Tacrolimus Exposure in Obese Patients: and A Case-Control Study in Kidney Transplantation

Post-Kidney Transplant Cancer: A Real-World Retrospective Analysis From a Single Italian Center

We describe the epidemiology of cancer after kidney transplantation (KTx), investigating its risk factors and impact on therapeutic management and survival in KTx recipients (KTRs). The association between modification of immunosuppressive (IS) therapy after cancer and survival outcomes was analyzed. We collected data from 930 KTRs followed for 7 [1-19] years. The majority of KTRs received KTx from a deceased donor (84%). In total, 74% of patients received induction therapy with basiliximab and 26% with ATG. Maintenance therapy included steroids, calcineurin inhibitors, and mycophenolate. Patients with at least one cancer (CA+) amounted to 19%. NMSC was the most common tumor (55%). CA+ were older and had a higher BMI. Vasculitis and ADPKD were more prevalent in CA+. ATG was independently associated with CA+ and was related to earlier cancer development in survival and competing risk analyses (p = 0.01 and <0.0001; basiliximab 89 ± 4 vs. ATG 40 ± 4 months). After cancer diagnosis, a significant prognostic impact was derived from the shift to mTOR inhibitors compared to a definitive IS drug suspension (p = 0.004). Our data confirm the relevance of cancer as a complication in KTRs with ATG as an independent risk factor. An individualized choice of IS to be proposed at the time of KTx is crucial in the prevention of neoplastic risk. Finally, switching to mTORi could represent an important strategy to improve patient survival.

A pharmacist-led intervention to improve kidney transplant recipient outcomes and identify patients at risk of highly variable trough tacrolimus levels: a cohort study

OBJECTIVES

Given the positive impact of appropriate medication management on graft outcome and therefore of patient survival and graft function, the pharmacist's role in the kidney transplantation team has evolved over recent decades. The primary objective of this study was to determine whether pharmacist-led intervention after kidney transplantation is associated with a lower graft rejection rate and intra-patient variation in tacrolimus trough concentrations (Cmin). The study's secondary objective was to develop a questionnaire to identify patients at risk for highly variable Cmin.

METHODS

We retrospectively analysed kidney transplant recipients at Rennes University Hospital (France) between January 2013 and December 2020. Patients who received pharmacist-led education (intervention group, n=139) were compared with patients who did not (control group, n=131), according to graft survival at 1 year post-transplant, coefficient of variation (%CV) for the tacrolimus Cmin, age, sex, length of hospital stay post-transplantation, body mass index, and Charlson Comorbidity Index. In the intervention group, a questionnaire assessing patient knowledge was introduced to compare scores with the %CV.

RESULTS

In the intervention group, 1 year post-transplant graft survival was higher (95.7% vs 88.5%, p=0.0289) and patients had fewer variabilities in Cmin. The %CV was correlated with questionnaire scores (r=-0.9758, p<0.0001).

CONCLUSIONS

Pharmacist-led interventions may have contributed to improved graft survival and patient management of immunosuppressants. Because %CV correlates with the patient questionnaire score, its introduction could be useful in identifying kidney transplant patients who would benefit most from a pharmacist-led patient education.

A retrospective analysis of haematological side effects of olaparib in excess-weight and normal BMI patients with ovarian cancer

Background

Olaparib is the first poly(ADP-ribose) polymerase inhibitor approved in Europe for the treatment of platinum-sensitive patients with newly diagnosed or recurrent platinum-sensitive ovarian cancer with a confirmed BRCA mutation or homologous recombination deficiency (HRD). Epidemiological studies have shown an incompatible association between ovarian cancer and obesity, but there have also been scientific reports indicating that obesity, especially severe obesity, increases the risk of ovarian cancer. Olaparib has a wide range of side effects, especially anaemia and neutropenia, which may lead to dose reduction or therapy discontinuation. Therefore, therapeutic drug monitoring (TDM) is recommended. The aim of the study was a retrospective analysis of threshold value of the trough concentration of olaparib (Ctrough) and haematological adverse reactions after olaparib treatment (300 mg/12 h) in excess-weight and normal body mass index (BMI) patients with ovarian cancer.

Materials and methods

The pilot study was conducted on 38 ovarian cancer patients who were divided into two groups: I - normal BMI patients (BMI = 18.5-24.9 kg/m2; n = 14), II - excess-weight patients, i.e. overweight and obese patients (BMI ≥ 25 kg/m2; n = 24). The severity of neutropenia and anaemia was graded according to the Common Terminology Criteria for Adverse Events (CTCAE v5.0). The values of the mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and red blood cell distribution width (RDW) parameters were also taken into account. HPLC-UV method (λ = 254 nm) was applied to measure olaparib plasma concentrations.

Results

There were no statistically significant differences in olaparib Ctrough between the groups - 1602.86 vs. 1567.40 ng/mL (p = 0.9156). However, the overweight and obese patients had slightly higher dose/kg-adjusted olaparib Ctrough - 204.17 vs. 159.32 ng/mL/mg/kg. The incidence of grade 1 anaemia in the groups was as follows: I - 42.86%, II - 41.67%. Grade 2 and 3 anaemia was observed only in group II - 4.17% and 8.33%, respectively. The incidence of neutropenia in the groups of patients was as follows: grade 1: group I - 21.43%, group II - 20.83%; grade 2: group I - 7.14%, group II - 4.17%.

Conclusions

The incidence of haematological adverse reactions to olaparib, such as neutropenia and grade 1 anaemia in the group of overweight and obese patients was the same as in the normal BMI group. The overweight and obese patients were characterised by higher severity of haematological adverse reactions to olaparib and slightly higher dose/kg-adjusted olaparib Ctrough. After one month of treatment with olaparib the overweight and obese patients had significantly lower red blood cells (RBC) and haemoglobin (Hgb) levels than the patients with normal BMI, which may indicate that anaemia develops faster in this group of patients.

Retrospective evaluation of LCP-tacrolimus (Envarsus XR) dosing in de novo kidney transplant

INTRODUCTION

Tacrolimus is known to exhibit significant inter- and intra-patient pharmacokinetic (PK) and pharmacodynamic (PD) variability regarding therapeutic response. LCP-tacrolimus (LCPT-Envarsus XR) was approved in 2018 for use as a de novo immunosuppressive agent in kidney transplants, but there is limited evidence to guide de novo dosing of LCPT in patients with obesity. The primary objective of this study was to evaluate the impact of different calculated weight-based de novo LCPT dosing on early transplant outcomes.

METHODS

This was a retrospective study of patients with obesity (BMI ≥ 30 kg/m2 ) who received a kidney transplant at the University of Illinois Hospital and Health System (UIH), between March 2019 and March 2021. Subjects were included if were age 18 years or older and received de novo LCPT throughout index hospitalization. The primary endpoint of this study was to compare correlations between the first tacrolimus trough level and dosing weight strategy (e.g., TBW, AdjBW, IBW).

RESULTS

There was a statistically significant, though modest, correlation between all three dosing strategies and the first tacrolimus trough level (TBW correlation coefficient = .431, p < .001; AdjBW correlation coefficient = .455, p < .001; IBW correlation coefficient = .465; p < .001). In regression modeling for supratherapeutic levels each additional .01 mg/kg increase in dose by TBW, AdjBW, and IBW increased the odds of a supratherapeutic level by 1.46, 1.34, and 1.24, respectively (p < .001).

CONCLUSIONS

The use of LCPT in kidney transplant recipients with obesity dosed using TBW demonstrated the strongest correlation with initial supratherapeutic tacrolimus levels. Larger prospective studies are needed to investigate the further impact of body weight on dosing regimens in the obese population.

Evaluation of limited-sampling strategies to calculate AUC(0–24) and the role of CYP3A5 in Chilean pediatric kidney recipients using extended-release tacrolimus

Background: Kidney transplantation (KTx) requires immunosuppressive drugs such as Tacrolimus (TAC) which is mainly metabolized by CYP3A5. TAC is routinely monitored by trough levels (C0) although it has not shown to be a reliable marker. The area-under-curve (AUC) is a more realistic measure of drug exposure, but sampling is challenging in pediatric patients. Limited-sampling strategies (LSS) have been developed to estimate AUC. Herein, we aimed to determine AUC(0–24) and CYP3A5 genotype in Chilean pediatric kidney recipients using extended-release TAC, to evaluate different LSS-AUC(0–24) formulas and dose requirements.

Patients and methods: We analyzed pediatric kidney recipients using different extended-release TAC brands to determine their trapezoidal AUC(0–24) and CYP3A5 genotypes (SNP rs776746). Daily TAC dose (TAC-D mg/kg) and AUC(0–24) normalized by dose were compared between CYP3A5 expressors (*1/*1 and *1/*3) and non-expressors (*3/*3). We evaluated the single and combined time-points to identify the best LSS-AUC(0–24) model. We compared the performance of this model with two pediatric LSS-AUC(0–24) equations for clinical validation.

Results: Fifty-one pharmacokinetic profiles were obtained from kidney recipients (age 13.1 ± 2.9 years). When normalizing AUC(0–24) by TAC-D significant differences were found between CYP3A5 expressors and non-expressors (1701.9 vs. 2718.1 ng*h/mL/mg/kg, p &lt; 0.05). C0 had a poor fit with AUC(0–24) (r2 = 0.5011). The model which included C0, C1 and C4, showed the best performance to predict LSS-AUC(0–24) (r2 = 0.8765) and yielded the lowest precision error (7.1% ± 6.4%) with the lowest fraction (9.8%) of deviated AUC(0–24), in comparison to other LSS equations.

Conclusion: Estimation of LSS-AUC(0–24) with 3 time-points is an advisable and clinically useful option for pediatric kidney recipients using extended-release TAC to provide better guidance of decisions if toxicity or drug inefficacy is suspected. The different CYP3A5 genotypes associated with variable dose requirements reinforce considering genotyping before KTx. Further multi-centric studies with admixed cohorts are needed to determine the short- and long-term clinical benefits.