An Allosteric Anti-tryptase Antibody for the Treatment of Mast Cell-Mediated Severe Asthma.

Severe asthma patients with low type 2 inflammation derive less clinical benefit from therapies targeting type 2 cytokines and represent an unmet need. We show that mast cell tryptase is elevated in severe asthma patients independent of type 2 biomarker status. Active ß-tryptase allele count correlates with blood tryptase levels, and asthma patients carrying more active alleles benefit less from anti-IgE treatment. We generated a noncompetitive inhibitory antibody against human ß-tryptase, which dissociates active tetramers into inactive monomers. A 2.15 Å crystal structure of a ß-tryptase/antibody complex coupled with biochemical studies reveal the molecular basis for allosteric destabilization of small and large interfaces required for tetramerization. This anti-tryptase antibody potently blocks tryptase enzymatic activity in a humanized mouse model, reducing IgE-mediated systemic anaphylaxis, and inhibits airway tryptase in Ascaris-sensitized cynomolgus monkeys with favorable pharmacokinetics. These data provide a foundation for developing anti-tryptase as a clinical therapy for severe asthma.

Exploring Definitions and Predictors of Severe Asthma Clinical Remission after Biologic Treatment in Adults.

Rationale: There is no consensus on criteria to include in an asthma remission definition in real life. Factors associated with achieving remission after biologic initiation remain poorly understood. Objectives: To quantify the proportion of adults with severe asthma achieving multidomain-defined remission after biologic initiation and identify prebiologic characteristics associated with achieving remission that may be used to predict it. Methods: This was a longitudinal cohort study using data from 23 countries from the International Severe Asthma Registry. Four asthma outcome domains were assessed in the 1 year before and after biologic initiation. A priori-defined remission cutoffs were: 0 exacerbations/yr, no long-term oral corticosteroid (LTOCS), partly/well-controlled asthma, and percent predicted FEV1 ⩾ 80%. Remission was defined using two (exacerbations + LTOCS), three (+control or +lung function), and four of these domains. The association between prebiologic characteristics and postbiologic remission was assessed by multivariable analysis. Measurements and Main Results: A total of 50.2%, 33.5%, 25.8%, and 20.3% of patients met criteria for two-, three- (+control), three- (+lung function), and four-domain remission, respectively. The odds of achieving four-domain remission decreased by 15% for every additional 10 years of asthma duration (odds ratio, 0.85; 95% confidence interval, 0.73-1.00). The odds of remission increased in those with fewer exacerbations per year, lower LTOCS daily dose, better control, and better lung function before biologic initiation. Conclusions: One in five patients achieved four-domain remission within 1 year of biologic initiation. Patients with less severe impairment and shorter asthma duration at initiation had a greater chance of achieving remission after biologic treatment, indicating that biologic treatment should not be delayed if remission is the goal.

A practical guide for implementing omalizumab therapy for food allergy.

The recent approval of omalizumab for the treatment of IgE-mediated food allergy is an important step forward for the millions of food allergy patients in the United States. Through the depletion of circulating IgE and the subsequent reduction of FcεR1 on key effector cells, patients increase their tolerance to food allergens. However, omalizumab does not permit patients to eat foods that they are allergic to with impunity. Rather, it protects them from most accidental exposures. In addition, omalizumab does not cure food allergy and has not demonstrated true immunomodulation. Thus, omalizumab might be a lifelong therapy for some patients. Furthermore, there are many important questions and issues surrounding the appropriate administration of omalizumab to treat food allergy, which we discuss. Managing treatment of patients with disease that falls outside the dosing range, assessing treatment response or nonresponse, addressing its appropriateness for patients older than 55, and determining whether immunotherapy plus omalizumab provides any advantage over omalizumab alone all need to be examined. Identifying appropriate patients for this therapy is critical given the cost of biologics. Indeed, not all food allergy patients are good candidates for this therapy. Also, when and how to stop omalizumab therapy in patients who may have outgrown their food allergy needs to be elucidated. Thus, although this therapy provides a good option for patients with food allergies, much information is needed to determine how best to use this therapy. Despite many unanswered questions and issues, we provide clinicians with some practical guidance on implementing this therapy in their patients.

Omalizumab reduces anaphylactic reactions and allows food introduction in food-allergic in children with severe asthma: An observational study.

BACKGROUND: In Europe, Omalizumab (anti-IgE) is indicated for the treatment of moderate to severe asthma, but not for IgE-mediated food allergy (FA). OBJECTIVE: We assessed the impact of Omalizumab on efficacy, safety, and quality of life (FA-QoL) in patients with moderate to severe asthma and who have a history of anaphylaxis to peanut, tree nuts, fish, egg, milk, and/or wheat. METHODS: Food-allergic children (6-18 years) with moderate to severe asthma underwent oral food challenges (OFCs) to establish the threshold of reaction to the culprit food(s) at baseline (T0) and at 4-month intervals (T1, T2, and T3) during their first year of treatment with Omalizumab. We recorded the number and severity of food-allergic reactions, Asthma Control Test (ACT) scores, FA-QoL, and total IgE levels. RESULTS: In 65 patients allergic to 107 foods, the No Observed Adverse Events Level (NOAEL) at T1 increased: 243- and 488-fold for fresh and baked milk, respectively; 172- and 134-fold for raw and baked egg; 245-fold for hazelnut; 55-fold for peanut; 31-fold for wheat; and 10-fold for fish. Full tolerance was achieved in 66.4% of OFCs at T1, 58.3% at T2, and 75% at T3. Ninety-five foods were liberalized in the diet of 55 patients; the remaining 12 were introduced by 10 patients at least in traces. Throughout the study, 40 out of 65 were able to get a free diet. ACT increased from 17 (Q1-Q3: 15-17) to 23.6 (Q1-Q3: 23-25). The FA-QoL score in children ≤12 years decreased from 4.63 ± 0.74 to 2.02 ± 1.13, and in adolescents from 4.68 ± 0.92 to 1.90 ± 1.50. CONCLUSIONS: During Omalizumab therapy, a safe reintroduction of allergenic foods is feasible. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT06316414.

Mast Cell-Targeting Therapies in Mast Cell Activation Syndromes.

PURPOSE OF REVIEW: Provide an overview of the expanding landscape of mast cell (MC)-targeting treatments in mast cell activation syndromes (MCAS). RECENT FINDINGS: Tyrosine-kinase inhibitors (TKIs) targeting wild-type and mutated KIT can efficiently induce MC depletion. Avapritinib and midostaurin can also temper IgE-mediated degranulation. Avapritinib has been recently approved by the FDA for the treatment of indolent systemic mastocytosis (ISM). Targeting activation pathways and inhibitory receptors is a promising therapeutic frontier. Recently, the anti Siglec-8 antibody lirentelimab showed promising results in ISM. MCAS is a heterogeneous disorder demanding a personalized therapeutic approach and, especially when presenting as anaphylaxis, has not been formally captured as outcome in prospective clinical trials with TKI. Long-term safety of TKI needs to be addressed. New drugs under investigation in diseases in which non-neoplastic MCs play a pivotal role can provide important inputs to identify new efficient and safe treatments for MCAS.

Expert opinion on diagnosis and management of Severe Asthma in low and middle income countries (LMIC) with focus on India.

OBJECTIVE: In this document, 9 Indian experts have evaluated the factors specific to LMICs when it came to Severe Asthma (SA) diagnosis, evaluation, biologic selection, non-biologic treatment options, and follow-up. DATA SOURCES: A search was performed using 50 keywords, focusing on the Indian/LMICs perspective, in PubMed, Cochrane Library, and Google Scholar. The key areas of the search were focused on diagnosis, phenoendotyping, non-biological therapies, selecting a biologic, assessment of treatment response, and management of exacerbation. STUDY SELECTIONS: The initial search revealed 1826 articles, from these case reports, observational studies, cohort studies, non-English language papers, etc., were excluded and we short-listed 20 articles for each area. Five relevant articles were selected by the experts for review. RESULTS: In LMICs, SA patients may be referred to the specialist for evaluation a little late for Phenoendotyping of SA. While biologic therapy is now a standard of care, pulmonologists in LMICs may not have access to all the investigations to phenoendotype SA patients like fractional exhaled nitric oxide (FeNO), skin prick test (SPT), etc., but phenotyping of SA patients can also be done with simple blood investigations, eosinophil count and serum immunoglobulin E (IgE). Choosing a biologic in the overlapping phenotype of SA and ACO patients is also a challenge in the LMICs. CONCLUSIONS: Given the limitations of LMIC, it is important to select the right patient and explain the potential benefits of biological therapy. Non-biologic add-on therapies can be attempted in a resource-limited setting where biological therapy is not available/feasible for patients.

Long-term use of omalizumab in patients with allergic bronchopulmonary aspergillosis: a tertiary-level care center experience.

INTRODUCTION: Allergic bronchopulmonary aspergillosis (ABPA) is a lung disease caused by a hypersensitivity reaction to antigens of Aspergillus fumigatus. OBJECTIVE: The aim of this study was to evaluate the long-term clinical outcomes of omalizumab use in patients with ABPA. METHODS: In this retrospective study, 12 patients diagnosed with ABPA and receiving omalizumab for at least 2 years, and 32 patients diagnosed with severe allergic asthma and receiving omalizumab for at least 2 years (control group) were evaluated. RESULTS: Evaluation was made of a total of 44 participants, comprising 11 (25%) males and 33 (75%) females, who received omalizumab for at least 2 years with the diagnosis of the control group (n = 32) and ABPA (n = 12). The increase in asthma control test (ACT) score after omalizumab was significant at 12 months and at 24 months in patients with ABPA. After omalizumab, the use of oral corticosteroid (OCS), the annual number of asthma attacks and hospitalizations were significantly decreased at 12 months and at 24 months in patients with ABPA. The increase in forced expiratory volume in 1 s (FEV1) (%) and ACT score after omalizumab were significant at 12 months and at 24 months in the control group. After omalizumab, the use of OCS, annual number of asthma attacks and hospitalizations were significantly decreased at 12 months and at 24 months in the control group. CONCLUSION: Long-term omalizumab use in patients with ABPA seems to be an effective treatment for improving pulmonary function and reducing asthma exacerbations and hospitalizations.

Comparative efficacy and safety of the treatment by Omalizumab for chronic idiopathic urticaria in the general population: A systematic review and network meta-analysis.

BACKGROUND: Omalizumab is the only licensed drug that serves as a third-line treatment for chronic idiopathic urticaria (CIU). The optimum doses of omalizumab remain controversial. Therefore, this study aims to estimate the efficacy and safety of different doses of omalizumab in the treatment of CIU patients. MATERIALS AND METHODS: Four databases were searched from the database's creation to April 8, 2023. Several keywords such as omalizumab and urticarias were used to retrieve related studies. The meta-analytical outcomes were analyzed in R 4.2.1 software and Stata 15.1 software. Cochrane risk-of-bias tool Ver. 2 was used to evaluate the risk of bias in randomized controlled trials (RCTs). RESULTS: In total, 2331 patients were included. Five indexes were employed to assess, including weekly Itch Severity Score (ISS7), weekly Hive Severity Score (HSS7), weekly Urticaria Activity Score (UAS7), Dermatology Life Quality Index (DLQI), and adverse events (AE). A 300 mg dose of omalizumab was the optimum dose to treat CIU, followed by the 150 mg dose. Furthermore, 600 mg of omalizumab only showed a significant difference from the placebo in HSS7. No significant statistical difference was observed in AE. Meta-regression analysis revealed that time, as a covariate, was statistically significant in the comparison of omalizumab 150 mg with placebo. CONCLUSION: 300 mg of omalizumab was the optimum dosage to treat CIU patients, with a 150 mg dose also exhibiting good efficacy. Further studies are required to explore the efficacy and safety of different doses of omalizumab in the treatment of CIU patients.

Omalizumab in the treatment of Morbihan syndrome in an adolescent girl - case report and literature review.

Morbihan syndrome (MS) is characterized by solid facial edema, usually related to rosacea or acne vulgaris. The facial edema deforms the patient's features, can impair peripheral vision, and affects quality of life. Its pathophysiology remains unclear. The disease usually has a slow and chronic course. MS most commonly affects middle-aged Caucasian men with rosacea and is rare in people below 20 years of age. MS is a diagnosis of exclusion. There is no standard treatment for MS, though systemic isotretinoin and antihistamines are mainly used. We present the case of an adolescent girl with MS nonresponding to 19 months of isotretinoin treatment with add-on antihistamines. Therapy with monthly administration of omalizumab (anti-IgE) for 6 months was an effective therapeutic option, improving the quality of life. Our case is the second description of omalizumab use in Morbihan syndrome, the first in an adolescent.

Single-Domain Antibodies-Novel Tools to Study and Treat Allergies.

IgE-mediated allergies represent a major health problem in the modern world. Apart from allergen-specific immunotherapy (AIT), the only disease-modifying treatment, researchers focus on biologics that target different key molecules such as allergens, IgE, or type 2 cytokines to ameliorate allergic symptoms. Single-domain antibodies, or nanobodies, are the newcomers in biotherapeutics, and their huge potential is being investigated in various research fields since their discovery 30 years ago. While they are dominantly applied for theranostics of cancer and treatment of infectious diseases, nanobodies have become increasingly substantial in allergology over the last decade. In this review, we discuss the prerequisites that we consider to be important for generating useful nanobody-based drug candidates for treating allergies. We further summarize the available research data on nanobodies used as allergen monitoring and detection probes and for therapeutic approaches. We reflect on the limitations that have to be addressed during the development process, such as in vivo half-life and immunogenicity. Finally, we speculate about novel application formats for allergy treatment that might be available in the future.

Comparison of Omalizumab Treatment Response in Patients with Chronic Spontaneous Urticaria and Symptomatic Dermographism: A Single-Center Retrospective Study.

INTRODUCTION: Omalizumab is a humanized anti-IgE monoclonal antibody, which is effective in the treatment in patients with chronic spontaneous urticaria (CSU) who are unresponsive to antihistamine therapy. There are few studies in the literature evaluating omalizumab treatment response in patients with symptomatic dermographism (SDerm). The aim of this study was to compare the response to omalizu-mab treatment in patients with CSU and SDerm. METHODS: Patients treated with omalizumab for the diagnosis of CSU and SDerm were evaluated retrospectively. Treatment response to omalizumab was evaluated with the urticaria control test (UCT). Quality of life was evaluated with the dermatology quality of life questionnaire (DLQI). Baseline UCT and DLQI were compared with UCT and DLQI after omalizumab treatment. RESULTS: Evaluation was made of a total of 116 patients (CSU: 92, SDerm: 24), comprising 36 (31%) males and 80 (69%) females with a mean age of 38.95 ± 13.64 years. The most common accompanying comorbid disease was allergic rhinitis (n = 40, 34.5%). There was no statistically significant difference between patients with CSU and SDerm in respect of response to omalizumab treatment (p = 0.890). After omalizumab treatment, the increase in UCT and decrease in DLQI was statistically significant in all patient groups (p < 0.001; p < 0.001, respectively), patients with CSU (p < 0.001; p < 0.001, respectively) and SDerm (p < 0.001; p < 0.001, respectively). There was no statistically significant difference between baseline (before omalizumab treatment) UCT (p = 0.804) and UCT after omalizumab treatment (p = 0.933) between patients with CSU and patients with SDerm. There was no statistically significant difference between baseline (before omalizumab treatment) DLQI (p = 0.356) and DLQI after omalizumab treatment (p = 0.145) between patients with CSU and patients with SDerm. CONCLUSION: Omalizumab treatment improved disease control and quality of life in patients with SDerm. The findings of this study should be supported by randomized placebo-controlled studies.

Anti-TPO IgG/Total IgE Ratio: Biomarker for Omalizumab Response Prediction in Chronic Spontaneous Urticaria.

BACKGROUND: According to recently published data, low total IgE, elevated IgG-anti-TPO, and a high IgG-anti-TPO/total IgE ratio are good biomarkers for subtype IIb autoimmune chronic spontaneous urticaria (CSU), which is frequently refractory to antihistamines and omalizumab. OBJECTIVES: The aim of the study was to evaluate IgG-anti-TPO/total IgE ratio's utility in omalizumab response prediction. METHODS: Retrospective study of CSU patients treated with omalizumab at a UCARE between January 2009 and February 2022. Patients were grouped according to response in the first 16 weeks of treatment: responders UAS7 < 7 versus partial/non-responders UAS7≥7. Total IgE, IgG-anti-TPO, and IgG-anti-TPO/total IgE ratio were compared. Other inflammatory biomarkers - eosinophils, basophils, C-reactive protein, erythrocyte sedimentation rate, and d-dimer - were analyzed. STATISTICAL ANALYSIS: SPSS® (v25.0), p < 0.05 statistically significant. RESULTS: Total of 175 patients, 140 (80%) women, median age 49 [9-88] years, mean CSU duration pre-omalizumab 5.6 ± 8.2 [0-54] years, omalizumab duration 3.2 ± 2.5 [0-12] years. 116 (66%) had angioedema, 77 (44%) inducible chronic urticaria, 60 (34%) atopy, 24 (14%) autoimmune disease. With omalizumab 300 mg q4 weeks, 69% were responders and 31% partial/non-responders. Although not reaching significant differences, mean total IgE values were lower and mean IgG-anti-TPO values were higher in partial/non-responders versus responders (152 vs. 242 kU/L, p = 0.207, and 38.3 vs. 25.7 U/mL, p = 0.408, respectively). A higher IgG-anti-TPO/total IgE ratio was significantly associated with poorer response to omalizumab (p = 0.040). A cut-off >0.154 increased 10 times the odd of poorer response [95% CI 4.62-22], AUC 0.872, p < 0.001, with 87.7% sensitivity, although the low specificity (22.4%) does not allow the assumption of response with values <0.154. Other laboratory biomarkers did not show significant differences between partial/non-responders versus responders. CONCLUSIONS: A high IgG-anti-TPO/total IgE ratio was a good biomarker of poor response to omalizumab in our CSU cohort, with a cut-off >0.154 increasing 10 times the odd of poorer response.

Ligelizumab in adolescents with chronic spontaneous urticaria: Results of a dedicated phase 2b randomized clinical trial supported with pharmacometric analysis.

BACKGROUND: Chronic spontaneous urticaria (CSU), a long-lasting disease in children, impacts their quality of life. We report the results of a phase 2b dose-finding trial of ligelizumab (NCT03437278) and a high-affinity humanized monoclonal anti-IgE antibody, in adolescents with CSU, supported by modeling and simulation analyses, mitigating challenges in pediatric drug development. METHODS: This multicenter, double-blind, placebo-controlled trial, randomized H1-antihistamine-refractory adolescent CSU patients (12-18 years) 2:1:1 to ligelizumab 24 mg, 120 mg, or placebo every 4 weeks for 24 weeks. Patients on placebo transitioned to ligelizumab 120 mg at week 12. Integrating data from the previous adult and present adolescent trial of ligelizumab, a nonlinear mixed-effects modeling described the longitudinal changes in ligelizumab pharmacokinetics, and its effect on weekly Urticaria Activity Score (UAS7). RESULTS: Baseline UAS7 (mean ± SD) was 30.5 ± 7.3 (n = 24), 29.3 ± 7.7 (n = 13), and 32.5 ± 9.0 (n = 12) for patients (median age, 15 years) on ligelizumab 24 mg, 120 mg, and placebo, respectively. Change from baseline in UAS7 at week 12 with ligelizumab 24 mg, 120 mg, and placebo was -15.7 ± 10.9, -18.4 ± 12.3, and -13.0 ± 13.0, respectively. Ligelizumab was well-tolerated. The modeling analysis showed that body weight, but not age, affected ligelizumab's apparent clearance. No significant differences between adolescents and adults were detected on the model-estimated maximum effect and potency. CONCLUSIONS: Ligelizumab exhibited efficacy and safety in adolescent CSU patients, consistent with that in adults. The PK and potency of ligelizumab were not impacted by age, and the same dose of ligelizumab can be used for treating adolescents and adults with CSU. Our study shows how modeling and simulation can complement pediatric drug development.

Biomarkers of Autoimmune Chronic Spontaneous Urticaria.

PURPOSEOF REVIEW: Chronic spontaneous urticaria and chronic inducible urticaria (CSU/CindU) are caused by mast cell and basophil activation leading to degranulation and the release of histamine and several other mediators. Three kinds of factors can trigger mast cells in CSU: (1) activation of stimulating receptor(s) on the mast cell membrane, (2) upregulation of certain receptor(s), and (3) intracellular dysregulation in signaling with overexpression of the spleen tyrosine kinase (SYK) or reduced activation of the inhibitory Src homology 2 (SH2)-containing inositol phosphatases (SHIP)-related pathways. In CSU, two major endotypes exist based on the primary receptor activating mechanism: type I hypersensitivity (IgE-mediated, directed against auto-allergens) and type IIb (autoimmune, via IgG autoantibodies directed against IgE or the IgE-receptor). Their treatment responses vary. We discuss in vitro and in vivo biomarkers. RECENT FINDINGS: Patients with auto-allergic CSU have clinical characteristics that can distinguish them partly from those with autoimmune CSU. Most importantly, their disease generally presents a less aggressive course, a better response to second generation (up-dosed) antihistamines and a good response to omalizumab, if necessary. Meanwhile, autoimmune CSU/CindU patients fare less well and often need immunosuppressive drugs. Biomarkers that might help endotype CSU/CindU patients and select the most appropriate treatment, dose, and duration, e.g., for autoallergic CSU, high total IgE and IgE against auto-allergens; for autoimmune CSU, low IgE, basopenia, and IgG against autoantigens like thyroid peroxidase and a positive autologous serum skin test (but sometimes also positive in autoallergy). Some biomarkers are easily accessible but of low specificity; others are highly specific but more futuristic.

Evaluation of the clinical features and laboratory data of patients with severe asthma classified as super-responder or non super-responder to omalizumab treatment: a single-center real-life study.

INTRODUCTION: Omalizumab is used for the treatment of severe allergic asthma. OBJECTIVE: The aim of this study was to evaluate the clinical features and laboratory data of patients with severe allergic asthma classified as super-responder or non super-responder to omalizumab. METHODS: Comparisons were made of the laboratory data and clinical features of patients with severe allergic asthma. Patients who had no asthma exacerbation, no oral corticosteroid (OCS) use, asthma control test (ACT) score >20 and forced expiratory volume in 1 s (FEV1) >80% were considered super-responder after omalizumab. RESULTS: A total of 90 patients were included in the study, comprising 19 (21.1%) males. The age at onset of asthma, allergic rhinitis rate, number of endoscopic sinus surgeries (ESS), intranasal corticosteroid (INS) use, baseline FEV 1 (%) and ACT score were significantly higher in the omalizumab super-responder group (p = 0.013, p = 0.015, p = 0.002, p = 0.001, p = 0.001 and p < 0.001, respectively). The duration of asthma, rate of Chronic Rhinosinusitis with Nasal Polyps (CRSwNP), regular use of OCS, baseline eosinophil count and eosinophil-to-lymphocyte ratio were significantly higher in the omalizumab non super-responder group (p = 0.015, p < 0.001, p = 0.004, p < 0.001 and p < 0.001, respectively). Blood eosinophil count (AUC: 0.187, p < 0.001), eosinophil-to-lymphocyte ratio (AUC: 0.150, p < 0.001) and FEV1 (%) (AUC:0.779, p = 0.001) were determined to have diagnostic value in predicting the treatment response to omalizumab of patients with severe allergic asthma. CONCLUSION: High-blood eosinophil levels, CRSwNP and low pretreatment lung capacity may affect omalizumab treatment response in patients with severe allergic asthma. These results should be supported by further multicenter real-life studies.

Effectiveness and safety of omalizumab in patients with allergic bronchopulmonary aspergillosis with or without allergic rhinitis: a retrospective chart review.

BACKGROUND: Omalizumab is a valuable alternative treatment for allergic bronchopulmonary aspergillosis (ABPA). The effectiveness and safety of this medication have not been confirmed. The main purpose of this study was to evaluate the effectiveness and safety of omalizumab for ABPA. METHODS: This study involved a retrospective chart review. The main indicators used were asthma control test (ACT) scores, lung function parameters, doses of corticosteroids, acute exacerbation, hospitalization rates, total serum immunoglobulin E (IgE) levels, and blood eosinophil counts. Related adverse events were also reviewed to evaluate the safety of omalizumab. RESULTS: Fourteen patients with ABPA were included, of whom 10 (71%) concurrently had allergic rhinitis (AR). There were improvements in the mean percentages of the forced vital capacity, percentages of the forced expiratory volume in 1 s, and ACT score after omalizumab administration (p < 0.05, p < 0.01, and p < 0.01, respectively). After the initiation of omalizumab administration, the median corticosteroid dose, acute exacerbation rate, hospitalization rate, and mean blood eosinophil count decreased when compared with the baseline values (p < 0.05, p < 0.05, p < 0.01, and p < 0.05, respectively). A reduction in the total serum IgE level was observed in patients with ABPA without AR compared with that in patients with AR (p < 0.05). One patient reported a concurrent skin rash, which spontaneously resolved without medication. CONCLUSION: It is safe and effective to prescribe omalizumab to patients with ABPA, irrespective of whether they have AR. Dose adjustment of omalizumab is safe after disease control. The total serum IgE level might be a predictor of the effectiveness of omalizumab in patients without AR.

Quantity increase and functional affinity/avidity decrease of anti-FcεRI and anti-IgE autoantibodies in chronic spontaneous urticaria.

Summary: Background. Patients with autoimmune forms of chronic spontaneous urticaria (aiCSU) exhibit autoantibodies against the high-affinity IgE receptor (FcεRI) and IgE. As the presence of these autoantibodies does not correlate with disease activity, the functional affinity/avidity may be relevant in aiCSU. This exploratory study aimed to characterize the quantity and avidity of autoantibodies against IgE and FcεRI over 6 months. Methods. The serum of 49 patients with CSU and 30 healthy control subjects was obtained at baseline and 6 months. Serum was analyzed by ELISA, to determine the quantity and avidity of anti-IgE and anti-FcεRI autoantibodies, and by basophil activation test (CU-BAT). Results. An increase in the quantity of anti-FcεRI and anti-IgE antibodies and a simultaneous decrease in avidity was found in all patients with CSU after 6 months: median anti-IgE increased from 6.7 ng/mL (IQR 5.1-12.5) to 23.8 ng/mL (IQR 12.3-121.5), p less than 0.001, median anti-FcεRI from 52.4 ng/mL (IQR 26.3-111.4) to 129.5 ng/mL (IQR 73.7-253.7), p less than 0.001. Median anti-IgE avidity decreased from 75.8% (IQR 55.3-90.8) to 56.4% (IQR 30.6-76.2), p=0.019 and median anti-FcεRI avidity from 75.1% (IQR 49.8-90.0) to 52.2 (IQR 38.2-60.1), p less than 0.001. In contrast, the frequency of activated basophils did not change significantly over time. Surprisingly, autoantibody avidity did not correlate with basophil activation. Conclusions. Both the quantity and avidity of anti-FcεRI and anti-IgE antibodies change over time, demonstrating that the CU-BAT is more suitable to diagnose aiCSU. In addition, the avidity of anti-FcεRI and anti-IgE antibodies do not correlate with CU-BAT and disease activity, suggesting that further factors independent of anti-FcεRI and anti-IgE autoantibodies contribute to aiCSU.

Biomarkers for Monitoring Treatment Response of Omalizumab in Patients with Chronic Urticaria.

Chronic urticaria (CU) is a debilitating skin disease affecting around 1% of the population. CU can be subdivided into chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU). Different pathophysiological mechanisms have been proposed to play a role in the development of CU, and these are also being investigated as potential biomarkers in the diagnosis and management of the disease. As of now the only assessment tools available for treatment response are patient reported outcomes (PROs). Although these tools are both validated and widely used, they leave a desire for more objective measurements. A biomarker is a broad subcategory of observations that can be used as an accurate, reproducible, and objective indicator of clinically relevant outcomes. This could be normal biological or pathogenic processes, or a response to an intervention or exposure, e.g., treatment response. Herein we provide an overview of biomarkers for CU, with a focus on prognostic biomarkers for treatment response to omalizumab, thereby potentially aiding physicians in personalizing treatments.

Development of a Cytotoxic Antibody-Drug Conjugate Targeting Membrane Immunoglobulin E-Positive Cells.

High numbers of membrane immunoglobulin E (IgE)-positive cells are characteristic of allergic conditions, atopic dermatitis, or IgE myeloma. Antibodies targeting the extracellular membrane-proximal domain of the membranous IgE-B-cell receptor (BCR) fragment can be used for specific depletion of IgE-BCR-positive cells. In this study, we derivatized such an antibody with a toxin and developed an antibody-drug conjugate (ADC) that showed strong cytotoxicity for an IgE-positive target cell line. Site-specific conjugation with maleimidocaproyl-valine-citrulline-p-aminobenzoyloxycarbonyl-monomethyl-auristatin E via a newly introduced single cysteine residue was used to prepare a compound with a drug-antibody ratio of 2 and favorable biophysical properties. The antibody was rapidly taken up by the target cells, showing almost complete internalization after 4 h of treatment. Its cytotoxic effect was potentiated upon cross-linking mediated by an anti-human IgG F(ab')2 fragment. Because of its fast internalization and strict target specificity, this antibody-drug conjugate presents a valuable starting point for the further development of an anti-IgE cell-depleting agent, operating by the combined action of receptor cross-linking and toxin-mediated cytotoxicity.

The clinical efficacy and safety of anti-IgE therapy in recessive dystrophic epidermolysis bullosa.

The treatment of recessive dystrophic epidermolysis bullosa (RDEB) remains challenging. Elevated IgE levels have previously been reported in several RDEB patients. In this prospective, single-centre, open intervention study, elevated IgE levels were seen in 11 out of 12 patients with intense pruritus, and the patients with elevated IgE levels received anti-IgE therapy every 4 weeks for at least three cycles. Compared with the baseline, 10 patients with RDEB had good clinical outcomes with enhanced wound healing, a reduction in Birmingham (epidermolysis bullosa) EB severity score by 15%, a reduction in affected body surface area by 23.3%, amelioration of skin inflammation, and an increase in type VII collagen deposition by 13.1-fold. All the patients had a good tolerance to anti-IgE therapy. Furthermore, patients with higher IgE levels tended to have higher disease severity and more favorable clinical outcomes. Our report also suggested the potential role of IgE in the pathogenesis of inflammatory conditions associated with RDEB. (ChiCTR1900021437).