Renal function in renal or liver transplant recipients after conversion from a calcineurin inhibitor to sirolimus

Cardiovascular Disease Outcomes Related to Early Stage Renal Impairment After Liver Transplantation

BACKGROUND

In the general population, even mild renal disease is associated with increased cardiovascular (CV) complications. Whether this is true in liver transplant recipients (LTR) is unknown.

METHODS

This was a retrospective cohort study of 671 LTR (2002-2012) from a large urban tertiary care center and 37 322 LTR using Vizient hospitalization data linked to the United Network for Organ Sharing. The 4-variable Modification of Diet in Renal Disease equation estimated glomerular filtration rate (eGFR). Outcomes were 1-year CV complications (death/hospitalization from myocardial infarction, heart failure, atrial fibrillation, cardiac arrest, pulmonary embolism, or stroke) and mortality. Latent mixture modeling identified trajectories in eGFR in the first liver transplantation (LT) year in the 671 patients.

RESULTS

Mean (SD) eGFR was 72.1 (45.7) mL/min per 1.73 m. Six distinct eGFR trajectories were identified in the local cohort (n = 671): qualitatively normal-slow decrease (4% of cohort), normal-rapid decrease (4%), mild-stable (18%), mild-slow decrease (35%), moderate-stable (30%), and severe-stable (9%). In multivariable analyses adjusted for confounders and baseline eGFR, the greatest odds of 1-year CV complications were in the normal-rapid decrease group (odds ratio, 10.6; 95% confidence interval, 3.0-36.9). Among the national cohort, each 5-unit lower eGFR at LT was associated with a 2% and 5% higher hazard of all-cause and CV-mortality, respectively (P < 0.0001), independent of multiple confounders.

CONCLUSIONS

Even mild renal disease at the time of LT is a risk factor for posttransplant all-cause and CV mortality. More rapid declines in eGFR soon after LT correlate with risk of adverse CV outcomes, highlighting the need to study whether early renal preservation interventions also reduce CV complications.

The Role of mTOR Inhibitors in Liver Transplantation: Reviewing the Evidence

Despite the success of liver transplantation, long-term complications remain, including de novo malignancies, metabolic syndrome, and the recurrence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC). The current mainstay of treatment, calcineurin inhibitors (CNIs), can also worsen posttransplant renal dysfunction, neurotoxicity, and diabetes. Clearly there is a need for better immunosuppressive agents that maintain similar rates of efficacy and renal function whilst minimizing adverse effects. The mammalian target of rapamycin (mTOR) inhibitors with a mechanism of action that is different from other immunosuppressive agents has the potential to address some of these issues. In this review we surveyed the literature for reports of the use of mTOR inhibitors in adult liver transplantation with respect to renal function, efficacy, safety, neurological symptoms, de novo tumors, and the recurrence of HCC and HCV. The results of our review indicate that mTOR inhibitors are associated with efficacy comparable to CNIs while having benefits on renal function in liver transplantation. We also consider newer dosing schedules that may limit side effects. Finally, we discuss evidence that mTOR inhibitors may have benefits in the oncology setting and in relation to HCV-related allograft fibrosis, metabolic syndrome, and neurotoxicity.

Sirolimus in liver transplant recipients with renal dysfunction offers no advantage over low-dose calcineurin inhibitor regimens

The purpose of this study is to review the clinical experience with sirolimus immunosuppression in liver transplant patients with calcineurin inhibitor-induced chronic renal insufficiency. The study design is a case-control retrospective series. Fifty-seven liver transplant patients with renal insufficiency that were started on sirolimus at greater than 90 days postoperatively and treated for more than 90 days were identified. A control group of 57 patients maintained on low-dose calcineurin inhibitors, matched for gender, year of transplant, and baseline creatinine clearance, was also identified. There were no significant differences in the absolute creatinine clearance values between the sirolimus and control groups from 6 months before sirolimus conversion to 12 months after sirolimus conversion. Patients exposed to calcineurin inhibitors for more than 5 years or those with an initial creatinine clearance of less than 30 mL/minute who were converted to sirolimus did worse than control patients maintained on low-dose calcineurin inhibitors. Progression to renal replacement therapy, episodes of acute and chronic rejection, and death were similar between the sirolimus and control groups. The overall prevalence of side effects was significantly higher in the sirolimus group compared with the control group, although these were generally tolerable in most patients. In conclusion, this study suggests that conversion to sirolimus in liver transplant patients with chronic renal insufficiency is associated with stabilization of renal function but confers no additional benefit to low-dose calcineurin inhibitor regimens and may in fact be disadvantageous in patients with a creatinine clearance of less than 30 mL/minute.

Clinical trial: switch to combined mycophenolate mofetil and minimal dose calcineurin inhibitor in stable liver transplant patients--assessment of renal and allograft function, cardiovascular risk factors and immune monitoring

BACKGROUND

Calcineurin inhibitor (CNI)-related nephrotoxicity significantly contributes to chronic renal failure after liver transplantation.

METHODS

In this prospective study, liver transplantation patients with renal dysfunction were randomized either to receive mycophenolate mofetil (MMF) followed by stepwise reduction of CNI with defined minimal CNI-trough levels (MMF group), or to continue their maintenance CNI dose (control group). Immune monitoring was performed in a subgroup of the patients.

RESULTS

In the MMF group (n = 50), renal function assessed by serum creatinine improved >10% in 62% of patients, was stable in 36% and deteriorated >10% in 2% after 12 months compared with baseline values. Mean serum creatinine levels (+/- s.d.) significantly decreased from 1.90 +/- 0.44 mg/dL to 1.61 +/- 0.39 mg/dL and the corresponding calculated glomerular filtration rate significantly increased from 38.8 +/- 9.6 mL/min/1.73 m(2) to 47.0 +/- 11.8 mL/min/1.73 m(2) over a 12-month follow-up period. Blood pressure and levels of liver enzymes significantly decreased. In the control group (n = 25), there were no significant changes with respect to the investigated parameters. The MMF group had significantly lower numbers of circulating cytotoxic T cells compared with the controls; whereas regulatory T cells significantly increased.

CONCLUSION

Combined MMF and minimal dose CNI therapy after liver transplantation is nephroprotective and may promote allograft tolerance.

Sirolimus conversion in liver transplant recipients with renal dysfunction: a prospective, randomized, single-center trial

This pilot trial was designed to assess the safety and efficacy of SRL in liver transplant recipients with renal dysfunction. Forty patients with renal dysfunction (24-hr CrCl 40-80 mL/min) were randomized to be withdrawn from the calcineurin inhibitor (CNI) and receive sirolimus (SRL) or to continue CNI (control arm). Improvement in 24-hour CrCl was seen in the SRL arm at 3 months (75 mL/min SRL vs. 56 mL/min control, P=0.012), whereas at 12 months there was a trend toward improvement in the SRL arm (72 mL/min SRL vs. 58 mL/min control, P=0.09). Two patients, one in each arm, developed steroid-sensitive rejection. Side effects of SRL were limited and included hyperlipidemia requiring treatment (15%), pruritus (5%), and mouth sores (25%). In this trial, SRL-based immunosuppression was a safe alternative to CNI. Although early improvements were observed, withdrawing CNI and replacing it with SRL did not result in a statistically significant improvement in renal function at 12 months of follow-up.

Sirolimus and liver transplantation: clinical implications for hepatocellular carcinoma

Sirolimus (SRL) is a macrolide antibiotic that has potent antifungal and immunosuppressive properties; preclinical studies suggest that SRL may possess a significant antiproliferative influence in vitro. Recently, several studies have documented a negative effect by SRL on both primary tumor growth and the proliferation of metastatic foci in various rodent models of hepatocellular carcinoma (HCC). Orthotopic liver transplantation (OLT) is increasingly becoming a viable treatment option for patients with end stage liver disease and concomitant HCC. As such, an immunosuppressive agent with antineoplastic activity is inherently attractive in the setting of OLT for malignancy. Regrettably, the cumulative experience with SRL-based immunosuppression in this patient population is limited. Herein, the authors review the experience to date with SRL as a primary immunosuppressive agent following OLT, and discuss the clinical implications of SRL-based therapy in OLT recipients with cirrhosis and cancer.