Therapeutic monoclonal antibodies in allergy: Targeting IgE, cytokine, and alarmin pathways.

The etiology of allergy is closely linked to type 2 inflammatory responses ultimately leading to the production of allergen-specific immunoglobulin E (IgE), a key driver of many allergic conditions. At a high level, initial allergen exposure disrupts epithelial integrity, triggering local inflammation via alarmins including IL-25, IL-33, and TSLP, which activate type 2 innate lymphoid cells as well as other immune cells to secrete type 2 cytokines IL-4, IL-5 and IL-13, promoting Th2 cell development and eosinophil recruitment. Th2 cell dependent B cell activation promotes the production of allergen-specific IgE, which stably binds to basophils and mast cells. Rapid degranulation of these cells upon allergen re-exposure leads to allergic symptoms. Recent advances in our understanding of the molecular and cellular mechanisms underlying allergic pathophysiology have significantly shaped the development of therapeutic intervention strategies. In this review, we highlight key therapeutic targets within the allergic cascade with a particular focus on past, current and future treatment approaches using monoclonal antibodies. Specific targeting of alarmins, type 2 cytokines and IgE has shown varying degrees of clinical benefit in different allergic indications including asthma, chronic spontaneous urticaria, atopic dermatitis, chronic rhinosinusitis with nasal polyps, food allergies and eosinophilic esophagitis. While multiple therapeutic antibodies have been approved for clinical use, scientists are still working on ways to improve on current treatment approaches. Here, we provide context to understand therapeutic targeting strategies and their limitations, discussing both knowledge gaps and promising future directions to enhancing clinical efficacy in allergic disease management.

Efficacy and safety of a proposed omalizumab biosimilar compared to the reference product in the management of uncontrolled moderate-to-severe allergic asthma: a multicenter, phase III, randomized, double-blind, equivalency clinical trial.

Background and aims: Allergic asthma has a considerable burden on the quality of life. A significant portion of moderate-to-severe allergic asthma patients need omalizumab, an anti-immunoglobulin-E monoclonal antibody, as an add-on therapy. In this phase III clinical trial P043 (Zerafil®, CinnaGen, Iran) efficacy, safety, and immunogenicity were compared with Xolair® (the originator omalizumab). The primary outcome was the rate of protocol-defined asthma exacerbations. Methods: Exacerbation rates, Asthma Control Test (ACT) results, spirometry measurements, immunogenicity, and safety were evaluated. Each subject received either medication with a dose ranging from 150 to 375 mg based on pre-treatment serum total IgE level (IU/mL) and body weight (kg) every two or four weeks for a duration of 28 weeks. Results: Exacerbation rates were 0.150 (CI: 0.079-0.220) in the P043 group, and 0.190 (CI: 0.110-0.270) in the omalizumab group (per-protocol). The least squares mean differences of predicted Forced Expiratory Volume in the First second (FEV1) were -2.51% (CI: -7.17-2.15, P=0.29) and -3.87% (CI: -8.79-1.04, P=0.12), pre- and post-bronchodilator use. The mean ± SD of ACT scores at the screening and the last visit were 10.62 ± 2.93 and 20.93 ± 4.26 in P043 and 11.09 ± 2.75 and 20.46 ± 5.11 in the omalizumab group. A total of 288 adverse events were reported for the 256 enrolled participants. Among all, "dyspnea" and "headache" were the most reported ones. The overall incidence of adverse events (P=0.62) and serious adverse events (P=0.07) had no significant differences between the two groups. None of the samples were positive for anti-drug antibodies. Conclusion: P043 was equivalent to omalizumab in the management of asthma in reduction of exacerbations. There was no significant difference in other efficacy and safety parameters. Clinical trial registration: www.clinicaltrials.gov (NCT05813470) and www.IRCT.ir (IRCT20150303021315N20).

A comprehensive analysis on the safety of two biologics dupilumab and omalizumab.

Dupilumab was approved for the treatment of several dermatologic immune-mediated inflammatory diseases, such as atopic dermatitis and bullous pemphigoid; whereas omalizumab is the first biological agent which was approved to treat chronic spontaneous urticaria. None of the published meta-analyses has provided the sufficient data regarding the safety of these two biologics, especially regarding their potential serious adverse events (SAEs). The aim of this study was, to comprehensively evaluate the safety of the two biologics dupilumab and omalizumab. In this study, we included 32 randomized trials, and performed meta-analyses on 113 types of SAEs regarding dupilumab and 61 types of SAEs regarding omalizumab. We identified that: (1) use of dupilumab was significantly associated with the lower incidence of atopic dermatitis, while use of omalizumab was significantly associated with the lower incidence of asthma; and (2) use of dupilumab was not significantly associated with the incidences of 112 other kinds of SAEs including various infectious diseases, while use of omalizumab was not significantly associated with the incidences of 60 other kinds of SAEs including various infectious diseases. This meta-analysis for the first time assessed the association between use of dupilumab or omalizumab and incidences of various SAEs, and identified that neither dupilumab use nor omalizumab use was associated with the increased risks of any SAEs including various infectious diseases. These findings further confirm the general safety of the two biologics dupilumab and omalizumab. This informs clinicians that there is no need to worry too much about the safety issues of these two biologics.

Comparative Effectiveness of Dupilumab and Omalizumab on Asthma Exacerbations and Systemic Corticosteroid Prescriptions: Real-World US ADVANTAGE Study.

BACKGROUND: In the US, dupilumab is approved for moderate-to-severe eosinophilic or oral corticosteroid-dependent asthma, while omalizumab is approved for managing moderate-to-severe allergic asthma uncontrolled by inhaled corticosteroids. However, limited comparative effectiveness data exist for these biologics due to differing patient characteristics and treatment histories. OBJECTIVE: This analysis assessed the real-world effectiveness of dupilumab and omalizumab for asthma among patients in the US. METHODS: In this retrospective observational study, TriNetX Dataworks electronic medical record data were used to identify asthma patients (age: ≥12 years) who initiated (index) dupilumab or omalizumab between November 2018 and September 2020, and who had at least 12 months of pre- and post-index clinical information. Inverse probability of treatment weighting (IPTW) was applied to balance potential confounding in treatment groups. Asthma exacerbation rates and systemic corticosteroid (SCS) prescriptions were compared using a doubly robust negative binomial regression model, adjusting for baseline exacerbation/SCS rates and patient characteristics with ≥10% standardized differences after IPTW. RESULTS: Overall, 2,138 patients in dupilumab and 1,313 in omalizumab treatment groups met all inclusion and exclusion criteria. After weighting, the majority of baseline characteristics were balanced (standard difference <10%) between the two groups. Dupilumab was associated with a 44% lower asthma exacerbation rate (p<0.0001) than omalizumab. Additionally, dupilumab treatment significantly (p<0.05) reduced SCS prescriptions by 28% during the follow-up period compared to omalizumab treatment. CONCLUSION: The US ADVANTAGE real-world study demonstrated a significant reduction in severe asthma exacerbations and SCS prescriptions for patients prescribed dupilumab compared to those prescribed omalizumab during 12 months of follow-up.

Does angioedema in patients with chronic spontaneous urticaria impact response to omalizumab?

The presence of angioedema, or deep skin swelling, in addition to hives (wheals) in patients with chronic spontaneous urticaria (CSU) can complicate disease management. There is evidence that omalizumab is effective for patients with CSU with angioedema, but the time to a clinically meaningful response has not been assessed. This post hoc analysis examined data from the phase 3, randomized, double-blind ASTERIA I and ASTERIA II studies: patients with CSU with hives were grouped by presence (n = 216) or absence of angioedema (n = 265) at baseline. The time to minimally important difference (MID, change from baseline of ≥11 points) in weekly Urticaria Activity Score (UAS7) was analyzed using Kaplan-Meier analyses. Median time to MID for omalizumab 300 mg was similar in patients with and without angioedema. Median time to MID for omalizumab 150 mg was similar to 300 mg for patients without angioedema, and was longer for patients with angioedema. Therefore, the response to omalizumab for patients with CSU with angioedema was dose dependent. We recommend that the best approach for clinicians, in line with guidelines, would be initial administration of omalizumab 300 mg every 4 weeks for all patients. Clinical trials registration: Clinicaltrials.gov NCT01287117 (registered 27 January 2011) and NCT01292473 (registered 7 February 2011).

Food Allergy Yardstick: Where Does Omalizumab Fit?

Food allergy management has greatly evolved over the last several years, moving from passive approaches such as strict food allergen avoidance, to more active treatments, including regulatory approval of the first specifically indicated immunotherapy product (for peanut) in 2020. In 2024, a second therapy, omalizumab, received regulatory approval for the treatment of one or more IgE-mediated food allergies, providing clinicians with multiple treatment options to offer patients and families. With this expanded armamentarium of food allergy treatment options, the practicing clinician requires detailed knowledge of benefits and risks of omalizumab, how omalizumab fits into the management landscape, and how to utilize shared decision-making to optimize therapy. This yardstick aims to provide the clinician with a review of data leading to omalizumab's food allergy indication, and an evidence-based expert opinion approach regarding how best to utilize this and other therapies available to optimize patient management.

Omalizumab in Chronic Spontaneous Urticaria: A Real-World Study on Effectiveness, Safety and Predictors of Treatment Outcome.

Background: Although omalizumab has shown success in treating chronic spontaneous urticaria (CSU) patients unresponsive to antihistamines, the exact mechanism of action and predictive markers of response remain unclear. Purpose: The aim of this study was to examine the correlation between baseline levels of biomarkers and clinical parameters with omalizumab response and response rate in patients with CSU. Methods: This retrospective study included 82 adult CSU patients who received omalizumab 300mg every 4 weeks for 16 weeks between January 2022 and December 2023. Treatment response was assessed using UAS7 and DLQI scores at baseline and weeks 4, 8, 12, and 16. Responders were defined as patients achieving UAS7 < 7, with early and late responders categorized based on response within or after 4 weeks, respectively. Baseline clinical features and laboratory biomarkers were compared between responders and non-responders. Results: The overall response rate was 71.95% (59/82), with 23 early responders and 36 late responders. Responders had significantly lower baseline UAS7 (median: 28 vs 35, P < 0.01), DLQI (median: 8 vs 15, P < 0.001), and IL-17 levels (median: 0.53 vs 1.26 pg/mL, P < 0.001) compared to non-responders. Baseline UAS7 > 31, DLQI > 9.5, and IL-17 > 0.775 pg/mL predicted non-response with sensitivities of 78.26%, 100%, and 78.26%, and specificities of 67.8%, 59.32%, and 72.88%, respectively. ASST positivity and comorbid allergic diseases were associated with early response (P < 0.05). Adverse events were reported in 6.09% of patients, including mild injection site reactions and transient urticaria exacerbation, not requiring treatment discontinuation. Conclusion: This study suggests that omalizumab is an effective and safe treatment option for antihistamine-refractory CSU. Baseline UAS7, DLQI, ASST status, serum total IgE levels, and IL-17 may serve as potential predictors of omalizumab response. Notably, ASST positivity and comorbid allergic diseases were associated with an early response to treatment. These findings highlight the importance of considering individual patient characteristics when predicting the likelihood and timing of response to omalizumab in CSU.

Biologics in T2 Severe Asthma: Unveiling Different Effectiveness by Real-World Indirect Comparison.

Background: Indirect comparison among biologics in severe asthma (SA) is a challenging but desirable goal for clinicians in real life. The aim of the study is to define characteristics of a biologic-treated T2-driven-SA population and to evaluate the effectiveness of biologic treatments in a real-world setting by variation in intra/inter-biologic parameters in an up to 4-year follow-up. Methods: Demographic, clinical, functional, and biological characteristics were evaluated retrospectively in 104 patients recruited until July 2022 at baseline (T0) and over a maximum of 4 years (T4) of biologic therapy (omalizumab/OmaG = 41, from T0 to T4, mepolizumab/MepoG = 26, from T0 to T4, benralizumab/BenraG = 18, from T0 to T2, and dupilumab/DupiG = 19, from T0 to T1). Variations of parameters using means of paired Delta were assessed. Results: At baseline, patients had high prevalence of T2-driven comorbidities, low asthma control test (ACT mean 17.65 ± 4.41), impaired pulmonary function (FEV1 65 ± 18 %pred), frequent exacerbations/year (AEs 3.5 ± 3), and OCS dependence (60%). DupiG had lower T2 biomarkers/comorbidities and AEs, and worse FEV1 (57 ± 19 %pred) compared to other biologics (p < 0.05). All biologics improved ACT, FEV1%, FVC%, AEs rate, and OCS use. FEV1% improved in MepoG and BenraG over the minimal clinically important difference and was sustained over 4 years in OmaG and MepoG. A significant RV reduction in OmaG (T4) and DupiG (T1), and BenraG normalization (T2) of airflow limitation were found. We observed through inter-biologic parameters pair delta variation comparison a significant nocturnal awakenings reduction in BenraG vs. OmaG/MepoG, and neutrophils reduction in BenraG/DupiG vs. OmaG. Conclusions: Indirect comparison among biologics unveils clinical and functional improvements that may mark a different effectiveness. These results may highlight the preference of a single biologic compared to another with regard to specific treatable traits.

Omalizumab and Dupilumab for the Treatment of Bullous Pemphigoid: A Systematic Review.

Background: Bullous pemphigoid (BP) is an autoimmune disease characterized by the appearance of very pruritic subepidermal blisters. It appears mostly in the elderly and is associated with multiple comorbidities, which makes its management and treatment difficult. The purpose of this systematic review is to compile current information on published cases of BP treated with omalizumab (omalizumab) and dupilumab (dupilumab) in order to obtain information on clinical efficacy and safety data available. Methods: A literature search of all cases of BP treated with omalizumab/dupilumab published in the literature up to January 2024 was performed using the Pubmed database. After an exhaustive search, a total of 61 studies encompassing 886 patients met the inclusion criteria and were included in the review. Results: The majority of patients with BP treated with omalizumab/dupilumab presented a significant improvement in symptomatology, being very safe drugs with minimal side effects. The main limitation of the presented review is the quality of the included studies, most of them being case series or individual cases. The development of studies with a higher level of scientific evidence in the near future would be of great interest. Conclusions: Both omalizumab and dupilumab appear to be effective options for treating BP in patients refractory to other pharmacological therapies. They are drugs with a good safety profile and the adverse reactions associated with their use are infrequent and generally mild.

Evaluating the Efficacy of Omalizumab in Severe Cedar Seasonal Allergic Rhinitis in Japan.

BACKGROUND: Traditional treatments for cedar seasonal allergic rhinitis include second-generation antihistamines, nasal corticosteroids, and sublingual immunotherapy (SLIT). Omalizumab (Xolair®), an anti-immunoglobulin E (IgE) monoclonal antibody, is an additional option for severe cases unresponsive to existing therapies. Numerous studies have demonstrated the therapeutic effectiveness of omalizumab for cedar seasonal allergic rhinitis; however, most reported results after only up to four weeks of follow-up. Therefore, this study evaluates the clinical efficacy of omalizumab throughout one whole cedar pollen season.   Subjects and methods: This study included patients from our department and the Otorhinolaryngology Department of Minami Osaka Hospital between 2021 and 2023 who were ≥ 12 years old and had serum total IgE levels of 30-1,500 IU/mL, a baseline weight of 30-150 kg, and persistent severe nasal symptoms despite conventional treatments. Patients taking oral steroids at the time of enrollment or had fewer than two omalizumab doses were excluded. Forty-six patients (26 males, 20 females; mean age, 19.1 ± 11.2 years) met these criteria and received subcutaneous omalizumab every 2 or 4 weeks based on their IgE levels and weight. Symptoms were assessed at baseline and 4, 8, and 12 weeks post-administration using the Total Nasal Symptom Score (TNSS) and the Japanese Standard Quality of Life Questionnaire (JRQLQ No. 1) for allergic rhinitis.   Results: Thirty-six patients were followed up for 8 weeks and 13 for 12 weeks. TNSS significantly improved from 6.6 to 4.5 at 4 weeks, 4.2 at 8 weeks, and 4.1 at 12 weeks (p<0.05). Nasal discharge, sneezing, nasal obstruction, itchy eyes, and tearfulness showed significant improvements (p<0.05). Quality of life scores improved in daily activities, sleep, and physical health from week 4 to week 12.   Discussion: Consistent with previous findings, omalizumab significantly improved nasal and ocular symptoms and quality of life in patients with severe cedar seasonal allergic rhinitis. Despite many patients discontinuing the drug after eight weeks due to high costs, the drug's effectiveness in preventing symptom recurrence suggests potential long-term benefits. Combining omalizumab with SLIT showed no significant differences in outcomes; however, further pharmacoeconomic studies are warranted to evaluate cost-effectiveness.   Conclusion: Omalizumab proved to be an effective treatment for severe cedar seasonal allergic rhinitis, providing significant symptom relief and quality of life improvements. Further studies should investigate its long-term efficacy and safety, including potential adverse effects and the development of anti-omalizumab antibodies.

Model-based comparisons of post-treatment free IgE and FEV1 between omalizumab asthma dosing tables in the United States and European Union.

AIMS: Omalizumab is an anti-immunoglobulin E (IgE) monoclonal antibody that was first approved by the United States (US) Food and Drug Administration (FDA) for the treatment of allergic asthma in 2003. The pivotal trials supporting the initial approval of omalizumab used dosing determined by patient's baseline IgE and body weight, with the goal of reducing the mean free IgE level to approximately 25 ng/mL or less. While the underlying parameters supporting the dosing table remained the same, subsequent studies and analyses have resulted in approved alternative versions of the dosing table, including the European Union (EU) asthma dosing table, which differs in weight bands and maximum allowable baseline IgE and omalizumab dose. In this study, we leveraged modelling and simulation approaches to predict and compare the free IgE reduction and forced expiratory volume in 1 second (FEV1) improvement with omalizumab dosing based on the US and EU asthma dosing tables. METHODS: Previously established population pharmacokinetic-IgE and IgE-FEV1 models were used to predict and compare post-treatment free IgE and FEV1 based on the US and EU dosing tables. Clinical trial simulations (with virtual asthma populations) and Monte Carlo simulations were performed to provide both breadth and depth in the comparisons. RESULTS: The US and EU asthma dosing tables were predicted to result in generally comparable free IgE suppression and FEV1 improvement. CONCLUSIONS: Despite the similar free IgE and FEV1 outcomes from simulations, this has not been clinically validated with respect to the registrational endpoint of reduction in annualized asthma exacerbations.

Race & ethnicity, not just insurance, is associated with biologics initiation in asthma and related conditions.

BACKGROUND: There are pre-existing inequities in asthma care. OBJECTIVE: To evaluate effect modification by race of the effect of insurance on biologic therapy use in patients with asthma and related diseases. METHODS: We conducted inverse probability weighted (IPW) analyses using electronic health records data from 2011-2020 from a large healthcare system in Boston, MA. We evaluated the odds of not initiating omalizumab or mepolizumab therapy within one year of prescription for an approved indication. RESULTS: We identified 1,132 individuals who met study criteria. Twenty-seven percent of these patients had public insurance and 12% belonged to a historically marginalized group (HMG). A quarter of patients did not initiate the prescribed biologic. Among patients with asthma, individuals belonging to HMG had higher exacerbation rates in the period before initiation compared to non-HMG individuals, regardless of insurance type. Among HMG patients with asthma, those with private insurance were less likely to not initiate therapy compared to those with public insurance, (Odds Ratio, (OR) 0.67, and 95% Confidence Interval, [CI] 0.56 - 0.79). Among non-HMG with asthma, privately insured and publicly insured individuals had similar rates of not initiating the prescribed biologic (OR: 1.02; 95% CI: 0.95 -1.09). Among those publicly insured with asthma, HMGs had higher odds of not initiating therapy compared to non-HMGs (OR 1.16; 95% CI 1.03 - 1.31), but privately-insured HMG and non-HMG did not differ significantly (OR: 0.99; 95% CI: 0.91 - 1.07). CONCLUSION: Publicly insured individuals belonging to HMG are less likely to initiate biologics when prescribed despite having more severe asthma, while there are no inequities by insurance in individuals belonging to other groups.

Characterization of omalizumab updosing patterns and predictive factors in chronic spontaneous urticaria: A prospective multicentric observational study.

BACKGROUND: Limited information is available on the use of omalizumab (OMA) updosing since its introduction as a second-line therapy in chronic spontaneous urticaria (CSU) in 2014. Practical guidelines from health authorities are lacking, and the specific characteristics of patients requiring higher doses remain unknown. Our objectives were to characterize the patterns of OMA updosing (defined as changes in dose and/or injection intervals), to identify the predictive factors associated with updosing, and to improve CSU management. METHODS: We conducted a prospective, multicentric, real-life observational study, including patients diagnosed with CSU and starting OMA. The data were collected at 0, 3, 6, and 9 months. The primary endpoint was the frequency of OMA updosing at 3 months. The secondary endpoints included an analysis of updosed patients' profile, and an assessment of OMA efficacy and safety. RESULTS: We included 153 patients. Twenty percent of patients were updosed at 3 months, and 27% in total during the 9-month follow-up. Practitioners mainly chose to increase the frequency of injections (66%). At baseline, the updosed patients were more likely to have more severe CSU (UCT < 4, p < 0.030), a lower lymphocyte count (<2000/mm3, p = 0.037), and low IgE levels (<70 UI/mL, p = 0.024). The side effects of OMA were not more frequent after updosing. CONCLUSION: One in five patient underwent updosing within just 3 months. OMA updosing is frequent in particular in cases of severe disease and low IgE blood levels.

Omalizumab for management of hypersensitivity reactions to anticancer drugs.

Hypersensitivity reactions to anticancer drugs include treatment-limiting toxicity. Standard drug desensitisation offers temporary tolerance and hence requires repetition. We used omalizumab, an anti-immunoglobulin E antibody, to overcome immediate and delayed hypersensitivity reactions to various anticancer drugs. Seven of the eight patients in the current study successfully resumed the desired anticancer drug regimen without standard desensitisation. No safety issues from omalizumab were observed.

Favorable clinical course after discontinuation of omalizumab treatment in patients with allergic severe asthma: A real-world clinical practice.

The success rate of omalizumab discontinuation is 50-75.5%. However, such data are scarce in Japan. We retrospectively investigated the clinical progression following the cessation of long-term omalizumab treatment (>5 years) in severe allergic asthma patients who have achieved super-responder status, defined as being off any oral maintenance corticosteroids without experiencing exacerbations requiring systemic corticosteroids for >1 year. Six (28.6%) among 21 patients recommenced after a median period of 5.5 (4.3-12.5) months later due to exacerbated asthma control, resulting in improved asthma management for all patients. The rates of patients who successfully remained off omalizumab treatment for 1 and 2 years were 72.4% and 65.8%, respectively. Specific IgE levels after discontinuing omalizumab treatment significantly decreased compared to those at initiating this treatment in 10 patients who successfully remained off this treatment. Therefore, discontinuing omalizumab treatment may be considered for patients continuing treatment beyond 5 years and achieving super-responder status.

Acute Motor Conduction Block Neuropathy After Initiation of Omalizumab: Case Report and Literature Review for Possible Causality.

Background: Omalizumab is an established therapy for allergic conditions, yet its neurological effects remain underexplored compared to other biological agents. Case description: A 45-year-old male with asthma developed acute quadriparesis one week after receiving the first dose of omalizumab. Electrophysiological studies have shown partial motor conduction block in multiple nerves, with reduced CMAP amplitudes and absent F-waves in others. CSF showed cyto-albuminous dissociation. The diagnosis was a variant of Guillain-Barré syndrome. Despite intravenous immunoglobulin (IVIG) therapy, the patient experienced persistent neuropathic symptoms. Discussion: The patient presented with acute quadriparesis devoid of sensory or cranial nerve involvement, suggestive of a variant of Guillain-Barré syndrome (GBS) known as acute motor conduction block neuropathy (AMCBN). Electrophysiological studies have indicated conduction block without demyelination, implicating axonal degeneration. Despite negative findings for common etiologies, the temporal association between omalizumab administration and symptom onset suggests a potential link, supported by criteria for drug-induced illness. Conflicting evidence exists regarding omalizumab's neurological effects, with proposed mechanisms including autoimmune reactions and mast cell dysfunction. Comparisons to TNF-α antagonists highlight similar neuropathy patterns, indicating a need for further research to clarify omalizumab's neurotoxicity. Conclusion: In conclusion, while omalizumab holds promise for allergic conditions, including chronic urticaria, its potential impact on peripheral nerves necessitates vigilance among clinicians. Further studies are imperative to ascertain the risk-benefit profile and elucidate underlying mechanisms and risk factors of neurological complications associated with omalizumab therapy.

Time-course and dose-effect of omalizumab in treating chronic idiopathic urticaria/chronic spontaneous urticaria.

PURPOSE: Several studies have shown that subcutaneous injections of omalizumab can treat chronic idiopathic/spontaneous urticaria (CIU/CSU) patients by only assessing the efficacy on specific endpoints. This study aimed to quantitatively analyze different doses of omalizumab in CIU/CSU and compare it with ligelizumab. METHODS: Literature searches were performed in PubMed, Embase, and Web of Science databases. A model-based meta-analysis (MBMA) was utilized to develop a model incorporating time since the initiation of treatment and dose for omalizumab, with the change from baseline in Urticaria Activity Score (CFB-UAS7) as the primary efficacy endpoint. The time-course and dose-effect relationship throughout the omalizumab treatment period was analyzed, and the findings were compared with those of the investigational ligelizumab. RESULTS: The model equation for the CFB-UAS7 was established as E = -Emax × time/(ET50 + time) × (b0 + b1 × dose). The estimated values of the model parameters E max , ET 50 , b 0 , and b 1 were -1.16, 1.26 weeks, -9.90, and -0.0361 mg-1, respectively. At week 12 after the first dose, the model-predicted CFB-UAS7 for 150 mg and 300 mg of omalizumab were -16.0 (95% CI, -17.2 to -14.8) and -21.7 (95% CI, -22.9 to -20.5), respectively. In the PEARL-1 trial, the CFB-UAS7 for 72 mg and 120 mg of ligelizumab were -19.4 (95% CI, -20.7 to -18.1) and -19.3 (95% CI, -20.6 to -18.0), respectively. In the PEARL-2 trial, these values were -19.2 (95% CI, -20.5 to -17.9) and -20.3 (95% CI, -21.6 to -19.0), respectively. CONCLUSION: Omalizumab showed a significant dose-dependent effect in the treatment of CSU. Both 72 mg and 120 mg ligelizumab might have the potential to outperform 150 mg (but not 300 mg) omalizumab.

Paradoxical Worsening of Chronic Spontaneous Urticaria Following Omalizumab Administration: The Missing Link.

Omalizumab, a humanized anti-IgE monoclonal antibody, is commonly employed in the treatment of antihistamine-refractory chronic spontaneous urticaria (CSU), where it significantly reduces free IgE levels, minimizing histamine release from basophils and mast cells. Despite its efficacy, there are concerns regarding its effect on parasitic defense due to IgE's role in combating parasitic infestations. We present a case of a 28-year-old female agriculturist with a six-month history of CSU who experienced a paradoxical exacerbation of her symptoms following an increase in the omalizumab treatment dose. This deterioration coincided with a serologically confirmed parasitic infection with Echinococcus granulosus and Toxocara canis. Despite normal eosinophil counts and IgE levels, which are typically used to identify parasitic infections, the patient's clinical worsening prompted further investigation that led to the identification of the parasitic infection. Treatment with albendazole and omalizumab discontinuation led to the resolution of her CSU, suggesting that the parasitic infection was contributing to the symptom exacerbation. This case highlights the need for careful screening for parasitic infections before initiating omalizumab in antihistamine-refractory CSU patients from endemic regions, or patients who deteriorate clinically on omalizumab, especially when other indicators such as eosinophil count and IgE levels might not suggest infection. It also underscores the importance of considering a tailored approach to managing CSU that balances effective treatment with the potential for adverse effects related to immunomodulation.