Comparison of the Cognitive and Motor Effects of Treatment Between an Immediate- and Extended-release Tacrolimus (Envarsus® XR) Based Immunosuppression Regimen in Kidney Transplant Recipients

Between four (4) months and 14 months after receiving a kidney transplant and, per standard
of care (SOC), having been placed on an immediate-release (IR) tacrolimus immunosuppressant
regimen, participants in this study will undergo cognitive and motor function testing and
have a blood sample collected (BASELINE). Half of the participants will then be randomly
converted to extended-release (XR) tacrolimus (Envarsus® XR) while the other half will remain
on IR tacrolimus for the duration of the study. Both the IR and XR groups will repeat the
cognitive and motor function testing and have a blood sample collected at 6, 12, and 24 weeks
Post-BASELINE. A practice version of the cognitive and motor function tests will be
administered no more than 60 days prior to the baseline visit (Pre-BASELINE). Alternate
versions of the cognitive and motor tests will be used at each Post-BASELINE testing session
to control for possible practice effects.

The primary objective is to compare the effect of treatment with an immediate-release
tacrolimus to an extended-release tacrolimus (i.e., Envarsus® XR) immunosuppressive regimen
on cognitive and motor function in kidney transplant recipients.

The secondary objective is to determine the factors that explain inter-individual variability
in cognitive response. Pharmacokinetic and demographic factors will be explored. Variability
in cognitive response between individuals can be large. A population approach (nonlinear,
mixed effects) will be used. Measurement of drug concentration will be the dependent
variable.

Inclusion Criteria:

1. Male or female kidney transplant recipient;

2. 18-65 years of age;

3. receiving a kidney transplant from a living or deceased donor;

4. if female, premenopausal and heterosexually active, must be using two forms of highly
effective birth control (at least one of which must be a barrier method) which
includes consistent and correct usage of established oral contraception, established
intrauterine device or intrauterine system, or barrier methods of contraception:
condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal
foam/gel/film/cream/suppository, starting at screening and throughout the study period
and for 90 days after the final study drug administration;

5. written informed consent to participate in the study

Exclusion Criteria:

1. younger than 18 years of age;

2. older than 65 years of age;

3. Non-native level English speaker;

4. pregnant women

5. breastfeeding women