Molecular Therapeutics in Development for Epidermolysis Bullosa: Update 2020

Comprehensive orthodontic treatment using miniscrews and digital rehabilitation in a patient with severe recessive dystrophic epidermolysis bullosa

INTRODUCTION

Epidermolysis bullosa (EB) is a rare genetic disorder characterized by skin fragility and blister formation. The phenotypic presentation is broad with four major types, being Recessive Dystrophic EB (RDEB) the most severe, including oral anomalies such as severe microstomia, ankyloglossia, vestibule obliteration and occlusal anomalies, turning orthodontic treatment into a challenge.

AIM

This case report aims to present the comprehensive treatment of a patient with severe RDEB, including periodontal surgery, orthodontic fixed braces with mini-screws and oral rehabilitation with anterior veneers.

CASE REPORT

A 27-year-old female patient with severe RDEB received orthodontic treatment in the upper jaw to improve malalignment and anterior crossbite. After 13 months of treatment with fixed appliances, miniscrews were placed in the anterior segment to intrude and procline the upper incisors. Oral surgery was performed to increase the vestibule depth of the upper lip. Once edge-to-edge occlusion was obtained, anterior veneers were placed to improve aesthetic and stabilize occlusion, especially with the lack of posterior support.

DISCUSSION

The multidisciplinary treatment approach, involving orthodontic treatment, periodontal surgery and oral rehabilitation, played a crucial role in achieving favorable results. This case highlights the successful use of miniscrews as a viable orthodontic approach for patients with severe RDEB.

Gene-edited cells: novel allogeneic gene/cell therapy for epidermolysis bullosa

Epidermolysis bullosa (EB) is a group of rare genetic skin fragility disorders, which are hereditary. These disorders are associated with mutations in at least 16 genes that encode components of the epidermal adhesion complex. Currently, there are no effective treatments for this disorder. All current treatment approaches focus on topical treatments to prevent complications and infections. In recent years, significant progress has been achieved in the treatment of the severe genetic skin blistering condition known as EB through preclinical and clinical advancements. Promising developments have emerged in the areas of protein and cell therapies, such as allogeneic stem cell transplantation; in addition, RNA-based therapies and gene therapy approaches have also become a reality. Stem cells obtained from embryonic or adult tissues, including the skin, are undifferentiated cells with the ability to generate, maintain, and replace fully developed cells and tissues. Recent advancements in preclinical and clinical research have significantly enhanced stem cell therapy, presenting a promising treatment option for various diseases that are not effectively addressed by current medical treatments. Different types of stem cells such as primarily hematopoietic and mesenchymal, obtained from the patient or from a donor, have been utilized to treat severe forms of diseases, each with some beneficial effects. In addition, extensive research has shown that gene transfer methods targeting allogeneic and autologous epidermal stem cells to replace or correct the defective gene are promising. These methods can regenerate and restore the adhesion of primary keratinocytes in EB patients. The long-term treatment of skin lesions in a small number of patients has shown promising results through the transplantation of skin grafts produced from gene-corrected autologous epidermal stem cells. This article attempts to summarize the current situation, potential development prospects, and some of the challenges related to the cell therapy approach for EB treatment.

Management of Skin Lesions in Patients with Epidermolysis Bullosa by Topical Treatment: Systematic Review and Meta-Analysis

Epidermolysis bullosa (EB) is the overarching term for a set of rare inherited skin fragility disorders that result from mutations in at least 20 different genes. Currently, there is no cure for any of the EB subtypes associated with various mutations. Existing therapies primarily focus on alleviating pain and promoting early wound healing to prevent potential complications. Consequently, there is an urgent need for innovative therapeutic approaches. The objective of this research was to assess the efficacy of various topical treatments in patients with EB with the goal of achieving wound healing. A secondary objective was to analyse the efficacy of topical treatments for symptom reduction. A literature search was conducted using scientific databases, including The Cochrane Library, Medline (Pubmed), Web of Science, CINHAL, Embase, and Scopus. The protocol review was registered in PROSPERO (ID: 418790), and inclusion and exclusion criteria were applied, resulting in the selection of 23 articles. Enhanced healing times were observed compared with the control group. No conclusive data have been observed on pain management, infection, pruritus episodes, and cure rates over time. Additionally, evidence indicates significant progress in gene therapies (B-VEC), as well as cell and protein therapies. The dressing group, Oleogel S-10, allantoin and diacerein 1%, were the most represented, followed by fibroblast utilisation. In addition, emerging treatments that improve the patient's innate immunity, such as calcipotriol, are gaining attention. However, more trials are needed to reduce the prevalence of blistering and improve the quality of life of individuals with epidermolysis bullosa.

Challenges in the transfer and scale-up of mini-tableting: Case study with losartan potassium

Mini-tablets (MTs) with losartan potassium were developed to treat the rare disease Epidermolysis Bullosa. The focus was placed on transfer and scale-up of a direct compressible formulation from the compaction simulator STYL'One Evo (CS) to the rotary tablet press Korsch XM 12 (RP). Transfer of tabletability and compactibility profiles from CS to RP did not show good agreement, e.g. at a tableting pressure of 125 MPa mean tensile strengths (TS) of 4 MPa on CS and 1-1.5 MPa on RP were reached. These results highlight the impact of the feed frame on final product qualities depending on process and material factors. In the scale-up studies the critical quality attributes (CQAs) mass variation, content uniformity, TS and disintegration time were investigated. After an appropriate run-up time, most CQAs reached a plateau, after reaching a balance between influx, efflux and distribution of lubricant in the feed frame. TS values of 1-2 MPa, disintegration times of max. 50 s, mass variation of 0.9-2.2 % (CV) and acceptance values below 15.0 were reached depending on chosen process parameters.

Interpretation of genomic sequence variants in heritable skin diseases: A primer for clinicians

Over 1000 heritable disorders have cutaneous manifestations, some of which are syndromicin association with extracutaneous manifestations, whereas others are limited to the skin. The genetic basis of many of these conditions has been deciphered, and mutation analyses using next-generation sequencing approaches, including whole-exome sequencing, whole-genome sequencing, and whole-transcriptome analysis, are now increasingly becoming part of the diagnostic process. Besides confirming the diagnosis, information on the specific mutations can be used for subclassification with prognostication and identification of the carriers, leading to accurate genetic counseling. It also forms a basis for prenatal testing and preimplantation genetic diagnosis. Furthermore, the ongoing therapeutics developments for heritable skin diseases are often allele-specific, necessitating the knowledge of the specific genes and mutations. Although practicing clinicians increasingly employ molecular diagnostics for heritable skin diseases, they often lack the sufficient knowledge required to interpret the implications of the mutations with precision. The purpose of this primer is to provide an overview of mutation-detection strategies and how to interpret genetic information for improved diagnostics and the management of such patients.

Impression technique modification and oral contracture release surgery for orthodontic treatment in a patient with severe microstomia due to recessive dystrophic epidermolysis bullosa

INTRODUCTION

Epidermolysis bullosa (EB) is a group of genetic disorders characterized by fragility of the skin and mucosal membranes. Dystrophic EB (DEB) is caused by mutations in the gene coding for type VII collagen. Among the most frequent oral manifestations in Recessive DEB (RDEB) are oral ulcers and blisters, absence of tongue papillae and palatal rugae, ankyloglossia, oral vestibule obliteration, and microstomia. The following report describes a modified impression technique used in a patient with severe RDEB and severe microstomia to obtain models for orthodontic treatment with aligners.

CASE REPORT

A 25-year-old female patient with severe RDEB was referred for orthodontic treatment. Severe microstomia (8 mm), hindered the use of conventional trays or intraoral scanners to design the aligners. Therefore, a contracture release surgery in combination with a modified impression technique was performed to obtain an optimal impression and subsequent aligners for orthodontic treatment.

DISCUSSION

This case presents an alternative strategy to provide orthodontic treatment with aligners in patients with severe microstomia due to severe RDEB. Reports of orthodontic treatment in people living with EB, especially in RDEB, are still rare, with few publications about fixed braces, early teeth extraction and removable devices, and none using aligners. Most of the impression techniques reported are aimed at oral rehabilitation. The multidisciplinary approach and impression technique reported should broaden the alternatives of orthodontic techniques provided to patients with EB and severe microstomia.

CONCLUSIONS

This article describes an oral contracture release surgery and modified impression technique for obtaining good quality impression for the design of orthodontic aligners in patients with severe microstomia due to severe RDEB.

Heterogeneity of reported outcomes in epidermolysis bullosa clinical research: a scoping review as a first step towards outcome harmonization

BACKGROUND

Epidermolysis bullosa (EB) is a rare, genetically and clinically heterogeneous group of skin fragility disorders. No cure is currently available, but many novel and repurposed treatments are upcoming. For adequate evaluation and comparison of clinical studies in EB, well-defined and consistent consensus-endorsed outcomes and outcome measurement instruments are necessary.

OBJECTIVES

To identify previously reported outcomes in EB clinical research, group these outcomes by outcome domains and areas and summarize respective outcome measurement instruments.

METHODS

A systematic literature search was performed in the databases MEDLINE, Embase, Scopus, Cochrane CENTRAL, CINAHL, PsycINFO and trial registries covering the period between January 1991 and September 2021. Studies were included if they evaluated a treatment in a minimum of three patients with EB. Two reviewers independently performed the study selection and data extraction. All identified outcomes and their respective instruments were mapped onto overarching outcome domains. The outcome domains were stratified according to subgroups of EB type, age group, intervention, decade and phase of clinical trial.

RESULTS

The included studies (n = 207) covered a range of study designs and geographical settings. A total of 1280 outcomes were extracted verbatim and inductively mapped onto 80 outcome domains and 14 outcome areas. We found a steady increase in the number of published clinical trials and outcomes reported over the past 30 years. The included studies mainly focused on recessive dystrophic EB (43%). Wound healing was reported most frequently across all studies and referred to as a primary outcome in 31% of trials. Great heterogeneity of reported outcomes was observed within all stratified subgroups. Moreover, a diverse range of outcome measurement instruments (n = 200) was identified.

CONCLUSIONS

We show substantial heterogeneity in reported outcomes and outcome measurement instruments in EB clinical research over the past 30 years. This review is the first step towards harmonization of outcomes in EB, which is necessary to expedite the clinical translation of novel treatments for patients with EB.

Biomarker Discovery in Rare Malignancies: Development of a miRNA Signature for RDEB-cSCC

Machine learning has been proven to be a powerful tool in the identification of diagnostic tumor biomarkers but is often impeded in rare cancers due to small patient numbers. In patients suffering from recessive dystrophic epidermolysis bullosa (RDEB), early-in-life development of particularly aggressive cutaneous squamous-cell carcinomas (cSCCs) represents a major threat and timely detection is crucial to facilitate prompt tumor excision. As miRNAs have been shown to hold great potential as liquid biopsy markers, we characterized miRNA signatures derived from cultured primary cells specific for the potential detection of tumors in RDEB patients. To address the limitation in RDEB-sample accessibility, we analyzed the similarity of RDEB miRNA profiles with other tumor entities derived from the Cancer Genome Atlas (TCGA) repository. Due to the similarity in miRNA expression with RDEB-SCC, we used HN-SCC data to train a tumor prediction model. Three models with varying complexity using 33, 10 and 3 miRNAs were derived from the elastic net logistic regression model. The predictive performance of all three models was determined on an independent HN-SCC test dataset (AUC-ROC: 100%, 83% and 96%), as well as on cell-based RDEB miRNA-Seq data (AUC-ROC: 100%, 100% and 91%). In addition, the ability of the models to predict tumor samples based on RDEB exosomes (AUC-ROC: 100%, 93% and 100%) demonstrated the potential feasibility in a clinical setting. Our results support the feasibility of this approach to identify a diagnostic miRNA signature, by exploiting publicly available data and will lay the base for an improvement of early RDEB-SCC detection.

Molecular genetic basis of epidermolysis bullosa

Epidermolysis bullosa (EB) is an inherited disorder of skin fragility, caused by mutations in a large number of genes associated with skin integrity and dermal-epidermal adhesion. Skin fragility is manifested by a decrease in resistance to external mechanical influences, the clinical signs of which are the formation of blisters, erosions and wounds on the skin and mucous membranes. EB is a multisystemic disease and characterized by a wide phenotypic spectrum with extracutaneous complications in severe types, besides the skin and mucous membranes, with high mortality. More than 30 clinical subtypes have been identified, which are grouped into four main types: simplex EB, junctional EB, dystrophic EB and Kindler syndrome. To date, pathogenic variants in 16 different genes are associated with EB and encode proteins that are part of the skin anchoring structures or are signaling proteins. Genetic mutations cause dysfunction of cellular structures, differentiation, proliferation and apoptosis of cells, leading to mechanical instability of the skin. The formation of reduced proteins or decrease in their level leads mainly to functional disorders, forming mild or intermediate severe phenotypes. Absent protein expression is a result of null genetic variants and leads to structural abnormalities, causing a severe clinical phenotype. For most of the genes involved in the pathogenesis of EB, certain relationships have been established between the type and position of genetic variant and the severity of the clinical manifestations of the disease. Establishing an accurate diagnosis depends on the correlation of clinical, genealogical and immunohistological data in combination with molecular genetic testing. In general, the study of clinical, genetic and ultrastructural changes in EB has significantly expanded the understanding of the natural history of the disease and supplemented the data on genotype-phenotype correlations, promotes the search and study of epigenetic and non-genetic disease modifier factors, and also allows developing approaches to radical treatment of the disease. New advances of sequencing technologies have made it possible to describe new phenotypes and study their genetic and molecular mechanisms. This article describes the pathogenetic aspects and genes that cause main and rare syndromic subtypes of EB.

Clinical and molecular diagnosis of genodermatoses: Review and perspectives

Genodermatoses are a complex and heterogeneous group of genetic skin disorders characterized by variable expression and clinical and genetic heterogeneity, rendering their diagnosis challenging. DNA-based techniques, like whole-exome sequencing, can establish a diagnosis in 50% of cases. RNA-sequencing is emerging as an attractive tool that can obtain information regarding gene expression while integrating functional genomic data with regard to the interpretation of variants. This increases the diagnostic rate by an additional 10-15%. In the present review, we detail the clinical steps involved in the diagnosis of genodermatoses, as well as the current DNA-based technologies available to clinicians. Herein, the intention is to facilitate a better understanding of the possibilities and limitations of these diagnostic technologies. In addition, this review could guide dermatologists through new emerging techniques, such as RNA-sequencing and its applications to familiarizing them with future techniques. Currently, this multi-omics approach is likely the best strategy designed to promote the diagnosis of patients with genodermatoses and discover new skin disease genes that could result in novel targeted therapies.

Epidemiology of inherited epidermolysis bullosa in Germany

BACKGROUND

Epidermolysis bullosa (EB) is a rare genetic disorder manifesting with skin and mucosal membrane blistering in different degrees of severity.

OBJECTIVE

Epidemiological data from different countries have been published, but none are available from Germany.

METHODS

In this population-based cross-sectional study, people living with EB in Germany were identified using the following sources: academic hospitals, diagnostic laboratories and patient organization.

RESULTS

Our study indicates an overall EB incidence of 45 per million live births in Germany. With 14.23 per million live births for junctional EB, the incidence is higher than in other countries, possibly reflecting the availability of early molecular genetic diagnostics in severely affected neonates. Dystrophic EB was assessed at 15.58 cases per million live births. The relatively low incidence found for EB simplex, 14.93 per million live births, could be explained by late or missed diagnosis, but also by 33% of cases remaining not otherwise specified. Using log-linear models, we estimated a prevalence of 54 per million for all EB types, 2.44 for junctional EB, 12.16 for dystrophic EB and 28.44 per million for EB simplex. These figures are comparable to previously reported data from other countries.

CONCLUSIONS

Altogether, there are at least 2000 patients with EB in the German population. These results should support national policies and pharmaceutical companies in decision-making, allow more precise planning of drug development and clinical trials, and aid patient advocacy groups in their effort to improve quality of life of people with this orphan disease.

Efficacy and safety of Oleogel-S10 (birch triterpenes) for epidermolysis bullosa: results from the phase III randomized double-blind phase of the EASE study

BACKGROUND

Epidermolysis bullosa (EB) is a heterogeneous group of rare, difficult-to-treat, inherited multisystem diseases affecting epithelial integrity. Patients with EB are affected by mechanical fragility of epithelial surfaces including the skin and, as a result, extensive recurrent blistering is a characteristic of the condition. Chronic wounds predispose patients with EB to the development of squamous cell carcinoma, which is a major cause of premature death.

OBJECTIVES

EASE was a double-blind, randomized, vehicle-controlled, phase III study to determine the efficacy and safety of the topical gel Oleogel-S10 (birch triterpenes) in EB. EASE was funded by Amryt Research Limited.

METHODS

Patients with dystrophic EB, junctional EB or Kindler EB and a target partial-thickness wound lasting ≥ 21 days and < 9 months that was 10-50 cm2, were enrolled and randomized via computer-generated allocation tables 1 : 1 to Oleogel-S10 or control gel - both with standard-of-care dressings. Study gel was applied to all wounds at least every 4 days. The primary endpoint was the proportion of patients with first complete closure of target wound within 45 days.

RESULTS

A total of 223 patients were enrolled and treated (109 treated with Oleogel-S10, 114 with control gel). The primary endpoint was met; Oleogel-S10 resulted in 41·3% of patients with first complete target wound closure within 45 days, compared with 28·9% in the control gel arm (relative risk 1·44, 95% confidence interval (CI) 1·01-2·05; P = 0·013). Adverse events (AEs) occurred with similar frequency for Oleogel-S10 (81·7%) compared with control gel (80·7%). AEs were predominantly of mild-to-moderate intensity (4·6% were severe).

CONCLUSIONS

Oleogel-S10 is the first therapy to demonstrate accelerated wound healing in EB. Oleogel-S10 was well -tolerated.

Revertant Mosaicism in Genodermatoses: Natural Gene Therapy Right before Your Eyes

Revertant mosaicism (RM) is the intriguing phenomenon in which nature itself has successfully done what medical science is so eagerly trying to achieve: correcting the effect of disease-causing germline variants and thereby reversing the disease phenotype back to normal. RM was molecularly confirmed for the first time in a genodermatosis in 1997, the genetic skin condition junctional epidermolysis bullosa (EB). At that time, RM was considered an extraordinary phenomenon. However, several important discoveries have changed this conception in the past few decades. First, RM has now been identified in all major subtypes of EB. Second, RM has also been identified in many other genodermatoses. Third, a theoretical mathematical exercise concluded that reverse mutations should be expected in all patients with a recessive subtype of EB or any other genodermatosis. This has shifted the paradigm from RM being an extraordinary phenomenon to it being something that every physician working in the field of genodermatoses should be looking for in every patient. It has also raised hope for new treatment options in patients with genodermatoses. In this review, we summarize the current knowledge on RM and discuss the perspectives of RM for the future treatment of patients with genodermatoses.

Mechanistic interrogation of mutation-independent disease modulators of RDEB identifies the small leucine-rich proteoglycan PRELP as a TGF-β antagonist and inhibitor of fibrosis

Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic extracellular matrix disease caused by deficiency in type VII collagen (Col VII). The disease manifests with devastating mucocutaneous fragility leading to progressive fibrosis and metastatic squamous cell carcinomas. Although collagen VII abundance is considered the main predictor of symptom course, previous studies have revealed the existence of mutation-independent mechanisms that control disease progression. Here, to investigate and validate new molecular modifiers of wound healing and fibrosis in a natural human setting, and toward development of disease-modulating treatment of RDEB, we performed gene expression profiling of primary fibroblast from RDEB siblings with marked phenotypic variations, despite having equal COL7A1 genotype. Gene enrichment analysis suggested that severe RDEB was associated with enhanced response to TGF-β stimulus, oxidoreductase activity, and cell contraction. Consistently, we found an increased response to TGF-β, higher levels of basal and induced reactive oxygen species (ROS), and greater contractile ability in collagen lattices in RDEB fibroblasts (RDEBFs) from donors with severe RDEB vs mild RDEB. Treatment with antioxidants allowed a reduction of the pro-fibrotic and contractile phenotype. Importantly, our analyses revealed higher expression and deposition in skin of the relatively uncharacterized small leucine-rich extracellular proteoglycan PRELP/prolargin associated with milder RDEB manifestations. Mechanistic investigations showed that PRELP effectively attenuated fibroblasts' response to TGF-β1 stimulus and cell contractile capacity. Moreover, PRELP overexpression in RDEBFs enhanced RDEB keratinocyte attachment to fibroblast-derived extracellular matrix in the absence of Col VII. Our results highlight the clinical relevance of pro-oxidant status and hyper-responsiveness to TGF-β in RDEB severity and progression. Of note, our study also reveals PRELP as a novel and natural TGF-β antagonist with a likely dermo-epidermal pro-adhesive capacity.

Generation of a recessive dystrophic epidermolysis bullosa mouse model with patient-derived compound heterozygous mutations

Recessive dystrophic epidermolysis bullosa (RDEB) is an intractable genetic disease of the skin caused by mutations in the COL7A1 gene. The majority of patients with RDEB harbor compound heterozygous mutations-two distinct mutations on each chromosome-without any apparent hotspots in the COL7A1 mutation pattern. This situation has made it challenging to establish a reliable RDEB mouse model with mutations that accurately mimic the genomic background of patients. Here, we established an RDEB mouse model harboring patient-type mutations in a compound heterozygous manner, using the CRISPR-based genome-editing technology i-GONAD. We selected two mutations, c.5818delC and E2857X, that have frequently been identified in cohorts of Japanese patients with RDEB. These mutations were introduced into the mouse genome at locations corresponding to those identified in patients. Mice homozygous for the 5818delC mutation developed severe RDEB-like phenotypes and died immediately after birth, whereas E2857X homozygous mice did not have a shortened lifespan compared to wild-type mice. Adult E2857X homozygous mice showed hair abnormalities, syndactyly, and nail dystrophy; these findings indicate that E2857X is indeed pathogenic in mice. Mice with the c.5818delC/E2857X compound heterozygous mutation presented an intermediate phenotype between the c.5818delC and E2857X homozygous mice. Single-cell RNA sequencing further clarified that the intrafollicular keratinocytes in c.5818delC/E2857X compound heterozygous mice exhibited abnormalities in cell cycle regulation. The proposed strategy to produce compound heterozygous mice, in addition to the established mouse line, will facilitate research on RDEB pathogenesis to develop a cure for this devastating disease.

Epidermolysis Bullosa—A Different Genetic Approach in Correlation with Genetic Heterogeneity

Epidermolysis bullosa is a heterogeneous group of rare genetic disorders characterized by mucocutaneous fragility and blister formation after minor friction or trauma. There are four major epidermolysis bullosa types based on the ultrastructural level of tissue cleavage: simplex, junctional, dystrophic, and Kindler epidermolysis bullosa. They are caused by mutations in genes that encode the proteins that are part of the hemidesmosomes and focal adhesion complex. Some of these disorders can be associated with extracutaneous manifestations, which are sometimes fatal. They are inherited in an autosomal recessive or autosomal dominant manner. This review is focused on the phenomena of heterogeneity (locus, allelic, mutational, and clinical) in epidermolysis bullosa, and on the correlation genotype–phenotype.

Losartan treatment improves recessive dystrophic epidermolysis bullosa: A case series

Recessive dystrophic epidermolysis bullosa (RDEB) manifests with blistering and erosions of the skin and mucous membranes due to mutations in COL7A1. The repetitive wound healing processes lead to extensive cutaneous scarring. The scarring is driven by inflammatory processes, particularly the TGF-β signaling pathways, resulting in excess synthesis and deposition of the extracellular matrix, especially collagen. There is currently no effective or specific treatment for RDEB. Losartan, an angiotensin II type 1 receptor antagonist, is an inhibitor of TGF-β activity. Previous preclinical studies with hypomorphic Col7A1 mice recapitulating features of RDEB have suggested that losartan may improve the clinical features of RDEB. In this case series, we assessed the effects of losartan on the clinical and histopathologic features in seven patients with RDEB; three females and four males; ages 18.1 ± 9.1 years. The diagnosis was based on characteristic clinical features and the presence of biallelic loss-of-function mutations in COL7A1. Daily oral administration of losartan (0.7 mg/kg) for six weeks resulted in subjective improvement of the clinical features, as judged by the treating physicians and the patients, and the severity of the disease objectively improved based on Birmingham Epidermolysis Bullosa Severity (BEBS) score (30.1 ± 12.8 vs. 23.3 ± 10.4, before and after treatment, p = 0.018), accompanied by improvement of quality of life, as determined by the EB-QoL questionnaire (24.0 ± 8.1 vs. 17.7 ± 5.5, p = 0.018). Histopathology of the selected lesions revealed increased number of mast cells, and enhanced microvasculature in the mid and lower dermis. The width of collagen bundles in dermis was suggested to be decreased in four samples and changed from dense to loose in appearance. In summary, this case series reports beneficial effects of losartan on RDEB as a potentially novel treatment. This article is protected by copyright. All rights reserved.

Pharmaceutical Development of Film-Coated Mini-Tablets with Losartan Potassium for Epidermolysis Bullosa

Epidermolysis bullosa is a genetically heterogenous skin fragility disorder with multiorgan involvement appearing already in newborn children. Severe progressive fibrosis follows skin blistering, mucosa lesions, and wound healing, favouring development of highly aggressive squamous cell carcinomas. Losartan potassium (LP) has been described to show positive effects; therefore, it was of clinical interest to develop 2 mm mini-tablets with LP for treatment of the affected children. Several challenges emerged during development: limited flowability and sticking to punches were observed in the first tableting experiments due to a high drug load, and a bitter taste of the LP was reported. Sticking to punches was reduced by using SMCC 50 and a combination of different lubricants; however, direct compression trials on a Korsch XM 12 rotary press were not successful due to compaction phenomena in the hopper. Thus, an intermediate dry granulation was successfully introduced. Two final formulations of the mini-tablets complied with the requirements of the European Pharmacopoeia regarding disintegration times (<15 min) and friability (<1.0%); mean tensile strengths amounted to about 1 MPa as a compromise between manufacturability and sufficient mechanical strength for further coating studies. The subsequent coating step succeeded delaying the initial drug release for more than 2 min. An acceptance value ≤15 was matched for the coated mini-tablets, and stability studies showed a promising shelf life.

Genes and compounds that increase type VII collagen expression as potential treatments for dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB) is a skin-blistering disease caused by mutations in COL7A1, which encodes type VII collagen (C7). There is no cure for DEB, but previous work has shown potential therapeutic benefit of increased production of even partially functional C7. Genome-wide screens using CRISPR-Cas9 have enabled the identification of genes involved in cancer development, drug resistance, and other genetic diseases, suggesting that they could be used to identify drivers of C7 production. A keratinocyte C7 reporter cell line was created and used in a genome-wide CRISPR activation (CRISPRa) screen to identify genes and pathways that increase C7 expression. The CRISPRa screen results were used to develop a targeted drug screen to identify compounds that upregulate C7 expression. The C7_tdTomato cell line was validated as an effective reporter for detection of C7 upregulation. The CRISPRa screen identified DENND4B and TYROBP as top gene hits plus pathways related to calcium uptake and immune signaling in C7 regulation. The targeted drug screen identified several compounds that increase C7 expression in keratinocytes, of which kaempferol, a plant flavonoid, also significantly increased C7 mRNA and protein in DEB patient cells.

Predominance of Staphylococcus correlates with wound burden and disease activity in dystrophic epidermolysis bullosa: a prospective case-control study

Recessive dystrophic epidermolysis bullosa (RDEB) is characterized by skin blistering and wounds. To uncover changes in skin and mucosal microbiome related to age and disease progression, and microbiome impact on clinical and inflammatory laboratory parameters, swabs from wounded and unwounded skin, oral mucosa and stool samples of 28 children with RDEB and 28 healthy controls were subjected to 16S-rRNA gene sequencing. Skin microbiome of RDEB patients showed significantly reduced alpha diversity compared to healthy controls and early, age-dependent predominance of Staphylococcus aureus first in wounds, then in unwounded skin. These findings were more pronounced in severe disease with higher abundances of Staphylococcus aureus compared to intermediate disease. Staphylococcus aureus abundance correlated significantly with both acute and chronic wound burden. Changes in oral mucosal and gut microbiome were discrete with no significant differences in alpha diversity. Our findings show that children with RDEB experience skin microbiome changes early in life. Longitudinal studies should confirm that dysbiosis starts in wounds and later extends to unwounded skin. The predominance of Staphylococcus aureus significantly correlates with wound burden and disease activity, and to some extent with systemic inflammation.

Current topics in Epidermolysis bullosa: Pathophysiology and therapeutic challenges

Epidermolysis bullosa (EB) is a group of inherited skin and mucosal fragility disorders resulting from mutations in genes encoding basement membrane zone (BMZ) components or proteins that maintain the integrity of BMZ and adjacent keratinocytes. More than 30 years have passed since the first causative gene for EB was identified, and over 40 genes are now known to be responsible for the protean collection of mechanobullous diseases included under the umbrella term of EB. Through the elucidation of disease mechanisms using human skin samples, animal models, and cultured cells, we have now reached the stage of developing more effective therapeutics for EB. This review will initially focus on what is known about blister wound healing in EB, since recent and emerging basic science data are very relevant to clinical translation and therapeutic strategies for patients. We then place these studies in the context of the latest information on gene therapy, read-through therapy, and cell therapy that provide optimism for improved clinical management of people living with EB.

Wnt/β-Catenin Signaling Stabilizes Hemidesmosomes in Keratinocytes

Hemidesmosomes (HDs) are adhesion complexes that promote epithelial-stromal attachment in stratified and complex epithelia, including the epidermis. In various biological processes, such as differentiation and migration of epidermal keratinocytes during wound healing or carcinoma invasion, quick assembly and disassembly of HDs are prerequisites. In this study, we show that inhibition of Wnt/β-catenin signaling disturbs HD organization in keratinocytes. Screening with inhibitors identified the depletion of HD components and HD-like structures through Wnt inhibition, but keratinocyte differentiation was not affected. Wnt inhibition significantly diminished plectin and type XVII collagen expression in the basal side of Wnt-inhibited cells and the dermo-epidermal junction of the Wnt-inactive murine basal epidermis. Similar to Wnt inhibition, PLEC-knockout cells or cells with plectin-type XVII collagen binding defects showed type XVII collagen reduction in the basal side of the cells, implying the possible involvement of Wnt/β-catenin signaling in HD assembly. Atypical protein kinase C inhibition ameliorated the phenotypes of Wnt-inhibited cells. These findings show that Wnt/β-catenin signaling regulates the localization of HD components in keratinocytes and that the atypical protein kinase C pathway is involved in Wnt inhibition‒induced HD disarrangement. Our study suggests that the Wnt signaling pathway could be a potential therapeutic target for treating HD-defective diseases, such as epidermolysis bullosa.

Molekulare Diagnostik und Therapie der Epidermolysis bullosa

Unter Epidermolysis bullosa (EB) subsumiert man genetische Erkrankungen, die durch gesteigerte Hautfragilität mit Blasenbildung nach bereits geringen mechanischen Belastungen gekennzeichnet sind. Hochvariable kutane, extrakutane und Organmanifestationen verursachen eine signifikante Morbidität und Mortalität sowie eine hohe Krankheitslast für Betroffene und Angehörige. Obwohl derzeit nicht heilbar, eröffnen Fortschritte in der molekularen Charakterisierung pathogenetischer Prozesse, in den diagnostischen Techniken und molekularen Therapieansätzen neue Perspektiven. Neben korrektiven, potenziell kurativen Behandlungszugängen mit dem Ziel der Wiederherstellung der Funktion von Gen bzw. Protein stellen krankheitsmodifizierende Strategien eine wertvolle Ergänzung dar. Unter Letztere fallen symptomatische Therapien, die sekundär dysregulierte, den Phänotyp modulierende Entzündungskaskaden adressieren oder zielgerichtete Interventionen hinsichtlich bestimmter Symptome wie Fibrosierung, Juckreiz oder kanzerogener Zelltransformation. Molekulare Verfahren erlauben heute zudem, eine Diagnose und damit Prognose früher und präziser zu stellen, was die genetische Beratung erleichtert.

Das Management von EB-Patienten ist komplex und bedarf einer Spezialexpertise und multidisziplinär akkordierten Versorgung. Entsprechende Ressourcen halten designierte Expertisezentren wie das EB-Haus Austria vor, das als Mitglied des Europäischen Referenznetzwerks für Seltene Hauterkrankungen (ERN Skin) sowohl klinische Versorgung, Grundlagen- und klinische Forschungsaktivitäten sowie Zugang zu Aus- und Weiterbildungsprogrammen für Betroffene, Betreuende und medizinisches Fachpersonal gewährleistet.

Clinical Perspectives of Gene-Targeted Therapies for Epidermolysis Bullosa

New insights into molecular genetics and pathomechanisms in epidermolysis bullosa (EB), methodological and technological advances in molecular biology as well as designated funding initiatives and facilitated approval procedures for orphan drugs have boosted translational research perspectives for this devastating disease. This is echoed by the increasing number of clinical trials assessing innovative molecular therapies in the field of EB. Despite remarkable progress, gene-corrective modalities, aimed at sustained or permanent restoration of functional protein expression, still await broad clinical availability. This also reflects the methodological and technological shortcomings of current strategies, including the translatability of certain methodologies beyond preclinical models as well as the safe, specific, efficient, feasible, sustained and cost-effective delivery of therapeutic/corrective information to target cells. This review gives an updated overview on status, prospects, challenges and limitations of current gene-targeted therapies.

Current knowledge of immunomodulation strategies for chronic skin wound repair

In orchestrating the wound healing process, the immune system plays a critical role. Hence, controlling the immune system to repair skin defects is an attractive approach. The highly complex immune system includes the coordinated actions of several immune cells, which can produce various inflammatory and antiinflammatory cytokines and affect the healing of skin wounds. This process can be optimized using biomaterials, bioactive molecules, and cell delivery. The present review discusses various immunomodulation strategies for supporting the healing of chronic wounds. In this regard, following the evolution of the immune system and its role in the wound healing mechanism, the interaction between the extracellular mechanism and immune cells for acceleration wound healing will be firstly investigated. Consequently, the immune-based chronic wounds will be briefly examined and the mechanism of progression, and conventional methods of their treatment are evaluated. In the following, various biomaterials-based immunomodulation strategies are introduced to stimulate and control the immune system to treat and regenerate skin defects. Other effective methods of controlling the immune system in wound healing which is the release of bioactive agents (such as antiinflammatory, antigens, and immunomodulators) and stem cell therapy at the site of injury are reviewed.

Intrinsic disorder in integral membrane proteins

The well-defined roles and specific protein-protein interactions of many integral membrane proteins (IMPs), such as those functioning as receptors for extracellular matrix proteins and soluble growth factors, easily align with considering IMP structure as a classical "lock-and-key" concept. Nevertheless, continued advances in understanding protein conformation, such as those which established the widespread existence of intrinsically disordered proteins (IDPs) and especially intrinsically disordered regions (IDRs) in otherwise three-dimensionally organized proteins, call for ongoing reevaluation of transmembrane proteins. Here, we present basic traits of IDPs and IDRs, and, for some select single-span IMPs, consider the potential functional advantages intrinsic disorder might provide and the possible conformational impact of disease-associated mutations. For transmembrane proteins in general, we highlight several investigational approaches, such as biophysical and computational methods, stressing the importance of integrating them to produce a more-complete mechanistic model of disorder-containing IMPs. These procedures, when synergized with in-cell assessments, will likely be key in translating in silico and in vitro results to improved understanding of IMP conformational flexibility in normal cell physiology as well as disease, and will help to extend their potential as therapeutic targets.

Immunological mechanisms underlying progression of chronic wounds in recessive dystrophic epidermolysis bullosa

Hereditary epidermolysis bullosa (EB) is a mechanobullous skin fragility disorder characterized by defective epithelial adhesion, leading to mechanical stress‐induced skin blistering. Based on the level of tissue separation within the dermal‐epidermal junction, EB is categorized into simplex (EBS), junctional (JEB), dystrophic (DEB) and Kindler syndrome. There is no cure for EB, and painful chronic cutaneous wounds are one of the major complications in recessive (RDEB) patients. Although RDEB is considered a cutaneous disease, recent data support the underlying systemic immunological defects. Furthermore, chronic wounds are often colonized with pathogenic microbiota, leading to excessive inflammation and altered wound healing. Consequently, patients with RDEB suffer from a painful sensation of chronic, cutaneous itching/burning and an endless battle with bacterial infections. To improve their quality of life and life expectancy, it is important to prevent cutaneous infections, dampen chronic inflammation and stimulate wound healing. A clear scientific understanding of the immunological events underlying the maintenance of chronic poorly healing wounds in RDEB patients is necessary to improve disease management and better understand other wound healing disorders. In this review, we summarize current knowledge of the role of professional phagocytes, such as neutrophils, macrophages and dendritic cells, the role of T‐cell‐mediated immunity in lymphoid organs, and the association of microbiota with poor wound healing in RDEB. We conclude that RDEB patients have an underlying immunity defect that seems to affect antibacterial immunity.

Advances in gene therapy and their application to skin diseases: A review

With recent advances in genetic engineering technology, gene therapy is now being considered as a treatment not only for congenital diseases but also acquired diseases, such as cancer. Gene therapeutic agents for hereditary immune disorders, haemophilia, retinal diseases, neurodegenerative diseases, and lymphoma have been approved in the United States and Europe. In the field of dermatology, clinical trials of gene therapy have been conducted, because the skin is an easily accessible organ that represents an attractive tissue for gene therapy. In recent years, gene therapy has been attempted for a variety of skin diseases, such as genodermatoses (including epidermolysis bullosa and Netherton syndrome), cutaneous lymphoma, and malignant melanoma. As a result, it is difficult to grasp the current status of gene therapy in dermatology. This review focuses on each of the gene-transfer techniques currently in use and describes the current status of gene therapy for skin diseases using each technology.

Impaired Wound Healing, Fibrosis, and Cancer: The Paradigm of Recessive Dystrophic Epidermolysis Bullosa

Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a devastating skin blistering disease caused by mutations in the gene encoding type VII collagen (C7), leading to epidermal fragility, trauma-induced blistering, and long term, hard-to-heal wounds. Fibrosis develops rapidly in RDEB skin and contributes to both chronic wounds, which emerge after cycles of repetitive wound and scar formation, and squamous cell carcinoma-the single biggest cause of death in this patient group. The molecular pathways disrupted in a broad spectrum of fibrotic disease are also disrupted in RDEB, and squamous cell carcinomas arising in RDEB are thus far molecularly indistinct from other sub-types of aggressive squamous cell carcinoma (SCC). Collectively these data demonstrate RDEB is a model for understanding the molecular basis of both fibrosis and rapidly developing aggressive cancer. A number of studies have shown that RDEB pathogenesis is driven by a radical change in extracellular matrix (ECM) composition and increased transforming growth factor-beta (TGFβ) signaling that is a direct result of C7 loss-of-function in dermal fibroblasts. However, the exact mechanism of how C7 loss results in extensive fibrosis is unclear, particularly how TGFβ signaling is activated and then sustained through complex networks of cell-cell interaction not limited to the traditional fibrotic protagonist, the dermal fibroblast. Continued study of this rare disease will likely yield paradigms relevant to more common pathologies.

Personalized Development of Antisense Oligonucleotides for Exon Skipping Restores Type XVII Collagen Expression in Junctional Epidermolysis Bullosa

Intermediate junctional epidermolysis bullosa caused by mutations in the COL17A1 gene is characterized by the frequent development of blisters and erosions on the skin and mucous membranes. The rarity of the disease and the heterogeneity of the underlying mutations renders therapy developments challenging. However, the high number of short in-frame exons facilitates the use of antisense oligonucleotides (AON) to restore collagen 17 (C17) expression by inducing exon skipping. In a personalized approach, we designed and tested three AONs in combination with a cationic liposomal carrier for their ability to induce skipping of COL17A1 exon 7 in 2D culture and in 3D skin equivalents. We show that AON-induced exon skipping excludes the targeted exon from pre-mRNA processing, which restores the reading frame, leading to the expression of a slightly truncated protein. Furthermore, the expression and correct deposition of C17 at the dermal-epidermal junction indicates its functionality. Thus, we assume AON-mediated exon skipping to be a promising tool for the treatment of junctional epidermolysis bullosa, particularly applicable in a personalized manner for rare genotypes.

Immunofluorescence mapping, electron microscopy and genetics in the diagnosis and sub-classification of inherited epidermolysis bullosa: a single-centre retrospective comparative study of 87 cases with long-term follow-up

BACKGROUND

Epidermolysis bullosa (EB) comprises a heterogeneous group of skin fragility disorders, classified in four major types based on skin cleavage level, i.e. EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), Kindler EB, and in more than 30 subtypes defined by the combination of laboratory and clinical data, including disease course.

OBJECTIVES

Our aims were to address whether, in the age of genomics, electron microscopy (TEM) has still a role in diagnosing EB, and whether the genotype per se may be sufficient to sub-classify EB.

METHODS

A thoroughly characterized single-centre EB case series was retrospectively evaluated to compare the power of TEM with immunofluorescence mapping (IFM) in establishing the EB type, and the ability of TEM, IFM and genetics to predict selected EB subtypes, i.e. severe dominant EBS (DEBS), severe JEB, severe recessive DEB (RDEB) and DEB self-improving, using genetic and final diagnosis, respectively, as gold standard.

RESULTS

The series consisted of 87 patients, including 44 newborns, with a median follow-up of 54 months. Ninety-five mutations were identified in EB-associated genes, including 25 novel variants. Both IFM and TEM were diagnostic in about all cases of JEB (21/21 for both) and DEB (43/44 for IFM, 44/44 for TEM). TEM sensitivity was superior to IFM for EBS (19/20 vs. 16/19). As to EB subtyping, IFM performed better than genetics in identifying severe JEB cases due to laminin-332 defect (14/14 vs. 10/14) and severe RDEB (eight/nine vs. seven/nine). Genetics had no role in self-improving DEB diagnosis; it almost equalled TEM in predicting severe DEBS (eight/nine vs. nine/nine) and enabled to discriminate dominant from recessive non-severe DEB phenotypes and to identify special subtypes, e.g. DEBS with KLHL24 mutations.

CONCLUSIONS

Transmission electron microscopy remains relevant to the diagnosis of EBS. IFM and genetics are essential and complementary tools in the vast majority of EB cases.

Advances in gene editing strategies for epidermolysis bullosa

Epidermolysis bullosa represents a monogenetic disease comprising a variety of heterogeneous mutations in at least 16 genes encoding structural proteins crucial for skin integrity. Due to well-defined mutations but still lacking causal treatment options for the disease, epidermolysis bullosa represents an ideal candidate for gene therapeutic interventions. Recent developments and improvements in the genome editing field have paved the way for the translation of various gene repair strategies into the clinic. With the ability to accurately predict and monitor targeting events within the human genome, the translation might soon be possible. Here, we describe current advancements in the genome editing field for epidermolysis bullosa, along with a discussion of aspects and strategies for precise and personalized gene editing-based medicine, in order to develop efficient and safe ex vivo as well as in vivo genome editing therapies for epidermolysis bullosa patients in the future.

Research Techniques Made Simple: Whole-Transcriptome Sequencing by RNA-Seq for Diagnosis of Monogenic Disorders

Mendelian disorders with cutaneous manifestations comprise a genotypically heterogeneous group of over 1,000 diseases, and in most of them mutant genes have been identified. Mutation detection approaches in these diseases have largely focused on DNA analysis by next-generation sequencing techniques, including gene-targeted sequencing panels as well as whole-exome and whole-genome sequencing. Genome-wide homozygosity mapping (HM), based on DNA polymorphism, has also assisted in the identification of candidate genes in families with consanguinity. However, specific pathogenic variants have not been disclosed in many individual patients when analyzed by next-generation sequencing, and in particular, DNA-based analysis failed to identify many of the mutations impacting on splicing or gene expression. Whole-transcriptome sequencing by RNA sequencing (RNA-Seq), with appropriate bioinformatics, provides a robust tool to identify additional mutations to facilitate genetic diagnosis in genodermatoses. RNA-Seq can be used for variant calling and HM similar to DNA-based approaches, but it also allows for the identification of mutations that result in aberrant transcriptome expression, as displayed by heatmap analysis, and altered splicing patterns of RNA, as visualized by Sashimi plots. Thus, clinical RNA-Seq extends molecular diagnostics of rare genodermatoses, and it could provide a reliable first-tier diagnostic approach to extend mutation databases in patients with heritable skin diseases.

Three Decades of Research on Recombinant Collagens: Reinventing the Wheel or Developing New Biomedical Products?

Collagens provide the building blocks for diverse tissues and organs. Furthermore, these proteins act as signaling molecules that control cell behavior during organ development, growth, and repair. Their long half-life, mechanical strength, ability to assemble into fibrils and networks, biocompatibility, and abundance from readily available discarded animal tissues make collagens an attractive material in biomedicine, drug and food industries, and cosmetic products. About three decades ago, pioneering experiments led to recombinant human collagens' expression, thereby initiating studies on the potential use of these proteins as substitutes for the animal-derived collagens. Since then, scientists have utilized various systems to produce native-like recombinant collagens and their fragments. They also tested these collagens as materials to repair tissues, deliver drugs, and serve as therapeutics. Although many tests demonstrated that recombinant collagens perform as well as their native counterparts, the recombinant collagen technology has not yet been adopted by the biomedical, pharmaceutical, or food industry. This paper highlights recent technologies to produce and utilize recombinant collagens, and it contemplates their prospects and limitations.

Beneficial Effect of Systemic Allogeneic Adipose Derived Mesenchymal Cells on the Clinical, Inflammatory and Immunologic Status of a Patient With Recessive Dystrophic Epidermolysis Bullosa: A Case Report

Recessive dystrophic epidermolysis bullosa (RDEB) is an incurable inherited mucocutaneous fragility disorder characterized by recurrent blisters, erosions, and wounds. Continuous blistering triggers overlapping cycles of never-ending healing and scarring commonly evolving to chronic systemic inflammation and fibrosis. The systemic treatment with allogeneic mesenchymal cells (MSC) from bone marrow has previously shown benefits in RDEB. MSC from adipose tissue (ADMSC) are easier to isolate. This is the first report on the use of systemic allogeneic ADMSC, correlating the clinical, inflammatory, and immunologic outcomes in RDEB indicating long-lasting benefits. We present the case of an RDEB patient harboring heterozygous biallelic COL7A1 gene mutations and with a diminished expression of C7. The patient presented with long-lasting refractory and painful oral ulcers distressing her quality of life. Histamine receptor antagonists, opioid analgesics, proton-pump inhibitors, and low-dose tricyclic antidepressants barely improved gastric symptoms, pain, and pruritus. Concomitantly, allogeneic ADMSC were provided as three separate intravenous injections of 106 cells/kg every 21 days. ADMSC treatment was well-tolerated. Improvements in wound healing, itch, pain and quality of life were observed, maximally at 6-9 months post-treatment, with the relief of symptoms still noticeable for up to 2 years. Remarkably, significant modifications in PBL participating in both the innate and adaptive responses, alongside regulation of levels of profibrotic factors, MCP-1/CCL2 and TGF-β, correlated with the health improvement. This treatment might represent an alternative for non-responding patients to conventional management. It seems critical to elucidate the paracrine modulation of the immune system by MSC for their rational use in regenerative/immunoregulatory therapies.

Translational perspectives to treat Epidermolysis bullosa-Where do we stand?

Epidermolysis bullosa (EB) is the prototypical example of genetic skin fragility disorders. Genotypic heterogeneity, modifier genes, epigenetic, biochemical and environmental factors alter and determine pathogenic traits and, ultimately, the wide and striking phenotypic variability in EB. Besides the primary structural-functional defect, chronic tissue damage with induction and dysregulation of inflammatory pathways is a common pathogenic mechanism in EB. In localized variants, the inflammatory aberrations may mainly affect the micromilieu of lesional skin, while a systemic inflammatory response was shown to contribute to the systemic morbidity in severe EB subtypes with extensive cutaneous involvement. Our continued understanding of the pathophysiology of EB, as well as advances in molecular technologies, has paved the way for translational therapeutic approaches. The spectrum comprises of corrective and symptom-relieving therapies that include innovative therapeutic options garnered from the bench, repurposed drugs approved for other diseases, as well as strategies for gene-, protein- and cell-based therapies. Immunological traits further define new targets of therapy, aimed at improving skin barrier restoration, microbial surveillance and infection control, wound healing and anti-neoplastic effects. Clinical availability and feasibility of these approaches for all EB patients and subtypes are currently limited, reflecting issues of efficacy, specificity, tolerability and safety. A multistep targeting approach and highly individualized, risk-stratified combinatory treatment plans will thus be essential for sustained efficacy and improved overall quality of life in EB.

Small molecule drug development for rare genodermatoses - evaluation of the current status in epidermolysis bullosa

Background

Hereditary epidermolysis bullosa (EB) comprises a heterogeneous group of rare genodermatoses, which are caused by mutations in genes involved in the maintenance of the structural and functional integrity of dermo-epidermal adhesion in various stratified epithelia. In severe variants, generalized skin disease, extracutaneous manifestations and multi-organ involvement cause considerable morbidity and mortality. Causal and early treatment by re-expression of a respective mutated gene is the major long-term goal in therapy development. However, characterization and targeted modulation of pathogenic molecular cascades in EB also holds great promise as a symptom-relieving approach to ameliorate phenotype, complications and quality of life. Small molecules are chemical structures of less than 900 Da that can diffuse across cell membranes and interfere with target biomolecules, thus influencing their function at different levels. They constitute the vast majority of active components of all approved drugs.

Methods

We performed PubMed and Google Scholar search for publications and screened FDA- and EMA-hosted clinical trial registries to identify studies using small molecule-based drugs for epidermolysis bullosa. Upon detailed analysis this resulted in the identification of a total of 84 studies.

Results

We identified 52 publications and 32 registered trials that investigate small molecules for their safety and efficacy as treatment for different aspects of epidermolysis bullosa. Further, a total of 38 different small molecules clinically used in EB were found. Most frequent outcome measures concerned wound healing, reduction in blister numbers, as well as reduction of itch and pain, predominantly for EBS and RDEB.

Conclusion

We provide a comprehensive summary of the current status of clinical small molecule development for EB and discuss prospects and limitations in orphan drug development for rare conditions like EB.

Profiling trial burden and patients' attitudes to improve clinical research in epidermolysis bullosa

Background

Epidermolysis bullosa (EB) comprises inherited mechanobullous dermatoses with considerable morbidity and mortality. While current treatments are symptomatic, a growing number of innovative therapeutic compounds are evaluated in clinical trials. Clinical research in rare diseases like EB, however, faces many challenges, including sample size requirements and recruitment failures. The objective of this study was to determine attitudes of EB patients towards clinical research and trial participation as well as the assessment of contextual motivating and discouraging factors in an effort to support patient-centered RD trial designing.

Methods

A 53-items questionnaire was handed over to EB patients (of all types and ages) in contact with the EB House Austria, a designated national center of expertise for EB care. Main categories included level of interest in and personal knowledge about clinical studies, pros/cons for participation and extent of individual expenses considered acceptable for participation in a clinical study. Descriptive subgroup analysis was calculated with SPSS 20.0 and Microsoft Excel.

Results

Thirty-six individuals (mean age 25.7 years), diagnosed for recessive dystrophic EB (36.1%), EB simplex (33.4%), junctional EB (8.3%), dominant dystrophic EB (2.8%) and acral peeling syndrome (2.8%) participated. Motivation for participation in and the desire to increase personal knowledge about clinical trials were (outmost) high in 57.2 and 66.7%, respectively. Altruism was the major motivating factor, followed by hope that alleviation of the own symptoms can be achieved. The greatest hurdle was travel distance, followed by concerns about possible adverse reactions. Patients diagnosed for severe subgroups (RDEB, JEB) were more impaired by the extent of scheduled invasive investigations and possible adverse reactions of the study medication. Patients with generally milder EB forms and older patients were accepting more frequent outpatient study visits, blood takes, skin biopsies and inpatient admissions in association with trial participation.

Conclusions

This study provides additional indications to better determine and address attitudes towards clinical research among EB patients as well as guidance to improve clinical trial protocols for patient centricity.