Safety and impact of eculizumab withdrawal in patients with atypical haemolytic uraemic syndrome: protocol for a multicentre, open-label, prospective, single-arm study

INTRODUCTION

Atypical haemolytic uraemic syndrome (aHUS) is a rare, life-threatening disease caused by excessive activation of part of the immune system called complement. Eculizumab is an effective treatment, controlling aHUS in 90% of patients. Due to the risk of relapse, lifelong treatment is currently recommended. Eculizumab treatment is not without problems, foremost being the risk of severe meningococcal infection, the burden of biweekly intravenous injections and the high cost.This paper describes the design of the Stopping Eculizumab Treatment Safely in aHUS trial that aims to establish whether a safety monitoring protocol, including the reintroduction of eculizumab for those who relapse, could be a safe, alternative treatment strategy for patients with aHUS.

METHODS AND ANALYSIS

This is a multicentre, non-randomised, open-label study of eculizumab withdrawal with continuous monitoring of thrombotic microangiopathy-related serious adverse events using the Bayes factor single-arm design. 30 patients will be recruited to withdraw from eculizumab and have regular blood and urine tests for 24 months, to monitor for disease activity. If relapse occurs, treatment will be restarted within 24 hours of presentation. 20 patients will remain on treatment and complete health economic questionnaires only. An embedded qualitative study will explore the views of participants.

ETHICS AND DISSEMINATION

A favourable ethical opinion and approval was obtained from the North East-Tyne & Wear South Research Ethics Committee. Outcomes will be disseminated via peer-reviewed articles and conference presentations.

TRIAL REGISTRATION NUMBER

EudraCT number: 2017-003916-37 and ISRCTN number: ISRCTN17503205.

O030 Image-analysis algorithm to determine quality of cold perfusion in kidney transplantation

Introduction

Surgeon assessment of visual ‘quality of perfusion’ (QOP) influences kidney discard and predicts transplant outcome. However, this assessment is subjective and bias-prone.

We aimed to design an application utilising a smartphone camera to make this assessment objective and enhance decision making.

Methods

The QOP in photographs of backbench kidneys was graded from 1 (ideal) to 5 (very poor) by three independent surgeons. A training cohort was used to develop an image-analysis algorithm, which was validated in a separate cohort.

Results

Analysing surgeon scores of 174 kidney images revealed that inter-rater agreement was good for kidneys displaying the best (rated 1) and worst (rated 4 or 5) QOP. However, for intermediate scores inter-rater agreement was poor. Inter-rater agreement between surgeons decreased as they graded more images; as surgeons fatigued, their ability to classify images worsened. A training cohort (n=174 kidneys) was used for algorithm development. First, small regions within each image were mapped within the CEILAB colour-space, where well-perfused and poorly perfused areas show clear separation. To generate a score for each kidney these regions are compared with ideally flushed kidney tissue. Testing our algorithm (validation cohort - n=29 kidneys) revealed strong correlation between image-analysis QOP score and surgeon assessment, r=0.789 (0.587–0.899), P<0.001.

Conclusion

Surgeon inter-rater agreement on kidney QOP is low for kidneys with borderline QOP and worsens with fatigue. We provide a QOP score utilising an image-analysis algorithm, which correlates with surgeon scoring. With additional images and training this could provide an objective, numerical, point-of-care assessment of organ quality.

Take-home message

Current visual assessment of transplant organ quality is subjective and bias-prone. This body of work attempts to create a point-of-care image-analysis application to provide an objective numeric organ quality score.

Motion correction of free-breathing magnetic resonance renography using model-driven registration

INTRODUCTION

Model-driven registration (MDR) is a general approach to remove patient motion in quantitative imaging. In this study, we investigate whether MDR can effectively correct the motion in free-breathing MR renography (MRR).

MATERIALS AND METHODS

MDR was generalised to linear tracer-kinetic models and implemented using 2D or 3D free-form deformations (FFD) with multi-resolution and gradient descent optimization. MDR was evaluated using a kidney-mimicking digital reference object (DRO) and free-breathing patient data acquired at high temporal resolution in multi-slice 2D (5 patients) and 3D acquisitions (8 patients). Registration accuracy was assessed using comparison to ground truth DRO, calculating the Hausdorff distance (HD) between ground truth masks with segmentations and visual evaluation of dynamic images, signal-time courses and parametric maps (all data).

RESULTS

DRO data showed that the bias and precision of parameter maps after MDR are indistinguishable from motion-free data. MDR led to reduction in HD (HD_unregistered = 9.98 ± 9.76, HD_registered = 1.63 ± 0.49). Visual inspection showed that MDR effectively removed motion effects in the dynamic data, leading to a clear improvement in anatomical delineation on parametric maps and a reduction in motion-induced oscillations on signal-time courses.

DISCUSSION

MDR provides effective motion correction of MRR in synthetic and patient data. Future work is needed to compare the performance against other more established methods.

O25: TARGETING THE RENAL TUBULAR EPITHELIUM WITH ANTI-MIRNA THERAPY: A POTENTIAL MECHANISM FOR MINIMISING ISCHAEMIA REPERFUSION INJURY

Introduction

Ischaemia reperfusion injury (IRI) is an unavoidable, significant consequence of renal transplantation. MicroRNAs are small, non-coding RNA molecules that regulate multiple downstream mRNA targets. MiRNA-21-5p and miRNA-24-3p have been previously implicated in IRI. Antisense oligonucleotides (ASOs) block specific microRNAs, with previous work by our group demonstrating their delivery to kidneys using normothermic machine perfusion. Imaging these kidneys revealed ASO localisation around proximal tubule epithelial cells (PTECs). This project aimed to characterise ASO blockade against miRNA-21-5p and miRNA-24-3p in PTECs.

Method

HKC8 cells, a human PTEC cell line, were used throughout these experiments. Cells were placed in a hypoxic incubator for 24hrs, followed by 6hrs of reoxygenation to mimic IRI. HKC8s were transfected with ASOs using lipofectamine. RT-qPCR and Western Blots were used to evaluate expression of antioxidant targets, SOD2 and HMOX1.

Result

MiRNA-21-5p and miRNA-24-3p levels were high throughout hypoxia and reoxygenation. Single blockade with anti-miRNA-21-5p resulted in a significant increase in its downstream target SOD2 (P<0.05). Anti-miRNA-24-3p treatment resulted in no change in either of its downstream targets, HMOX1 or SOD2. This was reflected in the failure of dual blockade to produce a synergistic effect on the shared target, SOD2.

Conclusion

Anti-miRNA-21-5p results in a significant increase of SOD2, which is well characterised as protective during IRI. Anti-miRNA-24-3p appears to have no effect on PTECs, contrary to previous work in endothelial cells, perhaps suggesting a cell specific response of microRNAs. Normothermic machine perfusion could be used to deliver dual ASOs; allowing simultaneous targeting of different kidney cell types.

Take-home message

The delivery of anti-miRNA-21-5p therapy pre-transplant, using normothermic machine perfusion, has the potential to reduce ischaemia reperfusion injury and improve kidney transplant outcomes.

Obesity, Sex, Race, and Early Onset Hypertension

Investigation for secondary causes is recommended in early onset hypertension. However, obesity is associated with higher blood pressure (BP), so investigation for alternative secondary causes may not be necessary in all obese patients. We sought to define a rational approach to investigation across strata of age, body mass index (BMI) sex and race, based on BP distributions in the US National Health and Nutrition Examination Surveys 2005 to 2016. The majority (71% [95% CI, 59%–79%] and 64% [95% CI, 57%–69%] by European and US definitions respectively) of early onset hypertension cases were attributable to BP distribution shifts accompanying obesity and male sex. Male versus female sex, BMI>40 versus 18.2<BMI≤25 and Black versus White race were accompanied by adjusted mean systolic BP differences of 9 (95% CI, 8–9) mm Hg, 13 (95% CI, 12–15) mm Hg, and 3 (95% CI, 2–4) mm Hg respectively. Normal BMI women above the age cutoff for investigation were less likely to be hypertensive than obese younger men meeting current investigation criteria ( P <0.001). Targeting investigations to combinations of sex, BMI, and age with low hypertension prevalence would reduce the number investigated while still identifying as many secondary cases. Limiting investigations to patients with a BP exceeded by ≤5% of their respective sex/BMI/age category would give investigation thresholds ranging from ≥130/≥80 and ≥140/≥90 for normal BMI women and men, respectively, at age 20 to 30 years, to ≥160/≥100 and ≥170/≥105 for women and men with BMI ≥40 at age 30 to 40 years. In conclusion, we propose refined strategies for investigation of early onset hypertension in the context of an obesity epidemic.

Acute kidney injury electronic alerts: mixed methods Normalisation Process Theory evaluation of their implementation into secondary care in England

OBJECTIVE

Around one in five emergency hospital admissions are affected by acute kidney injury (AKI). To address poor quality of care in relation to AKI, electronic alerts (e-alerts) are mandated across primary and secondary care in England and Wales. Evidence of the benefit of AKI e-alerts remains conflicting, with at least some uncertainty explained by poor or unclear implementation. The objective of this study was to identify factors relating to implementation, using Normalisation Process Theory (NPT), which promote or inhibit use of AKI e-alerts in secondary care.

DESIGN

Mixed methods combining qualitative (observations, semi-structured interviews) and quantitative (survey) methods.

SETTING AND PARTICIPANTS

Three secondary care hospitals in North East England, representing two distinct AKI e-alerting systems. Observations (>44 hours) were conducted in Emergency Assessment Units (EAUs). Semi-structured interviews were conducted with clinicians (n=29) from EAUs, vascular or general surgery or care of the elderly. Qualitative data were supplemented by Normalization MeAsure Development (NoMAD) surveys (n=101).

ANALYSIS

Qualitative data were analysed using the NPT framework, with quantitative data analysed descriptively and using χ² and Wilcoxon signed-rank test for differences in current and future normalisation.

RESULTS

Participants reported familiarity with the AKI e-alerts but that the e-alerts would become more normalised in the future (p<0.001). No single NPT mechanism led to current (un)successful implementation of the e-alerts, but analysis of the underlying subconstructs identified several mechanisms indicative of successful normalisation (internalisation, legitimation) or unsuccessful normalisation (initiation, differentiation, skill set workability, systematisation).

CONCLUSIONS

Clinicians recognised the value and importance of AKI e-alerts in their practice, although this was not sufficient for the e-alerts to be routinely engaged with by clinicians. To further normalise the use of AKI e-alerts, there is a need for tailored training on use of the e-alerts and routine feedback to clinicians on the impact that e-alerts have on patient outcomes.

Changing Protein Permeability with Nephron Loss: Evidence for a Human Remnant Nephron Effect

BACKGROUND

If loss of functioning nephrons predisposes to glomerular barotrauma (a "remnant nephron" effect), then glomerular permeability should increase as glomerular filtration rate (GFR) falls, as is observed in animal models of nephron loss.

METHODS

Changes in net renal protein permeability, defined as proteinuria or albuminuria per mL/min of GFR, were measured in the setting of nephron loss due to kidney donation (Assessing Long Term Outcomes in Living Kidney Donors cohort) or progressive chronic kidney disease (CKD; Modification of Diet in Renal Disease [MDRD], African American Study of Kidney Disease [AASK], and Chronic Renal insufficiency Cohort [CRIC] studies).

RESULTS

Following kidney donation, renal albumin permeability increased by 31% from predonation levels (p < 0.001). With progression of CKD, a 50% loss of residual GFR was accompanied by increases in proteinuria per mL/min GFR of 1.8-, 2.1-, and 1.6-fold in the MDRD, AASK, and CRIC cohorts, respectively (p < 0.001 for all), independent of changes in systolic blood pressure and ACEi/ARB use. A 70% reduction in GFR was associated with permeability increases of 3.1-, 4.4-, and 2.6-fold in the same cohorts. Among MDRD participants with progression of nonglomerular primary disease, the 75th percentile of final permeability was 141 mg/24 h proteinuria per mL/min GFR. This degree of permeability would have resulted in nephrotic range proteinuria had it been present at the baseline mean GFR of 40 mL/min, implying the development of de novo glomerular pathology as GFR fell. Increasing permeability also accompanied CKD progression in participants with nephrotic syndrome at baseline. Consequently, these participants had little improvement in 24 h proteinuria or serum albumin, despite substantial loss of functioning nephron mass across which the protein leak occurred. In the absence of a fall in GFR, there was no increase in permeability in any cohort.

CONCLUSION

Nephron loss is accompanied by an increase in renal protein permeability, even in the absence of a primary glomerular disease. This is consistent with a remnant nephron effect in human CKD.

Glomerular filtration rate: new age- and gender- specific reference ranges and thresholds for living kidney donation

BACKGROUND

There is a need for a large, contemporary, multi-centre series of measured glomerular filtration rates (mGFR) from healthy individuals to determine age- and gender-specific reference ranges for GFR. We aimed to address this and to use the ranges to provide age- and gender-specific advisory GFR thresholds considered acceptable for living kidney donation.

METHODS

Individual-level data including pre-donation mGFR from 2974 prospective living kidney donors from 18 UK renal centres performed between 2003 and 2015 were amalgamated. Age- and gender-specific GFR reference ranges were determined by segmented multiple linear regression and presented as means ± two standard deviations.

RESULTS

Males had a higher GFR than females (92.0 vs 88.1 mL/min/1.73m2, P < 0.0001). Mean mGFR was 100 mL/min/1.73m2 until 35 years of age, following which there was a linear decline that was faster in females compared to males (7.7 vs 6.6 mL/min/1.73m2/decade, P = 0.013); 10.5% of individuals aged > 60 years had a GFR < 60 mL/min/1.73m2. The GFR ranges were used along with other published evidence to provide advisory age- and gender-specific GFR thresholds for living kidney donation.

CONCLUSIONS

These data suggest that GFR declines after 35 years of age, and the decline is faster in females. A significant proportion of the healthy population over 60 years of age have a GFR < 60 mL/min/1.73m2 which may have implications for the definition of chronic kidney disease. Age and gender differences in normal GFR can be used to determine advisory GFR thresholds for living kidney donation.

Methods for the evaluation of biomarkers in patients with kidney and liver diseases: multicentre research programme including ELUCIDATE RCT

Background

Protein biomarkers with associations with the activity and outcomes of diseases are being identified by modern proteomic technologies. They may be simple, accessible, cheap and safe tests that can inform diagnosis, prognosis, treatment selection, monitoring of disease activity and therapy and may substitute for complex, invasive and expensive tests. However, their potential is not yet being realised.

Design and methods

The study consisted of three workstreams to create a framework for research: workstream 1, methodology – to define current practice and explore methodology innovations for biomarkers for monitoring disease; workstream 2, clinical translation – to create a framework of research practice, high-quality samples and related clinical data to evaluate the validity and clinical utility of protein biomarkers; and workstream 3, the ELF to Uncover Cirrhosis as an Indication for Diagnosis and Action for Treatable Event (ELUCIDATE) randomised controlled trial (RCT) – an exemplar RCT of an established test, the ADVIA Centaur® Enhanced Liver Fibrosis (ELF) test (Siemens Healthcare Diagnostics Ltd, Camberley, UK) [consisting of a panel of three markers – (1) serum hyaluronic acid, (2) amino-terminal propeptide of type III procollagen and (3) tissue inhibitor of metalloproteinase 1], for liver cirrhosis to determine its impact on diagnostic timing and the management of cirrhosis and the process of care and improving outcomes.

Results

The methodology workstream evaluated the quality of recommendations for using prostate-specific antigen to monitor patients, systematically reviewed RCTs of monitoring strategies and reviewed the monitoring biomarker literature and how monitoring can have an impact on outcomes. Simulation studies were conducted to evaluate monitoring and improve the merits of health care. The monitoring biomarker literature is modest and robust conclusions are infrequent. We recommend improvements in research practice. Patients strongly endorsed the need for robust and conclusive research in this area. The clinical translation workstream focused on analytical and clinical validity. Cohorts were established for renal cell carcinoma (RCC) and renal transplantation (RT), with samples and patient data from multiple centres, as a rapid-access resource to evaluate the validity of biomarkers. Candidate biomarkers for RCC and RT were identified from the literature and their quality was evaluated and selected biomarkers were prioritised. The duration of follow-up was a limitation but biomarkers were identified that may be taken forward for clinical utility. In the third workstream, the ELUCIDATE trial registered 1303 patients and randomised 878 patients out of a target of 1000. The trial started late and recruited slowly initially but ultimately recruited with good statistical power to answer the key questions. ELF monitoring altered the patient process of care and may show benefits from the early introduction of interventions with further follow-up. The ELUCIDATE trial was an ‘exemplar’ trial that has demonstrated the challenges of evaluating biomarker strategies in ‘end-to-end’ RCTs and will inform future study designs.

Conclusions

The limitations in the programme were principally that, during the collection and curation of the cohorts of patients with RCC and RT, the pace of discovery of new biomarkers in commercial and non-commercial research was slower than anticipated and so conclusive evaluations using the cohorts are few; however, access to the cohorts will be sustained for future new biomarkers. The ELUCIDATE trial was slow to start and recruit to, with a late surge of recruitment, and so final conclusions about the impact of the ELF test on long-term outcomes await further follow-up. The findings from the three workstreams were used to synthesise a strategy and framework for future biomarker evaluations incorporating innovations in study design, health economics and health informatics.

Trial registration

Current Controlled Trials ISRCTN74815110, UKCRN ID 9954 and UKCRN ID 11930.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 6, No. 3. See the NIHR Journals Library website for further project information.

Long- and short-term outcomes in renal allografts with deceased donors: A large recipient and donor genome-wide association study

Improvements in immunosuppression have modified short-term survival of deceased-donor allografts, but not their rate of long-term failure. Mismatches between donor and recipient HLA play an important role in the acute and chronic allogeneic immune response against the graft. Perfect matching at clinically relevant HLA loci does not obviate the need for immunosuppression, suggesting that additional genetic variation plays a critical role in both short- and long-term graft outcomes. By combining patient data and samples from supranational cohorts across the United Kingdom and European Union, we performed the first large-scale genome-wide association study analyzing both donor and recipient DNA in 2094 complete renal transplant-pairs with replication in 5866 complete pairs. We studied deceased-donor grafts allocated on the basis of preferential HLA matching, which provided some control for HLA genetic effects. No strong donor or recipient genetic effects contributing to long- or short-term allograft survival were found outside the HLA region. We discuss the implications for future research and clinical application.

From a fish tank injury to hospital haemodialysis: the serious consequences of drug interactions

We present the case of a 68-year-old man admitted to hospital with severe acute kidney injury secondary to statin-induced rhabdomyolysis. Five weeks previously, the patient started a course of clarithromycin for infection of a finger wound with Mycobacterium marinum. His current medications included simvastatin, which he continued along with clarithromycin. The severity of the acute kidney injury necessitated initial continuous venovenous haemofiltration followed by 12 haemodialysis sessions before a spontaneous improvement in renal function occurred. Statins are widely prescribed and we report this case to encourage increased vigilance in avoiding drug interactions known to increase the risk of statin-induced myopathy, including macrolide antibiotics, calcium channel antagonists and amiodarone. The authors would also like to highlight recent guidance on atorvastatin as the statin of choice in patients with chronic kidney disease, and of the need for dose adjustment in those with an estimated glomerular filtration rate less than 30 mLs/min/1.73 m².

Campath, calcineurin inhibitor reduction and chronic allograft nephropathy (3C) study: background, rationale, and study protocol

Background

Kidney transplantation is the best treatment for patients with end-stage renal failure, but uncertainty remains about the best immunosuppression strategy. Long-term graft survival has not improved substantially, and one possible explanation is calcineurin inhibitor (CNI) nephrotoxicity. CNI exposure could be minimized by using more potent induction therapy or alternative maintenance therapy to remove CNIs completely. However, the safety and efficacy of such strategies are unknown.

Methods/Design

The Campath, Calcineurin inhibitor reduction and Chronic allograft nephropathy (3C) Study is a multicentre, open-label, randomized controlled trial with 852 participants which is addressing two important questions in kidney transplantation. The first question is whether a Campath (alemtuzumab)-based induction therapy strategy is superior to basiliximab-based therapy, and the second is whether, from 6 months after transplantation, a sirolimus-based maintenance therapy strategy is superior to tacrolimus-based therapy. Recruitment is complete, and follow-up will continue for around 5 years post-transplant. The primary endpoint for the induction therapy comparison is biopsy-proven acute rejection by 6 months, and the primary endpoint for the maintenance therapy comparison is change in estimated glomerular filtration rate from baseline to 2 years after transplantation. The study is sponsored by the University of Oxford and endorsed by the British Transplantation Society, and 18 centers for adult kidney transplant are participating.

Discussion

Late graft failure is a major issue for kidney-transplant recipients. If our hypothesis that minimizing CNI exposure with Campath-based induction therapy and/or an elective conversion to sirolimus-based maintenance therapy can improve long-term graft function and survival is correct, then patients should experience better graft function for longer. A positive outcome could change clinical practice in kidney transplantation.

Trial registration

ClinicalTrials.gov, NCT01120028 and ISRCTN88894088

Spontaneous abdominal hemorrhage with AA-amyloidosis and vasculitis in a patient with rheumatoid arthritis

Both rheumatoid vasculitis and amyloidosis in rheumatoid arthritis (RA) are uncommon. We describe a patient in whom they occurred together and were associated with fatal intra-abdominal hemorrhage. A 56-year-old Caucasian woman was referred because of increasing lethargy, edema, and proteinuria. She had suffered from seropositive, erosive, nodular RA for 14 years. Previously, she had undergone numerous joint replacements, a thyroidectomy for amyloid-associated (AA) amyloidosis of the thyroid that caused a large goiter and a renal biopsy that showed renal AA-amyloidosis in the context of nephrotic syndrome. As her condition deteriorated, this patient became increasingly reluctant to go to the hospital and to take drugs beyond analgesics. Thus, her RA was chronically under treated. While in the hospital for evaluation, this patient suddenly developed hypotension, tachycardia, and a severe colicky left-sided abdominal pain radiating from the left upper quadrant/epigastric region to the left iliac fossa. Computed tomography (CT) showed a large amount of echogenic free fluid within the abdomen and marked thickening of the omentum. At laparotomy, 2 liters of free blood was found adjacent to a hematoma of the greater omentum, and it was evacuated without identification of a discrete bleeding point. All solid and hollow organs were normal. The omentum was noted to be very friable. She developed a more disseminated bleeding diathesis and persistent peritoneal hemorrhage via her abdominal drains. She succumbed shortly afterward. Histology revealed extensive omental hemorrhage and one large vessel within the area of hemorrhage showed a severe necrotizing vasculitis. Extensive amyloid deposition was also found within the walls of the smaller omental arterioles. Vasculitis in the context of RA is relatively rare and is associated with under treated, seropositive disease. Skin and nerve involvement are most common, but bowel involvement has been reported, with a highly significant morbidity (partly due to late presentation/recognition). Similarly, AA-amyloidosis is a rare but feared long-term concomitant of under treated RA. Early recognition can permit successful anti-inflammatory therapy to affect a clinical and pathological remission; continued inflammatory stimulation is associated with rapid progression and demise. Chronically under treated patients with RA are more prone to rare but potentially devastating complications. Gastrointestinal catastrophes are a feature of both rheumatoid vasculitis and of amyloidosis, here uniquely co-localized.

Successful medical treatment of acute bilateral emphysematous pyelonephritis

Emphysematous pyelonephritis most often presents as an acute medical emergency, typically in a septic diabetic patient with acute renal failure. The management of this condition has traditionally been surgical, with nephrectomy. However, some recent reports have described successful medical interventions. We describe a case of acute bilateral emphysematous pyelonephritis in a frail patient not suitable for bilateral nephrectomy and long-term dialysis. This condition was managed medically, not surgically, with intensive antibiotic and circulatory support. The outcome was complete recovery after months of hospital-based treatment. We discuss the management of this rare but important condition in detail.

Obliterative bronchiolitis caused by multiple tumourlets and microcarcinoids successfully treated by single lung transplantation

Histological examination of a lung removed at transplantation revealed multiple peripheral tumourlets and microcarcinoids in close association with bronchioles causing an obliterative bronchiolitis. This was an unexpected finding but explained the progressive airflow limitation which characterised the patient's clinical course.

Bullous pemphigoid following radiotherapy

We report the case of a 57-year-old woman who developed bullous pemphigoid 3 weeks after electron beam radiotherapy. The bullae were confined to the area of the radiation field and responded to topical clobetasol propionate 0.05% cream (Dermovate). This is the second case of bullous pemphigoid confined to an area of previous radiotherapy. Radiotherapy may be a rare trigger for the development of bullous pemphigoid.