Impact of intrapatient variability (IPV) in tacrolimus trough levels on long-term renal transplant function: multicentre collaborative retrospective cohort study protocol

Platform introducing individually tailored variability in nerve stimulations and dietary regimen to prevent weight regain following weight loss in patients with obesity

Prevention of weight regain following successful weight loss is a major challenge in the treatment of obesity, irrespective of the weight reduction method used. The majority of individuals regain the lost weight over time; thus, achieving long-term sustainability in weight loss remains an unresolved issue. A compensatory adaptation to the weight loss methods occurs in several body organs and partly explains the lack of sustainable effect. Variability is inherent in many biological systems, and patterns of variability constitute a body mechanism that is active at several levels, starting from the genes and cellular pathways through to the whole-organ level. This study aimed to describe a platform that introduces individually tailored variability in vagal nerve stimulation and dietary regimen to ensure prolonged and sustainable weight loss and prevent weight regain. The platform is intended to provide a method that can overcome the body's compensatory adaptation mechanisms while ensuring a prolonged beneficial effect.

Current Concepts in Pharmacometabolomics, Biomarker Discovery, and Precision Medicine

Pharmacometabolomics (PMx) studies use information contained in metabolic profiles (or metabolome) to inform about how a subject will respond to drug treatment. Genome, gut microbiome, sex, nutrition, age, stress, health status, and other factors can impact the metabolic profile of an individual. Some of these factors are known to influence the individual response to pharmaceutical compounds. An individual’s metabolic profile has been referred to as his or her “metabotype.” As such, metabolomic profiles obtained prior to, during, or after drug treatment could provide insights about drug mechanism of action and variation of response to treatment. Furthermore, there are several types of PMx studies that are used to discover and inform patterns associated with varied drug responses (i.e., responders vs. non-responders; slow or fast metabolizers). The PMx efforts could simultaneously provide information related to an individual’s pharmacokinetic response during clinical trials and be used to predict patient response to drugs making pharmacometabolomic clinical research valuable for precision medicine. PMx biomarkers can also be discovered and validated during FDA clinical trials. Using biomarkers during medical development is described in US Law under the 21st Century Cures Act. Information on how to submit biomarkers to the FDA and their context of use is defined herein.

Tacrolimus Trough Level at the First Month May Predict Renal Transplantation Outcomes Among Living Chinese Kidney Transplant Patients: A Propensity Score-Matched Analysis

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Background:

Monitoring and maintaining a stable tacrolimus trough level is essential because of its narrow therapeutic window and considerable fluctuation in the early phase after kidney transplantation. However, optimal tacrolimus exposure early after transplantation remains unclear among Chinese patients.

Methods:

In this propensity score–matched cohort study, we thoroughly investigated the association between tacrolimus trough level at the first month and acute rejection (AR) as well as infection within the first year after kidney transplantation.

Results:

In a first step, a total of 1415 patients were divided into 3 groups according to the receiver operating characteristic curve: low-level group (410 patients with a tacrolimus trough level <5.35 ng/mL at the first month), median-level group (466 patients with a tacrolimus trough level from 5.35 to 7.15 ng/mL), and high-level group (539 patients with a tacrolimus trough level >7.15 ng/mL). Ultimately, 363 and 459 pairs of cases were enrolled by using 2 propensity score matches between low- and median-level groups and between high- and median-level groups, respectively. Compared with patients in the low-level group, patients in the median-level group had lower risk of AR without increased incidence of infection (AR, 12.4% versus 5.7%, P = 0.02; infection, 13.2% versus 13.2%, P = 1.00 for low- and median-level groups, respectively) within the first year. Compared with patients in the high-level group, patients in the median-level group had lower incidence of infection without the growing risk of AR (infection, 17.6% versus 12.2%, P = 0.021; AR, 4.6% versus 5.4%, P = 0.545 for high- and median-level groups, respectively) within the first year. Multilogistic analysis showed that tacrolimus trough levels were an independent factor for AR (odds ratio, 0.749, 95% confidence interval, 0.632–0.888, P = 0.001). Tacrolimus trough levels were also associated with infection (odds ratio 1.110, 95% confidence interval, 1.013–1.218, P = 0.001). Serum creatinine levels were similar among groups. No difference was found in 1-, 3-, and 5-year graft survival and patient survival among groups.

Conclusions:

The tacrolimus trough level maintained between 5.35 and 7.15 ng/mL at the first posttransplant month may prevent AR without increasing the incidence of infection within the first year after living kidney transplantation among Chinese patients.

High Calcineurin Inhibitor Intrapatient Variability Is Associated With Renal Allograft Inflammation, Chronicity, and Graft Loss

Background

High calcineurin inhibitor (CNI) intrapatient variability (IPV) has been associated with poor kidney allograft outcomes. However, the relationship between early allograft histological changes, their progression, and CNI-IPV is less well studied. Hence, we evaluated effect of CNI-IPV defined by the degree of fluctuation of CNI levels in all kidney transplant patients over 2 to 12 months posttransplant on early allograft inflammation, subsequent chronicity, and later clinical outcomes.

Methods

Two hundred eighty-six patients transplanted from January 2013 to November 2014 were enrolled with protocol and indication biopsies. The mean CNI-IPV was 28.5% and a quarter of our cohort had IPV of 35% or greater (high CNI IPV). Baseline demographic differences were similar between high and low CNI IPV groups.

Results

High CNI-IPV was associated with a higher incidence of acute rejection (AR) within 1 year (52% vs 31% P < 0.001), more persistent/recurrent AR by 1 year (18.2% vs 6.2%, P = 0.002), higher-grade AR (≥Banff 1B, 27.5% vs 7.3%, P < 0.001), and worse interstitial fibrosis/tubular atrophy (P = 0.005). High CNI-IPV was associated with increased graft loss (GL) and impending graft loss (iGL, defined as eGFR<30 ml/min and >30% decline in eGFR from baseline), regardless of donor-specific antibody, delayed graft function, rejection, or race. In a multivariate Cox Proportional Hazards Model, high CNI-IPV was independently associated with GL + iGL (hazard ratio, 3.1; 95% confidence interval, 1.6-5.9, P < 0.001).

Conclusions

High CNI-IPV within 1 year posttransplant is associated with higher incidence of AR, severe AR, allograft chronicity, GL, and iGL. This represents a subset of patients who are at risk for poor kidney transplant outcomes and potentially a modifiable risk factor for late allograft loss.