Conversion from twice daily tacrolimus capsules to once daily extended-release tacrolimus (LCP-Tacro): phase 2 trial of stable liver transplant recipients

Getting Tacrolimus Dosing Right

ABSTRACT

Tacrolimus (TAC) dosing is typically guided by the trough concentration (C0). Yet, significant relationships between TAC C0 and clinical outcomes have seldom been reported or only with adverse events. Large retrospective studies found a moderate correlation between TAC C0 and the area under the curve (AUC), where, for any given C0 value, the AUC varied 3- to 4-fold between patients (and vice versa). However, no randomized controlled trial evaluating the dose adjustment based on TAC AUC has been conducted yet. A few observational studies have shown that the AUC is associated with efficacy and, to a lesser extent, adverse effects. Other studies showed the feasibility of reaching predefined target ranges and reducing underexposure and overexposure. TAC AUC 0-12 h is now most often assessed using Bayesian estimation, but machine learning is a promising approach. Microsampling devices are well accepted by patients and represent a valuable alternative to venous blood sample collection during hospital visits, especially when a limited sampling strategy is required. As AUC monitoring cannot be proposed very frequently, C0 monitoring has to be used in the interim, which has led to fluctuating doses in patients with an AUC/C0 ratio far from the population mean, because of different dose recommendations between the 2 biomarkers. We proposed estimating the individual AUC/C0 ratio and derived individual C0 targets to be used in between or as a replacement for AUC monitoring. Existing technology and evidence are now sufficient to propose AUC monitoring interspersed with individualized-C0 monitoring for all patients with kidney transplants while collecting real-world data to strengthen the evidence.

Extended-release tacrolimus dosing and outcomes in pediatric and young adult transplant recipients - A single-center experience

BACKGROUND

Published data on LCP-tacrolimus (LCPT) in the pediatric population are limited.

METHODS

This single-center, retrospective, observational study describes LCPT doses needed to reach therapeutic ranges in pediatric and young adult kidney and liver transplant recipients in both de novo usage and conversion from immediate-release tacrolimus (IR-Tac). Adverse outcomes up to 12 months after LCPT initiation were also evaluated.

RESULTS

Forty-one transplant recipients (30 kidney, 11 liver) were included. The median initial doses of LCPT were 0.034 mg/kg (IQR 0.019) de novo and 0.09 mg/kg (IQR = 0.076) converted. The median doses at first therapeutic level were 0.086 mg/kg (IQR 0.028) de novo and 0.1 mg/kg (IQR 0.066) converted. The median LCPT:IR-Tac conversion ratio initially was 0.7 and 0.75 at therapeutic levels. The rate of AKI per 100 days of exposure to IR-Tac was 0.546 and 0.439 on LCPT. The percentage of patients with rejection was not different before and after conversion (clinical rejection 8.6% [n = 3] vs 11.4% [n = 4], p = .6; biopsy-proven rejection 2.9% [n = 1] vs 11.4% [n = 4], p = .11). One patient had graft loss unrelated to rejection, and the graft was explanted.

CONCLUSION

In this study, pediatric and young adult abdominal transplant recipients had therapeutic tacrolimus levels at LCPT doses below the adult-labeled dose; the conversion ratio from IR-Tac to LCPT at therapeutic level was similar. There were no identified safety concerns in de novo or converted LCPT use in pediatric and young adult patients.

Effectiveness and safety of once-daily tacrolimus formulations in de novo liver transplant recipients: The PRETHI study

Data comparing long-term effectiveness and safety of once-daily tacrolimus formulations in de novo liver transplantation are scarce. We compared the effectiveness, pharmacokinetic profile, and safety of LCPT (Envarsus) and PR-Tac (Advagraf) for up to 12 months post-transplant. Adult de novo liver transplant recipients who started IR-Tac (Prograf) and were converted to LCPT or PR-Tac 3-5 days post-transplant were included. Data from 163 patients were analyzed, 87 treated with LCPT and 76 with PR-Tac. The incidence of treatment failure was 30.5% in the LCPT group versus 23.0% in the PR-Tac group (p = .291). Biopsy-proven acute rejection (BPAR) was reported in 26.8% of patients in the LCPT group and 17.6% in the PR-Tac group (p = .166). Graft loss was experienced in one patient (1.2%) in the LCPT group and three patients (4.1%) in the PR-Tac group (p = .346). Death was registered in three patients (3.7%) in the LCPT group and three patients (4.1%) in the PR-Tac group (p > .999). Patients in the LCPT group showed 45.7% higher relative bioavailability (Cmin /total daily dose [TDD]; p < .01) with similar Cmin and 33.3% lower TDD versus PR-Tac (p < .01). The evolution of renal function, safety profile, and the incidence of post-transplant renal failure, dyslipidemia, obesity, hypertension, and diabetes mellitus were similar in patients treated with LCPT and PR-Tac. In de novo liver transplant patients, LCPT and PR-Tac showed comparable effectiveness with higher relative bioavailability, similar Cmin and lower TDD in the LCPT group. Renal function, safety, and post-transplant complications were comparable in LCPT and PR-Tac groups.

Tremor Induced by Cyclosporine, Tacrolimus, Sirolimus, or Everolimus: A Review of the Literature

Calcineurin inhibitors such as cyclosporine and tacrolimus are immunosuppressant drugs that are known to induce tremors. Non-calcineurin inhibitors such as sirolimus and everolimus have also reportedly been accompanied by tremors, albeit less likely. However, the prevalence rates reported in the literature are notably wide, and the risk profiles for these drug-induced tremors are less understood. We searched PubMed to extract data on the risk of tremors with these drugs when prescribed for various transplant and non-transplant indications. We ascertained whether the risk of drug-induced tremor is influenced by the underlying diagnosis, dosing formulations, drug concentrations, and blood monitoring. We extracted data on treatment strategies and outcomes for tremors. Articles were primarily screened based on English language publications, abstracts, and studies with n ≥ 5, which included case series, retrospective studies, case-controlled studies, and prospective studies. We found 81 eligible studies comprising 33 cyclosporine, 43 tacrolimus, 6 sirolimus, and 1 everolimus that discussed tremor as an adverse event. In the pooled analysis of studies with n > 100, the incidence of tremor was 17% with cyclosporine, 21.5% with tacrolimus, and 7.8% with sirolimus and everolimus together. Regarding the underlying diagnosis, tremor was more frequently reported in kidney transplant (cyclosporine 28%, tacrolimus 30.1%) and bone marrow transplant (cyclosporine 40%, tacrolimus 41.9%) patients compared with liver transplant (cyclosporine 9%, tacrolimus 11.5%) and nontransplant indications (cyclosporine 21.5%, tacrolimus 11.3%). Most studies did not report whether the risk of tremors correlated with drug concentrations in the blood. The prevalence of tremors when using the twice-daily formulation of tacrolimus was nearly the same as the once-daily formulation (17% vs 18%). Data on individual-level risk factors for tremors were lacking. Except for three studies that found some benefit to maintaining magnesium levels, there were minimal data on treatments and outcomes. A large body of data supports a substantive and wide prevalence of tremor resulting from tacrolimus use followed by cyclosporine, especially in patients receiving a kidney transplant. However, there is little reporting on the patient-related risk factors for tremor, risk relationship with drug concentrations, treatment strategies, and outcomes.

Insulin secretion in liver transplant recipients following conversion to a prolonged release tacrolimus formulation

Background

Post liver transplant diabetes mellitus (PLTDM) occurs in 10-40% of liver transplant recipients and is associated with increased morbidity and mortality. An important cause of PLTDM is tacrolimus induced, concentration-dependent, inhibition of insulin secretion.

Objective

To determine if a newly licenced formulation of tacrolimus (Envarsus-PA), which achieves peak tacrolimus concentrations 20-30% lower than other tacrolimus formulations has less of an inhibitory effect on insulin secretion.

Methods

Homeostatic model assessment (HOMA) for insulin secretion (HOMA-S) values and c-peptide levels were determined in 19 adult liver transplant recipients while being maintained on immediate- or slow-release tacrolimus formulations and repeated a minimum of 30 days following conversion to Envarsus-PA.

Results

Insulin secretion was unchanged following conversion to Envarsus-PA (HOMA-S pre-conversion: 154 ± 133 vs. 129 ± 75, post-conversion [p = 0.32], and c-peptide levels; 1059 ± 602 and 934 ± 463 respectively, p = 0.42). Fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels were also unchanged (FBG 5.7 ± 0.8 pre-conversion vs. 5.6 ± 0.7 post-conversion; p = 0.36 and HbA1c 4.9±1.2 pre-conversion versus 5.5±0.2 post-conversion, p = 0.34).

Conclusions

Envarsus-PA had no significant effect on insulin secretion or glucose homeostasis beyond that associated with other tacrolimus formulations in adult liver transplant recipients.

Tacrolimus-why pharmacokinetics matter in the clinic

The calcineurin inhibitor (CNI) Tacrolimus (Tac) is the most prescribed immunosuppressant drug after solid organ transplantation. After renal transplantation (RTx) approximately 95% of recipients are discharged with a Tac-based immunosuppressive regime. Despite the high immunosuppressive efficacy, its adverse effects, narrow therapeutic window and high intra- and interpatient variability (IPV) in pharmacokinetics require therapeutic drug monitoring (TDM), which makes treatment with Tac a major challenge for physicians. The C/D ratio (full blood trough level normalized by daily dose) is able to classify patients receiving Tac into two major metabolism groups, which were significantly associated with the clinical outcomes of patients after renal or liver transplantation. Therefore, the C/D ratio is a simple but effective tool to identify patients at risk of an unfavorable outcome. This review highlights the challenges of Tac-based immunosuppressive therapy faced by transplant physicians in their daily routine, the underlying causes and pharmacokinetics (including genetics, interactions, and differences between available Tac formulations), and the latest data on potential solutions to optimize treatment of high-risk patients.

Tacrolimus Exposure Before and After a Switch From Twice-Daily Immediate-Release to Once-Daily Prolonged Release Tacrolimus: The ENVARSWITCH Study

LCP-tacrolimus displays enhanced oral bioavailability compared to immediate-release (IR-) tacrolimus. The ENVARSWITCH study aimed to compare tacrolimus AUC0-24 h in stable kidney (KTR) and liver transplant recipients (LTR) on IR-tacrolimus converted to LCP-tacrolimus, in order to re-evaluate the 1:0.7 dose ratio recommended in the context of a switch and the efficiency of the subsequent dose adjustment. Tacrolimus AUC0-24 h was obtained by Bayesian estimation based on three concentrations measured in dried blood spots before (V2), after the switch (V3), and after LCP-tacrolimus dose adjustment intended to reach the pre-switch AUC0-24 h (V4). AUC0-24 h estimates and distributions were compared using the bioequivalence rule for narrow therapeutic range drugs (Westlake 90% CI within 0.90-1.11). Fifty-three KTR and 48 LTR completed the study with no major deviation. AUC0-24 h bioequivalence was met in the entire population and in KTR between V2 and V4 and between V2 and V3. In LTR, the Westlake 90% CI was close to the acceptance limits between V2 and V4 (90% CI = [0.96-1.14]) and between V2 and V3 (90% CI = [0.96-1.15]). The 1:0.7 dose ratio is convenient for KTR but may be adjusted individually for LTR. The combination of DBS and Bayesian estimation for tacrolimus dose adjustment may help with reaching appropriate exposure to tacrolimus rapidly after a switch.

EnGraft: a multicentre, open-label, randomised, two-arm, superiority study protocol to assess bioavailability and practicability of Envarsus® versus Advagraf™ in liver transplant recipients

BACKGROUND

Graft rejection and chronic CNI toxicity remain obstacles to organ transplant success. Current formulations of tacrolimus, such as Prograf® and Advagraf™, exhibit limitations in terms of pharmacokinetics and tolerability, related in part to suboptimal bioavailability. As dosing non-compliance can result in graft rejection, the once daily formulation of tacrolimus, Advagraf™, was developed (vs 2x/day Prograf®). Benefits of Advagraf™ are counterbalanced by delayed achievement of therapeutic trough levels and need for up to 50% higher doses to maintain Prograf®-equivalent troughs. Envarsus® is also a prolonged-release once-daily tacrolimus formulation, developed using MeltDose™ drug-delivery technology to increase drug bioavailability; improved bioavailability results in low patient drug absorption variability and less pronounced peak-to-trough fluctuations. In phase III de novo kidney transplant studies, Envarsus® proved non-inferior to twice-daily tacrolimus; however, no phase IV studies show superiority of Envarsus® vs Advagraf™ in de novo liver transplant (LTx) recipients.

METHODS

The EnGraft compares bioavailability and tests superiority of Envarsus® (test arm) versus Advagraf™ (comparator arm) in de novo LTx recipients. A total of 268 patients from 15 German transplant centres will be randomised 1:1 within 14 days post-LTx. The primary endpoint is dose-normalised trough level (C/D ratio) measured 12 weeks after randomisation. Secondary endpoints include the number of dose adjustments, time to reach first defined trough level and incidence of graft rejections. Additionally, clinical and laboratory parameters will be assessed over a 3-year period.

DISCUSSION

C/D ratio is an estimate for tacrolimus bioavailability. Improving bioavailability and increasing C/D ratio using Envarsus could reduce renal dysfunction and other tacrolimus-related toxicities; previous trials have shown that a higher C/D ratio (i.e. slower tacrolimus metabolism) is not only associated with improved renal function but also linked to reduced neurotoxic side effects. A higher C/D ratio could improve clinical outcomes for LTx recipients; EnGraft has begun, with one third of patients recruited by January 2022.

TRIAL REGISTRATION

This trial has been registered (4 May 2020) in the EU Clinical Trials Register, EudraCT-Nummer: 2020-000796-20. Additionally, this trial has been registered (22 January 2021) at ClinicalTrials.gov: NCT04720326. The trial received a favourable opinion from the concerned lead ethics committee at the University of Regensburg, under the reference 20-1842-112.

A Multi-Centre Non-Interventional Study to Assess the Tolerability and Effectiveness of Extended-Release Tacrolimus (LCPT) in De Novo Liver Transplant Patients

Background: Available tacrolimus formulations exhibit substantial inter- and intra-individual variability in absorption and metabolism. The present non-interventional cohort study aimed to assess the tolerability and effectiveness of the once-daily tacrolimus formulation, LCPT, in hepatic allograft recipients in real life. Materials and methods: This study was conducted in Austria and the Czech Republic between July 2016 and August 2019. Patients aged ≥ 18 years old received LCPT per the approved label and local clinical routine. All the participants provided informed consent. Patients newly treated with tacrolimus (de novo) directly after transplantation were observed for six months. The relevant clinical variables were tacrolimus trough level (TL), total daily dose (TDD), number of dose adjustments, kidney and liver function, and tolerability. Results: Of the 70 analyzed patients, 72.9% were male and 85.7% were aged < 65 years old. The mean (SD) time to achieve tacrolimus target TL was 6.4 (4.6) days after 4.4 (4.0) dose adjustments; thereafter, TL remained stable throughout observation at approximately 8 ng/mL. The LCPT TDD at initiation was 8 mg and decreased by a median of 41.4% to 5 mg at 6 months. Liver function continuously improved, and kidney function remained stable. LCPT was well tolerated with 24 adverse events in eight patients (17 related to immunosuppression, mostly mild renal insufficiency, and hematological adverse events); two serious unrelated adverse events were reported (atrial flutter and liver dysfunction). Conclusions: TL was rapidly attained with few dose adaptations after LCPT initiation in de novo liver transplant patients. Liver function rapidly improved, whereas kidney function remained normal. LCPT was well-tolerated in this population.

Improved Medication Adherence with the Use of Extended-Release Tacrolimus in Liver Transplant Recipients: A Pilot Randomized Controlled Trial

Background

Nonadherence to immunosuppression in liver transplant recipients (LTRs) leads to deterioration in health outcomes. Once-dailyextended-release tacrolimus (TAC-ER) may improve adherence when compared to twice-dailyimmediate-release tacrolimus (TAC-IR).

Methods

We conducted a randomized controlled study to evaluate medication adherence, clinical efficacy, and safety of TAC-ER in stable LTR. All patients >18 years who underwent liver transplantation before 6 months were eligible. Patients were randomized 1 : 1 to continued TAC-IR or conversion to TAC-ER. The primary outcome was change in medication adherence from baseline to 9 months, assessed using BAASIS. Secondary outcomes were tacrolimus trough levels, safety, and quality of life.

Results

Thirty-one patients were consented and randomized to either of the two groups: conversion to TAC-ER (n = 15) or continued TAC-IR (n = 16). Six patients in the TAC-ER group withdrew after randomization due to apprehension about switching medication (n = 2), unwillingness to travel (n = 2), and increased liver tests after conversion (n = 2, both were acute rejections despite therapeutic tacrolimus levels and were considered unrelated to TAC-ER). We compared the results of nine patients in the TAC-ER group that completed the study with those of sixteen in the TAC-IR group. At baseline, there was no difference in tacrolimus trough levels between groups. Improved adherence was observed in the TAC-ER group as 100% of patients reported at least one period of full adherence during the study period (100% vs. 62.6%, p = 0.035). Tacrolimus trough levels and liver tests were comparable between groups throughout the study. There were no differences in eGFR, HbA1c, or QoL between the groups.

Conclusion

TAC-ER improved medication adherence while maintaining comparable trough levels, liver function, and QoL as TAC-IR in LTR.

Renal Function, Adherence and Quality of Life Improvement After Conversion From Immediate to Prolonged-Release Tacrolimus in Liver Transplantation: Prospective Ten-Year Follow-Up Study

Immunosuppression non-adherence is a major cause of graft failure after liver transplantation. The aim of this study was to evaluate practice surrounding conversion from immediate-release to prolonged-release Tacrolimus formulation and to assess patient adherence and quality of life (QoL). One hundred and seven adult liver transplant recipients, receiving immediate-release Tacrolimus for a minimum of 6 months, were converted to prolonged-release formulation, based on a dose ratio of one (1:1). The median follow-up was 120 [IQR, 120-123] months. Tacrolimus dosage and blood level, liver and renal function, lipid and glucose profiles were recorded. In addition, questionnaires were submitted to evaluate adherence and QoL following conversion. No rejection was recorded. The median serum Tacrolimus blood level decreased over 1 month (5.80, [IQR, 2.0-10.8] vs. 3.8 [IQR, 1.4-8.7]; p < 0.0005). Significant improvement in renal function was noted (median GFR was 81.7 [IQR, 43.4-128.6] vs. 73.9 [IQR, 27.1-130.2]; p = 0.0002). At the end of the follow-up, conversion resulted in an overall decrease in non-adherence of 53.3% (p = 0.0001) and an improvement in QoL was reported by 76.2% of patients. Thus, 1:1 conversion from immediate to prolonged-release Tacrolimus is safe, feasible and efficient, avoiding under-therapeutic and toxic peak concentrations, improving renal function, adherence to immunosuppression and overall patient QoL.

Reducing the Pill Burden: Immunosuppressant Adherence and Safety after Conversion from a Twice-Daily (IR-Tac) to a Novel Once-Daily (LCP-Tac) Tacrolimus Formulation in 161 Liver Transplant Patients

Non-adherence to immunosuppressant therapy reduces long-term graft and patient survival after solid organ transplantation. The objective of this 24-month prospective study was to determine adherence, efficacy and safety after conversion of stable liver transplant (LT) recipients from a standard twice-daily immediate release Tacrolimus (IR-Tac) to a novel once-daily life cycle pharma Tacrolimus (LCP-Tac) formulation. We converted a total of 161 LT patients at baseline, collecting Tacrolimus trough levels, laboratories, physical examination data and the BAASIS^© questionnaire for self-reported adherence to immunosuppression at regular intervals. With 134 participants completing the study period (17% dropouts), the overall adherence to the BAASIS^© increased by 57% until month 24 compared to baseline (51% vs. 80%). Patients who required only a morning dose of their concomitant medications reported the largest improvement in adherence after conversion. The intra-patient variability (IPV) of consecutive Tacrolimus trough levels after conversion did not change significantly compared to pre-conversion levels. Despite reducing the daily dose by 30% at baseline as recommended by the manufacturer, Tac-trough levels remained stable, reflected by an increase in the concentration-dose (C/D) ratio. No episodes of graft rejection or loss occurred. Our data suggest that the use of LCP-Tac in liver transplant patients is safe and can increase adherence to immunosuppression compared to conventional IR-Tac.

Bioavailability of once-daily tacrolimus formulations used in clinical practice in the management of De Novo kidney transplant recipients: the better study

Multicenter, prospective, observational study to compare the relative bioavailability of once‐daily tacrolimus formulations in de novo kidney transplant recipients. De novo kidney transplant recipients who started a tacrolimus‐based regimen were included 14 days post‐transplant and followed up for 6 months. Data from 218 participants were evaluated: 129 in the LCPT group (Envarsus) and 89 in the PR‐Tac (Advagraf) group. Patients in the LCPT group exhibited higher relative bioavailability (C_min /total daily dose [TDD]) vs. PR‐Tac (61% increase; P < .001) with similar C_min and 30% lower TDD levels (P < .0001). The incidence of treatment failure was 3.9% in the LCPT group and 9.0% in the PR‐Tac group (P = .117). Study discontinuation rates were 6.2% in the LCPT group and 12.4% in the PR‐Tac group (P = .113). Adverse events, renal function and other complications were comparable between groups. The median accumulated dose of tacrolimus in the LCPT group from day 14 to month 6 was 889 mg. Compared to PR‐Tac, LCPT showed higher relative bioavailability, similar effectiveness at preventing allograft rejection, comparable effect on renal function, safety, adherence, treatment failure and premature discontinuation rates.

A single-center, open-label, randomized cross-over study to evaluate the pharmacokinetics and bioavailability of once-daily prolonged-release formulations of tacrolimus in de novo liver transplant recipients

BACKGROUND

The narrow therapeutic window of tacrolimus (Tac) requires intense drug monitoring to achieve adequate efficacy while minimizing dose-related toxicities. Once-daily formulations of Tac (LCP-Tac and PR-Tac) have been recently designed for higher bioavailability and a more consistent exposure over time, as opposed to the twice-daily, administered immediate-release formulation of Tac (IR-Tac).

METHODS

This single-center, open-label, randomized cross-over pharmacokinetic (PK) study compares extended-release LCP-Tac with the prolonged-release formulation of tacrolimus (PR-Tac) in adult de novo liver transplant recipients. Eligible patients were screened and randomized 1:1 to the two treatment arms up to 30 days after liver transplantation. Patients were administered either LCP-Tac or PR-Tac for 14 days followed by another 14-day time interval of the other once-daily Tac medication. A 24hr-PK profile was obtained at the end of each time interval.

RESULTS

Nine patients (45%) completed the study resulting in a total of 18 Tac PK profiles. Overall, the profile of the mean concentrations indicated a flattened kinetic of LCP-Tac compared to PR-Tac, especially in the first 3 h after drug intake. The average cumulative dose per day to achieve equivalent trough levels was approximately 25% lower for LCP-Tac (8.7 mg) than for PR-Tac (11.7 mg). LCP-Tac resulted in a longer tmax and fewer peak-to-trough fluctuations compared to PR-Tac.

CONCLUSION

Despite methodological weaknesses that limit the conclusions, we have found a more consistent drug exposure for LCP-Tac in de novo LT recipients. LCP-Tac demonstrated a greater bioavailability compared to PR-Tac.

Therapeutic Drug Monitoring Strategies for Envarsus in De Novo Kidney Transplant Patients Using Population Modelling and Simulations

INTRODUCTION

Tacrolimus, the cornerstone of transplantation immunosuppression, is a narrow therapeutic index drug with a low and highly variable bioavailability. Therapeutic drug monitoring based on trough level assessment is mandatory in order to target a personalised exposure and avoid both rejection and toxicity. Population pharmacokinetic (POPPK) models might be a useful tool for improving early attainment of target range by guiding initial doses until steady state is reached and trough levels can be reliably used as surrogate marker of exposure. Here we present the first POPPK for predicting the initial doses of the once-daily prolonged release tacrolimus Envarsus (LCPT) in adult kidney recipients.

METHODS

The model was developed exploiting the data from a recent pharmacokinetic randomised clinical study, in which 69 de novo kidney recipients, 33 of whom treated with LCPT, underwent an intensive blood sampling strategy for tacrolimus including four complete pharmacokinetic profiles.

RESULTS

The complex and prolonged absorption of LCPT is well described by the three-phase model that incorporates body weight and CYP3A5 genotype as significant covariates accounting for a great proportion of the inter-patient variability: in particular, CYP3A5*1/*3 expressors had a 66% higher LCPT clearance. We have then generated by simulation a personalised dosing strategy based on the model that could improve the early attainment of therapeutic trough levels by almost doubling the proportion of patients within target range (69.3% compared to 36.1% with the standard body weight-based approach) on post-transplantation day 4 and significantly reduce the proportion of overexposed patients at risk of toxicity.

CONCLUSIONS

A POPPK model was successfully developed for LCPT in de novo kidney recipients. The model could guide a personalised dosing strategy early after transplantation. For the model to be translated into clinical practice, its beneficial impact of earlier attainment of therapeutic trough levels should be demonstrated on hard clinical outcomes in further studies.

De novo tacrolimus extended-release tablets (LCPT) versus twice-daily tacrolimus in adult heart transplantation: Results of a single-center non-inferiority matched control trial

Extended-release tacrolimus for prophylaxis of allograft rejection in orthotopic heart transplant (OHT) recipients is currently not FDA-approved. One such extended-release formulation of tacrolimus known as LCPT allows once-daily dosing and improves bioavailability compared to immediate-release tacrolimus (IR-tacrolimus). We compared the efficacy and safety of LCPT to IR-tacrolimus applied de novo in adult OHT recipients. Twenty-five prospective recipients on LCPT at our center from 2017 to 2019 were matched 1:2 with historical control recipients treated with IR-tacrolimus based on age, gender, and baseline creatinine. The primary composite outcome of death, acute cellular rejection, and/or new graft dysfunction within 1 year was compared using non-inferiority analysis. LCPT demonstrated non-inferiority to IR-tacrolimus, with a primary outcome risk reduction of 20% (90% CI: -40%, -.5%; non-inferiority P = .001). Tacrolimus trough levels peaked at 2-3 months and were higher in LCPT (median 14.5 vs. 12.7 ng/ml; P = .03) with similar dose levels (LCPT vs. IR-tacrolimus: .08 vs. .09 mg/kg/day; P = .33). Cardiovascular-related readmissions were reduced by 62% (P = .046) in LCPT patients. The complication rate per transplant admission and all-cause readmission rate did not differ significantly. These results suggest that LCPT is non-inferior in efficacy to IR-tacrolimus with a similar safety profile and improved bioavailability in OHT.

Evaluating the conversion to extended-release tacrolimus from immediate-release tacrolimus in liver transplant recipients

BACKGROUND

A new formulation of once daily extended-release tacrolimus (LCP-tac, Envarsus XR) was approved for use in the USA for kidney transplant recipients in 2015. There are limited data regarding real-world observations with conversion to LCP-tac in liver transplant recipients.

METHODS

We performed a retrospective analysis of liver transplant recipients treated with LCP-tac. Data collection included (1) reasons for switching to LCP-tac; (2) conversion ratio used; (3) kidney function at time of conversion and 3 months after; (4) outcomes of conversion [acute cellular rejection rates and cytomegalovirus (CMV) viremia] within 3 months of conversion.

RESULTS

Average conversion ratio used to achieve therapeutic drug level without further dose adjustment was 1:0.73 (SD 0.11). Median time after transplant was 508 days (IQR 736). Common reasons patients were switched to LCP-tac were from fluctuations in tacrolimus levels (44%) and adverse effect of tremor (32%). Among patients who were switched due to tremors 88% noted significant improvement. There was no difference in serum creatinine (P = 0.55) or glomerular filtration rate (P = 0.64) from baseline to 3 months postconversion. There were no episodes of acute cellular rejections or CMV viremia postconversion.

CONCLUSION

This observational study demonstrated that conversion of immediate-release tacrolimus to LCP-tac in liver transplant recipients was well tolerated and effective.

Efficacy and safety of once daily tacrolimus compared to twice daily tacrolimus after liver transplantation

BACKGROUND

Once daily tacrolimus regimen was found to exhibits similar bioavailability, safety and efficacy properties compared to twice-daily tacrolimus in kidney transplantation patients.

AIM

To compare the efficacy and safety of once-daily prolonged release tacrolimus compared to twice-daily tacrolimus in liver transplantation patients.

METHODS

MEDLINE, EMBASE, CENTRAL databases were searched for clinical trials until December 2020. Efficacy outcome measured as the rate of treatment failure indicated by biopsy-proven acute rejection, Serum creatinine, graft loss, or death. Two reviewers independently selected studies, collected data and assessed risk of bias. The results are reported as risk ratio with 95% confidence interval (CI) for dichotomous data.

RESULTS

Seven studies included with 965 patients. All the included studies were of moderate quality according to the risk of bias assessment using Cochrane Risk of Bias tool. Biopsy-proven acute rejection was reported in four studies, and pooled analysis of those studies indicated similar rejections in both twice daily and once daily tacrolimus groups (risk ratio: 1.06, 95%CI: 0.84-1.34, n = 758, I² = 0%) and also we found no significant difference between both groups for renal outcome (serum creatinine; mean difference, 0.001 mg/dL, 95%CI: -0.042 to 0.043, n = 846, I² = 18.6%). Similarly, there was similar number of adverse events such as hypertension, headache, back pain, blood related disorders, infections and nausea observed in both groups.

CONCLUSION

The analysis findings confirm that both once daily and twice daily tacrolimus formulations are comparable in terms of efficacy and safety outcomes.

Volumetric absorptive microsampling for the quantification of tacrolimus in capillary blood by high performance liquid chromatography-tandem mass spectrometry

Volumetric absorptive microsampling (VAMS) is an innovative alternative strategy to venipuncture for monitoring tacrolimus levels in transplant recipients. In this study, we aimed to validate a new high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for quantifying tacrolimus in blood collected by VAMS. Tacrolimus was extracted from dried blood tips in an original process involving sonication, protein precipitation and salting out. The assay was validated in accordance with EMA and IATDMCT guidelines. For clinical validation, the tacrolimus concentrations measured in liquid venous whole blood (with the reference method) were compared with those measured in capillary whole blood collected simultaneously with VAMS by a nurse. The assay was then used to monitor tacrolimus exposure in transplant recipients. The method was linear, sensitive and fast. Within-day and between-day precisions and overall bias were within ±15%. No significant hematocrit effect was observed. The matrix effect was negligible and recovery exceeded 80% for every concentration and hematocrit levels. Tacrolimus was stable in blood collected by VAMS for 1 week at room temperature, 48 h at 60 °C and 4 °C and 1 month at -80 °C. Clinical validation (n = 42 paired samples) demonstrated a strong correlation between the two methods (r = 0.97 Pearson correlation). Bland-Altman analysis revealed that more than 90% of the differences between VAMS and liquid blood paired concentrations were within the ±20% acceptable range. The method had a satisfactory analytical performance and fulfilled clinical requirements. This minimally invasive VAMS-based assay appears reliable for the determination of tacrolimus levels in blood from transplanted patients.

Real-World Administration of Once-Daily MeltDose® Prolonged-Release Tacrolimus (LCPT) Allows for Dose Reduction of Tacrolimus and Stabilizes Graft Function Following Liver Transplantation

The calcineurin inhibitor tacrolimus is included in most immunosuppressive protocols after liver transplantation. This retrospective, observational 24-month study investigated the tolerability of once-daily MeltDose^® prolonged-release tacrolimus (LCPT) after switching from twice-daily immediate-release tacrolimus (IR-Tac) in a real-world cohort of 150 patients with previous liver transplantation. No graft rejection or new safety signals were observed. Only 7.3% of patients discontinued LCPT due to side effects. In the overall patient population, median liver transaminases, total cholesterol, triglycerides, glucose, and HbA_1c remained constant after switching to LCPT. Total cholesterol significantly decreased (p ≤ 0.002) in patients with initially elevated levels (>200 mg/dL). A total of 71.8% of 96 patients maintained a glomerular filtration rate > 60 mL/min/1.73 m² throughout the study, while 44.7% of patients were classified as fast metabolizers and 55.3% as slow metabolizers. Median daily tacrolimus dose could be reduced by 50% in fast metabolizers and by 30% in slow metabolizers, while trough levels were maintained in the target range (4–6 ng/mL). In conclusion, our observational study confirmed previous evidence of good overall tolerability and a favorable outcome for the patients after switching from IR-Tac to LCPT after liver transplantation.

Conversion from Standard-Release Tacrolimus to MeltDose® Tacrolimus (LCPT) Improves Renal Function after Liver Transplantation

Renal impairment is a typical side effect of tacrolimus (Tac) treatment in liver transplant (LT) recipients. One strategy to avoid renal dysfunction is to increase the concentration/dose (C/D) ratio by improving drug bioavailability. LT recipients converted from standard-release Tac to MeltDose^® Tac (LCPT), a novel technological formulation, were able to reduce the required Tac dose due to higher bioavailability. Hence, we hypothesize that such a conversion increases the C/D ratio, resulting in a preservation of renal function. In the intervention group, patients were switched from standard-release Tac to LCPT. Clinical data were collected for 12 months after conversion. Patients maintained on standard-release Tac were enrolled as a control group. Twelve months after conversion to LCPT, median C/D ratio had increased significantly by 50% (p < 0.001), with the first significant increase seen 3 months after conversion (p = 0.008). In contrast, C/D ratio in the control group was unchanged after 12 months (1.75 vs. 1.76; p = 0.847). Estimated glomerular filtration rate (eGFR) had already significantly deteriorated in the control group at 9 months (65.6 vs. 70.6 mL/min/1.73 m² at study onset; p = 0.006). Notably, patients converted to LCPT already had significant recovery of mean eGFR 6 months after conversion (67.5 vs. 65.3 mL/min/1.73 m² at study onset; p = 0.029). In summary, conversion of LT recipients to LCPT increased C/D ratio associated with renal function improvement.

The use of LCP-Tacrolimus (Envarsus XR) in simultaneous pancreas and kidney (SPK) transplant recipients

BACKGROUND

Extended release LCP-tacrolimus (LCPT) allows once-daily dosing in transplant recipients. The improved bioavailability may be beneficial for simultaneous pancreas-kidney recipients (SPK).

METHODS

This is a study of 39 SPK recipients on standard immediate-release tacrolimus (IR-TAC, n = 21) or LCPT (n = 18). Coefficient of variability (CV = 100∗standard deviation/mean) was calculated to assess drug levels. Hemoglobin A1c (HbA1c), tacrolimus and creatinine levels were measured postoperatively.

RESULTS

There was no difference in tacrolimus CV in the IR-TAC and LCPT groups at 1 month or 3 months postoperatively; however, a greater difference was observed at 1 year (41.0 vs. 33.1%; p = 0.19). There were six episodes of acute rejection in the IR-TAC group compared to zero episodes in the LCPT group (p = 0.01). HbA1c was significantly higher in the IR-TAC group compared to LCPT at 3 (5.5 vs. 4.9%, p = 0.01), 6 (5.6 vs. 4.9%, p = 0.01) and 12 months (5.8 vs. 5.1%, p = 0.07).

CONCLUSIONS

Significantly lower rates of rejection were observed in patients receiving LCPT. The once daily dosing may facilitate medication adherence and result in improved long-term outcomes.

Effectiveness and safety of the conversion to MeltDose® extended-release tacrolimus from other formulations of tacrolimus in stable kidney transplant patients: A retrospective study

Tacrolimus is the cornerstone of immunosuppressive therapy after kidney transplantation. Its narrow therapeutic window mandates serum level strict monitoring and dose adjustments to ensure the optimal risk‐benefit balance. This observational retrospective study analyzed the effectiveness and safety of conversion from twice‐daily immediate‐release tacrolimus (IR‐Tac) or once‐daily prolonged‐release tacrolimus (PR‐Tac) to the recent formulation once‐daily MeltDose^® extended‐release tacrolimus (LCP‐Tac) in 365 stable kidney transplant recipients. We compared kidney function three months before and three months after the conversion. Three months after conversion, the total daily dose was reduced ~35% (P < .0001), and improved bioavailability and stable serum LCP‐Tac concentrations were observed. There was no increase in the number of patients requiring tacrolimus dose adjustments after conversion. Renal function was unaltered, and no cases of BPAR were reported. Reports of tremors, as collected in the clinical histories for each patient, decreased from pre‐conversion (20.8%) to post‐conversion (11.8%, P < .0001). LCP‐Tac generated a cost reduction of 63% compared with PR‐Tac. In conclusion, the conversion strategy to LCP‐Tac from other tacrolimus formulations in stable kidney transplant patients showed safety and effectiveness in a real‐world setting, confirming the data from RCTs. The specific pharmacokinetic properties of LCP‐Tac could be potentially advantageous in patients with tacrolimus‐related adverse events.

Pharmacokinetics of Once-Daily Extended-Release Tacrolimus Tablets Versus Twice-Daily Capsules in De Novo Liver Transplant

The pharmacokinetics of once-daily extended-release tacrolimus tablets (LCPT) in de novo liver transplantation have not been previously reported. In this phase II, randomized, open-label study, de novo liver transplant recipients were randomized to LCPT 0.07-0.13 mg/kg/day (taken once daily; n = 29) or twice-daily immediate-release tacrolimus capsules (IR-Tac) at 0.10-0.15 mg/kg/day (divided twice daily; n = 29). Subsequent doses of both drugs were adjusted to maintain tacrolimus trough concentrations of 5 to 20 ng/mL through day 90, and 5-15 ng/mL thereafter. Twenty-four-hour pharmacokinetic profiles were obtained on days 1, 7, and 14, with trough concentration and efficacy/safety monitoring through year 1. Similar proportions of patients in both groups achieved therapeutic trough concentrations on days 7 and 14 (day 7: LCPT = 78%, IR-Tac = 75%; day 14: LCPT = 86%, IR-Tac = 91%) as well as similar systemic and peak exposure. There was a robust correlation between drug concentration at time 0 and area under the concentration-time curve for both LCPT and IR-Tac (respectively, day 7: r = 0.86 and 0.79; day 14: r = 0.93 and 0.86; P < .0001 for all). Dose adjustments during days 1 to 14 were frequent. Thirty-five patients completed the extended-use period. No significant differences in adverse events were seen between groups. Incidence of biopsy-proven acute rejection (LCPT = 6 and IR-Tac = 4) was similar on day 360. Between formulations, overall exposure was similar at 1 week after transplant with the characteristic delayed-release pharmacokinetic profile of LCPT demonstrated in this novel population. These data support further investigation of the safety and efficacy of LCPT in de novo liver transplantation.

Pharmacokinetic Study of Conversion Between 2 Formulations of Once-daily Extended-release Tacrolimus in Stable Lung Transplant Patients

BACKGROUND

The aim of this study was to compare the pharmacokinetic profile, tolerability, and safety of a novel once-daily extended-release formulation of tacrolimus (LCPT) with that of once-daily prolonged-release tacrolimus (ODT) in stable adult lung transplant (LT) recipients.

METHODS

Phase II, open-label, single-arm, single-center, prospective pilot pharmacokinetic study. Study population comprised 20 stable LT recipients receiving ODT, mean age 55.9 years (range, 38-67 years), 13 (65%) men. Patients were switched to LCPT in a 1:0.7 (mg/mg) conversion dose. Follow-up was 6 months, and cystic fibrosis patients were excluded. Two 24-hour pharmacokinetic profiles were obtained for each patient, the first on day -14 and the second on day +14 after switching to LCPT. Pharmacokinetic parameters and safety were compared.

RESULTS

Mean (SD) area under the concentration-time curve from 0 to 24 hours was 253.97 (61.90) ng/mL per hour for ODT and 282.44 (68.2) ng/mL per hour for LCPT. Systemic exposure was similar in both (Schuirmann two 1-sided test). Mean (SD) dose was 5.05 (1.67) mg in ODT and 3.36 (1.03) mg in LCPT (P = 0.0002). Time to maximum concentration was 125 minutes for ODT and 325 minutes for LCPT (P < 0.001). Correlation between area under the concentration-time curve from 0 to 24 hours and C24 was 0.896 (r) for ODT and 0.893 (r) for LCPT. There were no differences in adverse effects. At 6 months, conversion dose was 1:0.59 (mg/mg) in patients with unchanged minimum plasma concentration target levels.

CONCLUSIONS

Switching from ODT to LCPT was safe and well tolerated in stable LT recipients without cystic fibrosis. A significantly lower dose of LCPT allows similar bioavailability. A conversion ratio 1:0.6 could be enough to maintain similar target levels.

Once-daily tacrolimus in liver transplantation: a 'me-too drug', or a therapeutic advantage

PURPOSE OF REVIEW

To provide latest information on differences between standard tacrolimus (TAC BID) and slow-released formulation of tacrolimus (Advagraf) in liver transplantation (LTx), and to discuss the latter's therapeutic value as a distinct entity.

RECENT FINDINGS

Two articles on de-novo studies, several on conversion and one on survival analysis from the European Liver Transplant Registry published recently showed that low-dose Advagraf immediately after transplantation provided same protection to the kidney as standard dose delayed until day 5, and was associated with lower rejection rate; to maintain the same trough level after late conversion to Advagraf, an approximately 1.25-fold higher dose was needed on average; if studied by questionnaire, conversion improved medication adherence; and registry data provided evidence of long-term survival benefit of Advagraf over TAC BID (7 and 8% graft and patient survival rates over a 3-year period; P < 0.002 and P < 0.003, respectively).

SUMMARY

Pharmacokinetic differences between TAC BID and Advagraf translate into less interpatient and intrapatient variability and improve adherence. If survival benefit of Advagraf administration de novo after LTx as demonstrated by the European Liver Transplant Registry analysis is confirmed in an independent cohort, Advagraf will leave the area of the 'me-too' drugs to become the immunosuppressant of choice.

Conversion From Once-Daily Prolonged-Release Tacrolimus to Once-Daily Extended-Release Tacrolimus in Stable Liver Transplant Recipients

OBJECTIVES

After organ transplant, strategies to simplify the therapeutic regimen may improve adherence and prevent rejection and/or graft loss. The aim of the present study was to evaluate the safety of conversion from once-daily prolonged-release tacrolimus (Advagraf; Astellas Pharma Europe Limited, Middlesex, UK) to once-daily extended-release tacrolimus (Envarsus; Chiesi SAS, Nanterre, France) in stable adult liver transplant recipients.

MATERIALS AND METHODS

This observational study inclu-ded 44 liver transplant patients (median age of 59 y; 63.6% men; median delay after transplant of 72.5 mo). Conversion was based on a 1:0.70 proportion.

RESULTS

Mean dose of tacrolimus was 2.65 ± 1.24 mg/day before conversion and 2.09 ± 1.68 mg/day after conversion (P < .05), with ratio of 1:0.79. Mean serum tacrolimus trough level increased after conversion (4.92 ± 1.65 vs 5.60 ± 2.89 ng/mL; P < .05), with ratio of 1:1.14. Six months after conversion, mean dose of tacrolimus was 1.65 ± 0.93 mg/day (ratio of 1:0.62) and mean serum tacrolimus trough level was 4.82 ± 1.85 ng/mL, similar to the initial level before conversion. At the end of follow-up, 2 patients had returned to once-daily prolonged-release tacrolimus because of adverse effects (allergy, digestive trouble), which resolved thereafter. The mean cost of tacrolimus therapy was 5.54 ± 2.29 Euros/patient/day before conversion and 4.11 ± 2.32 Euros/patient/day after conversion (P < .05).

CONCLUSIONS

Conversion from prolonged-release to extended-release tacrolimus in stable liver transplant patients is safe and cost-effective; however, initially, dose adaptations and careful monitoring are required.

Emerging drugs for prevention of T-cell mediated rejection in liver and kidney transplantation

INTRODUCTION

Acute and chronic graft rejection continues to be an important problem after solid organ transplantation. With the introduction of potent immunosuppressive agents such as calcineurin inhibitors, the risk of rejection has been significantly reduced. However, the adverse effects of life-long immunosuppression remain a concern, and there exist a fine balance between over-immunosuppression and risk of rejection. Areas covered: In this review, the current standard of care in immunosuppressive therapy, including the use of steroids, calcineurin inhibitors, mycophenolate prodrugs and mammalian target of rapamycin inhibitors, will be discussed. Newer immunosuppressive agents showing promising early data after liver and kidney transplantation will also be explored. Expert Opinion: Currently, calcineurin inhibitors continue to be a vital component of immunosuppressive therapy after solid organ transplantation. Although minimization and avoidance strategies have been developed, the ultimate goal of inducing tolerance remains elusive. Newer emerging agents should have potent and specific immunosuppressive activity, with minimal associated side effects. An individualized approach should be adopted to tailor immunosuppression according to the different needs of recipients.

A Steady-State Head-to-Head Pharmacokinetic Comparison of All FK-506 (Tacrolimus) Formulations (ASTCOFF): An Open-Label, Prospective, Randomized, Two-Arm, Three-Period Crossover Study

This two-sequence, three-period crossover study is the first pharmacokinetic (PK) study to compare all three innovator formulations of tacrolimus (twice-daily immediate-release tacrolimus capsules [IR-Tac]; once-daily extended-release tacrolimus capsules [ER-Tac]; novel once-daily tacrolimus tablets [LCPT]). Stable renal transplant patients were dosed with each drug for 7 days, and blood samples were obtained over 24 h. Thirty subjects were included in the PK analysis set. A conversion factor of 1:1:0.80 for IR-Tac:ER-Tac:LCPT was used; no dose adjustments were permitted during the study. The median (interquartile range) total daily dose was 6.0 (4.0-8.0) mg for IR-Tac and ER-Tac and 4.8 (3.3-6.3) for LCPT. Significantly higher exposure on a per milligram basis, lower intraday fluctuation and prolonged time (Tmax ) to peak concentration (Cmax ) were found for LCPT versus IR-Tac or ER-Tac. ER-Tac showed no differences versus IR-Tac in exposure, Cmax , Tmax or fluctuation. The observed exposure of IR-Tac was used to normalize exposure for LCPT and ER-Tac, resulting in the following recommended total daily dose conversion rates: IR-Tac:ER-Tac, +8%; IR-Tac:LCPT, -30%; ER-Tac:LCPT, -36%. After exposure normalization, Cmax was ~17% lower for LCPT than for IR-Tac or ER-Tac; Cmin was ~6% lower for LCPT compared with IR-Tac and 3% higher compared with ER-Tac.

Meltdose Tacrolimus Pharmacokinetics

BACKGROUND

Nonadherence to immunosuppressive therapy contributes to the loss of grafts. One of the problem is the fractioning of immunosuppressive dose. In fact, it was demonstrated that a single daily dose (QD) is associated with an increased adherence to therapy compared with twice daily dosing (BID). Tacrolimus (TAC), calcineurin inhibitor, is one of immunosuppression pillar in organ transplantation and its action is strongly correlated with blood concentration and therefore the therapeutic drug monitoring is recommended in the guidelines. However, one of the critical points of TAC is the poor and variable bioavailability that influences immunosuppression, and is also responsible for adverse effects.

METHODS

MeltDose® Technology is a new technology to improve efficacy and/or reduce side effects. This new technology applied to TAC (Envarsus® or LCP-TAC) has achieved 4 main objectives: (1) improved bioavailability, (2) reduced dose fractioning to one tablet per day, (3) limited variability concentrations of TAC, and (4) lower doses of TAC will be administered.

RESULTS

We analyzed the pharmacokinetic profile, efficacy, and security of Envarsus®.

LCPT once-daily extended-release tacrolimus tablets versus twice-daily capsules: a pooled analysis of two phase 3 trials in important de novo and stable kidney transplant recipient subgroups

African-American and elderly kidney transplant recipients (KTR) have increased risk for poor clinical outcomes post-transplant. Management of immunosuppression may be challenging in these patients and contribute to worse outcomes. A novel once-daily formulation of tacrolimus (LCPT) has demonstrated noninferiority, similar safety, improved bioavailability, a consistent concentration time profile, and less peak and peak-trough fluctuations vs. tacrolimus twice-daily (Tac BID). This pooled analysis of two phase 3 randomized, controlled trials, including 861 (LCPT N = 428; Tac BID N = 433; 38% of patients were stable KTR, and 62% were de novo KTR) patients, examined the efficacy of LCPT in KTR subgroups (blacks, females, and age ≥65). Overall, treatment failure [death, graft failure, centrally read biopsy-proven acute rejection (BPAR), or lost to follow-up] at 12 months was as follows: LCPT: 11.9%, BID Tac: 13.4% [-1.48% (-5.95%, 2.99%)]. BPAR rates were as follows: LCPT: 8.2%, Tac BID: 9.5% [-1.29% (-5.14%, 2.55%)]. Numerically, fewer treatment failure events with LCPT were found in the majority of subgroups, with significantly less treatment failure associated with LCPT among black KTR [-13.82% (-27.22%, -0.31%)] and KTR ≥65 [-13.46% (-25.27%, -0.78%)]. This pooled analysis suggests numerically lower efficacy failure rates associated with LCPT among high-risk subgroups, in particular black KTR and KTR ≥65 years old.

Tacrolimus for the prevention and treatment of rejection of solid organ transplants

Since its introduction to the antirejection armamentarium in 1994, tacrolimus has become the workhorse of transplant professionals for avoidance of solid organ transplant rejection. Not only does tacrolimus have potent immunosuppressive qualities that prevent rejection, but dosing is straight forward and it is generally well tolerated. However, in the long term, conditions such as calcineurin inhibitor nephrotoxicity can become a problem. A discussion of the compound, the pharmacokinetics, history, and current approved uses for tacrolimus is described. Indeed, tacrolimus is the most important drug for preventing transplant rejection. However, the increased appreciation for significant side effects, particularly in the long term, has led to building interest in new agents with different mechanisms of action and different metabolism.

Novel Once-Daily Extended-Release Tacrolimus Versus Twice-Daily Tacrolimus in De Novo Kidney Transplant Recipients: Two-Year Results of Phase 3, Double-Blind, Randomized Trial

BACKGROUND

1-year data from this trial showed the noninferiority of a novel once-daily extended-release tacrolimus (LCPT; Envarsus XR) to immediate-release tacrolimus (IR-Tac) twice daily after kidney transplantation.

STUDY DESIGN

Final 24-month analysis of a 2-armed, parallel-group, randomized, double-blind, double-dummy, multicenter, phase 3 trial.

SETTING & PARTICIPANTS

543 de novo kidney recipients randomly assigned to LCPT (n=268) or IR-Tac (n=275); 507 (93.4%) completed the 24-month study.

INTERVENTION

LCPT tablets once daily at 0.17 mg/kg/d or IR-Tac twice daily at 0.1 mg/kg/d; subsequent doses were adjusted to maintain target trough ranges (first 30 days, 6-11 ng/mL; thereafter, 4-11 ng/mL). The intervention was 24 months; the study was double blinded for the entirety.

OUTCOMES & MEASUREMENTS

Treatment failure (death, transplant failure, biopsy-proven acute rejection, or loss to follow up) within 24 months. Safety end points included adverse events, serious adverse events, new-onset diabetes, kidney function, opportunistic infections, and malignancies. Pharmacokinetic measures included total daily dose (TDD) of study drugs and tacrolimus trough levels.

RESULTS

24-month treatment failure was LCPT, 23.1%; IR-Tac, 27.3% (treatment difference, -4.14% [95% CI, -11.38% to +3.17%], well below the +10% noninferiority criterion defined for the primary 12-month end point). Subgroup analyses showed fewer treatment failures for LCPT versus IR-Tac among black, older, and female recipients. Safety was similar between groups. From month 1, TDD was lower for LCPT; the difference increased over time. At month 24, mean TDD for LCPT was 24% lower than for the IR-Tac group (P<0.001), but troughs were similar (means at 24 months: LCPT, 5.47 ± 0.17 ng/mL; IR-Tac, 5.8 ± 0.30 ng/mL; P=0.4).

LIMITATIONS

Trial participant eligibility criteria may limit the generalizability of results to the global population of de novo kidney transplant recipients.

CONCLUSIONS

Results suggest that once-daily LCPT in de novo kidney transplantation has comparable efficacy and safety profile to that of IR-Tac. Lower TDD reflects LCPT's improved bioavailability and absorption.

Switching STudy of Kidney TRansplant PAtients with Tremor to LCP-TacrO (STRATO): an open-label, multicenter, prospective phase 3b study

Tremor is a common side effect of tacrolimus correlated with peak-dose drug concentration. LCPT, a novel, once-daily, extended-release formulation of tacrolimus, has a reduced Cmax with comparable AUC exposure, requiring a ~30% dose reduction vs. immediate-release tacrolimus. In this phase 3b study, kidney transplant recipients (KTR) on a stable dose of tacrolimus and with a reported clinically significant tremor were offered a switch to LCPT. Tremor pre- and seven d post-conversion was evaluated by independent, blinded movement disorder neurologists using the Fahn-Tolosa-Marin (FTM) scale and by an accelerometry device; patients completed the QUEST (quality of life in essential tremor) and the Patient Global Impression of Change. There were 38 patients in the mITT population. A statistically and clinically significant improvement in tremor (FTM score, amplitude as measured by the accelerometry device and QOL [p-values < 0.05]) resulted post-conversion. Change in QUEST was significantly (p = 0.006) correlated (R = 0.44) with change in FTM; 78.9% of patients reported an improvement after switching to LCPT (p < 0.0005). To our knowledge this is the first trial in KTR that utilizes a sophisticated and reproducible measurement of tremor. Results suggest LCPT is associated with clinically meaningful improvement of hand tremor and may be an alternative management approach in lieu of further dose reduction of immediate-release tacrolimus for patients experiencing tremor.

Once-daily LCP-Tacro MeltDose tacrolimus for the prophylaxis of organ rejection in kidney and liver transplantations

Tacrolimus is a cornerstone of the immunosuppression regimen for prevention of allograft rejection in kidney and liver transplantations, with efficacy proven in many clinical trials. The currently available and extensively used tacrolimus formulations are flawed by large inter- and intra-individual variability, low bioavailability, wide peak-to-trough fluctuations and a narrow therapeutic index. Drug delivery technology can significantly impact the pharmacologic action of a drug, influencing its pharmacokinetic and subsequent therapeutic profile. LCP-Tacro is a novel, prolonged-release, MeltDose(®) formulation of tacrolimus designed for once-daily administration. A hallmark differentiation between this formulation and other once- and twice-daily tacrolimus products is the proprietary MeltDose drug delivery technology which is designed to improve the bioavailability of drugs with low water solubility. Considering the studies conducted to date, once-daily LCP-Tacro has shown improved pharmacokinetic properties, rapid achievement of therapeutic trough levels, consistent exposure, non-inferior efficacy and similar safety, with lower tacrolimus dose than other tacrolimus formulations.

Novel once-daily extended-release tacrolimus (LCPT) versus twice-daily tacrolimus in de novo kidney transplants: one-year results of Phase III, double-blind, randomized trial

This Phase III randomized trial examined efficacy and safety of a novel once-daily extended-release tacrolimus formulation (LCP-Tacro [LCPT]) versus twice-daily tacrolimus in de novo kidney transplantation. Primary efficacy end point was proportion of patients with treatment failure (death, graft failure, biopsy-proven acute rejection or lost to follow-up) within 12 months. Starting doses were, LCPT: 0.17 mg/kg/day and tacrolimus twice-daily: 0.1 mg/kg/day; 543 patients were randomized, LCPT: n = 268; tacrolimus twice-daily: n = 275. At 12 months treatment failure was LCPT: 18.3% and tacrolimus twice-daily: 19.6%; the upper 95% CI of the treatment difference was +5.27%, below the predefined +10% noninferiority criteria. There were no significant differences in the incidence of individual efficacy events or adverse events. Target tacrolimus trough levels were more rapidly achieved in the LCPT group. Following initial dose, 36.6% of patients in the LCPT group had rapidly attained trough levels within 6-11 ng/mL versus 18.5% of tacrolimus twice-daily patients; majority of tacrolimus twice-daily patients (74.7%) had troughs <6 ng/mL compared with 33.5% in the LCPT group. Overall, cumulative study dose was 14% lower for LCPT. Results suggest that use of once-daily LCPT in de novo kidney transplantation is efficacious and safe. Lower LCPT dose reflects the improved absorption provided by the novel formulation.

Update on the clinical utility of once-daily tacrolimus in the management of transplantation

Adherence to immunosuppression and minimizing variability in drug exposure are important considerations in preventing rejection and maximizing overall transplant outcomes. The availability of once-daily tacrolimus may confer potential benefit by simplifying immunosuppressive regimens, thereby improving medication adherence among transplant recipients. Pharmacokinetic studies in healthy normal volunteers and stable transplant recipients suggest that once-daily tacrolimus is bioequivalent to twice-daily tacrolimus. Efficacy studies suggest that once-daily tacrolimus is noninferior to twice-daily tacrolimus with a concentration-dependent rejection risk. The incidence of biopsy-proven acute rejection, graft survival, and patient survival are more or less comparable between the two tacrolimus formulations. Once-daily tacrolimus has also been reported to have favorable effects on blood pressure, lipid profile, and glucose tolerance. Once-daily tacrolimus may be a viable option to consider for de novo immunosuppression or for conversion from conventional tacrolimus.