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

BACKGROUND: Graft rejection and chronic CNI toxicity remain obstacles to organ transplant success. Current formulations of tacrolimus, such as Prograf® and Advagraf™, exhibit limitations in terms of pharmacokinetics and tolerability, related in part to suboptimal bioavailability. As dosing non-compliance can result in graft rejection, the once daily formulation of tacrolimus, Advagraf™, was developed (vs 2x/day Prograf®). Benefits of Advagraf™ are counterbalanced by delayed achievement of therapeutic trough levels and need for up to 50% higher doses to maintain Prograf®-equivalent troughs. Envarsus® is also a prolonged-release once-daily tacrolimus formulation, developed using MeltDose™ drug-delivery technology to increase drug bioavailability; improved bioavailability results in low patient drug absorption variability and less pronounced peak-to-trough fluctuations. In phase III de novo kidney transplant studies, Envarsus® proved non-inferior to twice-daily tacrolimus; however, no phase IV studies show superiority of Envarsus® vs Advagraf™ in de novo liver transplant (LTx) recipients. METHODS: The EnGraft compares bioavailability and tests superiority of Envarsus® (test arm) versus Advagraf™ (comparator arm) in de novo LTx recipients. A total of 268 patients from 15 German transplant centres will be randomised 1:1 within 14 days post-LTx. The primary endpoint is dose-normalised trough level (C/D ratio) measured 12 weeks after randomisation. Secondary endpoints include the number of dose adjustments, time to reach first defined trough level and incidence of graft rejections. Additionally, clinical and laboratory parameters will be assessed over a 3-year period. DISCUSSION: C/D ratio is an estimate for tacrolimus bioavailability. Improving bioavailability and increasing C/D ratio using Envarsus could reduce renal dysfunction and other tacrolimus-related toxicities; previous trials have shown that a higher C/D ratio (i.e. slower tacrolimus metabolism) is not only associated with improved renal function but also linked to reduced neurotoxic side effects. A higher C/D ratio could improve clinical outcomes for LTx recipients; EnGraft has begun, with one third of patients recruited by January 2022. TRIAL REGISTRATION: This trial has been registered (4 May 2020) in the EU Clinical Trials Register, EudraCT-Nummer: 2020-000796-20. Additionally, this trial has been registered (22 January 2021) at ClinicalTrials.gov: NCT04720326. The trial received a favourable opinion from the concerned lead ethics committee at the University of Regensburg, under the reference 20-1842-112.

[Challenges in the organization of investigator initiated trials: in transplantation medicine]. / Herausforderungen in der Organisation "investigator initiated trials": Am Beispiel der Transplantationsmedizin.

INTRODUCTION: Transplantation medicine offers multiple translational questions which should preferably be transferred to clinical evidence. The current gold standard for testing such questions and hypotheses is by prospective randomized controlled trials (RCT). The trials should be performed independently from the medical industry to avoid conflicts of interests and to guarantee a strict scientific approach. A good model is an investigator initiated trial (IIT) in which academic institutions function as the sponsor and in which normally a scientific idea stands before marketing interests of a certain medical product. METHODS: We present a model for an IIT which is sponsored and coordinated by Regensburg University Hospital at 45 sites in 13 nations (SiLVER study), highlight special pitfalls of this study and offer alternatives to this approach. RESULTS: Finances: financial support in clinical trials can be obtained from the medical industry. Alternatively in Germany the Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung) offers annual grants. The expansion of financial support through foundations is desirable. Infrastructure: sponsorship within the pharmaceutics act (Arzneimittelgesetz) demands excellent infrastructural conditions and a professional team to accomplish clinical, logistic, regulatory, legal and ethical challenges in a RCT. If a large trial has sufficient financial support certain tasks can be outsourced and delegated to contract research organizations, coordinating centers for clinical trials or partners in the medical industry. CONCLUSIONS: Clinical scientific advances to improve evidence are an enormous challenge when performed as an IIT. However, academic sponsors can perform (international) IITs when certain rules are followed and should be defined as the gold standard when scientific findings have to be established clinically.