Anti-KIT antibody, barzolvolimab, reduces skin mast cells and disease activity in chronic inducible urticaria.

BACKGROUND: Chronic inducible urticaria (CIndU) is characterized by mast cell (MC)-mediated wheals in response to triggers: cold in cold urticaria (ColdU) and friction in symptomatic dermographism (SD). KIT receptor activation by stem cell factor (SCF) is essential for MC function. Barzolvolimab (CDX-0159) is a humanized antibody that inhibits KIT activation by SCF and was well tolerated in healthy volunteers with dose-dependent plasma tryptase suppression indicative of systemic mast cell ablation. METHODS: This is an open-label, trial in patients with antihistamine refractory ColdU or SD, receiving one IV dose of barzolvolimab (3 mg/kg), with a 12-week follow-up. Primary endpoint was safety/tolerability; pharmacodynamic (PD)/clinical endpoints included serum tryptase, plasma SCF, skin MC histology, provocation tests, urticaria control test (UCT), and dermatology life quality index (DLQI). RESULTS: Analysis populations were safety (n = 21) and pharmacodynamics/clinical activity (n = 20). Barzolvolimab was well tolerated; most adverse events were mild and resolved. Treatment resulted in significant depletion of skin MCs, decreased tryptase (

Safety and efficacy of lirentelimab in patients with refractory indolent systemic mastocytosis: a first-in-human clinical trial.

BACKGROUND: Indolent systemic mastocytosis (ISM) is characterized by excessive mast cell (MC) accumulation and MC-driven signs and symptoms. Currently used therapies are not approved and have limited efficacy. Lirentelimab (AK002) is a monoclonal antibody against sialic acid-binding immunoglobulin-like lectin (Siglec)-8 that inhibits MC activation. OBJECTIVES: To determine the safety, tolerability and efficacy of lirentelimab in reducing the symptoms of ISM. METHODS: At a specialty centre for mastocytosis in Germany, we conducted a phase I first-in-human single-ascending and multidose clinical trial of lirentelimab in patients with ISM. Eligible adults had World Health Organization-confirmed ISM and an unsatisfactory response to available treatment. In part A, patients received a single dose of lirentelimab 0.0003, 0.001, 0.003, 0.01 or 0.03 mg kg-1; in part B, patients received one lirentelimab dose of 0.3 mg kg-1 or 1.0 mg kg-1; and in part C, patients received either 1.0 mg kg-1 lirentelimab every 4 weeks for 6 months or ascending doses of lirentelimab (one dose of 1 mg kg-1 followed by five doses of 3-10 mg kg-1 every 4 weeks). The primary endpoint was safety/tolerability. Secondary endpoints included changes from baseline in Mastocytosis Symptom Questionnaire (MSQ), Mastocytosis Activity Score (MAS) and Mastocytosis Quality of Life Questionnaire (MC-QoL) scores at 2 weeks after the final dose. RESULTS: In 25 patients with ISM (13 in parts A + B and 12 in part C; median age 51 years, 76% female, median 4.6 years from diagnosis), the most common treatment-related adverse events (AEs) were feeling hot (76%) and experiencing a headache (48%). No serious AEs occurred. Median MSQ and MAS symptom severity scores in part C improved (vs. baseline) across all symptoms [MSQ: skin (38-56%), gastrointestinal (49-60%), neurological (47-59%), musculoskeletal (26-27%); MAS: skin (53-59%), gastrointestinal (72-85%), neurological (20-57%), musculoskeletal (25%)]. Median MC-QoL scores improved across all domains: symptoms (39%), social life/functioning (42%), emotions (57%) and skin (44%). CONCLUSIONS: Lirentelimab was generally well tolerated and improved symptoms and quality of life in patients with ISM. The therapeutic potential of lirentelimab should be considered for ISM.

A group of cationic amphiphilic drugs activates MRGPRX2 and induces scratching behavior in mice.

BACKGROUND: Mas gene-related G protein-coupled receptors (MRGPRs) are a G protein-coupled receptor family responsive to various exogenous and endogenous agonists, playing a fundamental role in pain and itch sensation. The primate-specific family member MRGPRX2 and its murine orthologue MRGPRB2 are expressed by mast cells mediating IgE-independent signaling and pseudoallergic drug reactions. OBJECTIVES: Our aim was to increase knowledge about the function and regulation of MRGPRX2/MRGPRB2, which is of major importance in prevention of drug hypersensitivity reactions and drug-induced pruritus. METHODS: To identify novel MRGPR (ant)agonists, we screened a library of pharmacologically active compounds by utilizing a high-throughput calcium mobilization assay. The identified hit compounds were analyzed for their pseudoallergic and pruritogenic effects in mice and human. RESULTS: We found a class of commonly used drugs activating MRGPRX2 that, to a large extent, consists of antidepressants, antiallergic drugs, and antipsychotics. Three-dimensional pharmacophore modeling revealed structural similarities of the identified agonists, classifying them as cationic amphiphilic drugs. Mast cell activation was investigated by using the 3 representatively selected antidepressants clomipramine, paroxetine, and desipramine. Indeed, we were able to show a concentration-dependent activation and MRGPRX2-dependent degranulation of the human mast cell line LAD2 (Laboratory of Allergic Diseases-2). Furthermore, clomipramine, paroxetine, and desipramine were able to induce degranulation of human skin and murine peritoneal mast cells. These substances elicited dose-dependent scratching behavior following intradermal injection into C57BL/6 mice but less so in MRGPRB2-mutant mice, as well as wheal-and-flare reactions following intradermal injections in humans. CONCLUSION: Our results contribute to the characterization of structure-activity relationships and functionality of MRGPRX2 ligands and facilitate prediction of adverse reactions such as drug-induced pruritus to prevent severe drug hypersensitivity reactions.

Sleep disturbance in adult dermatologic patients: A cross-sectional study on prevalence, burden, and associated factors.

BACKGROUND: Sleep disturbance remains insufficiently characterized in many dermatoses. OBJECTIVE: To investigate the prevalence, burden, and factors associated with sleep disturbance in dermatologic patients. METHODS: We recruited 800 patients and recorded pruritus characteristics and sociodemographic and clinical parameters. Validated questionnaires were used to assess sleep disturbance, psychological distress, health-related quality of life, and work productivity. RESULTS: Two thirds of patients met criteria of poor sleep, which was associated with psychological distress, diminished health-related quality of life, and lost work productivity. Patients with average and maximum pruritus on the visual analog scale exceeding 5 and 6.5 points, respectively, were at high risk of suffering pruritus-related sleep disturbance. Overall pruritus intensity and its nocturnal exacerbation contributed independently to sleep disturbance. Psychological distress was of even higher impact on sleep than pruritus and almost a third of the relationship between pruritus intensity and sleep was mediated by psychological distress. CONCLUSION: Sleep disturbance is prevalent in dermatologic patients and constitutes a considerable burden. CLINICAL IMPLICATION: Dermatologic patients with intense pruritus and psychological distress should be examined for sleep disorders. Adequate antipruritic therapy and complementary psychotherapy in affected patients may help them regain restorative sleep.

The characteristics and impact of pruritus in adult dermatology patients: A prospective, cross-sectional study.

BACKGROUND: Pruritus often accompanies chronic skin diseases, exerting considerable burden on many areas of patient functioning; this burden and the features of pruritus remain insufficiently characterized. OBJECTIVE: To investigate characteristics, including localization patterns, and burden of pruritus in patients with chronic dermatoses. METHODS: We recruited 800 patients with active chronic skin diseases. We assessed pruritus intensity, localization, and further characteristics. We used validated questionnaires to assess quality of life, work productivity and activity impairment, anxiety, depression, and sleep quality. RESULTS: Nine out of every 10 patients had experienced pruritus throughout their disease and 73% in the last 7 days. Pruritus often affected the entire body and was not restricted to skin lesions. Patients with moderate to severe pruritus reported significantly more impairment to their sleep quality and work productivity, and they were more depressed and anxious than control individuals and patients with mild or no pruritus. Suicidal ideations were highly prevalent in patients with chronic pruritus (18.5%) and atopic dermatitis (11.8%). CONCLUSIONS: Pruritus prevalence and intensity are very high across all dermatoses studied; intensity is linked to impairment in many areas of daily functioning. Effective treatment strategies are urgently required to treat pruritus and the underlying skin disease.

Worsening of chronic spontaneous urticaria after intake of hot pepper.

BACKGROUND: Patients with chronic spontaneous urticaria (CSU) have been reported to experience increased disease activity in response to the oral intake of hot pepper (Capsicum spp.). As of now, it is unclear how common this is. OBJECTIVE: We assessed patients with CSU for the prevalence of disease worsening after the intake of hot pepper and characterized its effects on their urticaria. METHODS: A questionnaire-based survey study in adult patients with CSU and a history of hot pepper consumption was carried out at a reference center for urticaria in Turkey. CSU patients who had co-existing chronic inducible urticaria were excluded from the study. RESULTS: Of the eighty-five patients with CSU included in this study, 46% (39 of 85) reported worsening of their urticaria after consuming hot pepper. Demographic features, duration of CSU and control status of urticaria were not different between patients who experienced worsening of their urticaria after the intake of hot pepper and those who did not. In affected patients, worsening of their symptoms started 1.2 ± 1.2 hours after the intake of hot pepper and lasted for 3.3 ± 6.8 hours. Symptoms disappeared significantly faster in patients who took antihistamines after worsening of their urticaria with hot pepper (0.7 ± 0.6 vs. 5.8 ± 8.8 hours; p = 0.003). CONCLUSIONS: Worsening of urticaria is common and relevant in patients with CSU in Turkey. Further studies are needed to explore if this is also the case in other geographical regions and to identify and characterize the underlying mechanisms.

Development of the Angioedema Control Test-A patient-reported outcome measure that assesses disease control in patients with recurrent angioedema.

BACKGROUND: Recurrent angioedema (AE) is an important clinical problem in the context of chronic urticaria (mast cell mediator-induced), ACE-inhibitor intake and hereditary angioedema (both bradykinin-mediated). To help patients obtain control of their recurrent AE is a major treatment goal. However, a tool to assess control of recurrent AE is not yet available. This prompted us to develop such a tool, the Angioedema Control Test (AECT). METHODS: After a conceptional framework was developed for the AECT, a list of potential AECT items was generated by a combined approach of patient interviews, literature review and expert input. Subsequent item reduction was based on impact analysis, inter-item correlation, additional predefined criteria for item performance, and a review of the item selection process for content validity. Finally, an instruction section was generated, and an US-American-English version was developed by a structured translation process. RESULTS: A 4-item AECT with recall periods of 4 weeks and 3 months was developed based on 106 potential items tested in 97 patients with mast cell mediator-induced (n = 49) or bradykinin-mediated recurrent AE (n = 48). Eighty-four items were excluded based on impact analysis. The remaining 22 items could be further reduced by a method-mix of inter-item correlation, additional predefined criteria for item performance and review for content validity. CONCLUSIONS: The AECT is the first tool to assess disease control in recurrent AE patients. Its retrospective approach, its brevity and its simple scoring make the AECT ideally suited for clinical practice and trials. Its validity and reliability need to be determined in future independent studies.

New treatments for chronic urticaria.

OBJECTIVE: Chronic urticaria (CU) is a common, heterogeneous, and debilitating disease. Antihistamines and omalizumab are the mainstay therapies of CU. Additional treatment options are needed. Here, we review the off and beyond label use of licensed drugs, novel treatments that are currently under development, and promising new targets. DATA SOURCES: MEDLINE was searched for recent reports of the successful use of treatments in CU and promising targets for the development of novel treatment options. We also searched ClinicalTrials.gov for recent and ongoing randomized clinical trials in CU. STUDY SELECTIONS: Relevant articles were selected and reviewed. RESULTS: Omalizumab, the treatment of choice in patients with antihistamine-resistant chronic spontaneous urticaria (CSU), should be explored for use in chronic inducible urticaria in children younger than 12 years with CSU and at higher doses. The off-label use of dupilumab, reslizumab, mepolizumab, and benralizumab can be effective in CU. Ligelizumab and UB-221, 2 novel anti-IgE monoclonal antibodies, are in clinical trials for CU. Other promising drugs that are currently under development for CU are a chemoattractant receptor-homologous molecule expressed on TH2 cell antagonist, a monoclonal antibody to Siglec-8 (AK002), Bruton tyrosine kinase inhibitors (fenebrutinib and Lou064), a spleen tyrosine kinase inhibitor, and dupilumab. Promising targets of future therapies include the Mas-related G-protein-coupled receptor X2; the histamine4 receptor; C5a and its receptor; inhibitory mast cell receptors other than Siglec-8; interleukin 33, interleukin 25, and thymic stromal lymphopoietin, and stem cell factor. CONCLUSION: Novel and better treatments for CU are very much needed. Some agents are in clinical trials already (eg, ligelizumab), and additional ones should be developed, making use of the many promising targets recently identified and characterized.

Flare Size but Not Intensity Reflects Histamine-Induced Itch.

INTRODUCTION: Flare reactions arise due to the release of vasodilators from sensory nerves caused by antidromic transmission of action potentials after the induction of itch. OBJECTIVE: We investigated the link between flare and itch using 3 models of itch. METHODS: Skin provocations with histamine, capsaicin, and cowhage were performed in 31 subjects. Itch was quantified using the visual analog scale. Flare was assessed using laser speckle contrast imaging (LSCI) and digital photography. RESULTS: The duration, intensity, and area under the curve of histamine-induced itch correlated with the area of increased blood flow measured with LSCI (r = 0.545, p = 0.002; r = 0.575, p = 0.001; and r = 0.649, p < 0.001, respectively). Itch and skin blood flow in response to capsaicin or cowhage did not correlate. CONCLUSION: In histamine-induced skin inflammation, itch and increased blood flow are linked. Thus, the area of histamine-induced flare may be used as a surrogate marker for histamine-induced itch.

Role of Substance P and Its Receptor Neurokinin 1 in Chronic Prurigo: A Randomized, Proof-of-Concept, Controlled Trial with Topical Aprepitant.

Substance P (SP) and its receptor neurokinin 1 (NK1R) are thought to be involved in the pathogenesis of chronic prurigo. Here, we assessed SP serum levels, cutaneous NK1R expression, and the effects of topical aprepitant, an NK1R antagonist, in patients with chronic prurigo. SP and NK1R were increased, compared with controls, in the serum and in lesional vs. non-lesional skin of the patients, respectively. Aprepitant, in a randomized, placebo-controlled, split-sided, doubleblind trial, reduced the intensity of pruritus as assessed by visual analogue scale by >50% from baseline to day 28 (-35.2), but so did placebo vehicle (-38.1, p= 0.76). Overall clinical scores improved significantly by day 28 in both treatment groups, with no significant difference between the 2 groups (p=0.32). Our findings imply that both SP and NK1R are involved in the pathogenesis of chronic prurigo. Parallel groupdesigned trials are needed to assess the efficacy of topical aprepitant treatment in this condition.

Lesions on the back of hands and female gender predispose to stigmatization in patients with psoriasis.

BACKGROUND: Psoriasis vulgaris is characterized by disfiguring and stigmatizing skin lesions. The links among lesions distribution, severity, and stigmatization remain unclear. OBJECTIVE: We sought to investigate if the involvement of visible and sensitive areas is linked to stigmatization. METHODS: In all, 115 patients with psoriasis vulgaris were assessed for disease severity, skin lesions distribution, itch, and stigmatization using the Feelings of Stigmatization Questionnaire. Quality of life was assessed with the Dermatology Life Quality Index and the World Health Organization Quality of Life-BREF. RESULTS: The localization of psoriatic lesions on the back of hands was related to higher stigmatization levels (P = .011, total score of the Feelings of Stigmatization Questionnaire), but not the involvement of nails, the palms, the face, or the genital area nor overall disease severity. All patients reported some level of stigmatization, regardless of the localization of lesions and type of psoriasis. Higher levels of stigmatization characterized patients who claimed not to be able to hide their lesions by clothing (P = .025), women (P = .001), and the unemployed (P = .004). Stigmatization was the strongest predictor of quality of life impairment. LIMITATIONS: Only hospitalized patients were included. CONCLUSIONS: Psoriatic lesions on the back of hands are debilitating and warrant effective treatment. Special attention should be paid to female patients, who are more sensitive to stigmatization.

Omalizumab for the treatment of chronic spontaneous urticaria: A meta-analysis of randomized clinical trials.

BACKGROUND: Chronic spontaneous urticaria (CSU) is defined by itchy hives, angioedema, or both for at least 6 weeks. Omalizumab, an anti-IgE antibody that affects mast cell and basophil function, is a promising new treatment option. As of now, however, the efficacy and safety of different doses of omalizumab used in clinical trials for CSU have not been systematically analyzed and summarized. OBJECTIVE: We sought to assess the efficacy and safety of different doses of omalizumab for the treatment of CSU in a meta-analysis of clinical trial results. METHODS: Suitable trials were identified by searching PubMed, Medline, Embase, and Web of Science databases and with the help of omalizumab's manufacturers. Only double-blind, randomized, placebo-controlled studies with omalizumab-treated versus placebo-treated patients with CSU were included in this analysis. RESULTS: We identified 7 randomized, placebo-controlled studies with 1312 patients with CSU. Patients treated with omalizumab (75-600 mg every 4 weeks) had significantly reduced weekly itch and weekly wheal scores compared with the placebo group. Omalizumab's effects were dose dependent, with the strongest reduction in weekly itch and weekly wheal scores observed with 300 mg. Rates of complete response were significantly higher in the omalizumab group (relative risk, 4.55; P < .00001) and dose dependent, with the highest rates in the 300-mg group. Rates of patients with adverse events were similar in the omalizumab and placebo groups. CONCLUSION: This meta-analysis provides high-quality evidence for the efficacy and safety of omalizumab in patients with CSU and for treating these patients with 300 mg of omalizumab every 4 weeks.

Development and validation of the Urticaria Control Test: a patient-reported outcome instrument for assessing urticaria control.

BACKGROUND: Chronic urticaria is a frequent and debilitating skin disease. Its symptoms commonly fluctuate considerably from day to day. As of yet, the only reliable tool to assess disease activity is the Urticaria Activity Score, which prospectively documents the signs and symptoms of urticaria for several days. OBJECTIVE: We sought to develop and validate a novel patient-reported outcome instrument to retrospectively assess urticaria control, the Urticaria Control Test (UCT). METHODS: Potential UCT items were developed by using established methods (literature research and expert and patient involvement). Subsequently, item reduction was performed by using a combined approach, applying impact and regression analysis. The resulting UCT instrument was then tested for its validity, reliability, and screening accuracy. RESULTS: A 4-item UCT with a recall period of 4 weeks was developed based on 25 potential UCT items tested in 508 patients with chronic urticaria. A subsequent validation study with the 4-item UCT in 120 patients with chronic urticaria demonstrated that this new tool exhibits good convergent and known-groups validity, as well as excellent test-retest reliability. In addition, the screening accuracy to identify patients with urticaria with insufficiently controlled disease was found to be high. CONCLUSIONS: The UCT is the first valid and reliable tool to assess disease control in patients with chronic urticaria (spontaneous and inducible). Its retrospective approach and simple scoring system make it an ideal instrument for the management of patients with chronic urticaria in clinical practice.

Polidocanol inhibits cowhage - but not histamine-induced itch in humans.

Polidocanol is a local anaesthetic and antipruritic compound that is used in the treatment of itching skin conditions such as eczema. Its mechanisms of action are largely ill defined. This study has compared the antipruritic efficacy of topical polidocanol in histamine-induced itch and a histamine-independent, cowhage-induced model of pruritus. Polidocanol (3%) or vehicle was applied topically under occlusion for 1 h to the forearms of 45 healthy volunteers before itch was provoked by rubbing in 40-45 spicules of cowhage or skin prick testing with 10 mg/ml histamine. Itch was recorded at 1-min intervals for 30 min on a 100-mm visual analogue scale. Polidocanol significantly reduced the area under the curve for cowhage-induced itch by 58% (P < 0.05), but had no significant effect on histamine-induced itch. This result underlines the importance of histamine-independent itch models in the development of topical antipruritic agents.