weighted average) of serum cholesterol (p = 0.0004) and mean arterial blood pressure (p = 0.0156), but in a higher summary measure of blood glucose (p = 0.0028) than cyclosporine. The summary measure of serum triglycerides was not different between treatment groups (p = 0.368). The mean 10-year coronary artery disease risk estimate was significantly lowered in men (p = 0.0032) treated with tacrolimus, but was unchanged in women. Tacrolimus and cyclosporine A microemulsion exert a compound-specific impact on cardiovascular risk factors and appear to affect the predicted rate of cardiovascular morbidity in different manners.

Tacrolimus in induction immunosuppressive treatment in renal transplantation: comparison with cyclosporine

The aim of the study was to compare the efficacy and safety of induction immunosuppression therapies based on tacrolimus or cyclosporine (CsA) in kidney transplantation. The 240 kidney allograft recipients were divided into two groups: group 1 (n=94) received tacrolimus (.01 mg/kg per day), mycophenolate mofetil (MMF, 2 g/d), and steroids (30 mg/d); and group 2 (n=146) CsA (6 mg/kg per day), MMF (2 g/d), and steroids (30 mg/d). Antilymphocyte serum was administered in cases of acute tubular necrosis. The acute rejection rate was higher among group 2 (30.6%) compared with group 1 patients (12.2%) (P=.001). There were no significant differences between the groups in terms of age, gender, body surface area, serologic virus markers (in donor and recipient), baseline creatinine levels, cause of death, HLA incompatibilities, response to acute tubular necrosis, and number of dialysis sessions. We conclude that both immunosuppressive regimens are effective and safe in kidney transplantation. The survival rates of patients and grafts were similar, but the incidence and degree of acute rejection events were reduced in group 1; this finding may forecast a decreased incidence of chronic renal allograft nephropathy.