Study in Recipients of Renal Transplant Allograft to Evaluate the Impact of Two Immunosuppressive Regimens

Immunosuppressive therapy with the calcineurin inhibitors (CNI) Cyclosporine (CsA) and
Tacrolimus (Tac), have radically changed the field of organ transplantation. Ironically,
although extensively and effectively used for kidney transplantation and other solid organ
transplants, CsA and Tac cause important adverse renal side effects: acute and chronic renal
dysfunction, hemolytic-uremic syndrome, hypertension, electrolyte disturbances and tubular
acidosis. Chronic nephrotoxicity from CNI has been implicated as a principal cause of
post-transplant renal dysfunction and it is characterized by an irreversible and progressive
tubular atrophy, interstitial fibrosis, and focal hyalinosis of small renal arteries and
arterioles. Furthermore, this class of medications is associated also, by blocking
Interleukin-2 (IL2) production, with negative impact on regulatory T cells (T-Regs)
generation (an important subpopulation of T helper cells that has been associated with
positive immunomodulation and donor specific hypo responsiveness).

In renal transplant recipients, complete avoidance of calcineurin inhibitors from the time of
renal transplant surgery has been associated with increased incidence of acute cellular
rejection, and the combination of mammalian target of rapamycin (mTOR) inhibitors with full
dose CNI has been shown to be synergistically nephrotoxic and it has been associated with
poor graft outcome. CNI conversion to mTOR inhibitors, at different time point
post-transplant, has been tested with promising results, by different investigators and by
the investigators group. The investigators have shown that in a Prednisone-free
immunosuppression, conversion from Tacrolimus to mTor inhibitors at different time point post
transplant is safe, it is not associated with an increased risk of acute rejection and more
importantly it is associated with an a persistent increase of regulatory T cells (Data
presented at the American Transplant Congress (ATC) 09 and 2010) Recently the A2309 study
allowed Everolimus to be FDA approved. The A2309 was a study designed to combined reduced
dose Cyclosporine+Everolimus. Interesting the reduced exposure to Cyclosporine was not
associated with an increase rate of albumin-creatinine ratio (ACR) and renal allograft
function was well maintained compared to the control group. The A2309 opens then an important
question regarding the mechanism(s) that can explain the efficacy of a low dose CNI with an
mTOR inhibitor in preventing acute allograft rejection.

The present proposal is designed to understand the mechanisms of the synergistic effect(s) of
low dose CNI and mTOR inhibitors (Everolimus) in controlling allo-reactive T and B cells
while expanding T-Regs.

The investigators hypothesis based in published data and from their laboratory (see
preliminary data-Supportive documents), is that mTOR inhibitors allow expansion of T-Regs and
low exposure of CNI is sufficient to control allo-reactive T cells. Decrease exposure to CNI
and concomitant increase of T-Regs will then translate in better renal allograft function and
histology.

Inclusion Criteria:

1. Subjects should be adults between 18 and 70 years of age

2. Subjects can be either gender or of any ethnic background

3. Subjects should be single organ recipients (kidney only)

4. Subjects must be able to understand the protocol and provide informed consent.

5. Recipient of living donor kidney transplants

6. Panel reactive antibody (PRA) < 20%

Exclusion Criteria:

1. Subjects with End Stage Renal Disease (ESRD) secondary to primary focal segmental
glomerulonephritis (FSGS).

2. Inability to fully understand the purpose of the study and the inability to sign the
informed consent

3. Subjects with a significant or active infection

4. Subjects who are pregnant or nursing females

5. Subjects with a history of severe hyperlipidemia not controlled with statins, patients
with Cholesterol > 400mg/dl

6. Subjects with a platelet count < 100,000mm3, WBC < 2,000mm3 (or clinical practice)

7. Subjects, who, due to the existence of a surgical, medical or psychiatric condition,
other than the current transplant, which in the opinion of the investigator, precludes
enrollment into this trial.