Exposure-response relationship of guselkumab and the potential of serum proteomics in identifying predictive biomarker candidates in psoriasis.

BACKGROUND: Response to biologics in psoriasis varies in real-world settings. Serum biomarkers could aid biologic selection and dose modifications to improve patient outcomes while encouraging cost-effective care. OBJECTIVES: To explore the exposure-response relationship for guselkumab (GUS), to define a GUS concentration target for optimal response and to evaluate the potential of serum protein levels as predictive biomarker candidates. METHODS: This is a prospective, multicentric, cohort study in psoriasis patients treated with GUS. Serum GUS trough concentrations (TCs) collected at multiple timepoints were measured using an in-house immunoassay. Next, proximity extension assay technology (Target 96 Inflammation Panel Olink®) was used to measure serum protein levels in a subcohort including 38 GUS patients (week 0 and week 4), six psoriasis patients naive for systemic treatment and four healthy controls. RESULTS: Seventy-five patients participated and 400 samples were collected. Guselkumab TCs and clinical response were correlated at week 4, week 12 and in steady-state (≥20 weeks). Optimal responders (Psoriasis Area and Severity Index [PASI] ≤ 2) had significantly higher TCs than suboptimal responders from week 4 onwards in treatment. An optimal steady-state TC of 1.6 µg/mL was defined. Although TC and absolute PASI were lower and worse, respectively, in patients weighing ≥90 kg, clinical outcomes referred to desirable to excellent PASI ranges. Therefore, we do not recommend systematically higher GUS doses in obese patients. We could not reveal early differentially expressed proteins to distinguish future optimal from suboptimal responders. CONCLUSIONS: We demonstrated an exposure-response relationship for GUS and an optimal steady-state TC of 1.6 µg/mL in real-world psoriasis patients. Hereby, we deliver more evidence that therapeutic drug monitoring poses a promising strategy in optimizing GUS treatment. No biomarker candidates were identified through serum proteomics. We propose protein screening should be repeated in larger cohorts to continue the quest for predictive biomarkers.

Validation of a Patient Global Assessment for extent, severity and impact to define the severity strata for the Self Assessment Vitiligo Extent Score (SA-VES).

BACKGROUND: The Self Assessment Vitiligo Extent Score (SA-VES) is a validated, patient-reported outcome measure to assess the body surface area affected with vitiligo. Information on how to translate the obtained score into extent, severity and impact strata (mild-moderate-severe) is still lacking. Stratification is helpful to define inclusion criteria for trials, enables comparison and pooling of trial results and can be used for epidemiological research. OBJECTIVES: The aim was to develop extent, severity and impact strata for the SA-VES based on validated anchor-based questions. METHODS: In total, 315 patients with vitiligo (non-segmental; age ≥ 16) recruited at the Ghent University Hospital (Belgium) completed a questionnaire that was conducted in cooperation with the Dutch Society for vitiligo patients to ensure content validity. First three anchor questions included in the questionnaire [Patient Global Assessment (PtGA) for vitiligo extent, severity and impact] were assessed for content validity, construct validity and intrarater reliability. Subsequently, the PtGAs were used to stratify the SA-VES based on ROC analysis. RESULTS: For all PtGAs (PtGA extent, PtGA severity, PtGA impact), at least 75% of hypotheses evaluated for construct validity were confirmed. Intrarater reliability of all PtGAs was good to excellent (ICCs PtGA extent: 0.623; PtGA severity: 0.828; PtGA impact: 0.851). The optimal cut-off values of the SA-VES between the three global categories (mild/limited - moderate - severe/extensive) were 1.05% and 6.45% based on PtGA extent, 2.07% and 4.8% based on PtGA severity and 2% and 3.35% based on PtGA impact. CONCLUSION: This study provides the first guide for the interpretation of the numerical output obtained by the SA-VES (vitiligo extent) and enables the translation into a global vitiligo grading for extent, severity and impact. As patients' interpretation of vitiligo extent, severity and impact may vary amongst patients worldwide, future international studies will be required.

A Belgian consensus on the definition of a treat-to-target outcome set in psoriasis management.

OBJECTIVE: Treat-to-target (T2T) is an algorithm to reach a predefined outcome. Here, we define a T2T outcome for moderate-to-severe psoriasis vulgaris. METHODS: Briefly, the study included a literature review, discussions with key opinion leaders, recruitment of additional dermatologists with experience in managing moderate-to-severe psoriasis, 3 eDelphi survey rounds and a patient focus group. Relevant topics were selected during discussions prior to the survey for the statements. Surveys were based on the eDelphi methodology for consensus-building using a series of statements. Consensus was defined as at least 80% of participants agreeing. A psoriasis patient focus group provided feedback on topic selection and outcome. RESULTS: A total of 5 discussions were held, and 3 eDelphi rounds were conducted with an average of 19 participants per round. The T2T outcome was set assuming shared decision between patient and dermatologist, awareness and referral for comorbidities by the dermatologist and appropriate treatment adherence by the patient. We defined 'ideal' and 'acceptable' targets; the latter referring to conditions restricting certain drugs. The T2T outcome was multidimensional, including ≥ ΔPASI90/75 or PGA ≤ 1, itch VAS score ≤ 1, absence of disturbing lesions, DLQI ≤ 1/3, incapacity daily functioning VAS score ≤ 1, safety ≤ mild side-effects and full/mild tolerability of treatment for the ideal and acceptable target, respectively. Finally, time to achieve the T2T outcome was set at 12 weeks after initiation for all treatments. At all times, safety should not exceed the presence of mild side-effects. CONCLUSION: With this novel T2T composite outcome for psoriasis, clinicians and patients can make shared decisions on the treatment goals they envisage, as a guidance for future treatment steps - leading to a tight control management of the disease.

Reference method for digital surface measurement of target lesions in vitiligo: a comparative analysis.

BACKGROUND: Objective measurement of target lesions in vitiligo is important for clinical practice and trials, yet no preferred tool has been defined. Reported digital tools have shortcomings related to feasibility aspects and often lack information on validity, reliability and responsiveness. Moreover, studies are not yet based on ultraviolet (UV) photography. OBJECTIVES: To assess the reliability, validity and feasibility of two functions in ImageJ for measurement of target lesions, based on three different types of images including UV pictures. METHODS: Planimetric measurements were performed on photographs with and without UV, and lesion contours on transparent sheets of 52 vitiligo lesions from 10 patients with vitiligo. The ImageJ functions 'wand' and 'threshold' were used by three and four assessors, respectively. Inter- and intrarater reliability, hypothesis testing for construct validity, and feasibility were evaluated. RESULTS: The inter- and intrarater reliability for the 'wand' and 'threshold' functions were excellent [intraclass correlation coefficient (ICC) > 0·9] for measurement on pictures (with or without UV). The highest agreement (ICC > 0·95) and lowest variance were obtained for measurements on transparent sheets. All four hypotheses for construct validity were confirmed for all measurements. Overall, all measurement methods scored satisfactorily for user-friendliness. However, measurements on transparent sheets were preferred and the completion time was significantly faster. CONCLUSIONS: This study confirmed the reliability, validity and feasibility of two functions in ImageJ to measure target lesions in vitiligo. Based on the feasibility and included three-dimensional aspects, transparent sheets measured with the ImageJ 'wand' function can be proposed for future trials as a reference method to investigate the criterion validity of other digital instruments.

Clinical visible signs of disease activity in vitiligo: a systematic review and meta-analysis.

Vitiligo is an unpredictable depigmenting disorder for which a static method to assess disease activity is lacking. Presence of certain skin manifestations may be indicative of disease activity. Here, we evaluated the current evidence for an association between clinical signs and reported disease activity in vitiligo. A systematic review and meta-analysis was performed based on a search in PubMed, Embase and Cochrane Library. Literature reporting skin manifestations and disease activity was analysed based on descriptive analyses and, if applicable, odd ratios. Forty-six observational studies were selected and analysed, including 28 case reports. Reported clinical signs in relation to active vitiligo were as follows: Koebner's phenomenon, confetti-like depigmentations, tri- and hypochromic lesions (including poorly defined borders), inflammatory borders/areas, itch and leukotrichia. Based on this search, strong evidence was found for Koebner's phenomenon. Poorly defined borders and confetti lesions are potential markers, although more data are needed to confirm this. Evidence for other skin manifestations was inconclusive, whereas case reports on inflammatory borders were indicative of active disease. Limitations included the lack of randomized controlled trials, large-scale prospective studies and heterogeneity due to inconsistent definitions. This systematic review urges the vitiligo community to come forward with consensus-based definitions as well as a reliable scoring system to assess these clinical signs and to design optimal trials to investigate their true predictive value.

The many faces of interleukin-17 in inflammatory skin diseases.

Interleukin (IL)-17 is an emerging target for inflammatory skin disorders. Given the remarkable success of its therapeutic inhibition in psoriasis, the pathogenic role of this cytokine is being explored in other immune-mediated diseases. Interestingly, IL-17 is linked to particular skin conditions where its activation coincides with disease flares. The leading hypothesis for its contribution to proinflammatory signalling cascades is driving inflammasome activation. However, IL-17 stimulation also releases a range of noninflammasome-related cytokines from human skin. Furthermore, a role in cytotoxic responses and an important interplay with the microbiome is hypothesized. While treatment failure would be surprising in neutrophilic dermatoses, the picture might be more complex in lymphocyte-mediated conditions. Nonetheless, increasing insights into the pathogenesis suggest that beneficial responses are also probable in the latter conditions. Study of this pathway in the skin reveals some intriguing aspects of the IL-17-related immunological network.

TNFR1-induced lethal inflammation is mediated by goblet and Paneth cell dysfunction.

Tumor necrosis factor (TNF) is a powerful activator of the immune system and a well-validated target for treatment of autoimmune diseases. Injection of TNF induces systemic lethal inflammation characterized by hypothermia, induction of multiple cytokines, and extensive damage to multiple organs. Previously, we reported that TNF-induced lethal inflammation is strictly TNFR1(P55)-dependent. We also uncovered a crucial role for P55 expression levels in intestinal epithelial cells (IECs), in which P55+/+ expression is sufficient to sensitize to TNF lethality in an otherwise fully protected P55+/- background. Here, we investigated the molecular mechanism that drives TNF toxicity in IECs. Unexpectedly, we found that the degree of TNF-induced enterocyte damage and apoptosis in IECs is equally strong in TNF-sensitive P55+/+ mice and TNF-resistant P55+/- mice. Our results suggest that P55+/+-induced signaling causes goblet and Paneth cell dysfunction, leading to severe epithelial barrier dysfunction. As a result, intestinal permeability and systemic bacterial spread are induced, causing lethal systemic inflammation. In conclusion, we identified P55-induced goblet and Paneth cell dysfunction as a crucial mechanism for TNF-induced systemic and lethal inflammation.