Results of ASERTAA, a randomized prospective crossover pharmacogenetic study of immediate-release versus extended-release tacrolimus in African American kidney transplant recipients

BACKGROUND: Differences in tacrolimus dosing across ancestries is partly attributable to polymorphisms in CYP3A5 genes that encode tacrolimus-metabolizing cytochrome P450 3A5 enzymes. The CYP3A5*1 allele, preponderant in African Americans, is associated with rapid metabolism, subtherapeutic concentrations, and higher dose requirements for tacrolimus, all contributing to worse outcomes. Little is known about the relationship between CYP3A5 genotype and the tacrolimus pharmacokinetic area under the curve (AUC) profile in African Americans or whether pharmacogenetic differences exist between conventional twice-daily, rapidly absorbed, immediate-release tacrolimus (IR-Tac) and once-daily extended-release tacrolimus (LifeCycle Pharma Tac [LCPT]) with a delayed absorption profile. STUDY DESIGN: Randomized prospective crossover study. SETTING & PARTICIPANTS: 50 African American maintenance kidney recipients on stable IR-Tac dosing. INTERVENTION: Recipients were randomly assigned to continue IR-Tac on days 1 to 7 and then switch to LCPT on day 8 or receive LCPT on days 1 to 7 and then switch to IR-Tac on day 8. The LCPT dose was 85% of the IR-Tac total daily dose. OUTCOMES: Tacrolimus 24-hour AUC (AUC MEASUREMENTS: CYP3A5 genotype, 24-hour tacrolimus pharmacokinetic profiles. RESULTS: ∼80% of participants carried the CYP3A5*1 allele (CYP3A5 expressers). There were no significant differences in AUC LIMITATIONS: This was primarily a pharmacogenetic study rather than an efficacy study; the follow-up period was too short to capture clinical outcomes. CONCLUSIONS: Achieving therapeutic tacrolimus trough concentrations with IR-Tac in most African Americans results in significantly higher peak concentrations, potentially magnifying the risk for toxicity and adverse outcomes. This pharmacogenetic effect is attenuated by delayed tacrolimus absorption with LCPT. TRIAL REGISTRATION: Registered at ClinicalTrials.gov, with study number NCT01962922

Three year outcomes following positive cross match renal transplantation despite failure to convert to Negative Flow Cross Match after Desensitization

Desensitization allows successful transplantation of patients with a positive crossmatch (PXM) against their live donor. We evaluated outcomes following PXM renal transplant despite failure to convert to negative flow cytometric crossmatch (FCXM) after desensitization. Patients that underwent desensitization before PXM transplant between 1/1/00 and 11/1/11 were identified for analysis. Patients who received a transplant despite failure to convert to negative FCXM were identified as the not converted group. Patients who converted to negative FCXM after desensitization comprised the converted group control arm. 108 patients were desensitized before PXM transplant, (not converted group=42; converted group=66). Mean eGFR was comparable between groups at all time points, and 3-year eGFR was 57.8 mL/min vs. 57.1 mL/min, p=0.91. Patients with eGFR < 30mL/min at 3 years did not differ significantly (28% vs. 14%, p=0.15). Biopsy-proven rejection rates were numerically higher within the not converted group for each type of rejection and time point, but the values did not differ significantly. Opportunistic infections rates were comparable. Patient survival (95% vs. 91%) and death-censored allograft survival (84% vs. 95%, p=0.07) were similar between arms at 3 years post-transplant

Time within therapeutic range: A comparison of three tacrolimus formulations in renal transplant recipients

Background: Currently there are three available formulations of tacrolimus in the United States; these include immediate-release capsules (TAC-IR), extended-release capsules (TAC-XL),and extended-release tablets (TAC-XR). Previous studies have demonstrated non-inferiority between the three formulations in terms of efficacy. The purpose of this study was to compare three formulations of tacrolimus (TAC) and assess differences in time within the therapeutic range (TTR) and variability in levels. Results: Renal transplant recipients from January 2013 to October 2017 were retrospectively identified for analysis. Deviation from standard TAC protocol or formulation changes excluded patients. The primary outcome compared percent TTR (TTR %) among 3 TAC formulations over the first 90 days post-transplant. TTR was calculated using the Rosendaal method. Secondary outcomes included differences in TAC levels, TAC dose, eGFR, rejection, patient and graft survival between the TAC formulations. TAC-XR demonstrated a significantly higher TTR % compared to TAC-IR and TAC-XL (62.8% vs. 53.3% vs. 60.9%, p = 0.048). In post-hoc analysis, TAC-XR had a higher TTR % compared to TAC-IR (p = 0.065), which approached statistical significance. Average TAC levels, weight-normalized TAC doses, median dose-normalized TAC levels, rejection rates, eGFR, and graft or patient survival were similar among groups. Conclusion: In the early transplant period, TTR was significantly different among the groups. TAC-XR demonstrated numerically superior time within the therapeutic range. Patient-specific factors such as race, obesity, genetic polymorphisms may impact this variability and clinical outcomes. Further analysis is necessary to understand the effect of each patient-specific factor on TAC exposure

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

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

Clinical Utility of the OmniGraf Biomarker Panel in the Care of Kidney Transplant Recipients (CLARITY): Protocol for a Prospective, Multisite Observational Study

BackgroundDeath with a functioning allograft has become the leading category of graft loss in kidney transplant recipients at all time points. Previous analyses have demonstrated that causes of death in kidney transplant recipients are predominated by comorbidities strongly associated with immunosuppressant medications. Adverse drug events (ADEs) have been strongly associated with nonadherence, health care utilization, and graft loss; clinicians face a difficult decision on whether making immunosuppressant adjustments in the face of ADEs will improve symptomology or simply increase the risk of acute rejection. Clinicians also face a treatment quandary in 50% of kidney transplant recipients with stage 3 or worse chronic kidney disease at 1 year post transplantation, as progressive decline in renal function has been strongly associated with inferior allograft survival. ObjectiveThe primary objective of the CLinical Utility of the omnigrAf biomarkeR Panel In The Care of kidneY Transplant Recipients (CLARITY) trial is to evaluate change in renal function over time in kidney transplant recipients who are undergoing OmniGraf monitoring in conjunction with monitoring of their medication-related symptom burden (MRSB). A secondary objective of this study is to identify the impact of OmniGraf use in conjunction with patient-reported MRSB as part of clinical care on patients’ self-efficacy and quality of life. MethodsCLARITY is a 3-year prospective, multisite, observational study of 2000 participants with a matched control, measuring the impact of real-time patients’ MRSB and the OmniGraf biomarker panel on change in renal function over time. Secondary outcome measures include the Patient-Reported Outcomes Measurement Information System (PROMIS) Self-Efficacy for Managing Chronic Conditions–Managing Medications and Treatment–Short Form 4a; the PROMIS-29 Profile (version 2.1); the PROMIS Depression Scale, hospitalizations—subcategorized for hospitalizations owing to infections; treated rejections, MRSB, and proportion of participants with overall graft survival at year 3 post transplantation; graft loss or death during the 3-year study follow-up period; and change in provider satisfaction. ResultsThe primary outcome measure of the study will be a comparison of the slope change in estimated glomerular filtration rate from baseline to the end of follow-up between study participants and a matched control group. Secondary outcome measures include changes over time in PROMIS Self-Efficacy for Managing Chronic Conditions–Managing Medications and Treatment–Short Form 4a, the PROMIS-29 Profile (version 2.1), and PROMIS Depression Scale in the study group, as well as a comparison of hospitalizations and causes, rejections, and graft and patient survival compared between participants and a matched cohort. The anticipated first enrollment in the study is October 2022 with data analysis and publication expected in October 2027. ConclusionsThrough this report, we describe the study design, methods, and outcome measures that will be utilized in the ongoing CLARITY trial. Trial RegistrationClinicalTrials.gov NCT05482100; https://clinicaltrials.gov/ct2/show/NCT05482100 International Registered Report Identifier (IRRID)PRR1-10.2196/4102