Update on Urticaria and Angioedema.

Urticaria and angioedema are caused by immunoglobulin E- and non-immunoglobulin E-mediated release of histamine and other inflammatory mediators from mast cells and basophils. Diagnosis is made clinically, and anaphylaxis must be ruled out if urticaria or angioedema is present. A limited nonspecific laboratory workup should be considered unless elements of the history or physical examination suggest specific underlying conditions. The mainstay of treatment is avoidance of triggers when and if triggers are identified. The first-line pharmacotherapy is second-generation H1 antihistamines, which can be titrated to greater than standard doses.

Advances in clinical application of H1 antihistamines in the treatment of skin diseases. / H1æŠ—ç»„èƒºè¯åœ¨çš®è‚¤ç— æ²»ç–—ä¸­çš„ä¸´åºŠåº”ç”¨è¿›å±•.

Histamine receptors are classified into 4 types: H1, H2, H3, and H4, each mediating distinct physiological effects and possessing its corresponding antagonistshat that can be used for the prevention and treatment of various diseases. Among them, H1 antihistamines are the fundamental medications in dermatology and are widely used in many diseases such as urticaria and atopic dermatitis. In recent years, with the emergence of novel antihistamines and the discovery of new potential indications for traditional H1 antihistamines, the clinical application of antihistamines is facing new challenges. Further investigation of the novel mechanism for H1 antihistamines, the use of multiple doses of common drugs and potential indications will furnish vital insights for practical clinical application.

Blockade of histamine receptor H1 augments immune checkpoint therapy by enhancing MHC-I expression in pancreatic cancer cells.

BACKGROUND: Although immune checkpoint blockade (ICB) therapy has proven to be extremely effective at managing certain cancers, its efficacy in treating pancreatic ductal adenocarcinoma (PDAC) has been limited. Therefore, enhancing the effect of ICB could improve the prognosis of PDAC. In this study, we focused on the histamine receptor H1 (HRH1) and investigated its impact on ICB therapy for PDAC. METHODS: We assessed HRH1 expression in pancreatic cancer cell (PCC) specimens from PDAC patients through public data analysis and immunohistochemical (IHC) staining. The impact of HRH1 in PCCs was evaluated using HRH1 antagonists and small hairpin RNA (shRNA). Techniques including Western blot, flow cytometry, quantitative reverse transcription polymerase chain reaction (RT-PCR), and microarray analyses were performed to identify the relationships between HRH1 and major histocompatibility complex class I (MHC-I) expression in cancer cells. We combined HRH1 antagonism or knockdown with anti-programmed death receptor 1 (αPD-1) therapy in orthotopic models, employing IHC, immunofluorescence, and hematoxylin and eosin staining for assessment. RESULTS: HRH1 expression in cancer cells was negatively correlated with HLA-ABC expression, CD8+ T cells, and cytotoxic CD8+ T cells. Our findings indicate that HRH1 blockade upregulates MHC-I expression in PCCs via cholesterol biosynthesis signaling. In the orthotopic model, the combined inhibition of HRH1 and αPD-1 blockade enhanced cytotoxic CD8+ T cell penetration and efficacy, overcoming resistance to ICB therapy. CONCLUSIONS: HRH1 plays an immunosuppressive role in cancer cells. Consequently, HRH1 intervention may be a promising method to amplify the responsiveness of PDAC to immunotherapy.

Clinical Characteristics, Investigations and Treatment in Children with Chronic Urticaria: An Observational Study.

Background and Objectives: The guidelines for chronic urticaria in children contain recommendations that are often based on adult studies. The diagnostic pathway has not been standardized and the effectiveness of anti-H1, omalizumab, montelukast, and systemic glucocorticoids is rarely reported in the pediatric population. There is a wide variation in the rate of remission of chronic urticaria between studies. The aim of this study is to enhance our understanding of pediatric chronic urticaria. Materials and Methods: This study enrolled 37 children with chronic urticaria aged from 0 to 18 years. Demographic parameters, medical history, clinical features, laboratory data and treatment information were collected. Children were treated with the recommended dosage of second-generation H1-antihistamines, which was increased by up to twofold. Omalizumab was added for refractory anti-H1 patients. A three-day course with systemic glucocorticoids was administered for severe exacerbations. Montelukast was administered to some children. Results: Wheals without angioedema were common. Chronic urticaria was spontaneous in 32 children (86.48%), inducible in 2 (5.41%), induced by a parasite in 1 and vasculitic in 2. Treatment of the potential causes of chronic urticaria was of no benefit, except for eradication of Dientamoeba fragilis. Chronic urticaria was resolved within three years in 45.9% of cases. Allergic diseases were present in nine children (24.32%) and autoimmune diseases were present in three (8.11%). All children were treated with anti-H1 at the licensed dose or at a higher dose. A partial or complete response to anti-H1 was observed in 29 (78.38%) patients. Montelukast showed no benefit. All children treated with omalizumab responded. Systemic glucocorticoids were successfully used to treat exacerbations. Conclusions: Our findings indicate that laboratory tests should not be routinely performed in children with chronic urticaria without clinical suspicion. However, comorbidities such as thyroid autoimmune disease and coeliac disease are suggested to be monitored over the chronic urticaria course. These clinical conditions could be diagnosed from the diagnostic framework of chronic urticaria. Increasing the dosage of anti-H1 and omalizumab was effective in children resistant to standard treatment but we still need further studies to generate a standard patient-centered treatment.

The antiglycation potential of H1 receptor antagonists - in vitro studies in bovine serum albumin model and in silico molecular docking analyses.

The H1 receptor belongs to the family of rhodopsin-like G-protein-coupled receptors activated by the biogenic amine histamine. H1 receptor antagonists are widely used in the treatment of allergies. However, these drugs could have a much broader spectrum of activity, including hypoglycemic effects, which can broaden the spectrum of their use. The aim of the study was to evaluate the antiglycation potential of twelve H1 receptor antagonists (diphenhydramine, antazoline, promethazine, ketotifen, clemastine, pheniramine, cetirizine, levocetirizine, bilastine, fexofenadine, desloratadine, and loratadine). Bovine serum albumin (BSA) was glycated with sugars (glucose, fructose, galactose, and ribose) and aldehydes (glyoxal and methylglyoxal) in the presence of H1 blockers. The tested substances did not induce a significant decrease in the content of albumin glycation end-products, and the inhibition rate of glycoxidation was not influenced by the chemical structure or generation of H1 blockers. None of the tested H1 receptor antagonists exhibited strong antiglycation activity. Antiglycemic potential of H1 blockers could be attributed to their antioxidant and anti-inflammatory activity, as well as their effects on carbohydrate metabolism/metabolic balance at the systemic level.

Dimetindene-Is the minimum toxic dose for children too strict?

Dimetindene is a sedating antihistamine indicated for the symptomatic treatment of allergic conditions. Dimetindene is marketed among others under the trade name Fenistil (oral solution). Toxicity data are limited, and there is no consensus on the dose at which children require hospitalization. Objective is to determine the potentially toxic dose in children. Data in children with age up to 15 years were obtained from hospital discharge reports. Of 139 paediatric hospital discharge reports, 23 cases (16.5%) were excluded because of uncertain ingestion. In 116 children (46 boys and 70 girls, mean age 2 years and 9 months ± 1 year and 1 month), the majority of children developed no symptoms (87 children, 75%, mean age 3 years±1 year) and the remaining 29 children (25%, mean age 2 years and 11 months ± 1 year and 3 months) developed only mild and spontaneously resolving symptoms of poisoning after a dose of 0.82 ± 0.32 mg/kg b.w. (range 0.26-1.82 mg/kg). In 98% of all cases, hospitalized children were observed for a maximum 24 h, and their condition did not require specific treatment. In conclusion, the prognosis for accidental dimetindene poisoning in children appears to be good and the minimum toxic dose has been determined to be 0.5 mg/kg b.w.

[Approved therapies and their effects on the main symptoms of urticaria : When symptom control of itchy wheals is not adequate-does updosing help?] / Zugelassene Therapien und ihre Wirkung auf die Leitsymptome der Urtikaria : Hilfreiche Therapieoptionen, wenn juckende Quaddeln nicht weichen ­ Viel hilft viel?

International guidelines for the treatment of chronic spontaneous urticaria support the updosing of second-generation antihistamines to four times of the approved dose when adequate symptom control cannot be achieved with the standard dosage. However, this recommendation is primarily based on expert opinions, and there is a lack of large, well-designed, double-blind clinical trials. Most the existing trials provide insufficient data, and due to the heterogeneity of the conducted trials on antihistamine effects (definition of control, design, quality, lack of an active comparator, no placebo arm, small sample size, outcomes) and their short duration, comparative analysis is challenging. However, it can be concluded that the use of modern second-generation antihistamines is both effective and safe based on the available data and our own long-term experiences in the specialized outpatient clinic of a university dermatology department, even though increased dosages (up to fourfold as per the current international guidelines) may be necessary for symptom control. Another therapeutic option for refractory symptoms in chronic spontaneous urticaria is subcutaneous administration of omalizumab at a dosage of 300 mg at 4­week intervals as a very safe and effective treatment.

UCOMB-real life data: treatment strategies for chronic urticaria patients with comorbidities.

BACKGROUND: There is a lack of real-life safety data on treatment options for chronic urticaria in the presence of comedication and comorbidities. METHODS: We present a single-center UCARE pilot study of 212 outpatients with chronic urticaria. Patients were divided into three groups according to different CU therapies according to international guidelines. RESULTS: Of 212 patients, 108 (mean age 48.9 years, 71.3% female) had 59 comorbidities, including cardiovascular, autoimmune and malignant diseases. Patients were followed for a mean of 24.6 months (SD ± 21.3). Urticaria therapies were divided into three groups: A: 105 (97.2%) with omalizumab and 2nd generation antihistamines), B: 16 patients (14.8%): dual therapy with antihistamines and cyclosporine in 10 (9.3%), montelukast in five (4. 6%), dapsone in four (3.7%), hydroxychloroquine in one patient (0.9%), C: 12 (11.1%) patients received a third drug for 4.9 months (SD ± 3.2) and one quadruple therapy (2.1 months). 10 out of 12 (83.3%) patients received montelukast, two (16.7%) cyclosporine, two (16.7%) dapsone and one (8.3%) hydroxychloroquine as a third drug for chronic urticaria. CONCLUSIONS: Combining treatment modalities for chronic urticaria and comorbidities are available and feasible with a good safety profile.

Allergic Rhinitis: A Review.

Importance: Allergic rhinitis affects an estimated 15% of the US population (approximately 50 million individuals) and is associated with the presence of asthma, eczema, chronic or recurrent sinusitis, cough, and both tension and migraine headaches. Observations: Allergic rhinitis occurs when disruption of the epithelial barrier allows allergens to penetrate the mucosal epithelium of nasal passages, inducing a T-helper type 2 inflammatory response and production of allergen-specific IgE. Allergic rhinitis typically presents with symptoms of nasal congestion, rhinorrhea, postnasal drainage, sneezing, and itching of the eyes, nose, and throat. In an international study, the most common symptoms of allergic rhinitis were rhinorrhea (90.38%) and nasal congestion (94.23%). Patients with nonallergic rhinitis present primarily with nasal congestion and postnasal drainage frequently associated with sinus pressure, ear plugging, muffled sounds and pain, and eustachian tube dysfunction that is less responsive to nasal corticosteroids. Patients with seasonal allergic rhinitis typically have physical examination findings of edematous and pale turbinates. Patients with perennial allergic rhinitis typically have erythematous and inflamed turbinates with serous secretions that appear similar to other forms of chronic rhinitis at physical examination. Patients with nonallergic rhinitis have negative test results for specific IgE aeroallergens. Intermittent allergic rhinitis is defined as symptoms occurring less than 4 consecutive days/week or less than 4 consecutive weeks/year. Persistent allergic rhinitis is defined as symptoms occurring more often than 4 consecutive days/week and for more than 4 consecutive weeks/year. Patients with allergic rhinitis should avoid inciting allergens. In addition, first-line treatment for mild intermittent or mild persistent allergic rhinitis may include a second-generation H1 antihistamine (eg, cetirizine, fexofenadine, desloratadine, loratadine) or an intranasal antihistamine (eg, azelastine, olopatadine), whereas patients with persistent moderate to severe allergic rhinitis should be treated initially with an intranasal corticosteroid (eg, fluticasone, triamcinolone, budesonide, mometasone) either alone or in combination with an intranasal antihistamine. In contrast, first-line therapy for patients with nonallergic rhinitis consists of an intranasal antihistamine as monotherapy or in combination with an intranasal corticosteroid. Conclusions and Relevance: Allergic rhinitis is associated with symptoms of nasal congestion, sneezing, and itching of the eyes, nose, and throat. Patients with allergic rhinitis should be instructed to avoid inciting allergens. Therapies include second-generation H1 antihistamines (eg, cetirizine, fexofenadine, desloratadine, loratadine), intranasal antihistamines (eg, azelastine, olopatadine), and intranasal corticosteroids (eg, fluticasone, triamcinolone, budesonide, mometasone) and should be selected based on the severity and frequency of symptoms and patient preference.

Discovery of the novel and potent histamine H1 receptor antagonists for treatment of allergic diseases.

Desloratadine, a second-generation histamine H1 receptor antagonist, has established itself as a first-line drug for the treatment of allergic diseases. Despite its effectiveness, desloratadine exhibits an antagonistic effect on muscarinic M3 receptor, which can cause side effects such as dry mouth and urinary retention, ultimately limiting its clinical application. Herein, we describe the discovery of compound Ⅲ-4, a novel H1 receptor antagonist with significant H1 receptor antagonistic activity (IC50 = 24.12 nM) and enhanced selectivity towards peripheral H1 receptor. In particular, Ⅲ-4 exhibits reduced M3 receptor inhibitory potency (IC50 > 10,000 nM) and acceptable hERG inhibitory activity (17.6 ± 2.1 µM) compare with desloratadine. Additionally, Ⅲ-4 exhibits favorable pharmacokinetic properties, as well as in vivo efficacy and safety profiles. All of these reveal that Ⅲ-4 has potential to emerge as a novel H1 receptor antagonist for the treatment of allergic diseases. More importantly, the compound Ⅲ-4 (HY-078020) has recently been granted clinical approval.

Risk calculator of the clinical response to antihistamines in chronic urticaria: Development and internal validation.

Early detection of CSU patients with low probability of a clinical response with antihistamines could undergo prompt initiation of therapeutic alternatives. The aim of the study was to develop and internally validate a model for predicting the clinical response to antihistamines in adult patients with chronic spontaneous urticaria (CSU), who consult allergology and dermatology care centers. A cohort of CSU patients, recruited from four participating centers, were followed up for 12 months. Fifteen candidate variables were selected to be included in the multivariate model and then internal validation was done with bootstrap analysis with 1000 simulations. The outcome variable, clinical response to antihistamines, was evaluated with the UAS (Urticaria Activity Score) scale for seven days: "No response to antihistamines" was defined as UAS7 ≥7 points after at least one month with a maximum dose of antihistamines, while "Response to antiH1" was defined as UAS7 ≤6 points for at least three months with the use of antiH1. A total of 790 patients were included. Among the different models analyzed, the model that included age, angioedema, anxiety/depression, time with the disease, NSAIDs (Non-steroidal anti-inflammatory drugs) intolerance, and UAS7 baseline was considered the one with the best performance (accuracy 0.675, HL 0.87, AUC 0.727). The internal validation analyses demonstrated good consistency of the model. In conclusion, this prediction model identifies the probability of response to antihistamines in patients with chronic spontaneous urticaria. The model could be useful for a personalized therapeutic approach according to individual patient risk.

Effectiveness of promethazine on preoperative and intraoperative sequelae in cleft palate surgeries.

INTRODUCTION: Anxiety and nosocomial infection are the most common reported problems in children undergoing cleft surgeries. Research shows that there is an enigma in the use of antihistamine therapy in children for the management of upper respiratory tract infection. 'Promethazine' is a first-generation H1 receptor antagonist, and antihistamine also has strong sedative effects. Our study aims at evaluating the Effectiveness of Promethazine (Phenergan) in preoperative and intra operative sequelae in cleft surgeries. MATERIALS AND METHODS: This is a single-centre, parallel, randomized, double-blinded randomized control clinical trial, which was conducted among 128 children between 2 and 4 years of age undergoing cleft palate surgery under general anaesthesia. After randomization, the case group was subjected to promethazine syrup 1 mg/kg body weight twice a day, orally for 3 days. The primary outcomes were preoperative anxiety levels which were recorded by children fear scale. The secondary outcomes include preoperative sleep quality and cough rate of children which are recorded by using sleep and cough objective scale respectively. The intraoperative heart rate is monitored with an ECG connected to a monitor. RESULTS: Promethazine causes a reduction in the anxiety level by 70%, 64% reduction in cold and cough, improvement in sleep score by 70% and the heart rate was found to be stable throughout the surgery when compared to the control group. CONCLUSION: As the benefits of promethazine in cleft palate surgery rule over its adverse effects, promethazine is considered safe to be used as premedication for children undergoing cleft palate surgeries.

Molecular mechanism of antihistamines recognition and regulation of the histamine H1 receptor.

Histamine receptors are a group of G protein-coupled receptors (GPCRs) that play important roles in various physiological and pathophysiological conditions. Antihistamines that target the histamine H1 receptor (H1R) have been widely used to relieve the symptoms of allergy and inflammation. Here, to uncover the details of the regulation of H1R by the known second-generation antihistamines, thereby providing clues for the rational design of newer antihistamines, we determine the cryo-EM structure of H1R in the apo form and bound to different antihistamines. In addition to the deep hydrophobic cavity, we identify a secondary ligand-binding site in H1R, which potentially may support the introduction of new derivative groups to generate newer antihistamines. Furthermore, these structures show that antihistamines exert inverse regulation by utilizing a shared phenyl group that inserts into the deep cavity and block the movement of the toggle switch residue W4286.48. Together, these results enrich our understanding of GPCR modulation and facilitate the structure-based design of novel antihistamines.

Evaluation of Pharmacological Treatments for Acute Urticaria: A Systematic Review and Meta-Analysis.

BACKGROUND: The effectiveness and safety of pharmacological treatments for acute urticaria remain unclear. OBJECTIVE: To systematically review and meta-analyze the efficacy and safety of pharmacological treatments for acute urticaria in emergency department (ED) and non-ED settings. METHODS: We searched electronic databases and gray literature up to July 8, 2023, without language restrictions. Randomized clinical trials (RCTs) relating to pharmacological interventions in patients with acute urticaria, regardless of age, were eligible for inclusion. The relevant outcomes of interest were the treatment efficacy and safety profiles. The results are presented as standardized mean differences (SMDs) or odds ratios (ORs). RESULTS: We identified 8 RCTs comprising 680 patients. Regarding the ED setting (2 trials, n = 118), intramuscular first-generation H1-antihistamine (fgAH) was more efficacious in decreasing pruritus symptoms (SMD, -0.38; 95% confidence interval [CI], -0.75 to -0.02) but had higher sedative effects than H2-blockers. With comparable pruritus symptom improvement (2 trials, n = 295), intravenous second-generation H1-antihistamine (sgAH) had favorable clinical outcomes compared with intravenous fgAH in the ED setting with a lower risk of return to any ED/clinic (OR, 0.31; 95% CI, 0.12-0.83) and lower risk of any adverse event (OR, 0.24; 95% CI, 0.09-0.63). The efficacy of adjunctive therapy with a short course of systemic glucocorticosteroids in ED and non-ED settings remains unclear. No serious concerns regarding the safety profiles were observed in any of the treatment comparisons. CONCLUSIONS: H1-antihistamine is a crucial and effective component of acute urticaria treatment, and intravenous sgAH is preferred as an initial treatment option.

A systematic review and meta-analysis of efficacy and safety of compound glycyrrhizin combined with second-generation non-sedated antihistamine for the treatment of chronic urticaria.

BACKGROUND: Chronic urticaria (CU) is a prevalent dermatologic disease that negatively affects life, current therapies remain suboptimal. Hence, there is an urgent need to identify effective and safe treatment. OBJECTIVE: Assess the efficacy and safety of compound glycyrrhizin (CG) combined with second-generation nonsedated antihistamine for the treatment of CU. METHODS: Nine databases were queried to screen RCTs related. Two reviewers independently assessed the risk of bias using Cochrane Collaboration. Primary objective was the total efficiency rate, while secondary was rate of recurrence, adverse events, and cure. Statistical analyses using Review Manager 5.4 and Stata17. RESULTS: Twenty-four RCTs were identified. Significant differences were noted in rate of total efficiency (n = 2649, RR = 1.36, 95%CI:1.30-1.43, p < 0.00001), cure (n = 2649, RR = 1.54, 95%CI:1.42-1.66, p < 0.00001) and recurrence (n = 446, RR = 0.34, 95%CI:0.20-0.58, p < 0.00001) between the combination of CG with second-generation non-sedated antihistamine and antihistamine monotherapy. Contrastingly, adverse events rate (n = 2317, RR = 0.76, 95% CI:0.59-0.97, p = 0.03) was comparable between the two groups. Our results indicated that CG combined with second-generation non-sedated antihistamine could significantly mitigate the symptoms in CU compared with antihistamine monotherapy. No serious adverse events were reported. CONCLUSIONS: CG combined with second-generation nonsedated antihistamine is effective for CU. Nevertheless, higher-quality studies are warranted to validate our results.

Impact of institutional interventions on the rate of paclitaxel hypersensitivity reactions.

PURPOSE: Paclitaxel is associated with hypersensitivity reactions (HSRs). Intravenous premedication regimens have been devised to decrease the incidence and severity of HSRs. At our institution oral histamine 1 receptor antagonists (H1RA) and histamine 2 receptor antagonists (H2RA) were adopted as standard. Standardizations were implemented for consistent premedication use in all disease states. The purpose of this retrospective study was to compare the incidence and severity of HSRs before and after standardization. METHODS: Patients who received paclitaxel from 20 April 2018 to 8 December 2020 having an HSR were included in analysis. An infusion was flagged for review if a rescue medication was administered after the start of the paclitaxel infusion. The incidences of all HSR prior to and post-standardization were compared. A subgroup analysis of patients receiving paclitaxel for the first and second time was performed. RESULTS: There were 3499infusions in the pre-standardization group and 1159infusions in the post-standardization group. After review, 100 HSRs pre-standardization and 38 HSRs post-standardization were confirmed reactions. The rate of overall HSRs was 2.9% in the pre-standardization group and 3.3% in the post-standardization group (p = 0.48). HSRs, during the first and second doses of paclitaxel, occurred in 10.2% of the pre-standardization and 8.5% of the post-standardization group (p = 0.55). CONCLUSIONS: This retrospective interventional study demonstrated that same-day intravenous dexamethasone, oral H1RA, and oral H2RA are safe premedication regimens for paclitaxel. No change in the severity of reactions was seen. Overall, better adherence to premedication administration was seen post-standardization.

Remibrutinib demonstrates favorable safety profile and sustained efficacy in chronic spontaneous urticaria over 52 weeks.

BACKGROUND: Remibrutinib (LOU064), an oral, highly selective Bruton tyrosine kinase inhibitor, offers fast disease control in patients with chronic spontaneous urticaria (CSU) who remain symptomatic despite treatment with second-generation H1 antihistamines. It is currently in phase 3 development for CSU. OBJECTIVE: We sought to evaluate long-term safety and efficacy of remibrutinib in patients with CSU inadequately controlled with H1 antihistamines. METHODS: In this phase 2b extension study, patients who completed the core study and had a weekly Urticaria Activity Score (UAS7) ≥16 at the beginning of the extension study received remibrutinib 100 mg twice daily for 52 weeks. The primary objective was to assess long-term safety and tolerability. Key efficacy end points included change from baseline in UAS7 and proportion of patients with complete response to treatment (UAS7 = 0) and well-controlled disease (UAS7 ≤6) at week 4 and over 52 weeks. RESULTS: Overall, 84.3% (194/230) of patients entered the treatment period and received ≥1 doses of remibrutinib. The overall safety profile of remibrutinib was comparable between the extension and core studies. Most treatment-emergent adverse events were mild to moderate and considered unrelated to remibrutinib by investigators. The 3 most common treatment-emergent adverse events by system organ class were infections (30.9%), skin and subcutaneous tissue (26.8%), and gastrointestinal disorders (16.5%). At week 4 and 52, mean ± SD change from baseline in UAS7 was -17.6 ± 13.40 and -21.8 ± 10.70; UAS7 = 0 (as observed) was achieved in 28.2% and 55.8% and UAS7 ≤6 (as observed) was achieved in 52.7% and 68.0% of patients, respectively. CONCLUSIONS: Remibrutinib demonstrated a consistent favorable safety profile with fast and sustained efficacy for up to 52 weeks in patients with CSU.

Efficacy and safety of ligelizumab in adults and adolescents with chronic spontaneous urticaria: results of two phase 3 randomised controlled trials.

BACKGROUND: Many patients with chronic spontaneous urticaria (CSU) do not achieve complete control of their symptoms with current available treatments. In a dose-finding phase 2b study, ligelizumab improved urticaria symptoms in patients with H1-antihistamine (H1-AH) refractory CSU. Here, we report the efficacy and safety outcomes from two ligelizumab phase 3 studies. METHODS: PEARL-1 and PEARL-2 were identically designed randomised, double-blind, active-controlled and placebo-controlled parallel-group studies. Patients aged 12 years or older with moderate-to-severe H1-AH refractory CSU were recruited from 347 sites in 46 countries and randomly allocated in a 3:3:3:1 ratio via Interactive Response Technology to 72 mg ligelizumab, 120 mg ligelizumab, 300 mg omalizumab, or placebo, dosed every 4 weeks, for 52 weeks. Patients allocated to placebo received 120 mg ligelizumab from week 24. The primary endpoint was change-from-baseline (CFB) in weekly Urticaria Activity Score (UAS7) at week 12, and was analysed in all eligible adult patients according to the treatment assigned at random allocation. Safety was assessed throughout the study in all patients who received at least one dose of the study drug. The studies were registered with ClinicalTrials.gov, NCT03580369 (PEARL-1) and NCT03580356 (PEARL-2). Both trials are now complete. FINDINGS: Between Oct 17, 2018, and Oct 26, 2021, 2057 adult patients were randomly allocated across both studies (72 mg ligelizumab n=614; 120 mg ligelizumab n=616; 300 mg omalizumab n=618, and placebo n=209). A total of 1480 (72%) of 2057 were female, and 577 (28%) of 2057 were male. Mean UAS7 at baseline across study groups ranged from 29·37 to 31·10. At week 12, estimated treatment differences in mean CFB-UAS7 were as follows: for 72 mg ligelizumab versus placebo, -8·0 (95% CI -10·6 to -5·4; PEARL-1), -10·0 (-12·6 to -7·4; PEARL-2); 72 mg ligelizumab versus omalizumab 0·7 (-1·2 to 2·5; PEARL-1), 0·4 (-1·4 to 2·2; PEARL-2); 120 mg ligelizumab versus placebo -8·0 (-10·5 to -5·4; PEARL-1), -11·1 (-13·7 to -8·5; PEARL-2); 120 mg ligelizumab versus omalizumab 0·7 (-1·1 to 2·5; PEARL-1), -0·7 (-2·5 to 1·1; PEARL-2). Both doses of ligelizumab were superior to placebo (p<0·0001), but not to omalizumab, in both studies. No new safety signals were identified for ligelizumab or omalizumab. INTERPRETATION: In the phase 3 PEARL studies, ligelizumab demonstrated superior efficacy versus placebo but not versus omalizumab. The safety profile of ligelizumab was consistent with previous studies. FUNDING: Novartis Pharma.