Sirolimus Associated with Tacrolimus at Low Doses in Elderly Kidney Transplant Patients: A Prospective Randomized Controlled Trial

Outcomes of sirolimus regimens in 65-year-old and older kidney transplant recipients: a registry-based observational study

PURPOSE

In large observational studies of adult kidney transplant recipients (KTRs) where older adults (65 years old and older) were not well represented, the mammalian target of rapamycin inhibitors (mTOR inhibitors) has poorer outcomes than the standard tacrolimus-mycophenolate-steroids (TAC-MPA-S) regimen. We conducted this study to compare the outcomes of regimens containing the common mTOR inhibitor, sirolimus (SRL) against TAC-MPA-S in older adult KTRs.

METHODS

Using the 2000-2016 Scientific Registry of Transplant Recipients, Cox multivariable regression models were conducted to analyze the patient and graft outcomes associated with regimens containing SRL, steroids (S) and cyclosporine (CSA), tacrolimus (TAC), or mycophenolate (MPA) vs. the standard (TAC-MPA-S) regimen in older adult KTRs.

RESULTS

Included in the analysis were 15,008 (95.19%) older adult KTRs on standard (TAC-MPA-S) regimen, 242 (1.53%) on SRL-MPA-S, 300 (1.90%) on SRL-TAC-S, and 217 (1.38%) on SRL-CSA-S. Compared with the standard regimen, the adjusted risks of all-cause death and overall graft loss over a maximum 5-year follow-up were highest with SRL-MPA-S, intermediate with SRL-TAC-S and not significantly different with SRL-CSA-S. The adjusted risks of all-cause death and overall graft loss were modified by a pre-transplant history of malignancy in older adult KTRs on SRL-TAC-S, not in those on SRL-MPA-S or SRL-CSA-S.

CONCLUSIONS

In older adult kidney transplant recipients, SRL-TAC-S or SRL-MPA-S, but not SRL-CSA-S is associated with higher risks of death and allograft loss than standard TAC-MPA-S regimen and a pre-transplant malignancy history worsens these risks in patients on SRL-TAC-S. Confirmation of our findings by a prospective randomized trial is needed before translation into clinical practice can be recommended.

Effect of sirolimus on carotid atherosclerosis in kidney transplant recipients: data derived from a prospective randomized controlled trial

Background

In animal models, the mammalian target of rapamycin inhibitors (mTORIs) may prevent atherogenesis by the regulation of homeostasis of cholesterol and by a reduced inflammatory response. The aim of this study is to compare the carotid intima–media thickness (cIMT) between de novo tacrolimus/mycophenolate and tacrolimus/sirolimus at low doses. The cIMT is considered a surrogate marker of atherosclerosis.

Methods

We evaluated cIMT at baseline and at 6 and 12 months after kidney transplantation in a database derived from a previously published trial. That trial had prospectively randomly assigned kidney transplant recipients older than 60 years of age to one of two groups: tacrolimus/sirolimus (n = 21) or tacrolimus/mycophenolate (n = 23). The cIMT was evaluated by using ultrasound in the common carotid artery wall on both sides.

Results

The total and high-density lipoprotein cholesterol levels were higher in the sirolimus group at 6 and 12 months. The cIMT decreased over time at 6 and 12 months in the sirolimus group (P = 0.012); this decrease continued to be significant in a model adjusted for age, sex, presence of diabetes, statin use and smoking.

Conclusions

The use of sirolimus plus tacrolimus de novo in kidney transplantation is associated with a reduction in cIMT after 12 months, a decrease more significant than seen with the combination of mycophenolate plus tacrolimus. This suggests a class effect of mTORI in the prevention of atherosclerosis.