Dataset Information

Elicitation of expert prior opinion: application to the MYPAN trial in childhood polyarteritis nodosa.

ABSTRACT:

Objectives

Definitive sample sizes for clinical trials in rare diseases are usually infeasible. Bayesian methodology can be used to maximise what is learnt from clinical trials in these circumstances. We elicited expert prior opinion for a future Bayesian randomised controlled trial for a rare inflammatory paediatric disease, polyarteritis nodosa (MYPAN, Mycophenolate mofetil for polyarteritis nodosa).

Methods

A Bayesian prior elicitation meeting was convened. Opinion was sought on the probability that a patient in the MYPAN trial treated with cyclophosphamide would achieve disease remission within 6-months, and on the relative efficacies of mycophenolate mofetil and cyclophosphamide. Expert opinion was combined with previously unseen data from a recently completed randomised controlled trial in ANCA associated vasculitis.

Results

A pan-European group of fifteen experts participated in the elicitation meeting. Consensus expert prior opinion was that the most likely rates of disease remission within 6 months on cyclophosphamide or mycophenolate mofetil were 74% and 71%, respectively. This prior opinion will now be taken forward and will be modified to formulate a Bayesian posterior opinion once the MYPAN trial data from 40 patients randomised 1:1 to either CYC or MMF become available.

Conclusions

We suggest that the methodological template we propose could be applied to trial design for other rare diseases.

SUBMITTER: Hampson LV

PROVIDER: S-EPMC4378846 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Elicitation of expert prior opinion: application to the MYPAN trial in childhood polyarteritis nodosa.

Hampson Lisa V LV Whitehead John J Eleftheriou Despina D Tudur-Smith Catrin C Jones Rachel R Jayne David D Jayne David D Hickey Helen H Beresford Michael W MW Bracaglia Claudia C Caldas Afonso A Cimaz Rolando R Dehoorne Joke J Dolezalova Pavla P Friswell Mark M Jelusic Marija M Marks Stephen D SD Martin Neil N McMahon Anne-Marie AM Peitz Joachim J van Royen-Kerkhof Annet A Soylemezoglu Oguz O Brogan Paul A PA

PloS one 20150330 3

<h4>Objectives</h4>Definitive sample sizes for clinical trials in rare diseases are usually infeasible. Bayesian methodology can be used to maximise what is learnt from clinical trials in these circumstances. We elicited expert prior opinion for a future Bayesian randomised controlled trial for a rare inflammatory paediatric disease, polyarteritis nodosa (MYPAN, Mycophenolate mofetil for polyarteritis nodosa).<h4>Methods</h4>A Bayesian prior elicitation meeting was convened. Opinion was sought o ...[more]

PMID: 25822991

Similar Datasets

Project description:Background and Purpose: The management of unruptured intracranial aneurysms remains controversial. The decisions to treat are heavily informed by estimated risk of bleeding. However, these estimates are imprecise, and better methods for stratifying the risk or tailoring treatment strategy are badly needed. Here, we demonstrate an initial proof-of-principle concept for endovascular biopsy to identify the key molecular pathways and gene expression changes associated with aneurysm formation. We couple this technique with single cell RNA sequencing (scRNAseq) to develop a roadmap of the pathogenic changes of a dolichoectatic vertebrobasilar aneurysm in a patient with polyarteritis nodosa. Methods: Endovascular biopsy and fluorescence activated cell sorting was used to isolate the viable endothelial cells (ECs) using the established techniques. A single cell RNA sequencing (scRNAseq) was then performed on 24 aneurysmal ECs and 23 patient-matched non-aneurysmal ECs. An integrated panel of bioinformatic tools was applied to determine the differential gene expression, enriched signaling pathways, and cell subpopulations hypothesized to drive disease pathogenesis. Results: We identify a subset of 7 (29%) aneurysm-specific ECs with a distinct gene expression signature not found in the patient-matched control ECs. A gene set enrichment analysis identified these ECs to have increased the expression of genes regulating the leukocyte-endothelial cell adhesion, major histocompatibility complex (MHC) class I, T cell receptor recycling, tumor necrosis factor alpha (TNFα) response, and interferon gamma signaling. A histopathologic analysis of a different intracranial aneurysm that was later resected yielded a diagnosis of polyarteritis nodosa and positive staining for TNFα. Conclusions: We demonstrate feasibility of applying scRNAseq to the endovascular biopsy samples and identify a subpopulation of ECs associated with cerebral aneurysm in polyarteritis nodosa. Endovascular biopsy may be a safe method for deriving insight into the disease pathogenesis and tailoring the personalized treatment approaches to intracranial aneurysms.

Project description:BACKGROUND:Excess cardiovascular mortality complicates systemic rheumatic disease, suggesting an accelerated atheromatous process, which it has been proposed relates to the vascular inflammation common in such diseases. Impaired endothelium dependent vasodilatation is an early marker of atheromatous disease. It has previously been shown that such endothelial cell dysfunction (ECD) occurring in the brachial artery can complicate primary systemic necrotising vasculitis (SNV). OBJECTIVE:To determine if ECD occurs in a wider spectrum of primary SNV, if it is restricted to the major arteries, and whether vasculitis subgroup, ANCA status, or renal involvement influenced the endothelial responses. METHODS:Fifty four patients attending the Birmingham vasculitis clinic, including patients with a range of ANCA and non-ANCA associated primary vasculitides, and a group of age matched controls were recruited. The length of patient follow up and disease activity was variable. Disease activity, damage scores, and cardiovascular risk factors were recorded before assessment of flow mediated brachial artery vasodilatation by high resolution ultrasound. Dermal microvascular responses to acetylcholine were also measured in 32 patients and 21 controls by laser Doppler flowmetry. RESULTS:ECD was demonstrated in all primary SNV subgroups of patients with ANCA associated vasculitis and in polyarteritis nodosa, compared with controls. Significant impairment occurred in both vascular beds, regardless of vessel size targeted in the inflammatory vasculitis, ANCA association and titre, or renal involvement. CONCLUSIONS:Diffuse endothelial dysfunction, a predictor of atherosclerotic disease, is found extensively in primary systemic vasculitis. Involvement of different vascular beds is independent of target vessel size or ANCA association, and is unrelated to local disease expression. It is suggested that this results from a systemic response that may be a consequence of primary vasculitis, but is distinct from the local inflammatory vasculitic process.

Project description:Nearly 4 years after the first report of the emergence of Middle-East respiratory syndrome Coronavirus (MERS-CoV) and nearly 1800 human cases later, the ecology of MERS-CoV, its epidemiology, and more than risk factors of MERS-CoV transmission between camels are poorly understood. Knowledge about the pathways and mechanisms of transmission from animals to humans is limited; as of yet, transmission risks have not been quantified. Moreover the divergent sanitary situations and exposures to animals among populations in the Arabian Peninsula, where human primary cases appear to dominate, vs. other regions in the Middle East and Africa, with no reported human clinical cases and where the virus has been detected only in dromedaries, represents huge scientific and health challenges. Here, we have used expert-opinion elicitation in order to obtain ideas on relative importance of MERS-CoV risk factors and estimates of transmission risks from various types of contact between humans and dromedaries. Fourteen experts with diverse and extensive experience in MERS-CoV relevant fields were enrolled and completed an online questionnaire that examined pathways based on several scenarios, e.g., camels-camels, camels-human, bats/other species to camels/humans, and the role of diverse biological substances (milk, urine, etc.) and potential fomites. Experts believed that dromedary camels play the largest role in MERS-CoV infection of other dromedaries; however, they also indicated a significant influence of the season (i.e. calving or weaning periods) on transmission risk. All experts thought that MERS-CoV-infected dromedaries and asymptomatic humans play the most important role in infection of humans, with bats and other species presenting a possible, but yet undefined, risk. Direct and indirect contact of humans with dromedary camels were identified as the most risky types of contact, when compared to consumption of various camel products, with estimated "most likely" incidence risks of at least 22 and 13% for direct and indirect contact, respectively. The results of our study are consistent with available, yet very limited, published data regarding the potential pathways of transmission of MERS-CoV at the animal-human interface. These results identify key knowledge gaps and highlight the need for more comprehensive, yet focused research to be conducted to better understand transmission between dromedaries and humans.

Project description:Purpose:To report a case of Polyarteritis Nodosa (PAN) presenting as bilateral episcleritis and interstitial keratitis along with erythema nodosum and atrial fibrillation and to review the ophthalmic literature on PAN with anterior segment findings. Observations:A 35-year old man presented with a two-month history of bilateral episcleritis, skin lesions consistent with erythema nodosum, joint effusions and episodes of prolonged diarrhea and atrial fibrillation. Ophthalmic examination was significant for bilateral diffuse episcleral injection and nummular corneal stromal infiltrates. The patient underwent an extensive infectious and inflammatory work-up that was negative except for a very elevated erythrocyte sedimentation rate (123 mm/h, normal < 20 mm/h) and C-reactive protein (51 mg/L, normal < 5 mg/L). In order to rule out inflammatory bowel disease upper endoscopy and colonoscopy were performed. Biopsies of the gastrointestinal mucosa were positive for a small- and medium-vessel necrotizing vasculitis consistent with polyarteritis nodosa. Disease control was achieved with systemic prednisone and azathioprine. Upon self-tapering both medications the patient developed hearing loss and interstitial keratitis recurred, hence the diagnosis of Cogan's syndrome/PAN was made. Intravenous pulse steroids were administered with resolution of his symptoms. The patient continues to be on azathioprine without disease recurrence for 1.5 years. ? review of the ophthalmic literature on PAN with anterior segment findings revealed only 10 cases; of these, 6 had originally presented with ocular manifestations alone (scleritis, peripheral ulcerative keratitis, episcleritis, dacryoadenitis) and 4 of these 6 were lethal due to delay in diagnosis. Conclusion and importance:Early diagnosis of PAN is crucial, as the five-year mortality rate is close to 90%; upon initiation of systemic immunosuppression the mortality rate drops to 20%. Though PAN manifestations in the anterior segment are rare, a high index of suspicion is warranted in cases of bilateral episcleritis and interstitial keratitis.

Dataset Information

Elicitation of expert prior opinion: application to the MYPAN trial in childhood polyarteritis nodosa.

Objectives

Methods

Results

Conclusions

Publications

Elicitation of expert prior opinion: application to the MYPAN trial in childhood polyarteritis nodosa.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets