How to use the Harmonising Outcome Measures for Eczema Core Outcome Set for atopic dermatitis trials: a users' guide.

BACKGROUND: The Harmonising Outcome Measures for Eczema (HOME) initiative has agreed upon the Core Outcome Set (COS) for use in atopic dermatitis (AD) clinical trials, but additional guidance is needed to maximize its uptake. OBJECTIVES: To provide answers to some of the commonly asked questions about using the HOME COS; to provide data to help with the interpretation of trial results; and to support sample size calculations for future trials. METHODS AND RESULTS: We provide practical guidance on the use of the HOME COS for investigators planning clinical trials in patients with AD. It answers some of the common questions about using the HOME COS, how to access the outcome measurement instruments, what training/resources are needed to use them appropriately and clarifies when the COS is applicable. We also provide exemplar data to inform sample size calculations for eczema trials and encourage standardized data collection and reporting of the COS. CONCLUSIONS: By encouraging adoption of the COS and facilitating consistent reporting of outcome data, it is hoped that the results of eczema trials will be more comprehensive and readily combined in meta-analyses and that patient care will subsequently be improved.

A core domain set for pyoderma gangrenosum trial outcomes: an international eDelphi and consensus study from the UPGRADE initiative.

BACKGROUND: Pyoderma gangrenosum (PG) is a rare ulcerative skin condition with no current standardized outcomes or outcome measures. With a rich investigational therapeutic pipeline, standardization of outcomes and improvement of data quality and interpretability will promote the appropriate and consistent evaluation of potential new therapies. Core outcome sets (COS) are agreed, standardized sets of outcomes that represent the minimum that should be measured and reported in all clinical trials of a specific condition. OBJECTIVES: To identify and reach a consensus on which domains (what to be measured) should be included in the Understanding Pyoderma Gangrenosum: Review and Analysis of Disease Effects (UPGRADE) core domain set for clinical trials in PG. METHODS: Collaborative discussions between patients and PG experts, and a systematic review of the literature identified items and prospective domains. A three-round international eDelphi exercise was performed to prioritize the domains and refine the provisional items (consensus: ≥ 70% of participants rating a domain as 'extremely important' and < 15% of participants voting 'not important'), followed by an international meeting to reach consensus on the core domain set (consensus: < 30% disagreement). Item-generation discussions and consensus meetings were hosted via online videoconferences. The eDelphi exercise and consensus voting were performed using Qualtrics survey software. Participants were adults with PG, healthcare professionals, researchers and industry representatives. RESULTS: Collaborative discussions and systematic reviews yielded 115 items, which were distilled into 15 prospective domains. The eDelphi exercise removed the three lowest-priority domains ('laboratory tests', 'treatment costs' and 'disease impact on family') and ranked 'pain', 'quality of life' and 'physical symptoms' as the highest-priority prospective domains. Consensus was reached on the domains of 'pain', 'quality of life' and 'clinical signs'. The domain of 'disease course/disease progression' narrowly failed to reach consensus for inclusion in the core set (32% of participants voted 'no'). Refinement of this domain definition will be required and presented for consideration at future consensus meetings. CONCLUSIONS: The UPGRADE core domain set for clinical trials in PG has been agreed by international multistakeholder consensus. Future work will develop and/or select outcome measurement instruments for these domains to establish a COS.

International consensus on methotrexate dosing for patients with atopic dermatitis: An eDelphi study.

BACKGROUND: Despite the widespread off-label use of methotrexate (MTX) for the treatment of atopic dermatitis (AD), there is limited high-quality evidence on dosing regimens and existing guidelines do not provide clear recommendations regarding dosing strategies. OBJECTIVE: The aim of this study was to achieve international consensus among AD experts to standardize the dosing regimen for MTX treatment in adults and children with AD. METHODS: An electronic Delphi (eDelphi) study was conducted from October 2021 to September 2022. Recruitment was conducted through dermatology societies and AD interest groups. Participation was open to dermatologists and dermatology residents experienced in treating AD patients with MTX. The study consisted of three online rounds. The first round was informed by a systematic review of relevant literature, and subsequent rounds were adjusted based on the results of the previous round. Participants voted on 19 proposals using a 9-point scale (1-3 disagree, 4-6 neither agree nor disagree, 7-9 agree). Consensus was achieved when at least 70% of participants agreed, and less than 15% disagreed. Proposals that did not reach consensus in the first three rounds were discussed in a consensus meeting, where consensus was defined as less than 30% disagreement. RESULTS: In total, 152 participants completed Round 1, 104 (68%) completed all survey rounds, and 43 (28%) joined the consensus meeting. Consensus was achieved on 7 proposals in Round 1, 4 in Round 2 and 6 in Round 3. The final 2 proposals reached consensus during the consensus meeting. Consensus topics include test dose, start dose, maximum dose, administration route, dosing schedule, management of stopping treatment, treatment duration and folic acid supplementation. CONCLUSIONS: This eDelphi study achieved consensus on 19 proposals related to MTX dosing for adults and children with AD. These results aim to guide prescribing decisions and encourage a standardized global approach to MTX use in AD.

The Harmonising Outcome Measures for Eczema (HOME) implementation roadmap.

BACKGROUND: Core outcome sets (COS) are consensus-driven sets of minimum outcomes that should be measured and reported in all clinical trials. COS aim to reduce heterogeneity in outcome measurement and reporting, and selective outcome reporting. Implementing COS into clinical trials is challenging. Guidance to improve COS uptake in dermatology is lacking. OBJECTIVES: To develop a structured practical guide to COS implementation. METHODS: Members of the Harmonising Outcome Measurement for Eczema (HOME) executive committee developed an expert opinion-based roadmap founded on a combination of a review of the COS implementation literature, the Core Outcome Measures in Effectiveness Trials (COMET) initiative resources, input from HOME members and experience in COS development and clinical trials. RESULTS: The data review and input from HOME members was synthesized into themes, which guided roadmap development: (a) barriers and facilitators to COS uptake based on stakeholder awareness/engagement and COS features; and (b) key implementation science principles (assessment-driven, data-centred, priority-based and context-sensitive). The HOME implementation roadmap follows three stages. Firstly, the COS uptake scope and goals need to be defined. Secondly, during COS development, preparation for future implementation is supported by establishing the COS as a credible evidence-informed consensus by applying robust COS development methodology, engaging multiple stakeholders, fostering sustained and global engagement, emphasizing COS ease of use and universal applicability, and providing recommendations on COS use. Thirdly, incorporating completed COS into primary (trials) and secondary (reviews) research is an iterative process starting with mapping COS uptake and stakeholders' attitudes, followed by designing and carrying out targeted implementation projects. Main themes for implementation projects identified at HOME are stakeholder awareness/engagement; universal applicability for different populations; and improving ease-of-use by reducing administrative and study burden. Formal implementation frameworks can be used to identify implementation barriers/facilitators and to design implementation strategies. The effect of these strategies on uptake should be evaluated and implementation plans adjusted accordingly. CONCLUSIONS: COS can improve the quality and applicability of research and, so, clinical practice but can only succeed if used and reported consistently. The HOME implementation roadmap is an extension of the original HOME roadmap for COS development and provides a pragmatic framework to develop COS implementation strategies.

Mapping exercise and status update of eight established registries within the TREatment of ATopic eczema Registry Taskforce.

BACKGROUND: The TREatment of ATopic eczema (TREAT) Registry Taskforce is a collaborative international network of registries collecting data of atopic eczema (AE) patients receiving systemic and phototherapy with the common goal to provide long-term real-world data on the effectiveness, safety and cost-effectiveness of therapies. A core dataset, consisting of domains and domain items with corresponding measurement instruments, has been developed to harmonize data collection. OBJECTIVES: We aimed to give an overview of the status and characteristics of the eight established TREAT registries, and to perform a mapping exercise to examine the degree of overlap and pooling ability between the national registry datasets. This will allow us to determine which research questions can be answered in the future by pooling data. METHODS: All eight registries were asked to share their dataset and information on the current status and characteristics. The overlap between the core dataset and each registry dataset was identified (according to the domains, domain items and measurement instruments of the TREAT core dataset). RESULTS AND CONCLUSIONS: A total of 4702 participants have been recruited in the eight registries as of 1st of May 2022. Of the 69 core dataset domain items, data pooling was possible for 69 domain item outcomes in TREAT NL (the Netherlands), 61 items in A-STAR (UK and Ireland), 38 items in TREATgermany (Germany), 36 items in FIRST (France), 33 items in AtopyReg (Italy), 29 items in Biobadatop (Spain), 28 items in SCRATCH (Denmark) and 20 items in SwedAD (Sweden). Pooled analyses across all registries can be performed on multiple important domain items, covering the main aims of analysing data on the (cost-)effectiveness and safety of AE therapies. These results will facilitate future comparative or joint analyses.

The HOME Core outcome set for clinical trials of atopic dermatitis.

Core outcome sets are critically important outcomes that should be measured in clinical trials. Their absence in atopic dermatitis is a form of research waste and impedes combining evidence to inform patient care. Here, we articulate the rationale for core outcome sets in atopic dermatitis and review the work of the international Harmonising Outcome Measures for Eczema group from its inception in Munich, 2010. We describe core domain determination (what should be measured), to instrument selection (how domains should be measured), culminating in the complete core outcome measurement set in Tokyo, 2019. Using a "road map," Harmonising Outcome Measures for Eczema includes diverse research methods including Delphi and nominal group techniques informed by systematic reviews of properties of candidate instruments. The 4 domains and recommended instruments for including in all clinical trials of atopic dermatitis are patient symptoms, measured by Patient-Oriented Eczema Measure and peak Numerical Rating Scale 11 for itch intensity over 24 hours, clinical signs measured using the Eczema Area and Severity Index, quality of life measured by the Dermatology Life Quality Index series for adults, children, and infants, and long-term control measured by either Recap of atopic eczema or Atopic Dermatitis Control Tool.

Long-term effectiveness and safety of treatment with dupilumab in patients with atopic dermatitis: Results of the TREAT NL (TREatment of ATopic eczema, the Netherlands) registry.

BACKGROUND: Evidence on long-term dupilumab treatment for atopic dermatitis in daily practice is lacking. OBJECTIVE: To investigate patient characteristics, treatment aspects, effectiveness, and safety of up to 84 weeks of dupilumab treatment. METHODS: An observational prospective cohort study was conducted of patients with atopic dermatitis starting dupilumab in routine clinical care. RESULTS: Of the 221 included patients, 103 used systemic therapy at baseline. At 84 weeks, we found a change of -15.2 (SE, 1.7) for the Eczema Area and Severity Index, -16.9 (SE, 1.4) for the Patient-Oriented Eczema Measure, and -17.2 (SE, 1.6) for the Dermatology Life Quality Index. We found a trend for improvement over time for the Investigator Global Assessment and Numerical Rating Scale for pruritus. Severe (n = 79) including serious (n = 11) adverse events were observed in 69 patients. Eye complaints were most frequently reported (n = 46). Twenty-one patients adjusted the regular dosing schedule, and 14 patients discontinued treatment, mainly due to ineffectiveness (n = 7). LIMITATIONS: Only adverse events of severe and serious nature were registered for feasibility reasons. CONCLUSION: Daily practice dupilumab treatment of up to 84 weeks is generally well-tolerated, apart from the reporting of eye complaints. It can be considered a long-term effective treatment for atopic dermatitis in combination with topical and initial concomitant systemic treatment, showing a sustained improvement of signs, symptoms, and quality of life.

Measuring atopic eczema symptoms in clinical practice: The first consensus statement from the Harmonising Outcome Measures for Eczema in clinical practice initiative.

BACKGROUND: Measuring patient-centered outcomes in clinical practice is valuable for monitoring patients and advancing real-world research. A new initiative from the Harmonising Outcome Measures for Eczema (HOME) group aims to recommend what might be recorded for atopic eczema patients in routine clinical care. OBJECTIVES: Prioritize outcome domains to measure atopic eczema in clinical practice and select valid and practical outcome measurement instruments for the highest-priority domain. METHODS: An online survey of HOME members identified and ranked 21 possible health domains. Suitable instruments were then selected for the top-prioritized domain at the HOME VI meeting, using established consensus processes informed by systematic reviews of instrument quality. RESULTS: Patient-reported symptoms was the top-prioritized domain. In accordance with psychometric properties and feasibility, there was consensus that the recommended instruments to measure atopic eczema symptoms in clinical practice are the POEM, the PO-SCORAD index, or both. The numeric rating scale for itch received support pending definition and validation in atopic eczema. CONCLUSION: Following the first step of the HOME Clinical Practice initiative, we endorse using the POEM, the PO-SCORAD index, or both for measuring atopic eczema symptoms in clinical practice. Additional high-priority domains for clinical practice will be assessed at subsequent HOME meetings.

The wide variety of methotrexate dosing regimens for the treatment of atopic dermatitis: a systematic review.

Background:Methotrexate is an off-label therapy for atopic dermatitis. A lack of consensus on dosing regimens poses a risk of underdosing and ineffective treatment or overdosing and increased risk of side effects. This systematic review summarizes the available evidence on dosing regimens.Materials and methods:A literature search was conducted, screening all randomized controlled trials (RCTs) and guidelines published up to 6 July 2023, in the MEDLINE, Embase, and Cochrane Library databases.Results:Five RCTs and 21 guidelines were included. RCTs compared methotrexate with other treatments rather than different methotrexate dosing regimens. The start and maintenance doses in RCTs varied between 7.5-15 mg/week and 14.5-25 mg/week, respectively. Despite varied dosing, all RCTs demonstrated efficacy in improving atopic dermatitis signs and symptoms. Guidelines exhibited substantial heterogeneity but predominantly proposed starting doses of 5-15 mg/week for adults and 10-15 mg/m2/week for children. Maintenance doses suggested were 7.5-25 mg/week for adults and 0.2-0.7 mg/kg/week for children. One guideline suggested a test dose and nearly half advised folic acid supplementation.Conclusion:This systematic review highlights the lack of methotrexate dosing guidelines for atopic dermatitis. It identifies commonly recommended and utilized dosing regimens, serving as a valuable resource for clinicians prescribing methotrexate off-label and providing input for an upcoming consensus study.

Measuring Signs of Atopic Dermatitis in Clinical Practice: A HOME-CP Consensus Statement.

Importance: Outcome measurement is an essential component of value-based health care and can aid patient care, quality improvement, and clinical effectiveness evidence generation. The Harmonising Outcome Measures for Eczema Clinical Practice initiative aims to identify a list of validated, feasible, outcome measurement instruments recommended to measure atopic dermatitis (AD) in the clinical practice setting. The clinical practice set is a list of instruments that clinicians can pick and choose from to suit their needs in the context of clinical care. Objective: To recommend instruments to measure clinical signs of AD in clinical practice. Evidence Review: Following the predefined roadmap, a mixed methods design was implemented and incorporated systematic reviews and qualitative consensus methods. Previous systematic reviews identified few clinical signs instruments with sufficient validation for recommendation. An updated systematic review evaluating the validity of clinical signs instruments informed an international meeting to reach consensus on recommended instruments to measure AD clinical signs in clinical practice. Consensus was defined as less than 30% disagreement. An in-person consensus exercise was held in Montreal, Canada, on October 16, 2022. The 34 attendees included patient and patient advocate research partners, health care professionals, researchers, methodologists, and industry representatives. Findings: The updated systematic review found that the Eczema Area and Severity Index (EASI), Scoring Atopic Dermatitis, and objective Scoring Atopic Dermatitis were the only instruments that demonstrated sufficient performance in all assessed measurement properties. The modified EASI and Signs Global Assessment × Body Surface Area instruments were also recommended. The EASI, Validated Investigator Global Assessment, and Investigator's Global Assessment multiplied by or measured concurrently with a body surface area measure achieved consensus in criteria and were adopted. Conclusions and Relevance: This consensus statement by the Harmonising Outcome Measures for Eczema initiative suggests that when assessing and documenting clinical signs of AD, there are several valid and feasible instruments that can best fit a clinician's specific practice needs. These instruments should improve and standardize the documentation of signs severity, help determine the effect of treatment, facilitate the generation of clinical effectiveness evidence, and enhance the implementation of value-based health care.

Eligibility Criteria for Active Ulcerative Pyoderma Gangrenosum in Clinical Trials: A Delphi Consensus on Behalf of the UPGRADE (Understanding Pyoderma Gangrenosum: Review and Assessment of Disease Effects) Group.

At present, there are no standardized guidelines for determining patient eligibility for pyoderma gangrenosum (PG) clinical trials. Thus, we aim to determine which clinical features, histopathological features, or laboratory features should be included in active ulcerative PG clinical trial eligibility criteria for treatment-naïve patients and patients already treated with immunomodulating medications (treatment-exposed patients). This study employed 4 rounds of the Delphi technique. Electronic surveys were administered to 21 international board-certified dermatologists and plastic surgeon PG experts (June 2022-December 2022). Our results demonstrated that for a patient to be eligible for a PG trial, they must meet the following criteria: (i) presence of ulcer(s) with erythematous/violaceous undermining wound borders, (ii) presence of a painful or tender ulcer, (iii) history/presence of rapidly progressing disease, (iv) exclusion of infection and other causes of cutaneous ulceration, (v) biopsy for H&E staining, and (vi) a presence/history of pathergy. These criteria vary in importance for treatment-naïve versus treatment-exposed patients. Given the international cohort, we were unable to facilitate live discussions between rounds. This Delphi consensus study provides a set of specific, standardized eligibility criteria for PG clinical trials, thus addressing one of the main issues hampering progress toward Food and Drug Administration approval of medications for PG.

Italian S3-Guideline on the treatment of Atopic Eczema - Part 1: Systemic therapy, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Environmental Dermatology (SIDAPA).

SIDeMaST (Società Italiana di Dermatologia Medica, Chirurgica, Estetica e delle Malattie Sessualmente Trasmesse) contributed to the development of the present guideline on the systemic treatment of chronic plaque psoriasis. With the permission of EuroGuiDerm, SIDeMaST adapted the guideline to the Italian healthcare context to supply a reliable and affordable tool to Italian physicians who take care of patients affected by atopic dermatitis. The evidence- and consensus-based guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. This first part of the guideline includes general information on its scope and purpose, the health questions covered, target users and a methods section. It also provides guidance on which patients should be treated with systemic therapies, as well as recommendations and detailed information on each systemic drug. The systemic treatment options discussed in the guideline comprise conventional immunosuppressive drugs (azathioprine, ciclosporin, glucocorticosteroids, methotrexate and mycophenolate mofetil), biologics (dupilumab, lebrikizumab, nemolizumab, omalizumab and tralokinumab) and janus kinase inhibitors (abrocitinib, baricitinib and upadacitinib). Part two of the guideline will address avoidance of provocation factors, dietary interventions, immunotherapy, complementary medicine, educational interventions, occupational and psychodermatological aspects, patient perspective and considerations for pediatric, adolescent, pregnant and breastfeeding patients.

Italian S3-Guideline on the treatment of Atopic Eczema - Part 2: non-systemic treatments and treatment recommendations for special AE patient populations, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Occupational Dermatology (SIDAPA).

SIDeMaST (Società Italiana di Dermatologia Medica, Chirurgica, Estetica e delle Malattie Sessualmente Trasmesse) contributed to the development of the present guideline on the systemic treatment of chronic plaque psoriasis. With the permission of EuroGuiDerm, SIDeMaST adapted the guideline to the Italian healthcare context to supply a reliable and affordable tool to Italian physicians who take care of patients affected by atopic dermatitis. The evidence- and consensus-based guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. This second part of the guideline includes recommendations and detailed information on basic therapy with emollients and moisturizers, topical anti-inflammatory treatment, antimicrobial and antipruritic treatment and UV phototherapy. Furthermore, this part of the guideline covers techniques for avoiding provocation factors, as well as dietary interventions, immunotherapy, complementary medicine and educational interventions for patients with atopic eczema and deals with occupational and psychodermatological aspects of the disease. It also contains guidance on treatment for pediatric and adolescent patients and pregnant or breastfeeding women, as well as considerations for patients who want to have a child. A chapter on the patient perspective is also provided. The first part of the guideline, published separately, contains recommendations and guidance on systemic treatment with conventional immunosuppressive drugs, biologics and janus kinase (JAK) inhibitors, as well as information on the scope and purpose of the guideline, and a section on guideline methodology.

Italian S3-Guideline on the treatment of Atopic Eczema - First Update, adapted from EuroGuiDerm by the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Occupational Dermatology (SIDAPA).

The evidence- and consensus-based guideline on atopic eczema, published in JEADV on 18 August 2022 (part 1) and 3 September 2022 (part 2) was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. To reflect the most recent evidence on novel systemic medications, an update was published in October 2022. According to the purpose of the Italian Society of Dermatology and STD (SIDEMAST), the Italian Association of Hospital Dermatologists (ADOI) and the Italian Society of Allergological and Environmental Dermatology (SIDAPA) to adapt the EuroGuiDerm guideline on the treatment of atopic eczema into the Italian Healthcare setting, the original update has been supplemented by inserting notes, well highlighted by the original text, to emphasize the laws, rules, procedures and suggestions of the Italian Ministry of Health and regional Health authorities.

The clinical relevance of dupilumab serum concentration in patients with atopic dermatitis: a two-center prospective cohort study.

BACKGROUND: Dupilumab is prescribed in one dosage across adult atopic dermatitis patients. Differences in drug exposure may explain variation in treatment response. OBJECTIVE: Investigating the clinical relevance of dupilumab serum concentration in atopic dermatitis in real-world practice. METHODS: In two centers (Netherlands, UK), adults treated with dupilumab for atopic dermatitis were evaluated for effectiveness and safety pretreatment and at 2, 12, 24, and 48 weeks; trough serum samples were analyzed for dupilumab concentration at corresponding time points. RESULTS: In 149 patients, median dupilumab levels during follow-up ranged from 57.4 to 72.4 µg/mL. Levels showed high inter-patient and low intra-patient variability. No correlation was found between levels and ΔEASI. At 2 weeks, levels of ≥64.1 µg/mL predict EASI ≤7 at 24 weeks (specificity:100%, sensitivity:60%; p = .022). At 12 weeks, ≤32.7 µg/mL predicts EASI >7 at 24 weeks (sensitivity:95%, specificity:26%; p = .011). Inverse correlations were found between baseline EASI and levels at 2, 12, and 24 weeks (r = -0.25 to 0.36; p ≤ .023). Low levels were particularly observed in patients with adverse events, treatment interval deviation, and discontinuation. CONCLUSION: At the on-label dosage, the measured range of dupilumab levels does not seem to yield differences in treatment effectiveness. However, disease activity does seem to influence dupilumab levels - higher baseline disease activity results in lower levels at follow-up.

Minimum data set for treatment effectiveness in pyoderma gangrenosum (MIDSTEP): an international protocol of an e-Delphi study to develop a clinical physician-driven treatment effectiveness registry on behalf of the UPGRADE initiative.

Pyoderma gangrenosum (PG) is a rare inflammatory condition with an immense disease burden that remains understudied. With limited approved treatments and low-quality clinical evidence, PG continues to have poor patient outcomes. Unfortunately, improvement in PG treatments and patient care is based on additional research endeavors that can only be developed from existing high-quality data. The following protocol outlines the development of the Minimum Data Set for Treatment Effectiveness in Pyoderma gangrenosum (MIDSTEP), a core set of domains and domain items for the Pyoderma Gangrenosum Treatment Effectiveness (PyGaTE) international registry. The outcomes and benefits are focused on providing real-world data for physicians to improve their clinical decisions on PG treatment and inform clinical trial design, promoting clinical research among the international scientific community. MIDSTEP is a multi-phase project. The first phase will produce a domain item list from a literature review to take into the second phase which would finalize the core data set by an e-Delphi exercise. There will be a single stakeholder group participating together in the e-Delphi consisting of PG experts (healthcare providers, researchers, methodologists, industry representatives, and regulators), ulcerative PG patients, and PG patient advocates. The methodology outlined in the protocol is a systematic method based on several guidelines through COMET and established dermatologic registries and outcome sets with systematic methodologies of their own. The third phase will identify the instruments for the items, the 'when to measure' the items, and the platform for the registry. The last phase is the implementation and continued maintenance of the international registry PyGaTE. By solidifying a consensus on standardized outcomes and collecting information on PG treatment effectiveness in a centralized database, existing treatments can be compared more systematically and analyzed with increased evidence. MIDSTEP and the PyGaTE international registry will have the ambitious goal to generate and disseminate real-world data that can be used by all stakeholders to improve health outcomes for PG patients. Future potential for the outcome of this project includes the development of a gold-standard PG treatment.

The "Understanding Pyoderma Gangrenosum, Review and Assessment of Disease Effects (UPGRADE)" Project: a protocol for the development of the core outcome domain set for trials in pyoderma gangrenosum.

INTRODUCTION: Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that affects approximately 0.3-6 out of every 100,000 people worldwide. Clinical trials are scarce but there is growing interest in using newer and more targeted therapeutics to achieve disease remission. However, there are no standardized instruments to measure outcomes in PG and, therefore, future clinical trials are hampered by the absence of established and accurate means of assessment and comparison. Therefore, we aim to produce an internationally accepted core outcome set (COS) that will overcome this obstacle. This protocol outlines our intended approach to achieve the first part of this process, establishing a core outcome domain set. METHODS: An international team of PG stakeholders, consisting of physicians, wound care nurses, patients, scientists and industry representatives, has been assembled for the purpose of building a comprehensive and universally established set of core outcome domains. During the first step, we will generate items of relevance using a nominal process from all stakeholders. Items will be distilled and collapsed into potential domains and subdomains. A systematic review of current methods for reporting PG has already been published and domains identified in this work will be considered in the generation of the core domains set. During the second step, after the potential domains and subdomains are identified, stakeholders will participate in an e-Delphi exercise to rate the importance of (sub)domains. A final consensus meeting will be organized with the goal of establishing a core domain set. CONCLUSION: Pyoderma gangrenosum lacks an established COS and previously published clinical trials have used inconsistent measures established from similarly inconsistent domains. As a first step this study seeks to create a core domain set within the COS, to build the foundation for future core outcome work for PG.