Generic immunosuppression in solid organ transplantation: systematic review and meta-analysis

Immunosuppression with Generics in Liver and Kidney Transplantation: A Real-World Evidence Study

Purpose

This study evaluates the use, benefit-risk profile, and economic impact of generic immunosuppressants (tacrolimus-TAC, cyclosporine-CsA, and mycophenolate-MYC) in kidney and liver transplant recipients compared to brand-name drugs.

Patients and Methods

A retrospective multicentre observational study, involving four Italian regions, was conducted based on the national transplant Information system and regional healthcare claims data. The analysis focused on incident patients who received kidney and liver transplants between 2013 and 2019 and evaluated the use of generic of CsA, TAC, and MYC during the 30-day period following discharge. For each type of transplant and immunosuppressive agent, the benefit-risk profile of generic vs branded drugs in a two-year window was estimated by multivariate Cox models (HR; 95% CI). Furthermore, the potential cost savings per person associated with one year of treatment using generics were calculated.

Results

The utilization of generic drugs showed a significant increase; over the study years, the proportion of users among kidney recipients ranged from 14.2% to 40.5% for TAC, from 36.9% to 56.7% for MYC, and from 18.2% to 94.7% for CsA. A great variability in generic uptake for region was found. A comparable risk-benefit profile between generic and branded formulations was shown for all immunosuppressors considered. Choosing generic immunosuppressants during maintenance could result in yearly savings of around 2000 euros per person for each therapy ingredient.

Conclusion

The study shows an increasing proportion of patients using generic immunosuppressive drugs over time suggesting a growing acceptance of generics within the transplant community and reveals comparable risk-benefit profiles between the generic and branded formulations of TAC, CsA, and MYC. A significant variability in the use of generics immunosuppressive agents was found both at the regional level and among transplant centers and future research should delve into regional prescribing variations.

Comparative safety of generic versus brand calcineurin inhibitors in solid organ transplant patients: a systematic review and meta-analysis

BACKGROUND

Although generic ciclosporin-A (CsA) and tacrolimus (TAC) have been used for the prophylaxis of organ rejection in transplant patients for decades, evidence in their safety profile compared to reference listed drugs (RLDs) in real-world transplant patients remains limited.

OBJECTIVES

To compare safety outcomes of generic CsA and TAC with the reference-listed drugs in solid organ transplant patients.

METHODS

We systematically searched MEDLINE, International Pharmaceutical Abstracts, PsycINFO, and Cumulative Index of Nursing and Allied Health Literature from inception until March 15, 2022, to select randomized and observational studies comparing safety profiles of generic versus brand CsA and TAC in de novo and/or stable solid organ transplant patients. Primary safety outcomes were changes in serum creatinine (Scr) and glomerular filtration rate (GFR). Secondary outcomes included incidences of infection, hypertension, diabetes, other serious adverse events (AEs), hospitalization, and death. Mean difference (MD) and relative risk (RR) with 95% confidence intervals (CIs) were calculated using random-effects meta-analyses.

RESULTS

Of 2612 publications identified, 32 studies met inclusion criteria. Seventeen studies had a moderate risk of bias. Scr was statistically significantly lower in patients using generic CsA compared to brand at 1 month (MD = -0.07; 95% CI: -0.11, -0.04), while there were no statistically significant differences at 4 months, 6 months, and 12 months. No differences were detected in Scr (MD = -0.04; 95% CI: -0.13, 0.04) and estimated GFR (MD = -2.06; 95% CI: -8.89, 4.77) between patients using generic and brand TAC at 6 months. No statistically significant differences between generic CsA and TAC with their RLDs were observed for secondary outcomes.

CONCLUSION

Findings support similarity in safety outcomes between generic and brand CsA and TAC in real-world solid organ transplant patients.

Generic switching: Do future physicians in Jordan have enough knowledge and a positive attitude?

Background: Generic switching is a policy that has shown success in minimising pharmaceutical costs. It has also been used to mitigate recurrent and sudden drug shortages. Not all countries have policies that allow pharmacists to switch to generic drugs independently. In Jordan, only pharmacists at Ministry of Health hospitals automatically switch to generics if doctors had not already done INN prescribing. Objectives: This study targeted medical students to assess their experience with generic switching as patients, their knowledge of the subject as students, and their attitude towards it as future prescribers and policymakers. Methods: This is a descriptive, cross-sectional study conducted online. Eligibility criteria were being a fourth, fifth, or sixth-year medical school student enrolled at any of the six Jordanian universities. The questionnaire was developed by the researchers after a careful review of the relevant literature. Results: Three hundred and ninety students responded to the online questionnaire. Most participants were females (244, 62.6%), senior students in their final (6th) year (162, 41.5%) and with very good academic achievement (166, 42.6%). The highest knowledge scores concerned patient rights (0.73/1.00), followed by knowledge about monitoring after generic switching (0.66/1.00), and patients with known drug allergies (0.66/1.00). Almost half of the participants believe that pharmacists should not be given the right to do generic switching and only 16% stated that they would choose generic drugs if they needed treatment in the future. Multivariate linear regression analysis showed that significant predictors of knowledge were gender, GPA, and family income. No correlations were found between participants' knowledge scores and their attitudes towards giving pharmacists the right to independently switch drugs, or whether they would accept a substitute from pharmacists rather than having to refer to the physician. Conclusion: Medical students in Jordan lack sufficient knowledge about generic switching. Students need to be more aware of the current policies and regulations of this practice, and the role of each healthcare worker involved in it. They also need to have a more positive attitude toward generic drugs and generic switching practice to facilitate its future implementation.

Islet allografts expressing a PD-L1 and IDO fusion protein evade immune rejection and reverse preexisting diabetes in immunocompetent mice without systemic immunosuppression

Allogeneic islet transplantation is a promising experimental therapy for poorly controlled diabetes. Despite pharmacological immunosuppression, long-term islet engraftment remains elusive. Here, we designed a synthetic fusion transgene coupling PD-L1 and indoleamine dioxygenase [hereafter PIDO] whose constitutive expression prevents immune destruction of genetically engineered islet allograft transplanted in immunocompetent mice. PIDO expressing murine islets maintain robust dynamic insulin secretion in vitro and when transplanted in allogeneic hyperglycemic murine recipients reverse pre-existing streptozotocin-induced and autoimmune diabetes in the absence of pharmacological immunosuppression for more than 50 and 8 weeks, respectively, and is dependent on host CD4 competence. Additionally, PIDO expression in allografts preserves endocrine functional viability of islets and promotes a localized tolerogenic milieu characterized by the suppression of host CD8 T cell and phagocyte recruitment and accumulation of FOXP3⁺ Tregs. Furthermore, in the canine model of xenogeneic islet transplantation, muscle implanted PIDO-expressing porcine islets displayed physiological glucose-responsive insulin secretion competency in euglycemic recipient for up to 20 weeks. In conclusion, the PIDO transgenic technology enables host CD4⁺ T cell-modulated immune evasiveness and long-term functional viability of islet allo- and xenografts in immune-competent recipients without the need for pharmacological immune suppression and would allow for improved outcomes for tissue transplantation.

An empirical evaluation of the impact scenario of pooling bodies of evidence from randomized controlled trials and cohort studies in medical research

BACKGROUND

Randomized controlled trials (RCTs) and cohort studies are the most common study design types used to assess treatment effects of medical interventions. We aimed to hypothetically pool bodies of evidence (BoE) from RCTs with matched BoE from cohort studies included in the same systematic review.

METHODS

BoE derived from systematic reviews of RCTs and cohort studies published in the 13 medical journals with the highest impact factor were considered. We re-analyzed effect estimates of the included systematic reviews by pooling BoE from RCTs with BoE from cohort studies using random and common effects models. We evaluated statistical heterogeneity, 95% prediction intervals, weight of BoE from RCTs to the pooled estimate, and whether integration of BoE from cohort studies modified the conclusion from BoE of RCTs.

RESULTS

Overall, 118 BoE-pairs based on 653 RCTs and 804 cohort studies were pooled. By pooling BoE from RCTs and cohort studies with a random effects model, for 61 (51.7%) out of 118 BoE-pairs, the 95% confidence interval (CI) excludes no effect. By pooling BoE from RCTs and cohort studies, the median I² was 48%, and the median contributed percentage weight of RCTs to the pooled estimates was 40%. The direction of effect between BoE from RCTs and pooled effect estimates was mainly concordant (79.7%). The integration of BoE from cohort studies modified the conclusion (by examining the 95% CI) from BoE of RCTs in 32 (27%) of the 118 BoE-pairs, but the direction of effect was mainly concordant (88%).

CONCLUSIONS

Our findings provide insights for the potential impact of pooling both BoE in systematic reviews. In medical research, it is often important to rely on both evidence of RCTs and cohort studies to get a whole picture of an investigated intervention-disease association. A decision for or against pooling different study designs should also always take into account, for example, PI/ECO similarity, risk of bias, coherence of effect estimates, and also the trustworthiness of the evidence. Overall, there is a need for more research on the influence of those issues on potential pooling.

An Italian multicentre distributed data research network to study the use, effectiveness, and safety of immunosuppressive drugs in transplant patients: Framework and perspectives of the CESIT project

The goal of post-transplant immunosuppressive drug therapy is to prevent organ rejection while minimizing drug toxicities. In clinical practice, a multidrug approach is commonly used and involves drugs with different mechanisms of action, including calcineurin inhibitors (CNI) (tacrolimus or cyclosporine), antimetabolite (antimet) (mycophenolate or azathioprine), inhibitors of mechanistic target of rapamycin (mTOR) (sirolimus or everolimus), and/or steroids. Although evidence based on several randomized clinical trials is available, the optimal immunosuppressive therapy has not been established and may vary among organ transplant settings. To improve the knowledge on this topic, a multiregional research network to Compare the Effectiveness and Safety of Immunosuppressive drugs in Transplant patients (CESIT) has been created with the financial support of the Italian Medicines Agency. In this article, we describe the development of this network, the framework that was designed to perform observational studies, and we also give an overview of the preliminary results that we have obtained. A multi-database transplant cohort was enrolled using a common data model based on healthcare claims data of four Italian regions (Lombardy, Veneto, Lazio, and Sardinia). Analytical datasets were created using an open-source tool for distributed analysis. To link the National Transplant Information System to the regional transplant cohorts, a semi-deterministic record linkage procedure was performed. Overall, 6,914 transplant patients from 2009–19 were identified: 4,029 (58.3%) for kidney, 2,219 (32.1%) for liver, 434 (6.3%) for heart, and 215 (3.1%) for lung. As expected, demographic and clinical characteristics showed considerable variability among organ settings. Although the triple therapy in terms of CNI + antimet/mTOR + steroids was widely dispensed for all settings (63.7% for kidney, 33.5% for liver, 53.3% for heart, and 63.7% for lung), differences in the active agents involved were detected. The CESIT network represents a great opportunity to study several aspects related to the use, safety, and effectiveness of post-transplant maintenance immunosuppressive therapy in real practice.

Evaluating agreement between bodies of evidence from randomized controlled trials and cohort studies in medical research: a meta-epidemiological study

BACKGROUND

Randomized controlled trials (RCTs) and cohort studies are the most common study design types used to assess the treatment effects of medical interventions. To evaluate the agreement of effect estimates between bodies of evidence (BoE) from randomized controlled trials (RCTs) and cohort studies and to identify factors associated with disagreement.

METHODS

Systematic reviews were published in the 13 medical journals with the highest impact factor identified through a MEDLINE search. BoE-pairs from RCTs and cohort studies with the same medical research question were included. We rated the similarity of PI/ECO (Population, Intervention/Exposure, Comparison, Outcome) between BoE from RCTs and cohort studies. The agreement of effect estimates across BoE was analyzed by pooling ratio of ratios (RoR) for binary outcomes and difference of mean differences for continuous outcomes. We performed subgroup analyses to explore factors associated with disagreements.

RESULTS

One hundred twenty-nine BoE pairs from 64 systematic reviews were included. PI/ECO-similarity degree was moderate: two BoE pairs were rated as "more or less identical"; 90 were rated as "similar but not identical" and 37 as only "broadly similar". For binary outcomes, the pooled RoR was 1.04 (95% CI 0.97-1.11) with considerable statistical heterogeneity. For continuous outcomes, differences were small. In subgroup analyses, degree of PI/ECO-similarity, type of intervention, and type of outcome, the pooled RoR indicated that on average, differences between both BoE were small. Subgroup analysis by degree of PI/ECO-similarity revealed high statistical heterogeneity and wide prediction intervals across PI/ECO-dissimilar BoE pairs.

CONCLUSIONS

On average, the pooled effect estimates between RCTs and cohort studies did not differ. Statistical heterogeneity and wide prediction intervals were mainly driven by PI/ECO-dissimilarities (i.e., clinical heterogeneity) and cohort studies. The potential influence of risk of bias and certainty of the evidence on differences of effect estimates between RCTs and cohort studies needs to be explored in upcoming meta-epidemiological studies.

Cyclosporin A alleviates trophoblast apoptosis and senescence by promoting autophagy in preeclampsia

INTRODUCTION

Abnormal extravillous trophoblast (EVT) function is closely related to preeclampsia (PE) and may be caused by inadequate autophagy, apoptosis, and senescence. Cyclosporin A (CsA) is an effective immunosuppressant that has been reported to stimulate autophagy and exert benign biological effects on EVTs. Therefore, we hypothesized that CsA may display therapeutic efficacy against PE by activating autophagy.

METHODS

We established the nitro-l-arginine methyl ester (l-NAME)-induced preeclamptic mice model and a hypoxia-reoxygenation (H/R) model in vitro. The effects of CsA on autophagy were evaluated by western blotting (WB). The effects of CsA on apoptosis were analyzed by Hematoxylin-eosin (H&E) staining, cell apoptosis assay and WB. Senescence-associated β-galactosidase (SA-β-gal) staining, RT-qPCR and WB were used to examine the senescence level. RT-qPCR were used to detect the senescence-associated secretory phenotype (SASP) level. DCFH-DA fluorescent probe, dihydroethidium (DHE) staining and mitochondrial membrane potential (ΔΨm) were used to detect senescence-associated mitochondrial dysfunction (SAMD).

RESULTS

CsA alleviated PE-like symptoms and reduced placental necrosis and senescence in mice injected with l-NAME. CsA ameliorated placental SASP and SAMD level induced by l-NAME. CsA also upregulated the expression of autophagic proteins in mouse placentas disrupted using l-NAME. In vitro, we found that CsA reversed H/R-induced apoptosis and senescence, as well as decreasing SASP and SAMD levels and upregulating autophagic proteins levels. Notably, 3-methyladenine (3-MA), an early phase inhibitor of autophagosome formation, abolished the protective effects of CsA against H/R.

DISCUSSION

CsA may display some therapeutic effects against PE by activating autophagy in vivo and in vitro.

Mycophenolate Mofetil Hepatotoxicity Associated With Mitochondrial Abnormality in Liver Transplant Recipients and Mice

OBJECTIVES

Mycophenolate mofetil (MMF) is a widely used immunosuppressive agent. MMF hepatotoxicity has been reported in non-transplant and renal transplant patients with minimal histologic description. This is the first study describing detailed histology and ultrastructure of MMF hepatotoxicity.

METHODS

Four liver-transplant recipients (Cases 1-4) were suspected to have MMF hepatotoxicity. Cases 1-3 (two females and one male; 4-17 years) had multiple biopsies for liver function test (LFT) abnormalities. Case 4 (female; 16 years) had a surveillance biopsy. Electron-microscopic examination (EM) was requested on Cases 1-3 for unexplained, persistent LFT elevation and histologic abnormalities despite therapy and Case 4 for unexplained histologic abnormalities despite a stable clinical course. To confirm the pathologic changes in the human allografts, livers from MMF-treated and untreated mice were also reviewed.

RESULTS

While the allograft biopsies showed nonspecific histologic changes, EM revealed unequivocal mitochondrial abnormalities similar to those seen in primary and secondary mitochondrial disorders. In Cases 1 and 2, LFTs improved after stopping and reducing MMF, respectively. In Case 3, pre- and post-MMF treatment biopsies were performed and only the post-MMF biopsy demonstrated mitochondrial abnormalities. Mitochondrial abnormality in Case 4 was subclinical. The mouse study confirmed that MMF caused various stress changes in the mitochondria; number of mitochondria/cell (mean ± standard deviation; untreated group: 58.25 ± 8.426; MMF-treated group: 76.37 ± 18.66), number of lipid droplets/cell (untreated: 0.9691 ± 1.150; MMF-treated: 3.649 ± 4.143) and sizes of mitochondria (μm, untreated: 0.8550 ± 0.3409; MMF-treated: 0.9598 ± 0.5312) were significantly increased in hepatocytes in the MMF-treated mice compared with the untreated mice (P < 0.0001).

CONCLUSIONS

Although MMF is safe for the majority of patients, MMF can cause mitochondrial stress, which may trigger more severe mitochondrial abnormalities in a small subset. MMF hepatotoxicity should be considered for MMF-treated patients with unexplained, persistent LFT abnormalities and nonspecific histologic findings. EM should be requested for these cases.

Mycophenolate mofetil versus azathioprine in kidney transplant recipients on steroid-free, low-dose cyclosporine immunosuppression (ATHENA): A pragmatic randomized trial

BACKGROUND

We compared protection of mycophenolate mofetil (MMF) and azathioprine (AZA) against acute cellular rejection (ACR) and chronic allograft nephropathy (CAN) in kidney transplant recipients on steroid-free, low-dose cyclosporine (CsA) microemulsion maintenance immunosuppression.

METHODS AND FINDINGS

ATHENA, a pragmatic, prospective, multicenter trial conducted by 6 Italian transplant centers, compared the outcomes of 233 consenting recipients of a first deceased donor kidney transplant induced with low-dose thymoglobulin and basiliximab and randomized to MMF (750 mg twice/day, n = 119) or AZA (75 to 125 mg/day, n = 114) added-on maintenance low-dose CsA microemulsion and 1-week steroid. In patients without acute clinical or subclinical rejections, CsA dose was progressively halved. Primary endpoint was biopsy-proven CAN. Analysis was by intention to treat. Participants were included between June 2007 and July 2012 and followed up to August 2016. Between-group donor and recipient characteristics, donor/recipient mismatches, and follow-up CsA blood levels were similar. During a median (interquartile range (IQR)) follow-up of 47.7 (44.2 to 48.9) months, 29 of 87 biopsied patients on MMF (33.3%) versus 31 of 88 on AZA (35.2%) developed CAN (hazard ratio (HR) [95% confidence interval (CI)]: 1.147 (0.691 to 1.904, p = 0.595). Twenty and 21 patients on MMF versus 34 and 14 on AZA had clinical [HR (95% CI): 0.58 (0.34 to 1.02); p = 0.057) or biopsy-proven subclinical [HR (95% CI): 1.49 (0.76 to 2.92); p = 0.249] ACR, respectively. Combined events [HR (95% CI): 0.85 (0.56 to 1.29); p = 0.438], patient and graft survival, delayed graft function (DGF), 3-year glomerular filtration rate (GFR) [53.8 (40.6;65.7) versus 49.8 (36.8;62.5) mL/min/1.73 m2, p = 0.50], and adverse events (AEs) were not significantly different between groups. Chronicity scores other than CAN predict long-term graft outcome. Study limitations include small sample size and unblinded design.

CONCLUSIONS

In this study, we found that in deceased donor kidney transplant recipients on low-dose CsA and no steroids, MMF had no significant benefits over AZA. This finding suggests that AZA, due to its lower costs, could safely replace MMF in combination with minimized immunosuppression.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00494741; EUDRACT 2006-005604-14.

Kinetics of generic tacrolimus in heart transplantation: A cautionary note

Tacrolimus is a core component of immunosuppressive regimens. This study compared active pharmaceutical ingredient (API) and dissolution kinetics of branded tacrolimus and formulations from three generic manufacturers (Mylan, Dr. Reddy's, Intas) including samples from patients who suffered acute cardiac allograft rejection. Generic samples showed similar API content compared to branded samples with no major impurities. Capsules that underwent uniformity testing had consistent capsule-to-capsule API. Dissolution testing showed similar profiles between branded tacrolimus and Mylan, but notable differences with Dr. Reddy's and Intas. The approximate maximal inhibitory concentration (IC₅₀) was highest in branded tacrolimus (29 minutes), followed by Mylan (26 minutes), Dr. Reddy's (19 minutes), and Intas (14 minutes) (Student-Newman-Keuls Multiple Comparisons Test; overall ANOVA: p = 0.0199, F = 6.469). This study suggests that the bioavailability of certain generic tacrolimus formulations peak significantly earlier than branded tacrolimus. Further study is needed to determine whether these differences are clinically relevant.

Differences in brand versus generic esmolol in the treatment of perioperative supraventricular tachycardia and hypertension: A pilot study

Background:

Once a patent expires, generic analogue drugs are alternatives to brand name drugs. Because bioequivalence/biodistribution problems have been reported for many generic analogue drugs, we prospectively evaluated 31 patients to reveal the differences in the doses used and the efficacy and adverse events of two different intravenous esmolol formulations.

Methods:

This was a prospective observational pilot study. Our aim was to reveal the possible differences in the required doses between two different formulations (brand name drug vs generic analogue drug) of intravenous esmolol in beats per minute, systolic blood pressure, diastolic blood pressure and mean arterial pressure in intra- and postoperative patients with supraventricular tachycardia and hypertension. The patients were categorised into two groups according to the medication they received (brand name drug or generic analogue drug).

Results:

Esmolol was given to 31 patients (16 generic analogue drug and 15 brand name drug). Although there was a statistically significant difference in bolus (mg/kg) and continued (mg/kg/h) drug dose used (brand name drug/generic analogue drug, mean (standard deviation), 0.3 (0.1) vs 0.38 (0.1), p = 0.03 for bolus dose, and 0.22 (0.09) vs 0.29 (0.08) for continued dose at 10 min (p = 0.03), 0.19 (0.06) vs 0.24 (0.05) at 20 min (p = 0.01) and 0.14 (0.05) vs 0.18 (0.05) at 30 min (p = 0.02)), there were no time-related statistical significant differences in the reduction rates of the two drugs (p = 0.47). There were no time-related statistically significant differences between the two groups in systolic blood pressure, diastolic blood pressure, mean arterial pressure and beats per minute, nor in their adverse events.

Conclusion:

In this pilot study, smaller doses were given for controlling the patient’s haemodynamics when a brand name drug was used. Because there were no significant time-related differences in the reduction rates of the two drugs nor in any haemodynamic differences between the two groups, optimal titration of the drug used could effectively control the patient’s haemodynamics. The adverse events were also similar in both groups.

The Efficacy of Outpatient Pulmonary Rehabilitation After Bilateral Lung Transplantation

PURPOSE

Pulmonary rehabilitation (PR) is advocated in the pre- and post-lung transplantation (LTx) periods. However, there is limited literature on the benefit of PR post-LTx. The aim of this study was to investigate the efficacy of an outpatient, multidisciplinary, comprehensive PR program in bilateral LTx recipients in the early period after LTx.

METHOD

Twenty-three LTx recipients were referred to the PR center. Change in incremental and endurance shuttle walk tests, hand and quadriceps strength, respiratory muscle strength (maximum inspiratory/expiratory pressure), dyspnea (Medical Research Council score), quality of life (St George's Respiratory Questionnaire, Chronic Respiratory Questionnaire), and psychological status (Hospital Anxiety Depression Scale) were compared pre- and post-PR.

RESULTS

Seventeen of 23 (74%) recipients completed PR, comprising 15 male and 2 female patients whose median age was 51 yr. The initiation of the program was 75 ± 15 d after LTx. The incremental shuttle walk test distance was predicted as 23% before PR and it increased to 36% after PR (P < .001); the endurance shuttle walk test distance also increased (P < .01). Significant improvement was seen in upper and lower extremity strength, and St George's Respiratory Questionnaire and Chronic Respiratory Questionnaire scores and Hospital Anxiety Depression Scale scores reflected less anxiety and depressive symptoms. Furthermore, body mass and fat-free mass indices, maximum inspiratory pressure, and maximum expiratory pressure improved significantly. There was no significant change in forced expiratory volume in the first second of expiration, forced vital capacity, or Medical Research Council scores.

CONCLUSION

This study demonstrated that patients who attended PR within 3 mo of bilateral LTx showed improvements in exercise capacity, respiratory muscle strength, quality of life, body composition, and psychological status.

Meeting Regulatory Requirements for Drugs with a Narrow Therapeutic Index: Bioequivalence Studies of Generic Once-Daily Tacrolimus

Despite growing clinical confidence in generics and their potential to reduce long-term healthcare costs, the transplant community have had real concerns about the use of generic immunosuppressants. One such immunosuppressant is tacrolimus, a cornerstone of lifelong treatment for patients who have undergone a solid organ transplant. Tacrolimus has a narrow therapeutic index (NTI), giving rise to questions about the potential for clinically relevant altered drug exposure. Its use in transplant patients also gives rise to questions about the most discriminative subject population for bioequivalence studies. The recognised need for stringent criteria to support approval of generic drugs with an NTI led the European Medicines Association and Health Canada to provide detailed information on requirements for bioequivalence studies and introduce tighter bioequivalence limits for these drugs, including tacrolimus. The aim of this article is to illustrate how regulatory guidance is implemented during the clinical development of generic immunosuppressants, using a generic, once-daily prolonged-release formulation of tacrolimus as an example.

Oral generic tacrolimus initiation and substitution in the Medicaid population: a new user cohort study

OBJECTIVE

Although existing studies have compared clinical efficacy and pharmacokinetics of generic with brand tacrolimus, little is known about generic tacrolimus utilization patterns or factors predicting generic substitution. This study examines associations between patient-level factors and generic tacrolimus initiation or substitution among new users of oral generic or brand-name tacrolimus.

METHODS

This new user retrospective cohort study identified 374 beneficiaries who initiated generic or brand tacrolimus treatment, using 100% Medicaid administrative claims data from 11 states in 2011-2012. Outcomes were generic tacrolimus initiation and substitution within 12 months of treatment initiation. Multivariable logistic regression and Cox proportional hazards models were used to identify factors associated with generic tacrolimus initiation and substitution.

RESULTS

Two-thirds of oral tacrolimus new users initiated generic tacrolimus. Patients who were older age and black were significantly more likely to initiate generic tacrolimus (adjusted odds ratio [AOR] = 1.02, 95% confidence interval [CI] = 1.001-1.03; AOR = 2.54, 95% CI = 1.40-4.62; respectively). Patients with more concomitant prescriptions, more comorbidities, or higher initial daily dosage had significantly lower likelihoods of initiating generic tacrolimus (AOR = 0.93, 95% CI = 0.87-0.99; AOR = 0.87, 95% CI = 0.77-0.99; AOR = 0.96, 95% CI = 0.93-0.993). Among brand tacrolimus new users, 23.6% substituted with generics within 12 months, and an addition of prior hospitalization or unit of initial daily dosage increment was associated with 35% (subdistribution hazard ratio [SHR] = 1.35, 95% CI = 1.02-1.76) or 2% (SHR = 1.02, 95% CI = 1.00-1.04) increase in likelihood of generic substitution, respectively.

CONCLUSIONS

Understanding associations between patient-level factors with generic tacrolimus initiation and substitution could help practitioners and policymakers monitor treatment effect and facilitate generic tacrolimus utilization.

Real-life Bioequivalence of Tacrolimus in Patients With Living-Related Donor De Novo Renal Transplantation: An Observational Study

Tacrolimus is a narrow therapeutic index drug. As a result, regulatory agencies worldwide recommend stringent bioequivalence evaluation criteria for approval of generics. Despite this, the professional transplantation societies have raised concerns over the safety and efficacy of generic substitutions. We conducted this pragmatic real-life bioequivalence study to assess the effect of generic substitutions of tacrolimus. This was an observational study including recipients of renal transplantation who were considered for generic medication substitution. Transplanted organs were from living-related donors and were performed at least 1 month before the study. Time of administration of the drug, time of dosing with respect to meals, and time of blood sample collection were controlled; however, the lot number of the generic drugs was not controlled. The participants were allowed to use their usual supplies irrespective of the lot number. Concentration (C₀) was quantified by liquid chromatography with tandem mass spectrometry after the generic substitution from ABC brand to XYZ brand. The average C₀ ± SD with generic ABC was 11.09 ± 4.26 ng/mL and generic ABC was 9.7 ± 4.12 ng/mL. Though there was no statistically significant difference observed between the concentrations, when the individual patient data was examined, 2 patients were found to have a very high concentration of tacrolimus and at least 7 patients fell below the therapeutic range. These derangements called for retitration with the new generic tacrolimus (40%). The results of our study suggest that generic-to-generic substitutions should be carried out very carefully in a closely observed setting in patients with renal transplants. The strength of our study is that it matched the real clinical practice setting as much as possible unlike a bioequivalence study. Therefore, we recommend repeating C₀ at least 3 times over a period of 7 to 10 days with a generic substitution to prevent untoward consequences.

Immunosuppression with generic tacrolimus in liver and kidney transplantation-systematic review and meta-analysis on biopsy-proven acute rejection and bioequivalence

While rejection prevention with innovator tacrolimus (Tac) is one of the key factors for long-lasting graft function, the use of generic Tac is still under debate. Thus, we performed a systematic review and meta-analysis to provide an overview on the current body of evidence for the effect of generic Tac in adult liver (LT) and kidney transplantation (KT) with focus on both biopsy-proven acute rejection (BPAR) and bioequivalence. A systematic literature search for trials comparing generic versus innovator Tac was conducted accordingly. Seventeen studies (5 LT, 11 KT, 1 LT/KT) including 1412 patients were identified. About 92.9% (13/14; 5/5 LT, 8/9 KT) of studies reported the same or lower BPAR with generics (pooled RR: 0.84, 95% CI: 0.65-1.09); however, de novo studies showed a significantly lower risk with generic Tac (RR: 0.75, 95% CI: 0.63-0.90), whereas conversion studies showed increased risk (RR: 1.93, 95% CI: 1.00-3.70). Bioequivalence was demonstrated primarily in studies on conversion. The current evidence is mostly based on observational data and studies showing some risk of bias. In conclusion, whereas overall there was no significant difference in terms of BPAR, there is some evidence suggesting lower BPAR risk with generic Tac for de novo use.

Generic Tacrolimus (Tacrobell®) Shows Comparable Outcomes to Brand-Name Tacrolimus in the Long-Term Period After Adult Deceased Donor Liver Transplantation

Background

Generic tacrolimus (Tacrobell^®) is commonly used in liver transplant patients in Korea. No previous studies have assessed the long-term efficacy and safety of generic tacrolimus for adult deceased donor liver transplantation (DDLT) patients. The aim of the present study was to evaluate the long-term efficacy and safety of generic tacrolimus compared to brand-name tacrolimus (Prograf^®) in adult DDLT recipients.

Methods

Two hundred sixty-five adult DDLTs were performed in our center between 2003 and 2017. To determine the efficacy and safety of generic tacrolimus, renal function (estimated glomerular filtration rate [eGFR] and creatinine), infectious complications, rejection-free survival rates, and patient survival rates were investigated.

Results

Of 265 patients, 193 were selected and divided into a generic tacrolimus group (n=147) and a brand-name group (n=46). Mean follow-up duration was 63.2 ± 44.3 months. The 1-year, 3-year, 5-year, and 10-year patient survival rates were 89.1%, 86.9%, 84.5%, and 75.2%, respectively, in the generic tacrolimus group and 95.7%, 88.9%, 86.3%, and 83.7% in the brand-name tacrolimus group. There were no statistically significant differences in the infectious complications, new-onset diabetes, and renal dysfunction included mean serum creatinine level or eGFR after DDLT between the two groups. Increased recipient age, continuous renal replacement therapy (CRRT) in the pre-transplant phase, and acute rejection were predisposing factors for patient death.

Conclusion

The present study shows that generic tacrolimus is an alternative comparable to brand-name tacrolimus in adult DDLT patients.

Limited sampling strategy to predict the area under the curve of tacrolimus in Mexican renal transplant pediatric patients receiving Prograf® or non-innovator formulations

TDM of tacrolimus is usually performed with trough levels (C_0h ). However, in pediatric patients, C_0h may not be an adequate marker. The AUC is considered a more suitable indicator of drug exposure. As several blood samples are needed for the estimation of AUC, and LSS for predicting tacrolimus AUC and optimizing the dose adjustment have been proposed. Moreover, in emerging countries such as Mexico, non-innovator formulations, which bioequivalence has not been demonstrated, are frequently used. Hence, the aim of this study was to develop and validate a LSS to predict the tacrolimus AUC_0-12h in Mexican pediatric kidney transplant recipients who received either Prograf^® or non-innovator tacrolimus formulations. A total of 56 pharmacokinetic profiles were randomized into two groups: model development (n = 28) and model validation (n = 28). The limited sampling equations were obtained after a stepwise multiple regression using AUC as the dependent variable and tacrolimus blood concentrations, quantified by CMIA, at different time points as the independent variables. The final equation included observed concentrations at 1 hour (C_1h ) and 4 hours (C_4h ) after dose administration. The predictive performance of the model was adequate in terms of both, bias and precision. Results strongly suggest that the clinical use of this LSS could provide an ethical, cost-, and time-effective method in the TDM of tacrolimus in pediatric patients with kidney transplant. The model proved to be adequate with either Prograf^® or non-innovator tacrolimus formulations of dubious bioequivalence.

The Association of Tacrolimus Formulation Switching with Trough Concentration Variability: A Retrospective Cohort Study of Tacrolimus Use Post-Kidney Transplantation Based on National Drug Code (NDC) Numbers

INTRODUCTION

It was hypothesized that patients experiencing at least one tacrolimus formulation switch may require more frequent therapeutic drug monitoring, subsequent dose adjustments, and a potential for untoward clinical outcomes than patients who remain on a single formulation.

METHODS

Eligible patients were adult kidney transplant recipients with stable renal function at month 3 post-transplant and no evidence of acute rejection, receiving an oral, tacrolimus-based regimen. Patients were categorized into two groups (fixed or variable formulation) using the US National Drug Code (NDC) on the basis of tacrolimus formulation usage over the 12-month period.

RESULTS

A total of 305 patients were enrolled from four US transplant centers; 44 (14.4%) received multiple formulations and 261 (85.6%) received a single formulation. Mean number of tacrolimus dose adjustments and mean cumulative milligram dose change were not statistically different between the two groups. Mean trough-to-dose ratio, frequency of trough level measurements, and mean number of excursions above 120% or below 80% of the patient's mean trough concentration were significantly higher in the variable compared to the fixed formulation group.

CONCLUSION

A variable tacrolimus formulation regimen was associated with a higher frequency of trough level measurements and a greater number of excursions in trough levels compared with continuing on a fixed formulation regimen of tacrolimus in this retrospective chart review study.

FUNDING

Astellas Pharma Global Development, Inc. Plain language summary available for this article.

Generic Substitution of Orphan Drugs for the Treatment of Rare Diseases: Exploring the Potential Challenges

Generic drugs are important components of measures introduced by healthcare regulatory authorities to reduce treatment costs. In most patients and conditions the switch from a branded drug to its generic counterpart is performed with no major complications. However, evidence from complex diseases suggests that generic substitution requires careful evaluation in some settings and that current bioequivalence criteria may not always be adequate for establishing the interchangeability of branded and generic products. Rare diseases, also called orphan diseases, are a group of heterogeneous diseases that share important characteristics: in addition to their scarcity, most are severe, chronic, highly debilitating, and often present in early childhood. Finding a treatment for a rare disease is challenging. Thanks to incentives that encourage research and development programs in rare diseases, several orphan drugs are currently available. The elevated cost of orphan drugs is a highly debated issue and a cause of limited access to treatment for many patients. As patent protection and the exclusivity period of several orphan drugs will expire soon, generic versions of orphan drugs should reach the market shortly, with great expectations about their impact on the economic burden of rare diseases. However, consistent with other complex diseases, generic substitution may require thoughtful considerations and may be even contraindicated in some rare conditions. This article provides an overview of rare disease characteristics, reviews reports of problematic generic substitution, and discusses why generic substitution of orphan drugs may be challenging and should be undertaken carefully in rare disease patients.

Establishing a Core Outcome Measure for Graft Health: A Standardized Outcomes in Nephrology-Kidney Transplantation (SONG-Tx) Consensus Workshop Report

BACKGROUND

Graft loss, a critically important outcome for transplant recipients, is variably defined and measured, and incompletely reported in trials. We convened a consensus workshop on establishing a core outcome measure for graft loss for all trials in kidney transplantation.

METHODS

Twenty-five kidney transplant recipients/caregivers and 33 health professionals from 8 countries participated. Transcripts were analyzed thematically.

RESULTS

Five themes were identified. "Graft loss as a continuum" conceptualizes graft loss as a process, but requiring an endpoint defined as a discrete event. In "defining an event with precision and accuracy," loss of graft function requiring chronic dialysis (minimum, 90 days) provided an objective and practical definition; retransplant would capture preemptive transplantation; relisting was readily measured but would overestimate graft loss; and allograft nephrectomy was redundant in being preceded by dialysis. However, the thresholds for renal replacement therapy varied. Conservative management was regarded as too ambiguous and complex to use routinely. "Distinguishing death-censored graft loss" would ensure clarity and meaningfulness in interpreting results. "Consistent reporting for decision making" by specifying time points and metrics (ie time to event) was suggested. "Ease of ascertainment and data collection" of the outcome from registries could support use of registry data to efficiently extend follow-up of trial participants.

CONCLUSIONS

A practical and meaningful core outcome measure for graft loss may be defined as chronic dialysis or retransplant, and distinguished from loss due to death. Consistent reporting of graft loss using standardized metrics and time points may improve the contribution of trials to decision making in kidney transplantation.

Effect of Systematic Conversion to Generic Mycophenolate Mofetil (MMF) in Kidney Transplantation: A Single-Center Clinical Experience from Japan

INTRODUCTION

Recently, more and more generic drugs have been used for immunosuppressive drugs in the field of organ transplantation. Some reports have indicated that blood concentration of most generic drugs is difficult to maintain stability, and it may cause the difference in graft survival of transplanted organs between original drugs and generic drugs. In this article, we report the cases could not maintain blood concentration of generic drugs of mycophenolate mofetil (MMF).

RESULTS

In 4 cases out of 5 cases that we had to change original MMF to generic MMF, there were cases that blood concentration level was not stabilized. There were possibility that the lowered blood concentration level of MMF caused a rejection, in two cases. Mean MMF trough level was decreased from 3.6 ± 1.9 μg/mL to 0.6 ± 0.4 μg/mL. Due to the early detection, it did not become severe or failure of graft function, however, we cannot deny the possibilities that side effects were increased and rejection rose. In these cases, we discontinued to use the generic drugs thereafter due to unstable plasma concentration of MMF.

DISCUSSION

Some reports have indicated that failure to maintain plasma concentration of MMF leads to rejection. Therefore, maintenance of effective plasma concentration and prevention of rejection are essential to long-term graft survival in kidney transplant.

CONCLUSION

Generic drug formulations may exhibit differences in effects and absorption compared to the brand-name drug. If the generic drug should be used, patients should be closely monitored.

Primary versus secondary source of data in observational studies and heterogeneity in meta-analyses of drug effects: a survey of major medical journals

Background

The data from individual observational studies included in meta-analyses of drug effects are collected either from ad hoc methods (i.e. “primary data”) or databases that were established for non-research purposes (i.e. “secondary data”). The use of secondary sources may be prone to measurement bias and confounding due to over-the-counter and out-of-pocket drug consumption, or non-adherence to treatment. In fact, it has been noted that failing to consider the origin of the data as a potential cause of heterogeneity may change the conclusions of a meta-analysis. We aimed to assess to what extent the origin of data is explored as a source of heterogeneity in meta-analyses of observational studies.

Methods

We searched for meta-analyses of drugs effects published between 2012 and 2018 in general and internal medicine journals with an impact factor > 15. We evaluated, when reported, the type of data source (primary vs secondary) used in the individual observational studies included in each meta-analysis, and the exposure- and outcome-related variables included in sensitivity, subgroup or meta-regression analyses.

Results

We found 217 articles, 23 of which fulfilled our eligibility criteria. Eight meta-analyses (8/23, 34.8%) reported the source of data. Three meta-analyses (3/23, 13.0%) included the method of outcome assessment as a variable in the analysis of heterogeneity, and only one compared and discussed the results considering the different sources of data (primary vs secondary).

Conclusions

In meta-analyses of drug effects published in seven high impact general medicine journals, the origin of the data, either primary or secondary, is underexplored as a source of heterogeneity.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0561-3) contains supplementary material, which is available to authorized users.

The adoption of generic immunosuppressant medications in kidney, liver, and heart transplantation among recipients in Colorado or nationally with Medicare part D

The transplant community is divided regarding whether substitution with generic immunosuppressants is appropriate for organ transplant recipients. We estimated the rate of uptake over time of generic immunosuppressants using US Medicare Part D Prescription Drug Event (PDE) and Colorado pharmacy claims (including both Part D and non-Part D) data from 2008 to 2013. Data from 26 070 kidney, 15 548 liver, and 6685 heart recipients from Part D, and 1138 kidney and 389 liver recipients from Colorado were analyzed. The proportions of patients with PDEs or claims for generic and brand-name tacrolimus or mycophenolate mofetil were calculated over time by transplanted organ and drug. Among Part D kidney, liver, and heart beneficiaries, the proportion dispensed generic tacrolimus reached 50%-56% at 1 year after first generic approval and 78%-81% by December 2013. The proportion dispensed generic mycophenolate mofetil reached 70%-73% at 1 year after generic market entry and 88%-90% by December 2013. There was wide interstate variability in generic uptake, with faster uptake in Colorado compared with most other states. Overall, generic substitution for tacrolimus and mycophenolate mofetil for organ transplant recipients increased rapidly following first availability, and utilization of generic immunosuppressants exceeded that of brand-name products within a year of market entry.

Generic immunosuppressants

Immunosuppressive drugs for solid organ transplantation are critical dose drugs with a narrow therapeutic index. Many of the most commonly used innovator drugs are off patent and have been replicated by generic counterparts, often at substantial cost-savings to the patient. However, serious adverse events caused by the transition from innovator to generic medications, specifically in pediatric solid organ transplant recipients, have questioned these autosubstitutions. The purpose of this review is to summarize the criteria set forth by the regulatory bodies, and to examine how major immunosuppressive drugs conform to these recommendations. Regulatory bodies have established inconsistent criteria to demonstrate bioequivalence between innovator and generic medications, causing approved generic variations to have varying levels of equivalence with the innovator drugs. In order to minimize the risk for under-immunosuppression, the following recommendations have been concluded. Brand prescribing of cyclosporine and tacrolimus are recommended due to evidence of adverse events after conversion to generic formulations and differences in dissolution parameters. Mycophenolate mofetil (MMF) shows better bioequivalence between innovator and generic formulations, however caution should be advised when switching between formulations. The institution of 'innovator only' policies may be appropriate at this time in order to minimize the risk of under-immunosuppressing patients until the evidence of more stringent bioequivalence has been established.

Comparison of clinical effects, trough and peak levels between branded and generic formulation of Cyclosporine in stable psoriatic patients

BACKGROUND

Cyclosporine A (CyA) is a drug for moderate-to-severe psoriasis. Recently, a generic formulation has been approved as bioequivalent to the branded one. The guidelines for the bioequivalence for critical-dose drugs with a narrow therapeutic range, such as CyA, are questionable. Therefore, it is important to assess the clinical outcome and the pharmacokinetics of different formulations in various patient groups. The current literature lacks of this information in dermatology. The primary objective of this prospective study is to investigate the clinical equivalence (in terms of maintenance of clinical effect) between the generic formulation of CyA and its branded one in patients with psoriasis. A secondary objective is to analyze their trough (C<inf>0</inf>) and peak levels (C<inf>2</inf>).

METHODS

Twenty patients with stable psoriasis under treatment with the branded CyA were monitored in terms of clinical efficacy (psoriasis area severity index, PASI), safety (laboratory values), and their pharmacokinetics utilizing trough (C<inf>0</inf>) and peak plasma concentration (C<inf>2</inf>). The same patients were subsequently shifted to the generic formulation for comparison.

RESULTS

In our sample the efficacy of the two formulations was equal in most cases (P=0.863). A non-significant difference between the C<inf>0</inf> and C<inf>2</inf> of the branded CyA compared to the generic one emerged (respectively P=0.738 and P=0.695).

CONCLUSIONS

The branded and the generic formulations of CyA seem to be not only bioequivalent, but also comparable in terms of clinical efficacy in patients with psoriasis. However, larger samples are required to confirm these findings.

[The use of generics in transplantation: Towards rational and safe solutions!]

Generic immunosuppressive drugs are available in Europe Canada and the United States. Between countries, there are large differences in penetration of generic drugs in general, and for immunosuppressive drugs in particular. The registration for generic immunosuppressive drugs are slightly different, but the criteria for registration of narrow therapeutic index drugs and bioequivalence studies, performed only in healthy volunteers, will remain in the medical landscape. About 50 studies compare the clinical efficacy and bioequivalence of the generic immunosuppressive drugs in patients with solid organ transplants. To allow for safe substitution, a number of criteria need to be fulfilled. Consensus statements were made by most transplant organizations. Authorities and payers should refrain from forcing pharmacists to dispense generic drugs in patients on maintenance immunosuppressive treatment. Generic substitution could be safe if realized by the treating physician, for a well-informed patient. Substitution must be followed by control visits to check if the patient is taking the medication correctly and if the drug exposure, through a close monitoring, remains stable. Substitution from one generic to another generic should be avoided, in all cases.

Comparison of the long-term efficacy and safety of generic tacrolimus, Tacrobell, with Prograf in liver transplant recipients

Introduction

The purpose of this study was to compare the safety and efficacy of generic tacrolimus (Tacrobell [TCB]) and a reference tacrolimus (Prograf [PGF]) in liver transplant recipients.

Patients and methods

We retrospectively analyzed 167 patients who used TCB or PGF between January 2009 and March 2016 for >1 year (TCB group, n=86; PGF group, n=81). To assess the efficacy and safety of TCB, we evaluated the relationship between drug dose and trough level, survival, rejection, infection, kidney function, and side effects.

Results

There was no difference in the preoperative demographics between the two groups. Moreover, there was no difference in the drug dose and trough level between the groups at 1 week after surgery. Coefficient of variation (CV) values were obtained at the drug trough level for each patient and no differences in CV values were identified within 1 year (p=0.587) and up to 5 years (p=0.824) in both groups. Rehospitalization (p=0.1) and total rejection (p=0.915) did not differ between the two groups, but the rejection severity, recorded as the rejection activity index value, was worse in the PGF group (p=0.039). No difference was found in the infection rate (p=0.818), and with regard to nephrotoxicity, there was no difference in the rate of patients with chronic kidney disease stage 3 and above during the follow-up period. No differences were found between the two groups in terms of drug side effects and adverse events.

Conclusion

The generic tacrolimus, TCB, is a comparable alternative to the original tacrolimus, PGF, as a main immunosuppressive drug for liver transplantation.

Performance of the Dimension TAC assay and comparison of multiple platforms for the measurement of tacrolimus

BACKGROUND

Therapeutic monitoring of tacrolimus is essential for reducing organ rejection and adverse effects. The measurement of tacrolimus in whole blood is taken by many automated platforms. We evaluated the analytical performance of the Dimension TAC assay, which is an upgraded reagent from the previous Dimension TACR assay.

METHODS

The evaluations involved determination of precision, linearity, detection capability, and reagent lot-to-lot variability between three lot numbers. Correlation studies were conducted using the Dimension TACR assay, Architect, Elecsys assay, and MassTrak LC-MS/MS.

RESULTS

The total coefficient of variation was below 10%. Acceptable linearity was observed in their respective reportable ranges. The limit of blank, limit of detection, and limit of quantification were 0.29, 0.47, and 0.81 ng/mL, respectively. Correlation analysis indicated that the Dimension TAC assay results were comparable to that of the Dimension TACR assay, Architect, and Elecsys results in liver and heart transplant patients. In kidney transplant patients, the Dimension TAC assay showed the poor correlation with Architect and Elecsys. The results from these assays were slightly higher than that of MassTrak. We found little lot-to-lot reagent variation among the reagents evaluated.

CONCLUSION

The overall analytical performance of the Dimension TAC assay is acceptable for therapeutic monitoring in clinical practice. Our study that compared different platforms may provide some useful information regarding which test method to use.

Bioequivalence between innovator and generic tacrolimus in liver and kidney transplant recipients: A randomized, crossover clinical trial

BACKGROUND

Although the generic drug approval process has a long-term successful track record, concerns remain for approval of narrow therapeutic index generic immunosuppressants, such as tacrolimus, in transplant recipients. Several professional transplant societies and publications have generated skepticism of the generic approval process. Three major areas of concern are that the pharmacokinetic properties of generic products and the innovator (that is, "brand") product in healthy volunteers may not reflect those in transplant recipients, bioequivalence between generic and innovator may not ensure bioequivalence between generics, and high-risk patients may have specific bioequivalence concerns. Such concerns have been fueled by anecdotal observations and retrospective and uncontrolled published studies, while well-designed, controlled prospective studies testing the validity of the regulatory bioequivalence testing approach for narrow therapeutic index immunosuppressants in transplant recipients have been lacking. Thus, the present study prospectively assesses bioequivalence between innovator tacrolimus and 2 generics in individuals with a kidney or liver transplant.

METHODS AND FINDINGS

From December 2013 through October 2014, a prospective, replicate dosing, partially blinded, randomized, 3-treatment, 6-period crossover bioequivalence study was conducted at the University of Cincinnati in individuals with a kidney (n = 35) or liver transplant (n = 36). Abbreviated New Drug Applications (ANDA) data that included manufacturing and healthy individual pharmacokinetic data for all generics were evaluated to select the 2 most disparate generics from innovator, and these were named Generic Hi and Generic Lo. During the 8-week study period, pharmacokinetic studies assessed the bioequivalence of Generic Hi and Generic Lo with the Innovator tacrolimus and with each other. Bioequivalence of the major tacrolimus metabolite was also assessed. All products fell within the US Food and Drug Administration (FDA) average bioequivalence (ABE) acceptance criteria of a 90% confidence interval contained within the confidence limits of 80.00% and 125.00%. Within-subject variability was similar for the area under the curve (AUC) (range 12.11-15.81) and the concentration maximum (Cmax) (range 17.96-24.72) for all products. The within-subject variability was utilized to calculate the scaled average bioequivalence (SCABE) 90% confidence interval. The calculated SCABE 90% confidence interval was 84.65%-118.13% and 80.00%-125.00% for AUC and Cmax, respectively. The more stringent SCABE acceptance criteria were met for all product comparisons for AUC and Cmax in both individuals with a kidney transplant and those with a liver transplant. European Medicines Agency (EMA) acceptance criteria for narrow therapeutic index drugs were also met, with the only exception being in the case of Brand versus Generic Lo, in which the upper limits of the 90% confidence intervals were 111.30% (kidney) and 112.12% (liver). These were only slightly above the upper EMA acceptance criteria limit for an AUC of 111.11%. SCABE criteria were also met for the major tacrolimus metabolite 13-O-desmethyl tacrolimus for AUC, but it failed the EMA criterion. No acute rejections, no differences in renal function in all individuals, and no differences in liver function were observed in individuals with a liver transplant using the Tukey honest significant difference (HSD) test for multiple comparisons. Fifty-two percent and 65% of all individuals with a kidney or liver transplant, respectively, reported an adverse event. The Exact McNemar test for paired categorical data with adjustments for multiple comparisons was used to compare adverse event rates among the products. No statistically significant differences among any pairs of products were found for any adverse event code or for adverse events overall. Limitations of this study include that the observations were made under strictly controlled conditions that did not allow for the impact of nonadherence or feeding on the possible pharmacokinetic differences. Generic Hi and Lo were selected based upon bioequivalence data in healthy volunteers because no pharmacokinetic data in recipients were available for all products. The safety data should be interpreted in light of the small number of participants and the short observation periods. Lastly, only the 1 mg tacrolimus strength was utilized in this study.

CONCLUSIONS

Using an innovative, controlled bioequivalence study design, we observed equivalence between tacrolimus innovator and 2 generic products as well as between 2 generic products in individuals after kidney or liver transplantation following current FDA bioequivalence metrics. These results support the position that bioequivalence for the narrow therapeutic index drug tacrolimus translates from healthy volunteers to individuals receiving a kidney or liver transplant and provides evidence that generic products that are bioequivalent with the innovator product are also bioequivalent to each other.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01889758.

Nationwide conversion to generic tacrolimus in pediatric kidney transplant recipients

BACKGROUND

Bioequivalence between Tacrolimus Prograf® and generic tacrolimus formulations has been demonstrated in adult populations, however clinical experience and safety data regarding generic tacrolimus in pediatric transplant recipients is limited. This study aimed to evaluate conversion from Tacrolimus Prograf® to Sandoz® in pediatric renal transplant recipients nationwide. The primary outcome was a change in mean trough tacrolimus concentration. Additionally, changes in tacrolimus intra-patient coefficient of variation (CoV), allograft function, requirement for dose adjustments, and episodes of biopsy-proven rejection were evaluated.

METHODS

Retrospective cohort study in 37 pediatric renal transplant recipients who switched to Tacrolimus Sandoz®. Each patient had three pre-conversion tacrolimus trough and creatinine concentrations within the 4 months prior and three post-conversion concentrations on day 3, 10, and the next subsequent level. Mean pre- and post-conversion tacrolimus trough concentrations and glomerular filtration rate (eGFR) were calculated. Tacrolimus concentration, CoV, and creatinine differences were compared by paired t test.

RESULTS

Thirty-seven patients (41% females, age 3-18 years) were included. Average intra-patient difference in trough tacrolimus concentration was 0.05μg/l (95% CI -0.37 to 0.47). Average intra-patient difference in eGFR was -1.20 ml/min/1.73² (95% CI -3.53 to 1.13). Three patients had acute rejection during 12 months post-conversion compared to none during 12 months pre-conversion.

CONCLUSIONS

Pediatric renal transplant recipients can be converted from Tacrolimus Prograf® to Sandoz® with negligible change in trough concentration, dose adjustments, or immediate allograft function. Of concern was the number of acute rejection episodes, however non-adherence contributed to at least one episode and this difference was determined clinically and statistically not significant.

Bioequivalence of twice-daily oral tacrolimus in transplant recipients: More evidence for consensus?

In this Perspective on the clinical trial by Rita Alloway and colleagues, Simon Ball explains the benefits to healthcare systems and individual patients of the bioequivalence established between generic and brand-name formulations of an immunosuppressive drug in transplant recipients.

Practical Recommendations for Long-term Management of Modifiable Risks in Kidney and Liver Transplant Recipients: A Guidance Report and Clinical Checklist by the Consensus on Managing Modifiable Risk in Transplantation (COMMIT) Group

Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs available for transplant. The clinical transplant community needs to identify and manage those patient modifiable factors, to decrease the risk of graft failure, and improve longer-term outcomes.COMMIT was formed in 2015 and is composed of 20 leading kidney and liver transplant specialists from 9 countries across Europe. The group's remit is to provide expert guidance for the long-term management of kidney and liver transplant patients, with the aim of improving outcomes by minimizing modifiable risks associated with poor graft and patient survival posttransplant.The objective of this supplement is to provide specific, practical recommendations, through the discussion of current evidence and best practice, for the management of modifiable risks in those kidney and liver transplant patients who have survived the first postoperative year. In addition, the provision of a checklist increases the clinical utility and accessibility of these recommendations, by offering a systematic and efficient way to implement screening and monitoring of modifiable risks in the clinical setting.

Cyclosporine A attenuates cardiac dysfunction induced by sepsis via inhibiting calcineurin and activating AMPK signaling

The aim of the present study was to investigate whether cyclosporine A (CSA) improved cardiac dysfunction at an early stage of sepsis. Male Wistar rats were randomly divided into the following three groups: the sham‑operated control group, the cecal ligation puncture (CLP) procedure‑induced sepsis group and the CSA intervention group. Cecal ligation was performed to generate a sepsis model. At different time points (2, 6, 12, 24 and 72 h) following sepsis induction, blood pressure, cardiac function, and non‑esterified free fatty acid (NEFA) levels in the plasma and myocardia were measured, and the expression levels of components associated with the AMP‑activated protein kinase (AMPK)‑acetyl CoA carboxylase (ACC)‑carnitine palmitoyl transferase 1 (CPT1) signaling pathway were compared among the three groups. Sepsis induced a decrease in blood pressure and cardiac function at 24 h following sepsis induction in the CLP group, and CSA treatment ameliorated these pathophysiological alterations. In addition, rats in the CLP group exhibited significant increases in calcineurin activity and NEFA accumulation in the heart when compared with those in the sham group. These effects were attenuated by CSA treatment. Mechanistically, the activity of the AMPK‑ACC‑CPT1 pathway was enhanced by CSA treatment. The present study revealed that CSA treatment increases cardiac function at an early stage of sepsis in rats. This treatment partially suppresses calcineurin activity while activating the AMPK‑TCC‑CPT1 pathway.

Thirty Years of Experience at the First Tunisian Kidney Transplant Center

OBJECTIVES

The aim of this study was to report the results of 30 years of experience at the first kidney transplant center in Tunisia.

MATERIALS AND METHODS

All kidney transplants performed at the center between June 1986 and June 2016 were included. The study period was divided into 3 decades. Recipient and donor data and follow-up information were obtained from a local database and patient medical records. Comparative analyses were performed using the t test for continuous variables and the Χ² test for qualitative variables. Patient and graft survival rates were calculated according to the actuarial method, and comparison of survival curves was performed according to the logrank test.

RESULTS

The mean age of recipients was 32.7 ± 11.5 years (range, 6-65 y) with a gender ratio of 2.2. Duration of prekidney transplant dialysis varied from 2 months to 20 years (median, 27.5 mo); 1.7% of patients underwent transplant preemptively. Kidneys were recovered from deceased donors in 21.2% of cases and from living donors in 78.8%. The proportion of deceased donors dropped from 27.4% during the period 2006-2010 to 12.9% during the period 2011-2015 (P < .04). Patient survival rates at 1, 5, 10, 15, and 20 years were 96%, 89.3%, 79.5%, 71.1%, and 65.4%. Graft survival rates were 95%, 86.5%, 76.2%, 66.3%, and 57.2%. The annual graft loss was 2.9%, with a mortality rate of 2.4% and without significant differences between patients receiving deceased-donor and living-donor organs.

CONCLUSIONS

Kidney transplant activity remains suboptimal in our country. The reduction in deceased-donor organs could be related to the political transformations facing our country with their resulting social and economic consequences. Efforts should be made to increase governmental resources and to improve both public awareness of organ donation and the motivation of transplant teams.

Comparison of the long-term efficacy and safety of generic Tacrobell with original tacrolimus (Prograf) in kidney transplant recipients

This study aimed to evaluate the long-term efficacy and safety of a generic tacrolimus (Tacrobell [TCB]) compared to the original tacrolimus (Prograf [PGF]) in kidney transplant recipients. In this retrospective observational study, we analyzed the data from 444 patients who took TCB as a first-line immunosuppressive drug and 245 patients who took PGF. The 5-year graft survival rate was 92% for patients in the PGF group and 97% for patients in the TCB group, respectively. Cox proportional hazards for a one-sided, noninferiority model showed noninferiority (upper confidence interval [CI] limit of the hazard ratio [HR]<1.2) for TCB compared to PGF (HR: 0.58; 95% CI: 0–1.14). The 5-year patient survival rate was 96% for patients in the PGF group and 97% for patients in the TCB group. Cox proportional hazards for a one-sided, noninferiority model showed noninferiority (upper confidence interval limit of the HR<2.0) for TCB compared to PGF (HR: 0.83; 95% CI: 0–1.95). The 5-year acute rejection-free graft survival rate was not significantly different between the groups (TCB 67%, PGF 68.8%; P=0.6286). The incidence of adverse events including adverse cardiovascular or cerebrovascular events, malignancies, new-onset diabetes after transplantation, and infection events did not differ significantly between the two groups. We conclude that TCB is a comparable alternative to the original tacrolimus as a first-line immunosuppressive drug. Producers of generics should support further study of their products after approval to assure physicians of their efficacy and safety.

Differences in Peripheral Blood Lymphocytes between Brand-Name and Generic Tacrolimus Used in Stable Liver Transplant Recipients

OBJECTIVES

In this study, peripheral blood lymphocytes were compared between a brand-name and a generic tacrolimus group in stable liver transplant recipients.

SUBJECTS AND METHODS

Sixteen patients who underwent ABO-compatible living donor liver transplants between 2012 and 2013 and had stable graft function were included in this study. Ten patients received brand-name tacrolimus and 6 patients received generic tacrolimus. CD3, CD4, CD8, γδ, CD4+FoxP3+, and CD3-CD56+ T cells were analyzed in peripheral blood obtained preoperatively and 4, 8, 12, and 24 weeks after liver transplantation. Categorical variables were compared using a χ2 test or Fisher exact test, and continuous variables were compared using the Mann-Whitney U test.

RESULTS

Regarding the baseline and perioperative characteristics, there were no statistically significant differences between the 2 groups. Immunosuppression also was not different. Subtype analysis of T-cell populations carried out in parallel showed similar levels of CD3, CD4, CD8, and γδT cells with brand-name tacrolimus and generic tacrolimus in stable liver transplant recipients. However, the levels of CD4+Foxp3+ and CD3-CD56+ T cells were higher in the brand-name tacrolimus group than in the generic tacrolimus group 8 weeks after transplantation (p < 0.05).

CONCLUSIONS

The level of CD4+Foxp3+ T cells was higher in the brand-name tacrolimus group than in the generic tacrolimus group after transplantation. This finding showed that brand-name tacrolimus could have more potential immunosuppressive activity than generic tacrolimus regarding the contribution of CD4+Foxp3+ T cells to graft tolerance in liver transplant recipients.

Two Decades of Tacrolimus in Renal Transplant: Basic Science and Clinical Evidences

Tacrolimus, a calcineurin inhibitor, has been the cornerstone of immunosuppressive regimens in renal transplant over 2 decades. This has significantly improved the outcomes of renal transplant, including reduction of acute rejection episodes, improvement of renal function and graft survival, and reduction of some of the adverse effects associated with cyclosporine. However, use of tacrolimus is associated with a number of undesirable effects, such as nephrotoxicity, posttransplant diabetes mellitus, neurotoxicity, and cosmetic and electrolyte disturbances. To alleviate these effects, several strategies have been adopted to minimize or eliminate tacrolimus from maintenance regimens of immunosuppression, with some success. This review focuses on advancements in the understanding of the basic science related to tacrolimus and the clinical evidences that have examined the efficacy and safety of tacrolimus in renal transplant over the past 2 decades and highlights the future directions.

Comparative analysis of the cost and effectiveness of generic and brand-name antibiotics: the case of uncomplicated urinary tract infection

PURPOSE

Generic medications used for chronic diseases are beneficial in containing healthcare costs and improving drug accessibility. However, the effects of generic drugs in acute and severe illness remain controversial. This study aims to investigate treatment costs and outcomes of generic antibiotics prescribed for adults with a urinary tract infection in outpatient settings.

METHODS

The data source was the Longitudinal Health Insurance Database of Taiwan. We included outpatients aged 20 years and above with a urinary tract infection who required one oral antibiotic for which brand-name and generic products were simultaneously available. Drug cost and overall healthcare expense of the index consultation, healthcare cost during a 42-day follow-up period, and treatment failure rates were the main dependent variables. Data were compared between brand-name and generic users from the entire cohort and a propensity score-matched samples.

RESULTS

Results from the entire cohort and propensity score-matched samples were similar. Daily antibiotic cost was significantly lower among generic users than brand-name users. Significant lower total drug claims of the index consultation only existed in patients receiving the investigated antibiotics, while the drug price between brand-name and generic versions were relatively large (e.g., >50%). The overall healthcare cost of the index consultation, healthcare expenditure during a 42-day follow-up period, and treatment failure rates were similar between the two groups.

CONCLUSIONS

Compared with those treated with brand-name antibiotics, outpatients who received generic antibiotics had equivalent treatment outcomes with lower drug costs. Generic antibiotics are effective and worthy of adoption among outpatients with simple infections indicating oral antibiotic treatment. Copyright © 2016 John Wiley & Sons, Ltd.

Renal transplant immunology in the last 20 years: A revolution towards graft and patient survival improvement

To deride the hope of progress is the ultimate fatuity, the last word in poverty of spirit and meanness of mind. There is no need to be dismayed by the fact that we cannot yet envisage a definitive solution of our problems, a resting-place beyond which we need not try to go. -P.B. Medawar, 1969 * Thomas E. Starlz, also known as the Father of Clinical Transplantation, once said that organ transplantation was the supreme exception to the rule that most major advances in medicine spring from discoveries in basic science [Starzl T. The mystique of organ transplantation. J Am Coll Surg 2005 Aug;201(2):160-170]. In fact, the first successful identical-twin kidney transplantation performed by Murray's team in December 1954 (Murray J et al. Renal homotransplantations in identical twins. Surg Forum 1955;6:432-436) was the example of an upside down translation medicine: Human clinical transplantation began and researchers tried to understand the underlying immune response and how to control the powerful rejection pathways through experimental models. In the last 20 years, we have witnessed an amazing progress in the knowledge of immunological mechanisms regarding alloimmune response and an outstanding evolution on the identification and characterization of major and minor histocompatibility antigens. This review presents an historical and clinical perspective of those important advances in kidney transplantation immunology in the last 20 years, which contributed to the improvement in patients' quality of life and the survival of end-stage renal patients. In spite of these significant progresses, some areas still need substantial progress, such as the definition of non-invasive biomarkers for acute rejection; the continuous reduction of immunosuppression; the extension of graft survival, and finally the achievement of real graft tolerance extended to HLA mismatch donor: recipient pairs.