Conversion from Prograf to Advagraf in stable kidney transplant recipients: better renal function after 3-year follow-up

Outcomes of pancreas transplantation over two decades: a single-center retrospective cohort study

Purpose

Pancreas transplantation (PT) is a definitive treatment for diabetes mellitus (DM), restoring endogenous insulin secretion and improving glycemic control. Despite its efficacy, PT is less common in South Korea compared to Western nations. This study aims to report the clinical outcomes of PT over 2 decades at a single center, focusing on surgical techniques, complications, and graft survival.

Methods

A retrospective analysis of 69 PT recipients at Seoul National University Hospital between January 2002 and December 2023 was conducted. Data on recipient and donor demographics, surgical details, immunosuppressive regimens, and graft outcomes were collected. Graft survival was evaluated using Kaplan-Meier analysis, with subgroup comparisons using the log-rank test. Graft failure was defined as graft removal, PT re-registration, insulin dependence exceeding 0.5 units/kg/day for more than 90 days, or patient death.

Results

Among the 69 recipients, 50 (72.5%) had type 1 DM, and 18 (26.1%) had type 2 DM. Simultaneous pancreas-kidney (SPK) transplantations comprised 84.1% (n = 58), and pancreas-after-kidney (PAK) transplantations accounted for 10.1%. The 1-year and 5-year death-censored pancreas graft survival rates were 92.7% and 89.6%, respectively, with no significant difference between SPK and PAK (P = 0.330). Graft failure occurred in 10 patients, primarily due to pancreatitis and rejection. Donor-related factors, particularly anoxic brain injury, were significantly associated with lower graft survival (P = 0.045).

Conclusion

PT outcomes in this cohort align with international standards, emphasizing the importance of donor selection and tailored immunosuppression. Expanding PT indications to include selective type 2 DM patients could benefit South Korea's PT programs with adequate resource allocation.

Guiding the starting dose of the once-daily formulation of tacrolimus in "de novo" adult renal transplant patients: a population approach

Aims

The once-daily extended-release tacrolimus formulation (ER-Tac) has demonstrated similar efficacy and safety to the twice-daily immediate-release formulation (IR-Tac), but few population-based pharmacokinetic models have been developed in de novo kidney transplant patients to optimize doses. Therefore, this study aimed i) at developing a population pharmacokinetic model for ER-Tac in de novo adult kidney transplant patients ii) and identifying genetic factors and time-varying covariates predictive of pharmacokinetic variability to guide tacrolimus dosage during the early post-transplant period.

Methods

A total of 1,067 blood tacrolimus concentrations from 138 kidney transplant patients were analyzed. A total of 29 out of 138 patients were intensively sampled for 24 h on the day 5 post-transplantation; meanwhile, for the remaining patients, concentrations were collected on days 5, 10, and 15 after transplantation. Tacrolimus daily doses and genetic and demographic characteristics were retrieved from the medical files. Biochemistry time-varying covariates were obtained on different days over the pharmacokinetic (PK) study. A simultaneous PK analysis of all concentrations was carried out using the non-linear mixed-effects approach with NONMEM 7.5.

Results

A two-compartment model with linear elimination and delayed absorption best described the tacrolimus pharmacokinetics. Between-patient variability was associated with oral blood clearance (CL/F) and the central compartment distribution volume (Vc/F). Tacrolimus concentrations standardized to a hematocrit value of 45% significantly improved the model (p < 0.001). This method outperformed the standard covariate modeling of the hematocrit-blood clearance relationship. The effect of the CYP3A5 genotype was statistically (p < 0.001) and clinically significant on CL/F. The CL/F of patients who were CYP3A5*1 carriers was 51% higher than that of CYP3A5*1 non-carriers. Age also influenced CL/F variability (p < 0.001). Specifically, CL/F declined by 0.0562 units per each increased year from the value estimated in patients who were 60 years and younger.

Conclusion

The 36% between-patient variability in CL/F was explained by CYP3A5 genotype, age, and hematocrit. Hematocrit standardization to 45% explained the variability of tacrolimus whole-blood concentrations, and this was of utmost importance in order to better interpret whole-blood tacrolimus concentrations during therapeutic drug monitoring. The dose requirements of CYP3A5*/1 carriers in patients aged 60 years or younger would be highest, while CYP3A5*/1 non-carriers older than 60 years would require the lowest doses.

Randomized controlled trial of sustained release tacrolimus vs twice daily tacrolimus in adult living donor liver transplantation

BACKGROUND

To compare the safety and efficacy of once-daily tacrolimus (ODT) versus twice-daily tacrolimus (BDT) in adult live donor liver transplantation (LDLT).

METHODS

In this open-labelled randomized trial, 174 adult patients undergoing LDLT were randomized into ODT or BDT, combined with basiliximab induction and mycophenolate mofetil (steroid-free regimen). Tacrolimus was started at a total dose of 1 mg and the trough level was aimed at 3-7 ng/ml. The primary endpoint was eGFR at 1,3- and 6 months post-transplant, using CKD- EPI equation. Secondary endpoints included biopsy-proven acute rejection (BPAR), metabolic complications, post-operative bilio-vascular complications and patient survival.

RESULTS

There was no statistically significant difference in eGFR between the two groups at 6 months (ODT -96 ± 19, BDT -91 ± 21, p value-0.164). BPAR was comparable (18/84 in ODT, 19/88 in BDT, p value-0.981). For a similar dosage of tacrolimus, the median trough tacrolimus levels attained were significantly lower for ODT than BDT during the first-month post-transplant (p value-0.001). Metabolic complications due to immunosuppression, post-operative bilio-vascular complications and patient survival was similar between the two groups at 6 months.

CONCLUSION

Once-daily tacrolimus has similar renal safety and efficacy as twice-daily tacrolimus when used in combination with basiliximab induction and mycophenolate in adult LDLT.

Age and sex determine conversion from immediate-release to extended-release tacrolimus in a multi-center cohort of Canadian pediatric renal transplant recipients

ER-Tac, taken once per day, is associated with improved adherence. This study examined the potential patient and clinical factors that influence clinicians to convert pediatric patients from immediate-release to ER-Tac. This prospective multi-center observational study followed Canadian pediatric kidney transplant recipients up to 5 years post-transplant. Cox Proportional Hazards Regression was used to examine the influence of factors on conversion to ER-Tac. Sixty-six participants were included in this analysis. For every additional year of age at the time of transplant, the likelihood of conversion was more than doubled (HR 2.54, CI 1.83, 3.54, P < 0.001). The impact of age reduced by three percent for every month after transplant (HR 0.97, CI 0.95, 0.98, P < 0.001). Girls were more likely to be converted than boys (HR 3.78, CI 1.35, 10.6, P 0.01). Adherence measures (MAM-MM and tacrolimus trough variability), individual barriers to adherence, renal function, HLA mismatch, and rejection were not significant predictors of conversion in the final regression model. ER-Tac was preferentially prescribed to older age and female patients. Female sex and adolescence are both associated with worse graft outcomes, but we found no link between individualized markers of adherence/graft risk and conversion. Clinicians appeared to be using demographic features to distinguish patients at perceived higher risk and converted accordingly, without a case-by-case evaluation of who is more susceptible to poor outcomes.

Thirty Years of Tacrolimus in Clinical Practice

Tacrolimus was discovered in 1984 and entered clinical use shortly thereafter, contributing to successful solid organ transplantation across the globe. In this review, we cover development of tacrolimus, its evolving clinical utility, and issues affecting its current usage. Since earliest use of this class of immunosuppressant, concerns for calcineurin-inhibitor toxicity have led to efforts to minimize or eliminate these agents in clinical regimens but with limited success. Current understanding of the role of tacrolimus focuses more on its efficacy in preventing graft rejection and graft loss. As we enter the fourth decade of tacrolimus use, newer studies utilizing novel combinations (as with the mammalian target of rapamycin inhibitor, everolimus, and T-cell costimulation blockade with belatacept) offer potential for enhanced benefits.

Adherence of Renal Transplant Recipients to Once-daily, Prolonged-Release and Twice-daily, Immediate-release Tacrolimus-based Regimens in a Real-life Setting in Sweden

BACKGROUND

In this study we investigated medication adherence of kidney transplant patients (KTPs) to an immediate-release tacrolimus (IR-T) regimen and, after conversion, to a prolonged-release tacrolimus (PR-T) regimen in routine clinical practice.

METHODS

This was a noninterventional, observational, multicenter Swedish study. We included adult KTPs with stable graft function, remaining on IR-T or converting from IR-T to PR-T. Data were collected at baseline, and months 3, 6, and 12 postbaseline. The primary endpoint was adherence using the Basel Assessment of Adherence to Immunosuppressive Medication Scale (BAASIS). Secondary assessments included tacrolimus dose and trough levels, clinical laboratory parameters (eg, estimated glomerular filtration rate), and adverse drug reactions (ADRs).

RESULTS

Overall, 233 KTPs were analyzed (PR-T, n = 175; IR-T, n = 58). Mean change in PR-T dose from baseline (4.8 mg/d) to month 12 was -0.2 mg/d, and for IR-T (4.2 mg/d) was -0.4 mg/d; tacrolimus trough levels remained similar. Overall adherence was similar between baseline and month 12 in both groups (PR-T: 54.4% vs 57.0%, respectively; IR-T: 65.5% vs 69.4%); timing adherence followed a similar pattern. The probability of taking adherence improved between baseline and month 12 (odds ratio, 1.97; P = .0092) in the PR-T group only. Mean BAASIS visual analog scale score at baseline was 94.3 ± 11.1% (PR-T) and 95.3 ± 7.6% (IR-T), and >95% at subsequent visits. Laboratory parameters remained stable. Eight (4.6%) patients receiving PR-T (none receiving IR-T) had ADRs considered probably/possibly treatment-related.

CONCLUSION

Disparity existed between high, patient-perceived and low, actual adherence. Overall adherence to the immunosuppressive regimen (measured by BAASIS) did not improve significantly over 12 months in stable KTPs converting to PR-T or remaining on IR-T; renal function remained stable.

A non-randomized trial of conversion from ciclosporin and tacrolimus to tacrolimus MR4 in stable long-term kidney transplant recipients: Graft function and influences of ABCB1 genotypes

TRIAL REGISTRATION

PEP Study: Ethics committee N° 393/2004, EudraCT 2004-004209-98. PEP-X Study: Ethics committee amendment application N° 154/01/2008. ClinicalTrials.gov NCT03751332.

Conversion From Twice-Daily to Once-Daily Tacrolimus Among Egyptian Living-Donor Kidney Allograft Recipients: A Single-Center Experience

OBJECTIVES

Adherence to immunosuppression and minimization of drug exposure are important con-siderations in preventing rejection and maximizing transplant outcomes. The once-daily tacrolimus protocol confers potential benefit by simplifying immunosuppressive regimens, thereby improving adherence among transplant recipients. Studies of stable transplant recipients have suggested that once-daily tacrolimus is bioequivalent to twice-daily tacrolimus and is noninferior to twice-daily tacrolimus with a concentration-dependent rejection risk. Our aim was to evaluate the safety and efficacy of conversion from twice-daily tacrolimus formulation to a once-daily formulation among a cohort of adult living related-donor renal transplant patients as a single-center experience.

MATERIALS AND METHODS

This prospective, one arm, single-center study included 238 patients with at least 12 months posttransplant follow-up and no rejection episodes in the last 3 months. Conversion from twice-daily to once-daily formulation was based on a 1:1 ratio.

RESULTS

The mean tacrolimus dose was 4.7 ± 2.7 mg/day preconversion versus 4.9 ± 3.2 mg/day postconversion (P = .8). The mean tacrolimus level was 7.4 ± 3.4 versus 6.1 ± 2.8 ng/mL (P = .75). Of total patients, 45% were maintained on a tacrolimus dose of less than 2 ng/dL. Renal function was comparable before and after conversion (mean serum creatinine was 1.25 ± 0.88 vs 1.23 ± 0.78 mg/dL; P = .9). The incidence of biopsy-proven acute rejection was 19.7% preconversion versus 4.2% postconversion. Graft and patient survival rates were comparable between the 2 tacrolimus formulations. Once-daily tacrolimus also had favorable effects on blood pressure, lipid profile, and glucose tolerance.

CONCLUSIONS

Conversion from conventional tacrolimus (twice daily) to once-daily tacrolimus may be a valuable option with comparable patient and graft survival and may lead to improved adherence that may be reflective of better long-term results. It should be considered for de novo immunosuppression among living-donor renal allotransplant recipients.

Safety and Efficacy of Reduced Prolonged-release Tacrolimus Exposure in De Novo Kidney Transplantation: A Randomized, Open-label, Pilot Study in Asia-OPTIMIZE Study

Background

A multicenter, randomized, open-label, parallel group, pilot, 52-week study in Asian countries that assessed the renal function, efficacy, and safety of reduced-exposure versus standard-exposure prolonged-release tacrolimus (PR-T) in adult kidney transplant recipients (KTRs).

Methods

Posttransplantation, KTRs received PR-T from weeks 0 to 4 (initial dose, 0.2-0.3 mg/kg; target trough level, 6-10 ng/mL). At week 4, KTRs were randomized (1:1) to receive reduced-exposure PR-T (target 4-6 ng/mL, weeks 4-12; 3-5 ng/mL, weeks 12-52) or standard-exposure PR-T (target: 6-10 ng/mL, weeks 4-52). Primary end point: estimated glomerular filtration rate (eGFR) over 52 weeks. Secondary end points (week 52) included creatinine clearance, serum creatinine, graft/patient survival, biopsy-confirmed acute rejection (AR), composite of graft loss/patient death/biopsy-confirmed AR, and steroid-resistant AR. Treatment-emergent adverse events were recorded.

Results

Sixty-six KTRs received PR-T (reduced-exposure, n = 32; standard-exposure, n = 34) and were analyzed. After per-protocol dose adjustment, mean ± standard deviation tacrolimus trough level was lower with reduced- versus standard-exposure PR-T (week 52, 4.5 ± 1.1 ng/mL vs 8.0 ± 2.2 ng/mL). In the reduced- versus standard-exposure group, eGFR was similar at weeks 8 to 52 (overall least-square mean difference, -2.82; 95% confidence interval, -7.91 to 2.27; P = 0.272). At week 52, there was no significant difference in creatinine clearance (P = 0.375) or serum creatinine (P = 0.547) between groups. All grafts/patients survived, no steroid-resistant AR was reported, and 4 and 3 patients had AR in reduced- and standard-exposure groups, respectively. Drug-related treatment-emergent adverse events were reported in 34.4% and 38.2% of patients, respectively.

Conclusions

Reducing exposure to PR-T resulted in a clinically acceptable short-term safety profile and was generally as effective as standard tacrolimus exposure for Asian patients.

Switch From Twice-daily Tacrolimus to Once-daily, Prolonged-release Tacrolimus in Kidney Transplantation: Long-term Outcome

BACKGROUND

One daily dose of tacrolimus (QDT) improves adherence in kidney transplant (KT) recipients. A switch from twice-daily tacrolimus (BDT) to QDT showed similar efficacy and safety.

METHODS

The aim of our study was to demonstrate the long-term efficacy and safety of switching from BDT to QDT in KT recipients. Preliminary results have already been published. Forty-one patients (34 men and 7 women), mean age at KT of 43.9 ± 12.7 years, underwent a 1:1 dose switch from BDT to QDT; the mean time from KT to switch was 36.6 ± 16.1 months. In our study population, 4 patients received a living donor KT and 2 received a second allograft.

RESULTS

The mean follow-up was 86.8 ± 13 months from the switch and 126.2 ± 22.3 months from KT. Graft and patient survival rates were 90.2% and 95.1%, respectively. All patients maintained stable renal function during follow-up. During the first 3 months after the switch we observed a significant decrease in tacrolimus blood level (P = .0001). No significant differences were observed regarding tacrolimus dose before and after QDT introduction (P = not significant [NS]). Fourteen patients who stopped steroids under BDT treatment and 16 patients who stopped steroids after the switch are currently steroid-free.

CONCLUSION

Our study showed safety and efficacy in switching from BDT to QDT. After early (<1 year) dose adjustment, tacrolimus blood levels remained stable throughout follow-up. Moreover, QDT represented a valid alternative for patients showing steroid side effects.

Clinical Evaluation of Modified Release and Immediate Release Tacrolimus Formulations

The science of drug delivery has evolved considerably and has led to the development of multiple sustained release formulations. Each of these formulations can present particular challenges in terms of clinical evaluation and necessitate careful study to identify their optimal use in practice. Tacrolimus is an immunosuppressive agent that is widely used in organ transplant recipients. However, it is poorly soluble, has an unpredictable pharmacokinetic profile subject to important genetic polymorphisms and drug-drug interactions, and has a narrow therapeutic index. For these reasons, it represents an agent that could benefit from modified release formulations to overcome these limitations. The objective of this review is to discuss the clinical evaluation of immediate and modified release tacrolimus formulations in renal transplant recipients. Clinical trials from early development of immediate release tacrolimus to formulation-specific post-marketing trials of modified release tacrolimus formulations are reviewed with an emphasis on key elements relating to trial design end endpoint assessment. Particular elements that can be addressed with formulation alterations, such as pharmacokinetics, pharmacogenomics, and toxicity and corresponding clinical evaluations are discussed. In addition, current knowledge gaps in the clinical evaluation of immediate and modified release tacrolimus formulations are discussed to highlight potential avenues for the future development of different tacrolimus formulations with outcomes relevant to the regulators, the transplant community, and to transplant recipients. This review shows that new formulations may alter tacrolimus bioavailability, alleviate certain adverse events while potentially enhancing patient convenience.

Immunosuppression for kidney transplantation: Where are we now and where are we going?

Advances in immunosuppression have propelled kidney transplantation from a scientific curiosity to the optimal treatment for patients with end stage kidney disease. Declining rates of acute rejection have led to improvements in short term kidney transplant survival, culminating in incrementally better long term patient and allograft outcomes. Contextualized around established immune-suppressing drug targets, this review summarizes the history of the clinical science and highlights the pivotal trials that have led to present-day treatment standards at the level of both individual agents and multidrug regimens for kidney recipients. Finally, recently approved and emerging therapies are discussed, with an emphasis on challenges faced by clinicians managing this increasingly complex patient population.