Viewpoint on the evaluation of severity and treatment effects in mild hidradenitis suppurativa: the cumulative IHS4 (IHS4-C).

Hidradenitis suppurativa (HS) is a chronic, recurrent and debilitating inflammatory skin disease, characterized by painful inflamed nodules, abscesses and tunnels in the skin folds. Up to 66% of HS patients can be classified as having mild disease. However, currently, most clinical trials are focusing on patients with moderate to severe disease, resulting in more available treatment options for this smaller group of patients. This difference in treatment options and lack of clinical trials for patients with mild HS has been noticed and additional focus on milder HS cases is requested. However, an important hurdle to overcome studying treatment efficacy in mild HS is an adequate treatment outcome. Patients with mild HS sometimes have no lesions due to waxing and waning of the disease. Furthermore, the difference in aim of a clinical trial for patients with mild disease should be taken into consideration. Where treatment of moderate to severe patients focusses on lowering the number of draining tunnels, abscesses and inflammatory nodules, in patient with mild disease, we focus on prevention of new lesions and progression to moderate and severe disease. This clinical characteristic of mild HS and difference in aim of clinical trials are the key challenges for efficacy measurement in mild HS. To overcome these challenges, we propose to measure the continuous international hidradenitis suppurativa severity score (IHS4) monthly and use the cumulative IHS4 score (IHS4-C) over all these visits as a primary outcome in clinical trials in patients with mild HS, to increase the probability to detect the inflammatory lesions with a temporary nature. We argue that this novel application of the IHS4, has the potential to better facilitate assessment of treatments or interventions in patients with mild HS and should be tested in future studies.

Needle-free electronically controlled jet injection with corticosteroids in recalcitrant keloid scars: a retrospective study and patient survey.

First-line treatment of keloids consists of intralesional needle injections with corticosteroids, but generally entails multiple painful sessions, resulting in variable clinical outcomes. Novel needle-free jet injectors may facilitate more effective and patient-friendly dermal drug delivery. Here, we evaluated the effectiveness, tolerability and patient satisfaction of intralesional triamcinolone-acetonide (TCA) treatment in recalcitrant keloids using an electronically controlled pneumatic injector (EPI). A retrospective study was conducted in recalcitrant keloid patients with a history of severe pain during needle injections who received three sessions of EPI + TCA. Outcome measures included Patient and Observer Scar Assessment Scale (POSAS), Global Aesthetic Improvement Scale (GAIS), treatment-related pain (NRS), adverse effects, and patient satisfaction (survey). Ten patients with in total 283 keloids were included. The POSAS score significantly improved at follow-up and GAIS was reported as '(very) improved' for all patients. EPI + TCA was well-tolerated with a significantly lower NRS pain score compared to needle + TCA (pilot treatment). Only minor adverse effects occurred, and 90% of patients preferred EPI over needle treatment. EPI + TCA is an effective and tolerable treatment for patients with recalcitrant keloids. The minimal treatment-related pain and high patient satisfaction makes it a promising treatment for patients with needle-phobia and/or severe pain during needle injections.

Oral prednisolone suppresses skin inflammation in a healthy volunteer imiquimod challenge model.

Imiquimod (IMQ) is a topical agent that induces local inflammation via the Toll-like receptor 7 pathway. Recently, an IMQ-driven skin inflammation model was developed in healthy volunteers for proof-of-pharmacology trials. The aim of this study was to profile the cellular, biochemical, and clinical effects of the marketed anti-inflammatory compound prednisolone in an IMQ model. This randomized, double-blind, placebo-controlled study was conducted in 24 healthy volunteers. Oral prednisolone (0.25 mg/kg/dose) or placebo (1:1) was administered twice daily for 6 consecutive days. Two days after treatment initiation with prednisolone or placebo, 5 mg imiquimod (IMQ) once daily for two following days was applied under occlusion on the tape-stripped skin of the back for 48 h in healthy volunteers. Non-invasive (imaging and biophysical) and invasive (skin punch biopsies and blister induction) assessments were performed, as well as IMQ ex vivo stimulation of whole blood. Prednisolone reduced blood perfusion and skin erythema following 48 h of IMQ application (95% CI [-26.4%, -4.3%], p = 0.0111 and 95% CI [-7.96, -2.13], p = 0.0016). Oral prednisolone suppressed the IMQ-elevated total cell count (95% CI [-79.7%, -16.3%], p = 0.0165), NK and dendritic cells (95% CI [-68.7%, -5.2%], p = 0.0333, 95% CI [-76.9%, -13.9%], p = 0.0184), and classical monocytes (95% CI [-76.7%, -26.6%], p = 0.0043) in blister fluid. Notably, TNF, IL-6, IL-8, and Mx-A responses in blister exudate were also reduced by prednisolone compared to placebo. Oral prednisolone suppresses IMQ-induced skin inflammation, which underlines the value of this cutaneous challenge model in clinical pharmacology studies of novel anti-inflammatory compounds. In these studies, prednisolone can be used as a benchmark.

Adalimumab combined with methotrexate versus adalimumab monotherapy in psoriasis: Three-year follow-up data of a single-blind randomized controlled trial.

BACKGROUND: Anti-drug antibodies (ADA) are formed in patients treated with adalimumab (ADL). This might increase clearance of ADL, potentially causing a (secondary) non-response. Combination therapy of ADL and methotrexate (MTX) reduces ADA levels and has a clinical benefit in rheumatologic diseases. In psoriasis however, the long-term effectiveness and safety have not been studied. OBJECTIVES: To investigate the three-year follow-up data of ADL combined with MTX compared to ADL monotherapy in ADL-naive patients with moderate to severe plaque type psoriasis. METHODS: We conducted a multicentre RCT in the Netherlands and Belgium. Randomization was performed by a centralized online randomization service. Patients were seen every 12 weeks until week 145. Outcome assessors were blinded. We collected data on drug survival, effectiveness, safety, pharmacokinetics and immunogenicity of patients that started ADL combined with MTX compared to ADL monotherapy. We present descriptive analysis and patients were analysed according to the group initially randomized to. Patients becoming non-adherent to the biologic were excluded from analyses. RESULTS: Sixty-one patients were included and 37 patients (ADL group n = 17, ADL + MTX group n = 20) continued in the follow-up study after 1 year. After 109 weeks and 145 weeks, there was a trend towards longer drug survival in the ADL + MTX group compared to the ADL group (week 109: 54.8% vs. 41.4%; p = 0.326, week 145: 51.6% vs. 41.4%; p = 0.464). At week 145, 7/13 patients were treated with MTX. In the ADL group, 4/12 patients that completed the study developed ADA, and 3/13 in the ADL + MTX group. CONCLUSIONS: In this small study, there was no significant difference in ADL overall drug survival when it was initially combined with MTX, compared to ADL alone. Discontinuation due to adverse events was common in the combination group. To secure accessible healthcare, combination treatment of ADL and MTX can be considered in individual patients.

Adalimumab in conjunction with surgery compared with adalimumab monotherapy for hidradenitis suppurativa: A Randomized Controlled Trial in a real-world setting.

BACKGROUND: Adalimumab, the only biologic registered for hidradenitis suppurativa, shows clinical response in up to 60% of patients, leaving many patients in need for other treatment options such as surgery. OBJECTIVE: To compare the clinical effectiveness of adalimumab combined with surgery vs adalimumab monotherapy in patients with moderate to severe hidradenitis suppurativa. METHODS: A pragmatic Randomized Controlled Trial was performed from August 2018 to July 2022. Primary outcome was the difference in mean International Hidradenitis Suppurativa Severity Score System reduction after 12 months of treatment with the difference in mean Dermatology Life Quality Index reduction as a key secondary outcome. RESULTS: Thirty-one patients were included per arm. The mean International Hidradenitis Suppurativa Severity Score System at baseline was 23.9 ± 10.7 in the surgery group and 20.9 ± 16.4, in the monotherapy group. After 12 months of treatment the surgery group had a significantly greater reduction in International Hidradenitis Suppurativa Severity Score System compared with the monotherapy group (-19.1 ± 11.3 vs -7.8 ± 11.8, P < .001). Moreover, the surgery group showed a greater reduction in Dermatology Life Quality Index after treatment compared with the monotherapy group (-8.2 ± 6.2 vs -4 ± 7.7, P = .02). LIMITATIONS: The study follow-up was too short to assess surgical recurrence rates. DISCUSSION: Combining adalimumab with surgery resulted in greater clinical effectiveness and improved quality of life after 12 months in patients with moderate to severe hidradenitis suppurativa.

A multimodal, comprehensive characterization of a cutaneous wound model in healthy volunteers.

Development of pharmacological interventions for wound treatment is challenging due to both poorly understood wound healing mechanisms and heterogeneous patient populations. A standardized and well-characterized wound healing model in healthy volunteers is needed to aid in-depth pharmacodynamic and efficacy assessments of novel compounds. The current study aims to objectively and comprehensively characterize skin punch biopsy-induced wounds in healthy volunteers with an integrated, multimodal test battery. Eighteen (18) healthy male and female volunteers received three biopsies on the lower back, which were left to heal without intervention. The wound healing process was characterized using a battery of multimodal, non-invasive methods as well as histology and qPCR analysis in re-excised skin punch biopsies. Biophysical and clinical imaging read-outs returned to baseline values in 28 days. Optical coherence tomography detected cutaneous differences throughout the wound healing progression. qPCR analysis showed involvement of proteins, quantified as mRNA fold increase, in one or more healing phases. All modalities used in the study were able to detect differences over time. Using multidimensional data visualization, we were able to create a distinction between wound healing phases. Clinical and histopathological scoring were concordant with non-invasive imaging read-outs. This well-characterized wound healing model in healthy volunteers will be a valuable tool for the standardized testing of novel wound healing treatments.

Clindamycin-Benzoyl Peroxide Gel Compared with Clindamycin Lotion for Hidradenitis Suppurativa: A Randomized Controlled Assessor-Blinded Intra-Patient Pilot Study.

BACKGROUND: Antibiotic resistance is a major concern, especially in hidradenitis suppurativa (HS). However, antibiotics form a cornerstone in its treatment. Topical clindamycin is known to cause bacterial resistance but is still advised as monotherapy for the treatment of mild to moderate HS. METHODS: This is a randomized, controlled, assessor-blinded, intra-patient pilot trial to compare the clinical efficacy of clindamycin-benzoyl peroxide gel with clindamycin lotion in patients with mild to moderate HS. Two contralateral body sites were randomized for treatment in each patient. The primary outcome was the difference in the International Hidradenitis Suppurativa Severity Score (IHS4) between the two groups after 12 weeks. Secondary objectives were feasibility of the intra-patient design, efficacy within treatment groups, effect on HS pain, HS itch, patient satisfaction, antibiotic resistance, and the prolonged efficacy after 16 weeks. RESULTS: Ten patients were included, resulting in two groups of 10 treated body sites. No significant differences were found between the two groups for all measurements after 12 or 16 weeks, while both therapies led to an improvement in the IHS4, pain, and itch scores. A significant decrease was observed in the IHS4 for both the clindamycin lotion (-1.5; p < 0.05) and the clindamycin-benzoyl peroxide gel (-2; p < 0.01) after 16 weeks, and the pain scores were reduced from 7 to 2.5, p < 0.01 and 6.5 to 3, p = 0.03, respectively. Using the IHS4-55, we identified 50% of patients as responders in both groups after 12 weeks. The intra-patient design, however, unexpectedly appeared to hinder the inclusion of patients. CONCLUSION: Clindamycin-benzoyl peroxide gel showed favorable clinical efficacy results, similar to clindamycin lotion, suggesting that it could replace clindamycin lotion in the treatment of mild to moderate HS and to prevent antibiotic resistance. A larger controlled trial is needed to validate these results.

Efficacy and Safety of Risankizumab for the Treatment of Hidradenitis Suppurativa: A Phase 2, Randomized, Placebo-Controlled Trial.

INTRODUCTION: Hidradenitis suppurativa (HS) is a chronic, immune-mediated skin condition characterized by inflammatory lesions that can cause pain, impaired physical activity, and reduced quality of life. This study evaluated the efficacy and safety of risankizumab, a humanized immunoglobulin G1 monoclonal antibody that specifically inhibits interleukin 23 by binding to its p19 subunit, for the treatment of HS. METHODS: This phase II multicenter, randomized, placebo-controlled, double-blind study investigated the efficacy and safety of risankizumab in patients with moderate-to-severe HS. Patients were randomized 1:1:1 to receive subcutaneous risankizumab 180 mg; risankizumab 360 mg; or placebo at weeks 0, 1, 2, 4, and 12. Patients initially randomized to placebo received blinded risankizumab 360 mg at weeks 16, 17, and 18; patients initially randomized to risankizumab received blinded matching placebo at the same time points. From weeks 20-60, all patients received open-label risankizumab 360 mg every 8 weeks. The primary endpoint was the achievement of HS Clinical Response (HiSCR) at week 16. Safety was assessed by monitoring of treatment-emergent adverse events (TEAEs). RESULTS: A total of 243 patients were randomized (risankizumab 180 mg, n = 80; risankizumab 360 mg, n = 81; placebo, n = 82). HiSCR was achieved by 46.8% of patients with risankizumab 180 mg, 43.4% with risankizumab 360 mg, and 41.5% with placebo at week 16. The primary endpoint was not met, and the study was terminated early. Incidence of TEAEs, severe TEAEs, TEAEs considered possibly related to study drug, and TEAEs leading to discontinuation of study drug were generally low and comparable across treatment groups. CONCLUSION: Risankizumab does not appear to be an efficacious treatment for moderate-to-severe HS. Future studies to understand the complex molecular mechanisms underlying HS pathogenesis and develop improved therapies are warranted. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03926169.

Guselkumab for hidradenitis suppurativa: a phase II, open-label, mode-of-action study.

BACKGROUND: The effectiveness of available biologics for the treatment of hidradenitis suppurativa (HS) is limited. Additional therapeutic options are needed. OBJECTIVES: To investigate the efficacy and mode of action of guselkumab [an anti-interleukin (IL)-23p19 monoclonal antibody] 200 mg subcutaneously every 4 weeks for 16 weeks in patients with HS. METHODS: An open-label, multicentre, phase IIa trial in patients with moderate-to-severe HS was carried out (NCT04061395). The pharmacodynamic response in skin and blood was measured after 16 weeks of treatment. Clinical efficacy was assessed using the Hidradenitis Suppurativa Clinical Response (HiSCR), the International Hidradenitis Suppurativa Severity Score System (IHS4), and the abscess and inflammatory nodule (AN) count. The protocol was reviewed and approved by the local institutional review board (METC 2018/694), and the study was conducted in accordance with good clinical practice guidelines and applicable regulatory requirements. RESULTS: Thirteen of 20 patients (65%) achieved HiSCR with a statistically significant decrease in median IHS4 score (from 8.5 to 5.0; P = 0.002) and median AN count (from 6.5 to 4.0; P = 0.002). The overall patient-reported outcomes did not show a similar trend. One serious adverse event, likely to be unrelated to guselkumab treatment, was observed. In lesional skin, transcriptomic analysis revealed the upregulation of various genes associated with inflammation, including immunoglobulins, S100, matrix metalloproteinases, keratin, B-cell and complement genes, which decreased in clinical responders after treatment. Immunohistochemistry revealed a marked decrease in inflammatory markers in clinical responders at week 16. CONCLUSIONS: Sixty-five per cent of patients with moderate-to-severe HS achieved HiSCR after 16 weeks of treatment with guselkumab. We could not demonstrate a consistent correlation between gene and protein expression and clinical responses. The main limitations of this study were the small sample size and absence of a placebo arm. The large placebo-controlled phase IIb NOVA trial for guselkumab in patients with HS reported a lower HiSCR response of 45.0-50.8% in the treatment group and 38.7% in the placebo group. Guselkumab seems only to be of benefit in a subgroup of patients with HS, indicating that the IL-23/T helper 17 axis is not central to the pathophysiology of HS.

External Validation of the IHS4-55 in a European Antibiotic-Treated Hidradenitis Suppurativa Cohort.

BACKGROUND: Previously, a new dichotomous outcome was developed, calculated as 55% reduction in the International Hidradenitis Suppurativa 4 (IHS4-55) score. It was validated in datasets of adalimumab and placebo-treated HS patients. External validation is an important aspect of clinical outcomes. OBJECTIVES: We aimed to externally validate the novel dichotomous IHS4-55 in a non-biologic treated dataset of HS patients. METHODS: Data from a previously published European-wide prospective clinical study of antibiotic treatment of HS patients were used to assess the association of IHS4-55 achievement with individual reduction in inflammatory nodules, abscesses, and draining tunnels. Moreover, the associations between IHS4-55 positivity and achievement of the minimal clinically important differences (MCIDs) for Dermatology Life Quality Index (DLQI), Numerical Rating Scale (NRS) Pain, and NRS Pruritus were analyzed. RESULTS: Data were obtained from 283 individual patients, of which 36.4% (103/283) were treated with clindamycin and rifampicin and 63.6% (180/283) with tetracyclines for 12 weeks. Achievers of the IHS4-55 demonstrated a significant reduction the counts of inflammatory nodules, abscesses, and draining tunnels (all p < 0.001). Additionally, IHS4-55 achievers had an odds ratio for achieving the MCID of DLQI, NRS Pain, and NRS Pruritus of 2.16 (95% CI 1.28-3.65, p < 0.01), 1.79 (95% CI 1.10-2.91, p < 0.05), and 1.95 (95% CI 1.18-3.22, p < 0.01), respectively. CONCLUSIONS: This study shows the external validity of the novel IHS4-55 by demonstrating a significant association between IHS4-55 achievement and a reduction in inflammatory lesion counts as well as achievement of MCIDs for DLQI, NRS Pain, and NRS Pruritus in an antibiotic-treated cohort. These findings support the use of the IHS4-55 as a novel primary outcome measure in clinical trials.

Validity and Reliability of Two Digital Wound Measurement Tools after Surgery in Patients with Hidradenitis Suppurativa.

BACKGROUND: After excision surgery in patients with hidradenitis suppurativa (HS), wounds are usually left open for secondary intention healing. To evaluate wound healing, reliable wound measurement is important. However, digital wound measurement tools for measuring the surface area are validated for small wounds located on flat or mildly convex body surfaces in studies, often powered inadequately. Up until now, a validated digital measurement tool to accurately measure wounds on all body surfaces, including the intertriginous areas, was not available. OBJECTIVES: The aim of this study was to validate two digital wound measurement tools for the measurement of the surface area of larger and concave wounds, using surgical wounds in patients with HS. METHODS: This prospective observational validation study included consecutive patients with HS undergoing excision surgery in the Department of Dermatology of the Erasmus University Medical Center, Rotterdam. Wound measurements using a ruler, the tracing method, the inSight® 3-dimensional (3D) device, and the ImitoWound app were performed by three investigators. The intraclass correlation coefficients (ICCs) for concurrent validity and the intra- and inter-rater reliability were analyzed. The standard error of measurement (SEm) and minimal detectable change were calculated, and Bland-Altman plots were constructed to determine the limits of agreement. RESULTS: Twenty patients with a total of 52 wounds were included. The wounds had a mean surface of 18.7 cm2. The inSight® 3D device showed an ICC of 0.987 for concurrent validity, 0.998 for intra-rater reliability, and 0.997 for inter-rater reliability. The ICCs from the ImitoWound application were 0.974, 0.978, and 0.964 for concurrent validity, intra-rater reliability, and inter-rater reliability, respectively. The SEms for intra- and inter-rater reliability were 0.95 cm2 and 1.11 cm2 for the inSight® 3D device and 3.33 cm2 and 3.51 cm2 for the ImitoWound app, respectively. CONCLUSION: Both the inSight® 3D device and the ImitoWound app demonstrated excellent concurrent validity and reliability for the surface measurements of concave wound, enabling these tools to be used reliably in clinical research and daily practice. Furthermore, it paves the way for broader application, such as telemonitoring of wound care at home.

Disease Association of Anti‒Carboxyethyl Lysine Autoantibodies in Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by recurring suppurating lesions of the intertriginous areas, resulting in a substantial impact on patients' QOL. HS pathogenesis remains poorly understood. An autoimmune component has been proposed, but disease-specific autoantibodies, autoantigens, or autoreactive T cells have yet to be described. In this study, we identify a high prevalence of IgM, IgG, and IgA antibodies directed against Nε-carboxyethyl lysine (CEL), a methylglyoxal-induced advanced glycation end-product, in the sera of patients with HS. Titers of anti-CEL IgG and IgA antibodies were highly elevated in HS compared with those in healthy controls and individuals with other inflammatory skin diseases. Strikingly, the majority of anti-CEL IgG was of the IgG2 subclass and correlated independently with both disease severity and duration. Both CEL and anti-CEL‒producing plasmablasts could be isolated directly from HS skin lesions, further confirming the disease relevance of this autoimmune response. Our data point to an aberration of the methylglyoxal pathway in HS and support an autoimmune axis in the pathogenesis of this debilitating disease.

Development and validation of IHS4-55, an IHS4 dichotomous outcome to assess treatment effect for hidradenitis suppurativa.

BACKGROUND: Validated, inclusive and easy-to-use outcomes for hidradenitis suppurativa are essential both in the clinical trial setting and clinical practice. The continuous IHS4 is a validated tool that dynamically assesses nodules/abscesses/draining tunnels and classifies disease severity as mild/moderate/severe. However, dichotomous outcomes are often required for clinical trials reporting. OBJECTIVE: To develop and validate a dichotomous outcome based on IHS4 that can be used in clinical trial settings and day-to-day clinical practice. METHODS: De-identified data from the PIONEER-I and -II studies were accessed through Vivli. Potential IHS4 thresholds were analysed using baseline to Week 12 data from adalimumab- and placebo-treated hidradenitis suppurativa patients in the PIONEER-I trial. The final threshold was chosen based on its ability to discriminate between patients treated with adalimumab or placebo and its association with reduction in inflammatory lesions. The final threshold was validated using data from baseline to Week 12 from adalimumab- and placebo-treated hidradenitis suppurativa patients in both the PIONEER-II and the combined PIONEER-I and -II studies. RESULTS: The best performing cut-off for the IHS4 was a 55% reduction of the IHS4 score (IHS4-55). Patients who achieved the IHS4-55 had an odd's ratio of 2.00 [95%-CI 1.26-3.18, p = 0.003], 2.79 (95%-CI 1.76-4.43, p < 0.001) and 2.16 (95%-CI 1.43-3.29, p < 0.001) for being treated with adalimumab rather than placebo in PIONEER-I, PIONEER-II and the combined dataset, respectively. Additionally, the achievement of the IHS4-55 was associated with a significant reduction in inflammatory nodules, abscesses and draining tunnels in all analysed datasets. CONCLUSIONS: IHS4-55, a novel dichotomous IHS4 version, based on a 55% reduction of the total score was developed. The IHS4-55 performs similarly to the HiSCR in discriminating between adalimumab- and placebo-treated hidradenitis suppurativa patients and shows significant associations with reductions in lesion counts. Moreover, the IHS4-55 addresses some of the HiSCR drawbacks by dynamically including draining tunnels in a validated manner. By allowing the analysis of hidradenitis suppurativa patients with an abscess and nodule count below 3 but many draining tunnels, this outcome measure will improve inclusivity in clinical trials.

IL-17A is a pertinent therapeutic target for moderate-to-severe hidradenitis suppurativa: Combined results from a pre-clinical and phase II proof-of-concept study.

Hidradenitis Suppurativa (HS) is a chronic, recurrent, inflammatory, follicular skin disease whose pathology is complex and not fully understood. The objective of this study was to elucidate the role of IL-17A in moderate-to-severe HS. Transcriptomic and histological analyses were conducted on ex vivo HS (n = 19; lesional and non-lesional) and healthy control (n = 8) skin biopsies. Further, a Phase II exploratory, randomized, double-blind, placebo-controlled study was carried out in moderate-to-severe HS patients. Patients were treated with either CJM112 300 mg (n = 33), a fully human anti-IL-17A IgG1/κ monoclonal antibody, or placebo (n = 33). The main outcome of the translational analyses was to identify IL-17A-producing cells and indications of IL-17A activity in HS lesional skin. The primary objective of the clinical study was to determine the efficacy of CJM112 in moderate-to-severe HS patients by HS-Physician Global Assessment (HS-PGA) responder rate at Week 16. Transcriptomic and histopathologic analyses revealed the presence of heterogeneous cell types in HS lesional skin; IL-17A gene signatures were increased in HS lesional vs non-lesional or healthy skin. High expression of IL-17A was localized to T cells, neutrophils, and mast cells, confirming the transcriptional data. Clinically, the proportion of Week 16 HS-PGA responders was significantly higher (p = 0.03) in the CJM112 group vs placebo (32.3% vs 12.5%). This study elucidated the role of the IL-17A pathway in HS pathogenesis and clinically validated the IL-17A pathway in moderate-to-severe HS patients in a proof-of-concept study using the anti-IL-17A-specific antibody CJM112.

Registries, multicentre and genome-wide association studies in hidradenitis suppurativa.

The European Hidradenitis Suppurativa Foundation (EHSF) e.V. has taken several initiatives for collaborative studies. They result from the data of the European Registry of Hidradenitis Suppurativa (ERHS) based on the knowledge obtained from the regional Northern countries (HISREG) and Italian (IRHIS) registries and the real-world data generated from claims data from insurance databases. Multicentre studies, such as the Hidradenitis Suppurativa collaborative study of subtypes (HORUS) and the Global Hidradenitis Suppurativa Atlas (GHISA), are planned to provide an ideal complement to the register studies. Most recently, the role of EHSF as a coordinator or key player is being explored in multiple genetic studies, such as a genome-wide association study (GWAS) and the exome sequencing and cellular/molecular profiling project, which will speed up gene and drug discovery in HS.

Insights into hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic, debilitating, inflammatory skin disorder with a prevalence of around 1% and a profound impact on patients' quality of life. Characteristic lesions such as inflammatory nodules, abscesses, and sinus tracts develop in the axillae, inguinal, and gluteal areas, typically during or after puberty. A complex interplay of genetic predisposition, hormonal factors, obesity, and smoking contributes to development and maintenance of the disease. HS is considered to arise from an intrinsic defect within the hair follicle, leading to follicular plugging, cyst formation, and subsequent rupture that in turn induce an acute inflammatory response characterized by elevated levels of IL-1ß, IL-17, and TNF. Over time, acute lesions transition into chronic disease, with active draining sinus tracts accompanied by extensive fibrosis. HS is associated with other immune-mediated inflammatory diseases, metabolic and cardiovascular disorders, and psychiatric comorbidities. Treatment of HS often requires a combination of antibiotic or immunosuppressing therapies and surgical intervention. Nonetheless, the currently available treatments are not universally effective, and many drugs, which are often repurposed from other inflammatory diseases, are under investigation. Studies into the early stages of HS may yield treatments to prevent disease progression; yet, they are hampered by a lack of appropriate in vitro and animal models.

Topical antimicrobial peptide omiganan recovers cutaneous dysbiosis but does not improve clinical symptoms in patients with mild to moderate atopic dermatitis in a phase 2 randomized controlled trial.

BACKGROUND: Dysbiosis and colonization with Staphylococcus aureus is considered to play an important role in the pathogenesis of atopic dermatitis (AD). Recovering this dysbiosis may improve AD symptoms. Omiganan is a synthetic indolicidin analogue antimicrobial peptide with activity against S aureus and could be a viable new treatment option for AD. OBJECTIVE: To explore the tolerability, clinical efficacy, and pharmacodynamics of omiganan in mild to moderate AD. METHODS: Eighty patients were randomized to omiganan 1%, 1.75%, or 2.5% or vehicle twice daily for 28 days on all lesions. Weekly visits included clinical scores and microbiological and pharmacodynamic assessments of 1 target lesion. RESULTS: In all omiganan treatment groups, dysbiosis was recovered by reducing Staphylococcus species abundance and increasing diversity. A reduction of cultured S aureus was observed in all omiganan treatment groups, with a significant reduction for omiganan 2.5% compared to vehicle (-93.5%; 95% CI, -99.2 to -28.5%; P = .02). No significant clinical improvement was observed. CONCLUSION: Topical administration of omiganan twice daily for up to 28 days in patients with mild to moderate AD led to a recovery of dysbiosis but without clinical improvement. Therefore, a monotreatment that selectively targets the microbiome does not appear to be a successful treatment strategy in mild to moderate AD.