Safety of omalizumab in asthma

Postmarketing Analysis of Eosinophilic Adverse Reactions in the use of Biologic Therapies for Type 2 Inflammatory Conditions

BACKGROUND

Temporary eosinophilia is a potential adverse reaction of monoclonal antibody therapies in the treatment of a variety of type 2 inflammatory conditions, including asthma and chronic rhinosinusitis with nasal polyposis (CRSwNP). The pathophysiology, epidemiology, and clinical significance of eosinophilia and eosinophilic adverse reactions following the initiation of biologic therapy are unclear.

OBJECTIVES

To describe the postmarketing, eosinophilic adverse reactions with clinical significance in patients treated with the 3 biologic therapies approved by the U.S. Food and Drug Administration (FDA) for CRSwNP: dupilumab, omalizumab, and mepolizumab.

METHODS

The FDA Adverse Event Reporting System (FAERS) Public Dashboard was searched for eosinophilic adverse reactions related to dupilumab, omalizumab, and mepolizumab treatments from November 2004 to December 2022. Data regarding each of the eosinophilic adverse reactions were extracted and analyzed.

RESULTS

A total of 218, 270, and 134 reports of eosinophilic adverse reactions were reported among patients who were treated with dupilumab, omalizumab, and mepolizumab, respectively. The most common eosinophilic adverse reaction was eosinophilic granulomatosis with polyangiitis (338 patients), followed by eosinophilic respiratory tract reactions (158 patients). The most common indication for biological treatment among the reaction groups was asthma.

CONCLUSIONS

Eosinophilic adverse reactions are rare but consequential complications of biological treatment. They are more common among patients treated for asthma and chronic rhinosinusitis with nasal polyposis. Measuring and monitoring blood eosinophil levels may be appropriate in specific clinical instances when patients are started on different biologic therapies for type 2 inflammatory conditions.

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.

Real-life safety and efficacy of omalizumab in Japanese patients with severe allergic asthma who were subjected to dosing table revision or expansion: A post-marketing surveillance

BACKGROUND

Omalizumab is an anti-immunoglobulin E monoclonal antibody approved for patients with severe allergic asthma in Japan. With regard to omalizumab dosage in Japanese adults with severe allergic asthma in clinical practice settings, this post-marketing surveillance evaluated safety and efficacy of the dosing table revision (DTR) based on a dosing regimen of omalizumab administration every 4 weeks dosing regimen and dosing table expansion (DTE) for patients with baseline IgE levels >700 IU/mL.

METHODS

This 52-week, multicenter study, conducted from September 2013 to November 2018, evaluated omalizumab safety outcomes including adverse events (AEs), serious AEs (SAEs), adverse drug reactions (ADRs), efficacy outcomes including Global Evaluation of Treatment Effectiveness (GETE), change in oral corticosteroid dose, and asthma exacerbation-related events such as hospitalization, emergency room visits, and worsening of symptoms.

RESULTS

Of the 405 patients registered in the study, safety was evaluated in 392 and efficacy in 390. The mean age of patients was 58.5 years and 58.7% were women. In total, 41.3% of the patients were subjected to DTE and 58.7% to DTR. In the safety dataset, 6.6% experienced an ADR, 32.9% experienced an AE, and 16.1% experienced an SAE. In the efficacy dataset, 63.3% of patients at Week 16 and 63.5% at Week 52 had an 'effective' or 'good' GETE score. Omalizumab was associated with a reduction in worsening of asthma symptoms requiring systemic corticosteroids and frequency of hospitalization. All outcomes were comparable among the DTE and DTR subgroups.

CONCLUSION

The findings from this study support the safety and efficacy of omalizumab administered based on the revised and expanded dosing table in Japanese patients with severe allergic asthma.

Short- and long-term real-world effectiveness of omalizumab in severe allergic asthma: systematic review of 42 studies published 2008-2018

INTRODUCTION

Omalizumab is a recombinant monoclonal anti-IgE antibody approved in the US as add-on treatment in moderate-to-severe allergic asthma (in severe allergic asthma [SAA] in Europe). A 2016 review of 24 real-world effectiveness studies in SAA published between 2008-2015 concluded that omalizumab was associated with significant improvements in objective and subjective outcomes with benefits extending beyond 2 years. Several new real-world studies have been published since, bringing the total to 42 studies. Areas covered: This systematic review of 42 studies published since 2008 updates and extends the 2016 review on the real-word evidence on omalizumab in SAA. It offers greater granularity as to time windows within which outcomes are reported and includes studies extending well beyond 4 years post omalizumab initiation. Expert commentary: This review firmly establishes the short-term effectiveness of omalizumab in adolescent and adult patients with SAA at 1 year, and provides strong evidence of long-term effectiveness up to 4 years and emergent evidence of effectiveness beyond 4 years. In the aggregate, these 42 studies underscore the long-term effectiveness of omalizumab in terms of: reducing exacerbations and symptoms, achieving asthma control, improving lung function, enhancing quality of life, decreasing emergency department visits and hospitalizations, and promoting concomitant medication-sparing.

Traditional Therapies for Severe Asthma

Severe asthma is a complex and heterogeneous disease. The European Respiratory Society and American Thoracic Society guidelines define severe asthma for patients 6 years or older as "asthma which requires treatment with high-dose inhaled corticosteroids…plus a second controller or systemic corticosteroids to prevent it from becoming 'uncontrolled' or which remains 'uncontrolled' despite this therapy." This article reviews available traditional therapies, data behind their uses in severe asthma, and varying recommendations. As various asthma endotypes and phenotypes are better understood and characterized, targeted therapies should help improve disease outcomes, efficacy, and cost-effectiveness.

Anti-IgE Monoclonal Antibody (Omalizumab) in Refractory and Relapsing Eosinophilic Granulomatosis With Polyangiitis (Churg-Strauss): Data on Seventeen Patients

OBJECTIVE

To describe the efficacy and safety of omalizumab, an anti-IgE monoclonal antibody, in patients with refractory and/or relapsing eosinophilic granulomatosis with polyangiitis (Churg-Strauss) (EGPA).

METHODS

We conducted a nationwide retrospective study including EGPA patients who received omalizumab. Response was defined as the absence of asthma and/or sinonasal exacerbations with a prednisone dosage of ≤7.5 mg/day (complete response) or >7.5 mg/day (partial response).

RESULTS

Seventeen patients (median age 45 years) received omalizumab for severe steroid-dependent asthma (88%) and/or sinonasal involvement (18%). After a median follow-up of 22 months, 6 patients (35%) achieved a complete response, 5 patients (30%) achieved a partial response, and 6 patients (35%) had no improvement. The median Birmingham Vasculitis Activity Score decreased from 2.5 at baseline to 0.5 at 12 months. The median number of exacerbations per month decreased from 1 at baseline to 0 at 12 months, and the median forced expiratory volume in 1 second increased from 63% of the percent predicted at baseline to 85% of the percent predicted at 12 months. The median prednisone dosage decreased from 16 mg/day at baseline to 11 mg/day at 6 months and 9 mg/day at 12 months. Omalizumab was discontinued in 8 patients (47%) during follow-up, because of remission (12.5%), adverse event despite disease remission (12.5%), refractory disease (25%), or relapse (50%). Relapses included retrobulbar optic neuritis attributable to EGPA in 2 patients and severe asthma flare in 2 others.

CONCLUSION

The results of this study suggest that omalizumab may have a corticosteroid-sparing effect in EGPA patients with asthmatic and/or sinonasal manifestations, but reducing the corticosteroid dose may also increase the risk of severe EGPA flares, which raises the question of the safety of omalizumab in patients with EGPA.

The safety of monoclonal antibodies in asthma

INTRODUCTION

In the last two decades the knowledge of the mechanisms of the inflammatory processes underlying asthma rapidly evolved, several key mediators (cytokines and receptors) were identified, and the laboratory techniques have allowed us to synthesize monoclonal antibodies highly specific for those target molecules. Nowadays, many biological agents are investigated in asthma (with anti IgE being the only commercially available). The clinical efficacy of some biologics was demonstrated in many cases, however, the safety issue has progressively emerged and has been recognized as a crucial aspect.

AREAS COVERED

We summarized the currently available knowledge on the safety and side effects of biologics in asthma, as derived by reviews, meta analyses and clinical trials. PubMed was searched with the terms anti IL-x [AND] safety [OR] side effects, within the categories "clinical trial", meta-analysis" and "review". Case reports were excluded. The authors collegially selected the relevant entries to be included.

EXPERT OPINION

Overall, the safety of most of the investigated agents seems to be satisfactory, a certain risk of side effects remains present, and is variable for the different molecules. Thus caution must be paid in evaluating the risk to benefit ratio. Specific biomarkers to predict the response to each biological are urgently needed to improve the safety profile.

Severe asthma: anti-IgE or anti-IL-5?

Severe asthma is a discrete clinical entity characterised by recurrent exacerbations, reduced quality of life and poor asthma control as ordinary treatment regimens remain inadequate. Difficulty in managing severe asthma derives partly from the multiple existing phenotypes and our inability to recognise them. Though the exact pathogenetic pathway of severe allergic asthma remains unclear, it is known that numerous inflammatory cells and cytokines are involved, and eosinophils represent a key inflammatory cell mediator. Anti-IgE (omalizumab) and anti-IL-5 (mepolizumab) antibodies are biological agents that interfere in different steps of the Th2 inflammatory cascade and are licensed in severe asthma. Both exhibit a favourable clinical outcome as they reduce exacerbation rate and improve asthma control and quality of life, while mepolizumab also induces an oral steroid sparing effect. Nevertheless, it is still questionable which agent is more suitable in the management of severe allergic asthma since no comparable studies have been conducted. Omalizumab's established effectiveness in clinical practice over a long period is complemented by a beneficial effect on airway remodelling process mediated mainly through its impact on eosinophils and other parameters strongly related to eosinophilic inflammation. However, it is possible that mepolizumab through nearly depleting eosinophils could have a similar effect on airway remodelling. Moreover, to date, markers indicative of the patient population responding to each treatment are unavailable although baseline eosinophils and exacerbation rate in the previous year demonstrate a predictive value regarding anti-IL-5 therapy effectiveness. On the other hand, a better therapeutic response for omalizumab has been observed when low forced expiratory volume in 1 sec, high-dose inhaled corticosteroids and increased IgE concentrations are present. Consequently, conclusions are not yet safe to be drawn based on existing knowledge, and additional research is necessary to unravel the remaining issues for the severe asthmatic population.

'Real-life' effectiveness studies of omalizumab in adult patients with severe allergic asthma: systematic review

We reviewed 24 'real-life' effectiveness studies of omalizumab in the treatment of severe allergic asthma that included 4117 unique patients from 32 countries with significant heterogeneity in patients, clinicians and settings. The evidence underscores the short- and long-term benefit of anti-IgE therapy in terms of the following: improving lung function; achieving asthma control and reducing symptomatology, severe exacerbations and associated work/school days lost; reducing healthcare resource utilizations, in particular hospitalizations, hospital lengths of stay and accident specialist or emergency department visits; reducing or discontinuing other asthma medications; and improving quality of life - thus confirming, complementing and extending evidence from randomized trials. Thus, omalizumab therapy is associated with signal improvements across the full objective and subjective burden of illness chain of severe allergic asthma. Benefits of omalizumab may extend up to 2-4 years, and the majority of omalizumab-treated patients may benefit for many years. Omalizumab has positive short- and long-term safety profiles similar to what is known from randomized clinical trials. Initiated patients should be monitored for treatment response at 16 weeks. Those showing positive response at that time are highly likely to show sustained treatment response and benefit in terms of clinical, quality of life and health resource utilization outcomes.

Omalizumab for the treatment of inadequately controlled allergic rhinitis: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Patients with moderate-to-severe allergic rhinitis who are inadequately controlled despite treatment according to current rhinitis management guidelines have a significant unmet medical need. Such patients have a negative impact on daily functioning and are at risk of developing serious comorbidities, such as asthma and chronic rhinosinusitis.

OBJECTIVE

To assess the efficacy and safety of omalizumab in poorly controlled allergic rhinitis under a meta-analysis framework.

METHODS

MEDLINE and the Cochrane Central Register of Controlled Trials were searched through September 2013. Studies on the efficacy of omalizumab in allergic rhinitis that assessed clinical outcomes were selected. Descriptive and quantitative information was extracted; mean differences and relative risk estimates were synthesized under a fixed or random effects model. Heterogeneity was assessed by using the Q statistic and the I(2) metric. Subgroup analyses were performed for the presence of specific immunotherapy treatment.

RESULTS

Of the 352 citations retrieved, 11 studies of 2870 patients were finally included. A statistically significant reduction in the daily nasal symptom severity score (standardized mean difference -0.67 [95% CI, -1.3 to -0.31]; P < .0001; I(2), 92%) and a statistically significant reduction in daily nasal rescue medication score (-0.22 [95% CI, -0.39 to -0.05; P = .01; I(2), 58%) were observed. There was not a statistically significant difference in the occurrence of any adverse event (relative risk 1.06 [95% CI, 0.94-1.19; I(2), 55%).

CONCLUSIONS

Omalizumab is statistically significantly associated with symptom relief, decreased rescue medication use, and improvement of quality of life in patients with inadequately controlled allergic rhinosinusitis.

Efficacy and safety of omalizumab in patients with chronic idiopathic/spontaneous urticaria who remain symptomatic on H1 antihistamines: a randomized, placebo-controlled study

ASTERIA I was a 40-week, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of subcutaneous omalizumab as add-on therapy for 24 weeks in patients with chronic idiopathic urticaria/spontaneous urticaria (CIU/CSU) who remained symptomatic despite H1 antihistamine treatment at licensed doses. Patients aged 12-75 years with CIU/CSU who remained symptomatic despite treatment with approved doses of H1 antihistamines were randomized (1:1:1:1) in a double-blind manner to subcutaneous omalizumab 75 mg, 150 mg, or 300 mg or placebo every 4 weeks for 24 weeks followed by 16 weeks of follow-up. The primary end point was change from baseline in weekly itch severity score (ISS) at week 12. Among randomized patients (N=319: placebo n=80, omalizumab 75 mg n=78, 150 mg n=80, 300 mg n=81), 262 (82.1%) completed the study. Compared with placebo (n=80), mean weekly ISS was reduced from baseline to week 12 by an additional 2.96 points (95% confidence interval (CI): -4.71 to -1.21; P=0.0010), 2.95 points (95% CI: -4.72 to -1.18; P=0.0012), and 5.80 points (95% CI: -7.49 to -4.10; P<0.0001) in the omalizumab 75-mg (n=77), 150-mg (n=80), and 300-mg groups (n=81), respectively. The omalizumab 300-mg group met all nine secondary end points, including a significant decrease in the duration of time to reach minimally important difference response (⩾5-point decrease) in weekly ISS (P<0.0001) and higher percentages of patients with well-controlled symptoms (urticaria activity score over 7 days (UAS7) ⩽6: 51.9% vs. 11.3%; P<0.0001) and complete response (UAS7=0: 35.8% vs. 8.8%; P<0.0001) versus placebo. During the 24-week treatment period, 2 (2.9%), 3 (3.4%), 0, and 4 (5.0%) patients in the omalizumab 75-mg, 150-mg, 300-mg, and placebo groups, respectively, experienced a serious adverse event. Omalizumab 300 mg administered subcutaneously every 4 weeks reduced weekly ISS and other symptom scores versus placebo in CIU/CSU patients who remained symptomatic despite treatment with approved doses of H1 antihistamines.

Concordance of preclinical and clinical pharmacology and toxicology of monoclonal antibodies and fusion proteins: soluble targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards soluble targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 14 currently approved mAbs and fusion proteins targeted to soluble targets. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions' and United States Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the following approved biopharmaceuticals were included: adalimumab, anakinra, bevacizumab, canakinumab, certolizumab pegol, denosumab, eculizumab, etanercept, golimumab, infliximab, omalizumab, ranibizumab, rilonacept and ustekinumab. Some related biopharmaceuticals in late-stage development were also included for comparison. Good concordance with human pharmacodynamics was found for both non-human primates (NHPs) receiving the human biopharmaceutical and mice receiving rodent homologues (surrogates). In contrast, there was limited concordance for human adverse effects in genetically deficient mice, mice receiving surrogates or NHPs receiving the human pharmaceutical. In summary, the results of this survey show that although both mice and NHPs have good predictive value for human pharmacodynamics, neither species have good predictive value for human adverse effects. No evidence that NHPs have superior predictive value was found.

IL-13 in asthma and allergic disease: asthma phenotypes and targeted therapies

Decades of research in animal models have provided abundant evidence to show that IL-13 is a key T(H)2 cytokine that directs many of the important features of airway inflammation and remodeling in patients with allergic asthma. Several promising focused therapies for asthma that target the IL-13/IL-4/signal transducer and activator of transcription 6 pathway are in development, including anti-IL-13 mAbs and IL-4 receptor antagonists. The efficacy of these new potential asthma therapies depends on the responsiveness of patients. However, an understanding of how IL-13-directed therapies might benefit asthmatic patients is confounded by the complex heterogeneity of the disease. Recent efforts to classify subphenotypes of asthma have focused on sputum cellular inflammation profiles, as well as cluster analyses of clinical variables and molecular and genetic signatures. Researchers and clinicians can now evaluate biomarkers of T(H)2-driven airway inflammation in asthmatic patients, such as serum IgE levels, sputum eosinophil counts, fraction of exhaled nitric oxide levels, and serum periostin levels, to aid decision making in clinical trials and drug development and to identify subsets of patients who might benefit from therapies. Although it is unlikely that these therapies will benefit all asthmatic patients with this heterogeneous disease, advances in understanding asthma subphenotypes in relation to clinical variables and T(H)2 cytokine responses offer the opportunity to improve the efficacy and safety of proposed therapies for asthma.

Omalizumab: clinical use for the management of asthma

Omalizumab, a humanized monoclonal antibody that binds circulating IgE antibody, is a treatment option for patients with moderate to severe allergic asthma whose asthma is poorly controlled with inhaled corticosteroids and inhaled long-acting β₂ agonist bronchodilators. This review considers the mechanism of action, pharmacokinetics, efficacy, safety and place in management of omalizumab in asthma and focuses particularly on key articles published over the last three years. Omalizumab reduces IgE mediated airway inflammation and its effect on airway remodeling is under investigation. Recent long-term clinical trials confirm the benefits of omalizumab in reducing exacerbations and symptoms in adults and in children with moderate to severe allergic asthma. No clinical or immunological factor consistently predicts a good therapeutic response to omalizumab in allergic asthma. In responders, the duration of treatment is unclear. The main adverse effect of omalizumab is anaphylaxis, although this occurs infrequently. Preliminary data from a five-year safety study has raised concerns about increased cardiovascular events and a final report is awaited. Clinical trials are in progress to determine whether omalizumab has efficacy in the treatment of non-allergic asthma.

Persistent elevation of peripheral blood myeloid cell counts associated with omalizumab therapy

PURPOSE

A case of persistent hematologic abnormalities in a patient receiving long-term omalizumab therapy for severe asthma is reported.

SUMMARY

During the course of her treatment at an asthma clinic, a 24-year-old woman was noted to have increased white blood cell counts, with elevated myeloid cell counts; the blood abnormalities were first documented more than 12 months previously. The woman had been taking omalizumab for more than 2 years and was also receiving immune globulin therapy for common variable immunodeficiency. Based on the results of bone marrow aspiration and biopsy, she was diagnosed as having mild neutrophilia, possibly related to past corticosteroid therapy, but there was no evidence of a malignancy, a hemophagocytic syndrome, or an infectious, myeloproliferative, or lymphoproliferative process. Pursuant to a multidisciplinary medication review, the use of omalizumab was identified as a potential factor in the myeloid cell elevations and discontinued. About 1 month after omalizumab therapy was halted, the patient's myeloid cell counts normalized. The temporal association of omalizumab use and blood abnormalities in this case, coupled with the lack of data on the drug's long-term hematologic effects, suggests a need for cautious use and close monitoring of omalizumab therapy, particularly in younger patients.

CONCLUSION

A patient with asthma and common variable immunodeficiency developed an elevation of peripheral blood myeloid cells that was first noticed 29 months after the initiation of monthly omalizumab injections. Omalizumab was discontinued, and the abnormality persisted for 1 month after the last dose. The patient's blood count results remained within normal limits 3 months after the last dose.

Targeting IgE in asthma

PURPOSE OF REVIEW

IgE plays a pivotal role in allergic asthma especially in the acute response to antigen and in the propagation of airway inflammation. Therefore, it has become apparent that targeting this antibody and blocking its function may lead to significant clinical effects in some patients with the disease. In this review, we describe the role of IgE in asthma and provide an update on the therapeutic implications of targeting this mediator in patients with severe allergic disease. We also outline future needs of research in this area.

RECENT FINDINGS

Several randomized clinical trials as well as observational real-world studies have confirmed the long-term efficacy of omalizumab in improving clinical outcomes when added to guideline-recommended maintenance of asthma medications (inhaled corticosteroids and long-acting β2-agonists) in patients with moderate-to-severe asthma. Recent pooled data from randomized clinical trials and from a large prospective cohort study provide reassurance about the long-term safety of omalizumab. Future research should explore the long-term effects of omalizumab on the natural history of the disease and identify more accurate predictors of response to this treatment.

SUMMARY

The anti-inflammatory effects of omalizumab at different sites of allergic inflammation and its clinical benefits in patients with allergic asthma emphasize the fundamental importance of IgE in allergic inflammation.

Identifying and testing potential new anti-asthma agents

INTRODUCTION

Inhaled corticosteroids alone or with long-acting beta-2 agonists (LABA) are the basic treatment for stable asthma. While the majority of patients are controllable, some patients retain chronic severe disease and develop permanent alterations in airway function. For patients such as these it is important to better understand the mechanisms of asthma so that alternative approaches can be developed.

AREA COVERED

Based on data from in vitro cell culture, animal models and clinical trials, this review discusses potential agents targeting either key effector cells, mediators and their receptors in asthma pathogenesis or their signaling cascade molecules.

EXPERT OPINION

As targeting single Th2 cytokines and their receptors has been shown to have limited clinical benefit, it is important to identify and test potential new therapeutic agents. Recent studies suggest that blockade of IgE synthesis, its interaction with its receptors and downstream signaling, identification of molecular targets in innate immune and airways structural cells, and fresh anti-neutrophil strategies should be prominent among these. Further studies are required to clarify the relationship between airways remodeling and asthma severity so that appropriate patients may be targeted.

Update on optimal use of omalizumab in management of asthma

Omalizumab is a humanized monoclonal anti-IgE antibody recently approved for the treatment of severe allergic asthma. This drug inhibits allergic responses by binding to serum IgE, thus preventing interaction with cellular IgE receptors. Omalizumab is also capable of downregulating the expression of high affinity IgE receptors on inflammatory cells, as well as the numbers of eosinophils in both blood and induced sputum. The clinical effects of omalizumab include improvements in respiratory symptoms and quality of life, paralleled by a reduction of asthma exacerbations, emergency room visits, and use of systemic corticosteroids and rescue bronchodilators. Omalizumab is relatively well-tolerated, and only rarely induces anaphylactic reactions. Therefore, this drug represents a valid option as add-on therapy for patients with severe persistent allergic asthma inadequately controlled by high doses of standard inhaled treatments.