Introduction

End-stage organ failure presents complex issues and challenges for patients, clinicians and the healthcare system. Organ transplantation saves lives, improves quality of life and is cost-effective; however, demand for organs routinely exceeds supply.1 2 Every year hundreds of Canadians and hundreds of thousands of people globally, die waiting for organ transplantation.3 4

In Canada, 80% of organ transplants originate from deceased donors, 75% of which have succumbed to death by neurological criteria (DNC).3 Compared with living donors, organs from deceased donors result in inferior graft function.5 6 Specifically, 15–40% of recipients endure early graft dysfunction within 7 days post-transplantation.7–10 For kidney transplants, early graft dysfunction is one of the strongest predictors of graft loss.11 Adverse consequences of graft dysfunction are substantial, and can include life-threatening critical illness, prolonged hospitalisation, need for invasive renal replacement support such as dialysis, increased risk of chronic disease and increased risk of rejection or graft loss.12–18 Many patients with graft dysfunction will require re-transplantation, further stressing limited organ supply.

Organs from DNC donors are associated with a high risk of post-transplant ischaemia reperfusion injury (IRI). IRI represents the cellular dysfunction and cell death that occurs when blood flow is restored to a transplanted organ (or graft). At the time of retrieval, arterial clamping causes ischaemia that leads to ATP depletion, mitochondrial failure, osmotic disequilibrium and cell membrane decay.19 The restoration of oxygen supply on transplantation catalyses the production of reactive oxygen species and recruits inflammatory cells into the graft, contributing to early graft dysfunction.20 This increased risk and reported inferiority of these organs is likely due to systemic inflammatory responses that follow neurological death, which further amplifies IRI and organ damage.

Clinical trial findings suggest that interventions that reduce IRI can improve graft viability. These interventions include procedures at organ recovery (eg, preservation solution, normothermic regional perfusion), ex situ treatments (eg, pulsatile machine perfusion, ex vivo lung perfusion) and post-transplant therapies (eg, nitric oxide, mannitol).21–27 However, interventions administered directly to the donor provide an opportunity to precondition organs against IRI.

Emerging evidence suggests that donor preconditioning with calcineurin inhibitors (cyclosporine and tacrolimus) may mitigate IRI. These agents can attenuate IRI by slowing ATP depletion, improving microcirculation and reducing free radical production.28 Most important to IRI, calcineurin inhibitors (CNIs) act on mitochondrial pores to limit the production of reactive species.29 30 A recent systematic review of 18 preclinical studies suggests the benefit of CNI treatment on early graft function in renal transplants, but not for liver transplants.31 Although CNIs may improve early kidney graft function, the limited ability to reproduce a true clinical environment in animal experiments precludes its current use in clinical settings.

Given the absence of clinical evidence in humans, a randomised controlled trial (RCT) is necessary to measure the efficacy of CNIs versus placebo administered to DNC donors, evaluating graft function in recipients in the first week after transplantation and graft and recipient survival at 1 year. Herein we describe the protocol of the CINERGY Pilot trial, designed to assess the feasibility of a larger scale RCT. Objectives of the pilot trial are to investigate the feasibility of (1) organ donor accrual; (2) organ recipient research consent; (3) 1-year outcome data acquisition from various data sources; (4) and to describe challenges encountered during the launch and implementation of this trial.

Methods and analysis

We report the CINERGY protocol and analysis plan using the Standard Protocol Items: Recommendations for Interventional Trials (see online supplemental appendix 1).32

Study design

This is a multicentre, concealed, parallel-group, placebo-controlled pilot RCT currently underway in the province of Québec, Canada. We launched donor enrolment on 11 July 2022 and will complete the recipient follow-up on 01 January 2025

Study setting

This protocol includes the enrolment of eligible donors from nine high-volume organ donation centres in the provinces of Québec and Ontario and enrolment of all transplant recipients from these donors at 28 transplant programmes in these two provinces.

Study populationEligible donors

Eligible donors are 18 years of age or older, have NDC, and their family has provided consent for organ donation. At least one kidney must be allocated for transplantation, and all intended organ recipients have agreed to receive an organ for transplantation from a donor enrolled in this study.

We exclude donors for any one or more of the following criteria:

A known hypersensitivity to tacrolimus.

≥1 transplant physician has judged that the donor tacrolimus will be unsuitable for an intended recipient.

Sites have unlikely access to study drug.

≥1 organ is allocated to a non-participating transplant programme.

≥1 organ allocated to a recipient under the age of 18.

The trial focuses on kidney donors, including multiorgan kidney donors, because: (1) explanatory preclinical studies examining the role of CNIs focused on kidney donation; (2) kidney recipients are most susceptible to nephrotoxicity; (3) delayed graft function is measured objectively and reliably in kidney transplantation; and (4) kidneys are the most common organs donated and transplanted in Canada, comprising 59% of transplants in 2022.3

Eligible non-randomised donors

We classify the reasons for eligible donors not being randomised as: (1) substitute decision-maker (SDM) declined research consent; (2) donor physician opposed to study participation; (3) research staff unavailable; (4) organ allocation not completed in time to allow for the study drug infusion; (5) and any other reasons.

Eligible transplant recipients

Eligible transplant recipients are all recipients of a donor eligible for the CINERGY study, without exclusion.

Overview of procedures for CINERGY organ allocation

As shown in figure 1, while provincial organ donation organisations (ODOs) (including Transplant Québec, and the Trillium Gift of Life Network of Ontario) work to identify the intended organ recipients, and ascertain their consent for the study, they communicate closely with research coordinators at donation hospitals for timely enrolment of eligible donors.

Figure 1

Overview of the CINERGY process. Eligible donors are identified, and the organ donation organisation notifies transplant programmes of potential eligibility. A mixed model of consent is used for CINERGY. Research consent is solicited from the deceased donor substitute decision-maker prospectively, in-person when possible; telephone and deferred are approved methods to be used when required. The recipients are asked if they will accept an organ from a CINERGY donor (‘clinical consent’) pre-transplant. If inclusion/exclusion criteria are met, a single 4-hour infusion of tacrolimus or placebo is administered to the donor, 4–8 hours prior to organ recovery. The recipient is then approached for formal research consent for data collection post-transplant (ideally in person, secondarily by phone or substitute decision-maker if needed). DNC, donor dead by neurological criteria; MC, method centre; ODO, organ donation organisation; OR, operating room; SDM, substitute decision-maker.

At the time of organ allocation, ODO coordinators notify transplant physicians/programmes about the possibility that the donor is eligible for the trial. Transplant programmes communicate with the intended organ recipients about the potential CINERGY donor. This first conversation about the study, is to solicit a verbal consent to receive (or to decline) an organ from a CINERGY donor; and we refer to this as a ‘clinical consent’ from the intended recipient. Transplant teams receive a list of study talking points and information sheets to provide to recipients. When the transplant team confirms acceptance of the organ with the ODO, they also report whether the recipient verbally consents to receive an organ from a donor in the CINERGY study. Once the allocation of all suitable organs is complete, the ODO staff inform CINERGY research coordinators and email an allocation form (see online supplemental appendix 2) to the methods centre, confirming the transplant programme and recipient’s verbal consent). The methods centre research staff subsequently informed corresponding transplant sites that a recipient received an organ from a donor enrolled in CINERGY. Post-transplant, the recipient is re-approached by the local research coordinators for a formal research consent.

Randomisation and blinding

Once donor eligibility is confirmed and all intended recipients have agreed to the CINERGY study, research coordinators at the donation sites randomise eligible donors using a central interactive web-based system (www.Randomize.net). Randomisation is concealed and uses a 1:1 ratio with variable block sizes, stratified by (1) donor site, and (2) kidney donor classification, as ‘standard’ versus ‘extended’ criteria donors. Kidney donor classification is an important stratification variable because extended criteria donors (ECDs) have a higher risk of delayed graft function and account for 40% of kidney donors in Canada.33 We have defined ECD donors as those who are (1) ≥60 years old or (2) ≥50 years old to 59 years of age with at least two of the following characteristics: (1) history of hypertension; (2) stroke as the cause leading to neurological death; (3) glomerular filtration rate at screening of <70 mL/min/1.73 m2.

Only research pharmacists preparing the study infusions at each site are aware of group assignment. Donor families, recipients, clinicians, ODO staff and all other research personnel are blinded to the trial intervention. Blinding prevents differential use of co-interventions for donors and recipients and prevents any bias in the reporting of adverse events. The placebo solution is identical in colour, consistency, volume and packaging to the tacrolimus solution. During the study, if a clinical situation calls for unblinding of research and clinical personnel, as assessed on case-by-case basis, the method centre will apply the unblinding procedure (see online supplemental appendix 3 unblinding procedure). The request for unblinding must be approved by one of the principal investigators.

Study intervention

Donors allocated to the tacrolimus group receive a 4-hour intravenous infusion, 0.02 mg/kg ideal body weight (diluted with 0.9% sodium chloride in 250 mL bags) administered 4–8 hours prior to scheduled organ retrieval. In the event that surgery is delayed, a second infusion will start 12 hours after the initiation of the first, replicating two times per day dosing as given in other settings.34 35 Should organ recovery be delayed by ≥24 hours, we elected to not administer one-third infusion, reasoning that the current standard of care would necessitate bloodwork that could result in the unblinding of clinicians.

Donors in the placebo group receive an infusion of 0.9% sodium chloride in 250 mL bags. In both study groups, for patients weighing ≥100 kg pharmacists add 20 mL and intensive care unit (ICU) staff run the infusion at a rate of 71.25 mL/hour to keep the concentration of tacrolimus in the range of 0.002–0.008 mg/mL as per the product monograph.36

Rationale for drug administration procedures

Tacrolimus has a well-known safety profile and is routinely prescribed to transplant recipients for immunosuppression with an initial oral dose. Alternatively, the intravenous route is also suitable for a starting dose, administering 0.01–0.05 mg/kg/day depending on the type of organ transplant. We opted for an intravenous route rather than oral because of potential variability in the absorption of tacrolimus after oral dosing, in general, and in DNC donors, specifically, who may have significant haemodynamic instability that can inhibit enteral absorption.37 The therapeutic reference range of tacrolimus in plasma is 0.5–2 µg/L.38 At this range, 90% of lymphocytes are inhibited.39 Doses of intravenous tacrolimus as low as 0.02 mg/kg over 2–4 hours can achieve this plasma concentration.36 40 The 4-hour duration and the dose levels in this study reflect usual protocols in previous post-transplantation clinical studies.35 40 41

Co-interventions

All other donor interventions are left to the discretion of the clinical team and we carefully record these treatments (eg, corticosteroids, temperature control). This protocol does not direct ex vivo interventions or transplant recipient care. We do record the use of immunosuppressive therapy among recipients in the week post-transplantation.

OutcomesFeasibility outcomes

There are two primary feasibility outcomes, donor accrual and recipient research consent. Donor accrual refers to the randomisation and study treatment of eligible donors. We perceive that a national study would be feasible if over 80% of eligible donors across all sites received study treatment. Recipient research consent refers specifically to the provision of a written or verbal consent to use recipient health data for the purpose of this study. This study involves no study-specific testing. We perceived that the study would be feasible if over 95% of eligible recipients consented, postoperatively, to this use of data.

Two secondary feasibility outcomes refer to the acquisition of recipient survival and graft survival at 1-year post-transplantation. In the pilot study, we use three sources of this data: (1) local transplant programme data (all recipients), (2) Canadian Institutes for Health Information (all recipients) and, if necessary, (3) we will contact participating transplant recipients by telephone to acquire this data. We aim to determine the most practical data source (with respect to availability, timeliness and cost) within each province.

We also assess systematically for unforeseen challenges or barriers to the launch and/or implementation of this study. To do so, we solicit feedback from research staff and co-investigators at participating sites as well as ODO leadership. While we are not applying a specific implementation science framework, our procedures adhere to many of the core concepts promoted in implementation science.42

Clinical outcomes

The primary clinical outcome for a larger future trial is delayed graft function, for which the organ-specific definitions appear in table 1. Research coordinators at the transplant sites record these data from electronic medical records. Secondary clinical outcomes include recipient survival and re-transplantation at 1 year, as described in the prior section.

Table 1

Early graft dysfunction—terminology, incidence, defining criteria

Other secondary outcomes relate to participant safety. The most important potential adverse effect for kidney and non-kidney recipients is acute kidney injury. For all non-kidney recipients, we measure acute kidney injury using the Kidney Disease Improving Global Outcomes classification of stage II (or higher) kidney injury, using the creatinine criteria, specifically.43 This classification is commonly used in RCTs in critical care.44 45 For all recipients we also measure (1) hyperkalaemia events defined as a potassium level >5 mmol/L and (2) allergic reactions (since they may be related to donor tacrolimus therapy), as identified by the hospital transplant clinicians. All recipient safety outcomes are measured up to 7 days post-transplant.

Similar safety outcomes (ie, acute kidney injury, hyperkalaemia and allergy) are measured among donors following the study treatment. Bedside staff will also record the following potential adverse effects of the donor study infusion, in real-time: hypertension (ie, change in systolic blood pressure during study drug infusion ≥20 mm Hg from pre-infusion for >15 min or if systolic blood pressure is less than 160 mm Hg pre-infusion, an increase to ≥160 mm Hg for >15 min) and cardiac arrhythmias (ie, a new episode of atrial fibrillation, ventricular fibrillation or tachycardia during study drug infusion).

Sample size

The target sample size for 1 year of enrolment is 414 participants, including 90 DNC donors and their corresponding transplant recipients (approximately 324). Extrapolating from a prior national cohort study in deceased organ donation, the nine participating donation centres are expected to provide 112 eligible donors in the year of study and each donor generates, on average, 3.6 recipients. The sample size determination allows for 20% of eligible donors to be missed for various reasons including staff availability, drug availability and declined consent from donor families. Thus, we expect to accrue 80% (90/112) (95% CI 72% to 87%) of study-eligible donors.46

Identification of barriers to study implementation

As with any pilot feasibility RCT, the overarching aim of this study is to identify, describe and quantify if possible, any barriers that arise prior to the launch of the trial and during study implementation. This study protocol applies guidance from the recently published CONSERVE guidelines to achieve this goal. During the COVID-19 pandemic an international panel of experts in RCT methodology developed the CONSERVE guidelines to improve the reporting of trial protocols and completed trials that undergo important modifications in response to extenuating circumstances, such as a global pandemic.47 This process can also be applicable to other situations.48 49 The implementation of a complex study such as CINERGY, which investigates recipient outcomes following a donor intervention presented unique barriers and, accordingly, we have and will likely continue to encounter barriers of extenuating circumstances. From the original version of the protocol (22 June 2020), we added an objective to describe such barriers to this research using the CONSERVE framework, identifying and reporting on their impact and developing a mitigating strategy.

Statistical analysis

The statistical analysis plan includes simple proportions to analyse the donor accrual rate and recipient consent rate. In describing participant donor and recipient characteristics, we will present continuous data as means and SDs, or medians and IQRs, as appropriate. To refine data procedures for the large-scale RCT, we will assess the accuracy of the three methods for obtaining 1-year outcome data. We will consider clinical data as our reference standard. We will measure chance-corrected agreement among the two methods of recording 1-year outcome data using the kappa statistic, and absolute agreement using intraclass correlation.

We will not compare clinical and safety outcomes by allocated study group since we tentatively plan to include the pilot trial participants in the final analysis of a larger RCT. In the future larger RCT, organs will be the unit of analysis for the comparison of the clinical outcomes across groups. For all early graft dysfunction in other organ recipients, we will conduct a univariate analysis using χ2 test and then a general linear mixed model to account for clustering effects of paired kidneys from the same donor. Next, we will use a multivariate analysis from the same model to adjust for key confounding factors. We will compare 1-year outcomes using the χ2 test.

A p value<0.05 will be considered statistically significant for all outcomes. A biostatistician blinded to study group allocation will conduct all analyses, adhering to the intention-to-treat principle.

We will use descriptive statistics to describe findings regarding any barriers to the launch and implementation of the CINERGY Pilot.

Data collection and management

This trial uses data sources including electronic records at donation centres, transplant programmes and the provincial ODOs. Trained research coordinators at each clinical site provide data to the methods centre (table 2). For donors, we collect data up to the time of organ retrieval; for recipients, we collect data daily up to 7 days post-transplantation and then again at 1 year.

Table 2

Overview of data collection from donors and recipients

Site research coordinators enter data on electronic case report forms (CRFs) for encrypted transmission to the method centre using the internet-based iDataFax System (DF/Net Research, Canada). Automated data verification programmed within the active iDataFax system alerts these research staff to potential errors (extreme or missing values). Staff at the method centre review incoming data for accuracy and completeness, generating data queries for local research staff to resolve before a CRF is designated as ‘complete’. A detailed instruction regarding CRF completion is provided at site initiations, along with an accompanying study manual.

To systematically assess important barriers to this research, we document the times to regulatory approvals by hospital research ethics boards as well as ODOs. For this relatively complex clinical trial, the need for study training of all donation centres, transplant programmes and the ODOs requires that methods centre personnel meet regularly with all contributors, both prior to the launch and on an ongoing basis. This allows for discussion of all barriers arising, and suggested solutions, which are documented and reviewed with the study principal investigators on a weekly basis.

Data monitoring

The day-to-day management of the CINERGY study is divided between two methods centres where the two principal investigators are located. The CLARITY methods centre at McMaster University, is responsible for the randomisation system and database. The ICU research unit at the Université de Sherbrooke oversees all matters involving donation and transplant sites and ODOs, including regulatory functions, training, monitoring, data validation, troubleshooting and payments. The methods centres trained research and clinical staff at participating sites and the provincial ODOs. They monitor monthly enrolment rates, protocol adherence, delivery of the study drug and provide rapid responses to questions from research coordinators, clinicians and patients. The steering committee includes local principal investigators, senior triallists in donation and transplantation, ODO representatives, a biostatistician and the recipient research partner (see online supplemental appendix 4). They address the need for any protocol modifications, adherence to study timelines and any other necessary methodology or practical decisions.

The four-person independent Data Safety Monitoring Committee (DSMC) includes two senior triallists and two transplant researchers. In the context of this feasibility study, the DSMC is responsible for ensuring the safety of study participants.

Ethics and dissemination

The CINERGY Pilot trial has been approved by Health Canada, and provincial Research Ethics Board (REB) in Ontario and all participating sites in Québec.

Donor research consent

Consent for eligible DNC donors to participate in this research is acquired from shared decision-makers (SDMs). We employ a mixed consent model of either prospective informed consent or deferred consent. Whenever possible, the site research coordinator approaches the donor’s SDM prospectively in the hospital, around the time of consent to organ donation (see online supplemental appendix 5). If visitation restrictions do not allow for this (eg, limited visitation due to COVID-19), or if the donation consent occurred late at night and the SDM is unlikely to return to the hospital, then the research coordinator solicit prospective verbal consent by telephone. However, whether or not the SDM is present in the hospital, if the treating clinician judges that a research consent discussion would be impracticable, insensitive or inappropriate at that time, then the research coordinator defer the written or verbal consent discussion for up to 2 weeks under a deferred consent model. This window was recommended by our donor and patient research collaborators to provide SDMs sufficient time to proceed with inevitable funeral arrangements and respite from the encompassing process of neurological death and organ donation of a family member.

We proposed a mixed consent model because this is a very low-risk study for deceased donors, and a prospective informed consent model is frequently impracticable because: (1) SDMs are frequently emotionally overwhelmed and unable to sufficiently engage, and (2) the time window for the study intervention is too short (typically 6–24 hours after the consent for organ donation) for the deliberations about research consent that can be common in the ICU.

Recipient research consent

Following transplantation, local research coordinators approach recipients who received an organ from a CINERGY donor (see online supplemental appendix 6). They remind the recipient of the CINERGY Pilot trial and solicit a written research consent to collect and use their data for study purposes, including a 1-year follow-up telephone call after transplantation. We approach the recipient’s SDM if the recipient lacks the capacity to make a decision regarding research consent. If in-person consent is not possible and an SDM is not available, then verbal consent will be obtained by telephone post-discharge.

This is a low-risk study for transplant recipients, and a prospective research consent model is impracticable because: (1) the approach at the pre-transplant clinic would require training of multiple staff at numerous transplant programmes and then consenting hundreds of patients who will never have an opportunity to participate in the study; (2) soliciting research consent during organ allocation may be perceived as coercive; and (3) research consent discussions immediately after the transplantation can be complicated by altered cognition.

Dissemination

We have presented the protocol to all transplant programmes, high-volume donation centres and ODO in Québec and Ontario and to members of the Canadian Critical Care Trials Group and the Canadian Donation and Transplant Research Program. We update our collaborators through weekly emails describing the current progress of the study. When the study is complete, we will collaborate with local investigators to present the findings at each participating site to: (1) share overall feasibility results, (2) reinforce the roles of clinicians as pivotal members to assure success in donor intervention trial and (3) seek feedback from clinicians and researchers to inform the larger trial. A similar presentation will be conducted with ODOs.

We will present study results at scientific meetings of the International Society of Organ Donation and Procurement, Canadian Critical Care Forum and published in peer-reviewed journals.

Discussion

Randomised controlled trials of experimental interventions in organ donors have the potential to improve the quantity, quality and longevity of organs for transplant recipients.50 51 However, the conduct of such trials of donor interventions is fraught with challenges, and progress has been slow on a global basis, hindering advances in this field.52 53 A multicentre pilot RCT is essential to determine the feasibility and inform the design of a larger trial across the provinces of Canada where donation and transplant services and supports vary substantially.

The largest threats to the feasibility of this pilot trial are donor accrual and recipient consenting. To enhance donor enrolment, we developed a province-specific enrolment procedure to learn immediately from ODOs about newly consented DNC donors and have trained ICU research staff on how to approach a family for research consent in these difficult moments. We have also presented and received endorsement from all transplant programmes prior to embarking on CINERGY Pilot. A limitation to donor enrolment is the lack of research and pharmacy team coverage after regular business hours, and second obtaining the recipient’s clinical consent (a donor eligibility criteria) within the time constraint. For recipient consent, we had originally planned to use a waiver of consent; however, after discussion with our patient partners and transplant colleagues we offered transplant programmes the prerogative to ‘veto’ ‘donor’ participation. After feedback from REB chairs, we revised the consent process further to the current two-step procedure: a verbal clinical consent to receive a CINERGY organ (solicited at the time of organ allocation), and a written or verbal research consent to the use of personal health data (solicited in the early post-transplant period). Specifically, the REB requested that the recipient must be made aware of the research study and be afforded the right to refuse the organ (which would mean the donor would not be enrolled), and that decision should be independent of the decision to take part in the observational component of the research. We have taken many steps to streamline our approach at the time of allocation between ODOs, transplant programmes, candidate recipients and methods centre. We have developed a study information sheet and poster to increase the knowledge of the patients on the transplant waiting list to facilitate enrolment in CINERGY.

Despite these limitations, the CINERGY Pilot trial is the first Canadian multicentre donor intervention RCT and will provide important feasibility data and generate interest in collaboration between donation and transplantation communities. The national research infrastructure and study procedures created for the CINERGY study will pave the way for further research in organ donation by establishing a framework for Canadian donor intervention trials.

Trial status

The current protocol is V.2.4, (13 March 2024). We launched donor enrolment on 11 July 2022 and completed the enrolment on 01 January 2024 in Québec. We will complete the recipient follow-up on 01 January 2025.