Altered skin microbiome, inflammation, and JAK/STAT signaling in Southeast Asian ichthyosis patients.

BACKGROUND: Congenital ichthyosis (CI) is a collective group of rare hereditary skin disorders. Patients present with epidermal scaling, fissuring, chronic inflammation, and increased susceptibility to infections. Recently, there is increased interest in the skin microbiome; therefore, we hypothesized that CI patients likely exhibit an abnormal profile of epidermal microbes because of their various underlying skin barrier defects. Among recruited individuals of Southeast Asian ethnicity, we performed skin meta-genomics (i.e., whole-exome sequencing to capture the entire multi-kingdom profile, including fungi, protists, archaea, bacteria, and viruses), comparing 36 CI patients (representing seven subtypes) with that of 15 CI age-and gender-matched controls who had no family history of CI. RESULTS: This case-control study revealed 20 novel and 31 recurrent pathogenic variants. Microbiome meta-analysis showed distinct microbial populations, decreases in commensal microbiota, and higher colonization by pathogenic species associated with CI; these were correlated with increased production of inflammatory cytokines and Th17- and JAK/STAT-signaling pathways in peripheral blood mononuclear cells. In the wounds of CI patients, we identified specific changes in microbiota and alterations in inflammatory pathways, which are likely responsible for impaired wound healing. CONCLUSIONS: Together, this research enhances our understanding of the microbiological, immunological, and molecular properties of CI and should provide critical information for improving therapeutic management of CI patients.

Scientific Rationale and Clinical Basis for Clindamycin Use in the Treatment of Dermatologic Disease.

Clindamycin is a highly effective antibiotic of the lincosamide class. It has been widely used for decades to treat a range of skin and soft tissue infections in dermatology and medicine. Clindamycin is commonly prescribed for acne vulgaris, with current practice standards utilizing fixed-combination topicals containing clindamycin that prevent Cutibacterium acnes growth and reduce inflammation associated with acne lesion formation. Certain clinical presentations of folliculitis, rosacea, staphylococcal infections, and hidradenitis suppurativa are also responsive to clindamycin, demonstrating its suitability and versatility as a treatment option. This review describes the use of clindamycin in dermatological practice, the mechanism of protein synthesis inhibition by clindamycin at the level of the bacterial ribosome, and clindamycin's anti-inflammatory properties with a focus on its ability to ameliorate inflammation in acne. A comparison of the dermatologic indications for similarly utilized antibiotics, like the tetracycline class antibiotics, is also presented. Finally, this review addresses both the trends and mechanisms for clindamycin and antibiotic resistance, as well as the current clinical evidence in support of the continued, targeted use of clindamycin in dermatology.

Rethinking Hidradenitis Suppurativa Management: Insights into Bacterial Interactions and Treatment Evolution.

Hidradenitis suppurativa (HS), or acne inversa, is a chronic inflammatory dermatological condition characterized by painful and recurrent nodules and purulent abscesses. HS can have a devastating impact on the quality of life of patients. This condition is commonly localized to the axilla, groin, perineal, and inframammary regions, and can develop fistulas and sinus tracts over time. Its pathogenesis remains elusive and is best characterized at the moment as multi-factorial. Additionally, questions remain about the role of cutaneous dysbiosis as a primary HS trigger or as a secondary perturbation due to HS inflammation. This article features works in relation to HS and its interplay with bacterial microflora. We address current treatment approaches and their impact on HS-related bacteria, as well as areas of therapeutic innovation. In the future, disease-modifying or remittive therapy will likely combine an advanced/targeted anti-inflammatory approach with one that effectively modulates cutaneous and deep tissue dysbiosis.

Early and Sustained Improvements in Symptoms and Quality of Life with Upadacitinib in Adults and Adolescents with Moderate-to-Severe Atopic Dermatitis: 52-Week Results from Two Phase III Randomized Clinical Trials (Measure Up 1 and Measure Up 2).

BACKGROUND: Atopic dermatitis is a chronic inflammatory disease characterized by increased itch, skin pain, poor sleep quality, and other symptoms that negatively affect patient quality of life. Upadacitinib, an oral selective Janus kinase (JAK) inhibitor with greater inhibitory potency for JAK1 than JAK2, JAK3, or tyrosine kinase 2, is approved to treat moderate-to-severe atopic dermatitis. OBJECTIVE: We aimed to evaluate the effect of upadacitinib on patient-reported outcomes over 52 weeks in adults and adolescents with moderate-to-severe atopic dermatitis. METHODS: Data from two phase III monotherapy trials of upadacitinib (Measure Up 1, NCT03569293; Measure Up 2, NCT03607422) were integrated. Changes in pruritus, pain, other skin symptoms, sleep, quality of life, mental health, and patient impression were evaluated. Patient-reported outcome assessments included the Worst Pruritus Numerical Rating Scale, Patient-Oriented Eczema Measure, Dermatology Life Quality Index, Atopic Dermatitis Symptom Scale, Atopic Dermatitis Impact Scale, Hospital Anxiety and Depression Scale, SCORing Atopic Dermatitis index, Patient Global Impression of Severity, Patient Global Impression of Change, and Patient Global Impression of Treatment. Minimal clinically important differences, achievement of scores representing minimal disease burden, and the change from baseline were evaluated in patients who received upadacitinib through week 52 and in patients who received placebo through week 16. RESULTS: This analysis included 1609 patients (upadacitinib 15 mg, N = 557; upadacitinib 30 mg, N = 567; placebo, N = 485). Baseline demographics and disease characteristics were generally similar across all arms. The proportion of patients treated with upadacitinib reporting improvements in itch increased rapidly by week 1, increased steadily through week 8, and was sustained through week 52. Patients receiving upadacitinib also experienced improvements in pain and other skin symptoms by week 1, which continued through week 16; improvements were maintained through week 52. Patient reports of improved sleep increased rapidly from baseline to week 1, increased steadily through week 32, and were sustained through week 52. Patients experienced quality-of-life improvements through week 8, which were maintained through week 52. By week 1, patients in both upadacitinib groups experienced rapid improvements in emotional state, and by week 12, patients also achieved meaningful improvements in anxiety and depression. Improvements in mental health continued steadily through week 32 and were maintained through week 52. Patients treated with upadacitinib 30 mg generally experienced improvements in patient-reported outcomes earlier than those treated with upadacitinib 15 mg. Through week 16, patients receiving upadacitinib experienced greater improvements versus those receiving placebo in all assessed patient-reported outcomes. CONCLUSIONS: Adults and adolescents with moderate-to-severe atopic dermatitis treated with once-daily upadacitinib 15 or 30 mg experienced early improvements in itch, pain, other skin symptoms, sleep, quality of life, and mental health that were sustained through week 52. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifiers NCT03569293 (13 August 2018) and NCT03607422 (27 July 2018).

Atopic dermatitis, or eczema, is a condition that causes painful itchy dry skin, which is burdensome for patients and has a negative impact on quality of life. These symptoms frequently lead to disruption of daily activities such as school and work, decreased self-confidence, social isolation, anxiety, depression, and sleep disturbance. Symptoms of atopic dermatitis, such as itch and sleep disturbance, can only be assessed by patients. Therefore, it is important to consider patients' perceptions of their symptoms and the related impact on their quality of life, especially when evaluating treatment benefits. Upadacitinib is an orally administered drug approved to treat moderate-to-severe atopic dermatitis. In two clinical trials (Measure Up 1 and Measure Up 2), we investigated how treatment with upadacitinib (15-mg or 30-mg dose) given once daily to adults and adolescents with moderate-to-severe atopic dermatitis would impact their symptoms and quality of life over a 1-year period. We measured changes over time in patients' assessments of itch, pain, other skin-related symptoms, sleep, daily activities, emotional state, mental health, and overall quality of life. Patients treated with upadacitinib experienced improvements in symptoms of atopic dermatitis and quality of life within the first 1­2 weeks of treatment. These improvements continued to steadily increase in the following weeks and lasted through 1 year of treatment. In conclusion, once-daily treatment with upadacitinib 15 or 30 mg led to early and lasting improvements in the well-being of patients with atopic dermatitis.

Structural Basis for p19 Targeting by Anti-IL-23 Biologics: Correlations with Short- and Long-Term Efficacy in Psoriasis.

IL-23 is central to psoriasis pathogenesis. Biologics targeting IL-23 are important therapies against psoriasis. IL-23 inhibitors risankizumab, tildrakizumab, and guselkumab bind the IL-23 p19 subunit, whereas ustekinumab binds p40; however, the structural composition of the IL-23-binding epitopes and how these molecular properties relate to clinical efficacy are not known. Utilizing epitope data derived from hydrogen-deuterium exchange or crystallographic experiments, we mapped inhibitor epitope locations, hydrophobicity, and surface charge onto the IL-23 surface. Molecular properties of each inhibitor epitope, including solvent-accessible surface area, were correlated to binding affinity, kinetic values, and clinical efficacy scores for plaque psoriasis through linear regression analysis. Each IL-23 inhibitor binds an epitope with a unique size, composition, and location except for a 10-residue overlap region outside of the IL-23 receptor epitope. We observed strong correlations between epitope surface area and KD and koff but not kon. Epitope surface area, KD, and koff were further associated with short-term (10-16 weeks) and long-term (44-60 weeks) clinical efficacy according to PASI-90 responses, with risankizumab demonstrating highest efficacy among IL-23 biologics. In contrast, kon, epitope hydrophobicity, polarity, and charge content did not correlate with efficacy. These data exemplify how molecular principles of medications within a therapeutic class can explain their differential clinical responses.

Triple-action inhibitory mechanism of allosteric TYK2-specific inhibitors.

Deucravacitinib, 6-(cyclopropanecarbonylamido)-4-[2-methoxy-3-(1-methyl-1,2,4-triazol-3-yl)anilino]-N-(trideuteriomethyl)pyridazine-3-carboxamide, is a highly selective inhibitor of protein tyrosine kinase 2 (TYK2) that targets the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. The structural basis for its selectivity and allosteric inhibition remains poorly understood. Here, we investigate the inhibition mechanism through analysis of available structures relevant to the STAT pathway, including crystal structures of the truncated TYK2 FERM-SH2 domain bound to the IFNα type I receptor (IFNαR1) and the truncated TYK2 JH2-JH1 domain. Our computational analysis provides a mechanistic hypothesis for the relatively rapid interferon-induced gene expression mediated by TYK2 relative to other cytokines. We find that deucravacitinib inhibits TYK2 kinase in three distinct states: the autoinhibited state and two activated states for autophosphorylation and phosphorylation of downstream protein substrates. Its binding to the TYK2 pseudokinase domain in the autoinhibited state restricts the essential dynamics of the TYK2 kinase domain required for kinase activity. Furthermore, it binds competitively with ATP in the pseudokinase domain, and also directly prevents formation of the active state of TYK2 through steric clashes.

Ensuring Dermatologists Practice Enhanced Antibiotic Stewardship With Sarecycline Mnemonic.

It must be ensured that dermatologists practice enhanced antibiotic stewardship to combat antimicrobial resistance and negative consequences of microbiome dysbiosis. In order to help achieve this, we have developed a mnemonic ENLIGHTEN to help healthcare providers and patients understand sarecycline’s features.J Drugs Dermatol. 2023;22(10):1061 doi:10.36849/JDD.7437R1.

Acne accounts for an almost 2.5-fold higher proportion of dermatology visits among adult females compared to adult males in the United States: A study of the national ambulatory medical care survey from 2002-2016.

BACKGROUND: Acne vulgaris affects a significant number of females into adulthood. Juvenile acne and adult acne have different presentations and potentially distinctive pathogeneses. However, patterns in treatments specifically related to the adult female population have previously not been studied. METHODS: Retrospective database analysis of healthcare utilization and medications prescribed for acne using the National Ambulatory Medical Care Survey (NAMCS) data from 2002-2016 was performed. RESULTS: After age 20, acne accounted for an almost 2.5-fold higher proportion of dermatology visits among females compared to males (10.1% vs. 4.1%, P < 0.001). Tetracycline-class antibiotics were the most prescribed therapy within all age groups of females between 2002-2016. However, there was also a substantial rise in prescriptions of spironolactone beginning in 2012. CONCLUSION: A significantly greater proportion of dermatology visits by adult females are for acne in comparison to adult males. Tetracycline-class antibiotics remain the most prescribed therapy in adult age groups despite a potentially different pathogenesis of adult acne. Therefore, there is a need for further studies comparing the effectiveness of therapies specifically for adult female acne.

Congenital Ichthyosis: A Practical Clinical Guide on Current Treatments and Future Perspectives.

Congenital ichthyoses are a group of hereditary disorders of keratinization that are challenging to treat. Affected individuals suffer not only from thickening of the skin but also associated complications such as growth restriction, hearing and eye complications, infections, and thermodysregulation. This clinical review provides a practical roadmap to the longitudinal care of patients with ichthyosis with both general and age- and disease-specific recommendations. The allure of pathogenesis-based and targeted treatments for these monogenetic severe but orphan conditions shines bright as dermatological therapies enter a new era.

Antimicrobial Wound Dressings: A Concise Review for Clinicians.

Wound management represents a substantial clinical challenge due to the growing incidence of chronic skin wounds resulting from venous insufficiency, diabetes, and obesity, along with acute injuries and surgical wounds. The risk of infection, a key impediment to healing and a driver of increased morbidity and mortality, is a primary concern in wound care. Recently, antimicrobial dressings have emerged as a promising approach for bioburden control and wound healing. The selection of a suitable antimicrobial dressing depends on various parameters, including cost, wound type, local microbial burden and the location and condition of the wound. This review covers the different types of antimicrobial dressings, their modes of action, advantages, and drawbacks, thereby providing clinicians with the knowledge to optimize wound management.

Circadian Oscillations of Minimal Erythema Dose (MED) are Also Influenced by Diet in Patients with Psoriasis: A Chronomedical Study.

INTRODUCTION: Minimal erythema dose (MED) remains a parameter of paramount importance to orient narrow-band (NB)-UVB phototherapy in psoriatic (PsO) patients. Recently, circadian rhythm and diet were recognized as potential MED modulators, but their mutual interaction remains understudied. Thus, we aimed to evaluate the potential diet modulation of MED circadian oscillations. METHODS: In the first phase, a cohort study was performed comparing potential MED oscillations (morning, afternoon, and evening) among omnivorous psoriatic patients before and after a phototherapy cycle and omnivorous healthy controls. The two groups were age-, gender-, skin-type-, MED-, and diet-matched. Then, in the second phase, another cohort study was carried out comparing MED oscillations 24 h after the last phototherapeutic session only in psoriatic patients cleared with NB-UVB and undergoing different diets (vegan, vegetarian, paleo , ketogenic, intermittent circadian fasting, and omnivore). Patients with different diets were age-, gender-, and skin-type matched. RESULTS: In the first phase, we enrolled only omnivores, specifically 54 PsO patients and 54 healthy individuals. Their MED before and after NB-UVB therapy changed significantly among the three different time-points (morning, afternoon, and evening) (p < 0.001). The time effect was statistically significant in both groups before and after phototherapy. In the second phase, we enrolled 144 PsO patients (vegan, vegetarian, paleo, ketogenic, intermittent circadian fasting, and omnivore). MED circadian oscillations preserved a significant difference also after clearance and were influenced by diet type and time of day (p < 0.001). In particular, vegans displayed the lowest MED values, whilst Ramadan fasting showed the highest values in morning, afternoon, and evening. CONCLUSIONS: Diet, like other ongoing therapies, should be reported in the medical records of patients with psoriasis undergoing NB-UVB and patients with lower MEDs should be preferentially treated in the morning when the MED is higher.

Topical Isotretinoin (TMB-001) Treatment for 12 Weeks Did Not Result in Clinically Relevant Laboratory Abnormalities in Participants with Congenital Ichthyosis in the Phase 2b CONTROL Study.

INTRODUCTION: Treatment with oral retinoids can be effective in patients with congenital ichthyosis (CI) but may be associated with clinically significant laboratory changes. In this Phase 2b CONTROL study analysis, we characterize the effects of TMB-001, a novel topical isotretinoin formulation, on laboratory values in participants with X-linked recessive (XLRI) and autosomal recessive lamellar (ARCI-LI) ichthyosis at 12 weeks. METHODS: A randomized, double-blind, vehicle-controlled, Phase 2b study was conducted with participants ≥ 9 years of age with confirmed XLRI and ARCI-LI. Participants were randomized 1:1:1 and stratified by CI subtype to receive TMB-001 0.05%:TMB-001 0.1%:vehicle twice daily for 12 weeks. Laboratory analyses were performed at screening and Week 12. RESULTS: Among 33 enrolled participants (TMB-001 0.05% n = 11, TMB-001 0.1% n = 10, and vehicle n = 12), 52% had ARCI-LI and 48% had XLRI. At 12 weeks, there were single reports of anemia, neutropenia, leukopenia, lymphocytosis, and leukocytosis after vehicle treatment; neutropenia was reported in one participant receiving TMB-001 0.1%. There were single reports of abnormal biochemistry values-liver enzymes, creatinine, urea nitrogen, hyperkalemia, and hyperproteinemia-across treatment cohorts. Non-fasting hyperglycemia was observed in three participants receiving TMB-001 0.1% and one participant receiving vehicle. Urinalysis abnormalities reported in > 1 participant included urobilinogen (TMB-001 0.1% n = 2, vehicle n = 2), protein (TMB-001 0.1% n = 3, vehicle n = 2), and leukocyte esterase (TMB-001 0.1% n = 2). Laboratory parameter changes were asymptomatic and did not require study discontinuation or drug withdrawal. CONCLUSION: There were no clinically significant laboratory changes in participants receiving TMB-001 isotretinoin ointment through 12 weeks of treatment, which differs from reported results for systemic isotretinoin. TRIAL REGISTRATION: NCT04154293.

Structural basis for differential p19 targeting by IL-23 biologics.

Background: IL-23 is central to the pathogenesis of psoriasis, and is structurally comprised of p19 and p40 subunits. "Targeted" IL-23 inhibitors risankizumab, tildrakizumab, and guselkumab differ mechanistically from ustekinumab because they bind p19, whereas ustekinumab binds p40; however, a knowledge gap exists regarding the structural composition of their epitopes and how these molecular properties relate to their clinical efficacy. Objectives: To characterize and differentiate the structural epitopes of the IL-23 inhibitors risankizumab, guselkumab, tildrakinumab, and ustekinumab, and correlate their molecular characteristics with clinical response in plaque psoriasis therapy. Methods: We utilized epitope data derived from hydrogen-deuterium exchange studies for risankizumab, tildrakizumab, and guselkumab, and crystallographic data for ustekinumab to map drug epitope locations, hydrophobicity, and surface charge onto the IL-23 molecular surface (Protein Data Bank ID Code 3D87) using UCSF Chimera. PDBePISA was used to calculate solvent accessible surface area (SASA). Epitope composition was determined by classifying residues as acidic, basic, polar, or hydrophobic and calculating their contribution to epitope SASA. Linear regression and analysis of variance was performed. Results: All the p19-specific inhibitor epitopes differ in location and size, with risankizumab and guselkumab having large epitope surface areas (SA), and tildrakizumab and ustekinumab having smaller SA. The tildrakizumab epitope was mostly hydrophobic (56%), while guselkumab, risankizumab, and ustekinumab epitopes displayed >50% non-hydrophobic residues. Risankizumab and ustekinumab exhibited acidic surface charges, while tildrakizumab and guselkumab were net neutral. Each inhibitor binds an epitope with a unique size and composition, and with mostly distinct locations except for a 10-residue overlap region that lies outside of the IL-23 receptor epitope. We observed a strong correlation between epitope SA and PASI-90 rates (R2 = 0.9969, p = 0.0016), as well as between epitope SA and KD (R2 = 0.9772, p = 0.0115). In contrast, we found that total epitope hydrophobicity, polarity, and charge content do not correlate with clinical efficacy. Conclusions: Structural analysis of IL-23 inhibitor epitopes reveals strong association between epitope SA and early drug efficacy in plaque psoriasis therapy, exemplifying how molecular data can explain clinical observations, inform future innovation, and help clinicians in specific drug selection for patients.

Characteristics and outcomes for participants with congenital ichthyosis who responded to treatment with the topical isotretinoin formulation TMB-001: results from the Phase IIb CONTROL study.

BACKGROUND: Emollients and keratolytics are frequently used to manage symptoms of congenital ichthyosis (CI). Systemic retinoid treatment is complicated by teratogenicity and dose-limiting adverse effects. OBJECTIVES: This analysis from the randomized Phase IIb CONTROL study investigated the characteristics of participants who responded to treatment with TMB-001, a novel topical isotretinoin ointment formulation. METHODS: Participants ≥ 9 years of age with genetically confirmed CI and ≥ 2 (out of 4) Visual Index for Ichthyosis Severity (VIIS) assessment areas with ≥ 3 scaling score were randomized 1 : 1 : 1 to TMB-001 0.05%, TMB-001 0.1% or vehicle, twice daily for 12 weeks. Efficacy endpoints included the proportion of participants with ≥ 50% reduction in VIIS-scaling (VIIS-50) compared with baseline and ≥ 2-grade reduction in Investigator's Global Assessment (IGA)-scaling score compared with baseline. Changes in body surface area (BSA) involvement, Dermatology Life Quality Index (DLQI) scores and Itch-Numeric Rating Scale (I-NRS) scores were assessed. RESULTS: Among the 33 participants (11 randomized to TMB-001 0.05%, 10 to TMB-001 0.1% and 12 to vehicle), median age was 29 years (range 9-80), and most were male (64%) and White (79%). Baseline demographics were generally similar among participants who did or did not achieve TMB-001 treatment success. Participants who had lower mean BSA involvement and higher DLQI and I-NRS scores at baseline were more likely to achieve VIIS-50. Similarly, higher baseline DLQI and I-NRS scores were associated with IGA response; BSA involvement was similar for IGA responders vs. nonresponders. CONCLUSIONS: Higher DLQI and I-NRS scores at baseline were associated with participants achieving treatment success by VIIS-50 and IGA response. Lower BSA involvement was associated with VIIS-50 success.

Sarecycline inhibits protein translation in Cutibacterium acnes 70S ribosome using a two-site mechanism.

Acne vulgaris is a chronic disfiguring skin disease affecting ∼1 billion people worldwide, often having persistent negative effects on physical and mental health. The Gram-positive anaerobe, Cutibacterium acnes is implicated in acne pathogenesis and is, therefore, a main target for antibiotic-based acne therapy. We determined a 2.8-Šresolution structure of the 70S ribosome of Cutibacterium acnes by cryogenic electron microscopy and discovered that sarecycline, a narrow-spectrum antibiotic against Cutibacterium acnes, may inhibit two active sites of this bacterium's ribosome in contrast to the one site detected previously on the model ribosome of Thermus thermophilus. Apart from the canonical binding site at the mRNA decoding center, the second binding site for sarecycline exists at the nascent peptide exit tunnel, reminiscent of the macrolides class of antibiotics. The structure also revealed Cutibacterium acnes-specific features of the ribosomal RNA and proteins. Unlike the ribosome of the Gram-negative bacterium Escherichia coli, Cutibacterium acnes ribosome has two additional proteins, bS22 and bL37, which are also present in the ribosomes of Mycobacterium smegmatis and Mycobacterium tuberculosis. We show that bS22 and bL37 have antimicrobial properties and may be involved in maintaining the healthy homeostasis of the human skin microbiome.

Phase IIb randomized CONTROL study demonstrates a novel topical isotretinoin formulation, TMB-001, is safe and effective in participants with either recessive X-linked or autosomal recessive lamellar congenital ichthyosis.

BACKGROUND: In two severe congenital ichthyosis subtypes, autosomal recessive lamellar ichthyosis (ARCI-LI) and X-linked recessive ichthyosis (XLRI), cutaneous manifestations include widespread scaling. Approved topical treatment options are limited to emollients and keratolytics. AIM: This analysis from the randomized phase IIb CONTROL study assessed whether the efficacy and safety of TMB-001, a novel topical isotretinoin ointment formulation, differed between ARCI-LI and XLRI subtypes. METHODS: Participants ≥ 9 years with genetically confirmed XLRI or ARCI-LI and ≥ 2 (of 4) Visual Index for Ichthyosis Severity (VIIS) assessment areas with ≥ 3 scaling score were randomized 1 : 1 : 1 to TMB-001 0.05%/TMB-001 0.1%/vehicle, twice daily for 12 weeks. The proportion of participants with ≥ 50% reduction vs. baseline in VIIS scaling (VIIS 50; primary endpoint) and ≥ 2-grade reduction in Investigator's Global Assessment (IGA)-scaling score vs. baseline (key secondary endpoint) were evaluated. Adverse events (AEs) were monitored. RESULTS: Among enrolled participants (TMB-001 0.05%, n = 11; 0.1%, n = 10; and vehicle, n = 12), 52% had ARCI-LI and 48% XLRI subtypes. Mean age was 33.6 and 35.4 years for participants with ARCI-LI and XLRI, respectively. Overall, 33%, 50% and 17% of participants with ARCI-LI and 100%, 33% and 75% of participants with XLRI achieved VIIS 50 in the TMB-001 0.05%, TMB-001 0.1% and vehicle groups, respectively (nominal P = 0.24 for 0.05% vs. vehicle, intent-to-treat population). Improvement of ≥ 2-grade IGA score was observed in 33%, 50% and 0% of participants with ARCI-LI and 83%, 33% and 25% of participants with XLRI in the TMB-001 0.05%, TMB-001 0.1% and vehicle groups, respectively (nominal P = 0.03 for 0.05% vs. vehicle, intention-to-treat population). Most AEs were application-site reactions. CONCLUSION: Regardless of congenital ichthyosis subtype, TMB-001 demonstrated greater proportions of participants achieving VIIS 50 and ≥ 2-grade IGA improvement vs. vehicle.