Lesional skin of seborrheic dermatitis patients is characterized by skin barrier dysfunction and correlating alterations in the stratum corneum ceramide composition.

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease characterized by erythematous papulosquamous lesions in sebum rich areas such as the face and scalp. Its pathogenesis appears multifactorial with a disbalanced immune system, Malassezia driven microbial involvement and skin barrier perturbations. Microbial involvement has been well described in SD, but skin barrier involvement remains to be properly elucidated. To determine whether barrier impairment is a critical factor of inflammation in SD alongside microbial dysbiosis, a cross-sectional study was performed in 37 patients with mild-to-moderate facial SD. Their lesional and non-lesional skin was comprehensively and non-invasively assessed with standardized 2D-photography, optical coherence tomography (OCT), microbial profiling including Malassezia species identification, functional skin barrier assessments and ceramide profiling. The presence of inflammation was established through significant increases in erythema, epidermal thickness, vascularization and superficial roughness in lesional skin compared to non-lesional skin. Lesional skin showed a perturbed skin barrier with an underlying skewed ceramide subclass composition, impaired chain elongation and increased chain unsaturation. Changes in ceramide composition correlated with barrier impairment indicating interdependency of the functional barrier and ceramide composition. Lesional skin showed significantly increased Staphylococcus and decreased Cutibacterium abundances but similar Malassezia abundances and mycobial composition compared to non-lesional skin. Principal component analysis highlighted barrier properties as main discriminating features. To conclude, SD is associated with skin barrier dysfunction and changes in the ceramide composition. No significant differences in the abundance of Malassezia were observed. Restoring the cutaneous barrier might be a valid therapeutic approach in the treatment of facial SD.

Treatment with the Topical Antimicrobial Peptide Omiganan in Mild-to-Moderate Facial Seborrheic Dermatitis versus Ketoconazole and Placebo: Results of a Randomized Controlled Proof-of-Concept Trial.

Facial seborrheic dermatitis (SD) is an inflammatory skin disease characterized by erythematous and scaly lesions on the skin with high sebaceous gland activity. The yeast Malassezia is regarded as a key pathogenic driver in this disease, but increased Staphylococcus abundances and barrier dysfunction are implicated as well. Here, we evaluated the antimicrobial peptide omiganan as a treatment for SD since it has shown both antifungal and antibacterial activity. A randomized, patient- and evaluator-blinded trial was performed comparing the four-week, twice daily topical administration of omiganan 1.75%, the comparator ketoconazole 2.00%, and placebo in patients with mild-to-moderate facial SD. Safety was monitored, and efficacy was determined by clinical scoring complemented with imaging. Microbial profiling was performed, and barrier integrity was assessed by trans-epidermal water loss and ceramide lipidomics. Omiganan was safe and well tolerated but did not result in a significant clinical improvement of SD, nor did it affect other biomarkers, compared to the placebo. Ketoconazole significantly reduced the disease severity compared to the placebo, with reduced Malassezia abundances, increased microbial diversity, restored skin barrier function, and decreased short-chain ceramide Cer[NSc34]. No significant decreases in Staphylococcus abundances were observed compared to the placebo. Omiganan is well tolerated but not efficacious in the treatment of facial SD. Previously established antimicrobial and antifungal properties of omiganan could not be demonstrated. Our multimodal characterization of the response to ketoconazole has reaffirmed previous insights into its mechanism of action.

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.

Clinical, Cellular, and Molecular Effects of Corticosteroids on the Response to Intradermal Lipopolysaccharide Administration in Healthy Volunteers.

The intradermal lipopolysaccharide (LPS) challenge in healthy volunteers has proven to be a valuable tool to study local inflammation in vivo. In the current study the inhibitory effects of oral and topical corticosteroid treatment on intradermal LPS responses were evaluated to benchmark the challenge for future investigational drugs. Twenty-four healthy male volunteers received a two-and-a-half-day twice daily (b.i.d.) pretreatment with topical clobetasol propionate 0.05% and six healthy volunteers received a two-and-a-half-day b.i.d. pretreatment with oral prednisolone at 0.25 mg/kg body weight per administration. Participants received one injection regimen of either 0, 2, or 4 intradermal LPS injections (5 ng LPS in 50 µL 0.9% sodium chloride solution). The LPS response was evaluated by noninvasive (perfusion, skin temperature, and erythema) and invasive assessments (cellular and cytokine responses) in suction blister exudate. Both corticosteroids significantly suppressed the clinical inflammatory response (erythema P = 0.0001 for clobetasol and P = 0.0016 for prednisolone; heat P = 0.0245 for clobetasol, perfusion P < 0.0001 for clobetasol and P = 0.0036 for prednisolone). Clobetasol also significantly reduced the number of monocytes subsets, dendritic cells, natural killer cells, and T cells in blister exudate. A similar effect was observed for prednisolone. No relevant corticosteroid effects were observed on the cytokine response to LPS. We successfully demonstrated that the anti-inflammatory effects of corticosteroids can be detected using our intradermal LPS challenge model, validating it for evaluation of future investigational drugs, as an initial assessment of the anti-inflammatory effects of such compounds in a minimally invasive manner.

Intradermal lipopolysaccharide challenge as an acute in vivo inflammatory model in healthy volunteers.

AIMS: Whereas intravenous administration of Toll-like receptor 4 ligand lipopolysaccharide (LPS) to human volunteers is frequently used in clinical pharmacology studies, systemic use of LPS has practical limitations. We aimed to characterize the intradermal LPS response in healthy volunteers, and as such qualify the method as local inflammation model for clinical pharmacology studies. METHODS: Eighteen healthy male volunteers received 2 or 4 intradermal 5 ng LPS injections and 1 saline injection on the forearms. The LPS response was evaluated by noninvasive (perfusion, skin temperature and erythema) and invasive assessments (cellular and cytokine responses) in skin biopsy and blister exudate. RESULTS: LPS elicited a visible response and returned to baseline at 48 hours. Erythema, perfusion and temperature were statistically significant (P < .0001) over a 24-hour time course compared to saline. The protein response was dominated by an acute interleukin (IL)-6, IL-8 and tumour necrosis factor response followed by IL-1ß, IL-10 and interferon-γ. The cellular response consisted of an acute neutrophil influx followed by different monocyte subsets and dendritic cells. DISCUSSION: Intradermal LPS administration in humans causes an acute, localized and transient inflammatory reaction that is well-tolerated by healthy volunteers. This may be a valuable inflammation model for evaluating the pharmacological activity of anti-inflammatory investigational compounds in proof of pharmacology studies.

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.

Host genetics and tumor environment determine the functional impact of neutrophils in mouse tumor models.

BACKGROUND: Neutrophils have been reported to have protumor, antitumor or neutral effects in cancer progression. The underlying causes for this functional variability are not clear. METHODS: We studied the role of neutrophils in six different mouse tumor models by intratumoral injection of antimicrobial peptides or vaccination. Changes in systemic and intratumoral immune cells were analyzed by flow-cytometry and mass-cytometry. The role of neutrophils was studied by antibody-mediated neutrophil depletion. Neutrophils from different mouse strains were compared by RNA sequencing. RESULTS: The antimicrobial peptide Omiganan reduced the growth of TC-1 tumors in BL/6 mice and CT26 tumors in BALB/c mice. No significant effects were observed in B16F10, MC38 and 4T1 tumors. Growth delay was associated with increased abundance of neutrophils in TC-1 but not CT26 tumors. Systemic neutrophil depletion abrogated Omiganan efficacy in TC-1 but further reduced growth of CT26, indicating that neutrophils were required for the antitumor effect in TC-1 but suppressed tumor control in CT26. Neutrophils were also required for a therapeutic vaccine-induced T-cell mediated control of RMA tumors in BL/6 mice. Clearly, the circulating and intratumoral neutrophils differed in the expression of Ly6G and CD62L, between TC-1 and CT26 and between blood neutrophils of tumor-naïve BL/6 and BALB/c mice. RNA-sequencing revealed that neutrophils from BL/6 mice but not BALB/c mice displayed a robust profile of immune activation, matching their opposing roles in TC-1 and RMA versus CT26. CONCLUSIONS: Neutrophil functionality differs strongly between mouse strains and tumor types, with consequences for tumor progression and therapy.

Antimicrobial Peptide Omiganan Enhances Interferon Responses to Endosomal Toll-Like Receptor Ligands in Human Peripheral Blood Mononuclear Cells.

LL-37 is a cationic antimicrobial peptide and the sole human member of cathelicidins. Besides its bactericidal properties, LL-37 is known to have direct immunomodulatory effects, among which enhancement of antiviral responses via endosomal toll-like receptors (TLRs). Omiganan pentahydrochloride is a synthetic cationic peptide in clinical development. Previously, omiganan was primarily known for its direct bactericidal and antifungal properties. We investigated whether omiganan enhances endosomal TLR responses, similar to LL-37. Human peripheral blood mononuclear cells were treated with endosomal TLR3, -7, -8, and -9 ligands in the presence of omiganan. Omiganan enhanced TLR-mediated interferon-α release. Subsequent experiments with TLR9 ligands showed that plasmacytoid dendritic cells were main contributors to omiganan-enhanced IFN production. Based on this type I interferon-enhancing effect, omiganan may qualify as potential treatment modality for virus-driven diseases. The molecular mechanism by which omiganan enhances endosomal TLR responses remains to be elucidated.

Pharmacodynamic Effects of Topical Omiganan in Patients With Mild to Moderate Atopic Dermatitis in a Randomized, Placebo-Controlled, Phase II Trial.

Omiganan is an indolicidin analog with antimicrobial properties that could be beneficial for patients with atopic dermatitis. In this randomized, double-blind, placebo-controlled, phase II trial we explored the efficacy, pharmacodynamics, and safety of topical omiganan once daily in 36 patients with mild to moderate atomic dermatitis. Patients were randomized to apply topical omiganan 1%, omiganan 2.5%, or vehicle gel to one target lesion once daily for 28 consecutive days. Small but significant improvements in local objective SCORing Atopic Dematitis index and morning itch were observed in the omiganan 2.5% group compared with the vehicle gel group (-18.5%; 95% confidence interval, -32.9 to -1.0; P = 0.04; and -8.2; 95% confidence interval, -16.3 to -0.2; P = 0.05, respectively). A shift from lesional to nonlesional skin microbiota was observed in both omiganan treatment groups, in contrast to the vehicle group. Thus, treatment with topical omiganan improved dysbiosis in patients with mild to moderate atopic dermatitis, and small but statistically significant improvements in clinical scores were detected. Our findings warrant further exploration in future clinical trials.

Omiganan Enhances Imiquimod-Induced Inflammatory Responses in Skin of Healthy Volunteers.

Omiganan (OMN; a synthetic cationic peptide) and imiquimod (IMQ; a TLR7 agonist) have synergistic effects on interferon responses in vitro. The objective of this study was to translate this to a human model for proof-of-concept, and to explore the potential of OMN add-on treatment for viral skin diseases. Sixteen healthy volunteers received topical IMQ, OMN, or a combination of both for up to 4 days on tape-stripped skin. Skin inflammation was quantified by laser speckle contrast imaging and 2D photography, and molecular and cellular responses were analyzed in biopsies. IMQ treatment induced an inflammatory response of the skin. Co-treatment with OMN enhanced this inflammatory response to IMQ, with increases in perfusion (+17.1%; 95% confidence interval (CI) 5.6%-30%; P < 0.01) and erythema (+1.5; 95% CI 0.25%-2.83; P = 0.02). Interferon regulatory factor-driven and NFκB-driven responses following TLR7 stimulation were enhanced by OMN (increases in IL-6, IL-10, MXA, and IFNÉ£), and more immune cell infiltration was observed (in particular CD4+, CD8+, and CD14+ cells). These findings are in line with the earlier mechanistic in vitro data, and support evaluation of imiquimod/OMN combination therapy in human papillomavirus-induced skin diseases.

Results of phase 2 trials exploring the safety and efficacy of omiganan in patients with human papillomavirus-induced genital lesions.

AIMS: To assess safety and tolerability and explore pharmacodynamics and efficacy of omiganan in external anogenital warts (AGW) and vulvar high-grade squamous intraepithelial lesions (HSIL). METHODS: Two randomized controlled trials in patients with external AGW and vulvar HSIL were conducted. Patients received topical omiganan 2.5% or placebo gel once daily for 12 weeks with a follow-up of 12 weeks. Safety and tolerability were monitored and pharmacodynamics and clinical efficacy of omiganan were assessed by analysing lesion count, size and viral load. Self-reported pain, itch and quality of life were assessed by an electronic diary and questionnaire. RESULTS: Twenty-four AGW and 12 vulvar HSIL patients were enrolled. All patients had a high treatment adherence (99%). No serious adverse events occurred and all adverse events (n = 27) were mild, transient and self-limiting. The treatment groups were not different in terms of safety and tolerability, lesion count and size, and patient-reported outcomes pain, itch and quality of life. Human papillomavirus load significantly reduced after 12 weeks of treatment with omiganan compared to placebo (-96.6%; 95% confidence interval -99.9 to -7.4%; P = .045) in AGW patients only. CONCLUSION: Topical omiganan appears to be safe in patients with AGW and vulvar HSIL and reduced human papillomavirus load after 12 weeks of treatment in AGW patients.

Comprehensive, Multimodal Characterization of an Imiquimod-Induced Human Skin Inflammation Model for Drug Development.

Imiquimod (IMQ) is often used as a topical challenge agent to provoke local skin inflammation. The objective of this study was to develop and refine a rapid, temporary, and reversible human skin inflammation model with IMQ for application in clinical drug development. A randomized, vehicle-controlled, open-label, dose-ranging study was conducted in 16 healthy male subjects. IMQ (5 mg) was applied once daily for 72 hours under occlusion to intact skin (n = 8) or tape stripped (TS) skin (n = 8). Although IMQ alone induced limited effects, TS+IMQ treatment showed larger responses in several domains, including erythema and perfusion (P < 0.0001), mRNA expression of inflammatory markers (P < 0.01), and inflammatory cell influx compared with vehicle. In conclusion, a rapid, human IMQ skin inflammation challenge model was successfully developed with a clear benefit of TS prior to IMQ application. Future interaction studies will enable proof-of-pharmacology of novel compounds targeting the innate immune system.

Evaluation of a pharmacology-driven dosing algorithm of 3-weekly paclitaxel using therapeutic drug monitoring: a pharmacokinetic-pharmacodynamic simulation study.

BACKGROUND AND OBJECTIVE: Severe neutropenia is the most frequent and important toxicity of 3-weekly paclitaxel and puts patients at substantial risk of infectious complications. It is well known that the time during which paclitaxel plasma concentrations exceed 0.05 µmol/L (T(C>0.05)) correlates with the extent of neutropenia. This study was initiated to develop a dosing algorithm that would be able to reduce severe neutropenia by targeting an individual paclitaxel T(C>0.05) between 26 and 31 hours, and could be validated in a prospective randomized trial by comparing it to conventional dosing of paclitaxel. METHODS: Paclitaxel plasma concentration-time (n = 273) and absolute neutrophil count (ANC) data (152 of the 273 patients) were pooled from two previous studies and submitted to population pharmacokinetic and pharmacodynamic modelling using nonlinear mixed-effects modelling software NONMEM® version VII. To fit the data, we used a previously described 3-compartment model with saturable elimination and distribution, coupled to a semiphysiological model with a linear function to describe the myelotoxic effect of paclitaxel (E(paclitaxel)) on circulating neutrophils (neutropenia). Patient age, sex, body surface area (BSA), bilirubin and renal function were tested as potential covariates on the maximum elimination capacity of paclitaxel (VM(EL)). Limited sampling strategies were tested on the pharmacokinetic model for their accuracy to predict paclitaxel T(C>0.05). Subsequently, we proposed a first-cycle dosing algorithm that accounted for BSA, patient age and sex, while later cycles accounted for the previous-cycle paclitaxel T(C>0.05) (target: 26 to 31 hours) and ANC nadir to adapt the paclitaxel dose for the next treatment cycle. To test the adequacy of the proposed dosing algorithm, we used extensive data simulations on the final pharmacokinetic/pharmacodynamic model, generating datasets of 1000 patients for six subsequent treatment cycles. Grade 4 neutropenia was tested as a potential endpoint for a prospective clinical trial and simulated for two scenarios, i.e. conventional dosing of paclitaxel 200 mg/m(2) every 3 weeks, and personalized, pharmacology-driven dosing as outlined above. RESULTS: Concentration-time data for paclitaxel were adequately described by the 3-compartment model. Also, individual ANC counts were adequately described by the semiphysiological model using a linear function to describe E(paclitaxel) on neutropenia. Patient age, sex, bilirubin and BSA were significant and independent covariates on the elimination of paclitaxel. Paclitaxel VM(EL) was 16% higher in males than in female patients, and a 10-year increase in age led to a 13% decrease in VM(EL). A single paclitaxel plasma concentration 24 hours after the start of infusion was adequate to predict paclitaxel T(C>0.05) (root squared mean error [RSME] = +0.5%), and the addition of an end-of-infusion sample did not further improve precision (RSME = -0.6%). Data simulations on the final pharmacokinetic/pharmacodynamic model and using the proposed dosing algorithm resulted in a first-cycle paclitaxel dose ranging from 150 to 185 mg/m(2) for women and from 165 to 200 mg/m(2) for men. Dose adaptations for cycles two to six ranged from -40% to +30%, with a final median paclitaxel dose of 167 mg/m(2) (range 76 to 311 mg/m(2)). When compared with conventional dosing (paclitaxel 200 mg/m(2) every 3 weeks), personalized dosing reduced grade 4 neutropenia in cycle one from 15% to 7%, and further to 4% in cycle 2. CONCLUSION: This study proposes a pharmacology-driven dosing algorithm of 3-weekly paclitaxel to reduce the incidence of grade 4 neutropenia. A randomized clinical trial comparing this dosing algorithm with conventional BSA-based dosing of paclitaxel in patients with advanced non-small cell lung cancer is currently ongoing.

Evaluation of a new, rapid test for detecting HCV infection, suitable for use with blood or oral fluid.

The availability of a highly accurate, rapid, point-of-care test for hepatitis C virus (HCV) may be useful in addressing the problem of under-diagnosis of HCV, by increasing opportunities for testing outside of traditional clinical settings. A new HCV rapid test device (OraQuick® HCV Rapid Antibody Test), approved recently in Europe for use with venous blood, fingerstick blood, serum, plasma, or oral fluid was evaluated in a multi-center study and performance compared to established laboratory-based tests for detection of HCV. The HCV rapid test was evaluated in prospective testing of subjects with signs and/or symptoms of hepatitis, or who were at risk for hepatitis C using all 5 specimen types. Performance was assessed relative to HCV serostatus established by laboratory methods (EIA, RIBA and PCR) approved in Europe for diagnosis of hepatitis C infection. Sensitivity to antibody in early infection was also compared to EIA in 27 seroconversion panels. In addition, the reliability of the oral fluid sample for accurate detection of anti-HCV was assessed by studying the impact of various potentially interfering conditions of oral health, use of oral care products and consumption of food and drink. In this large study of at-risk and symptomatic persons, the overall specificities of the OraQuick® HCV Rapid Antibody Test were equivalent (99.6-99.9%) for all 5 specimen types and the 95% CIs substantially overlapped. Overall sensitivities were virtually identical for venous blood, fingerstick blood, serum and plasma (99.7-99.9%). Observed sensitivity was slightly lower for oral fluid at 98.1% though the upper CI (99.0%) was equal to the lower CI for venous blood and fingerstick blood. Most of the HCV positive subjects which gave nonreactive results in oral fluid had serological and virological results consistent with resolved infection. Sensitivity for anti-HCV in early seroconversion was virtually identical between the HCV rapid test and EIA. Detection of anti-HCV in oral fluid appeared generally robust to conditions of oral health, consumption of food and drink and use of oral care products. The OraQuick® HCV Rapid Antibody Test demonstrated clinical performance that was equivalent to current laboratory-based EIA. This new, HCV rapid test appears suitable as an aid in the diagnosis of HCV infection and may increase testing opportunities due to its simplicity and flexibility to use multiple specimen types, including fingerstick blood and oral fluid.