Treatment of childhood asthma with anti-immunoglobulin E antibody (omalizumab)

Anti-IgE and chemotherapy: a critical appraisal of treatment options for severe asthma

In this narrative review the scientific rationale for the development of a therapeutic modality for asthma based on decreasing the circulating and cell-bound levels of immunoglobulin-E (IgE) is outlined. The one drug that has so far entered clinical practice to do this is a humanised monoclonal antibody to the Fc portion of the IgE molecule, omalizumab. It is highly effective in reducing IgE blood levels and its established mode of delivery is by subcutaneous injection. The clinical trial development of omalizumab is reviewed and the published data and claims for its efficacy and role in clinical practice is critically appraised. The target group of omalizumab has become focused on severe asthmatics who are still symptomatic after being administered with high-dose inhaled corticosteroids plus long-acting beta-agonists. The strongest evidence for effect is in those with frequent severe exacerbations.

Does anti-IgE therapy help in asthma? Efficacy and controversies

Omalizumab, a humanized monoclonal antibody against IgE, is clinically efficacious when it neutralizes almost all free IgE and reduces IgE receptors on basophils and mast cells. Asthmatic subjects on inhaled corticosteroids who are treated with omalizumab as an add-on therapy experience only modest benefits in symptoms and perhaps in quality of life, but the most significant effects are reductions in airway inflammation and in exacerbation rate. Airway obstruction and hyperresponsiveness do not change significantly. Although the magnitude of the beneficial effects is small, they are observed even in the most severe cases, particularly the reduction in exacerbation rate. The safety profile of omalizumab is very encouraging, although phase IV studies are ongoing to clarify the incidence of neoplasias. Because of its cost, omalizumab therapy may be most cost-effective in patients with severe and refractory asthma, particularly those with frequent exacerbations requiring hospital care. Further clinical studies are now evaluating the best place for omalizumab in the algorithm of asthma management.

Tobacco as an allergen in bronchial disease

BACKGROUND

Skin testing and sera measurements have verified the existence of tobacco specific IgE. However, the few published studies on this matter report conflicting results concerning their clinical significance.

OBJECTIVE

To verify if a specific clinical allergenic response against tobacco might be possible in allergenic and nonallergenic bronchial diseases.

METHODS

We performed a cross-sectional observational case-control analysis on 180 patients with asthma, chronic obstructive pulmonary disease (COPD), and bronchial carcinoma and controls who were randomly chosen. Skin prick tests and serum specific IgE to tobacco and related allergens, bronchial challenge with cigarettes and tobacco extract, patch tests with tobacco and nicotine, sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting, and Enzyme AllergoSorbent Test (EAST) inhibition were performed.

RESULTS

Twenty-eight patients had positive tobacco skin prick test results. The association among positive skin prick test results, IgE, and bronchial challenge was strong (P < .001). Tobacco sensitivity was higher in patients with pollen asthma than in patients with COPD and carcinoma and negative in patients with intrinsic asthma and controls. A positive bronchial challenge result was related to the length of habit (P < .001) and the tobacco index in patients who had stopped smoking (P < .001). Delayed bronchial and patch response was more common in patients with COPD (P < .001). Tobacco IgE response (EAST) was related to sensitivity to Lolium perenne (rye grass) pollen (P < .001) but not to other vegetables that belong to the Solanaceae family. EAST inhibition showed cross-reactivity between tobacco and Lolium pollen.

CONCLUSIONS

Tobacco may be responsible for a specific IgE response. Patients with pollen asthma were those with more positive responses to tobacco due to cross-reactivity between Lolium and tobacco allergens.

Interleukin-16 Inhibits Immunoglobulin E Production by B Lymphocytes

BACKGROUND

The increased production of IgE is a hallmark of atopic disorders. CD4+ T cells regulate the production of Immunoglobulin (Ig) E by B cells. Interleukin (IL) 16, a CD4+ specific cytokine, is highly expressed at sites of allergic inflammation. Our aim was to determine the effect of IL-16 on IgE production in atopic subjects.

METHODS

Freshly isolated peripheral blood mononuclear cells (PBMC) from atopic subjects were stimulated with recombinant IL (rIL) 4 and anti-CD40 antibody to promote IgE production in the presence or absence of rIL-16 added at different time intervals prior to stimulation. The levels of IgE in cell culture supernatants collected at day 14 were measured by ELISA. The effect of IL-16 on the expression of the Cepsilon transcript was evaluated by reverse-transcription polymerase chain reaction. To evaluate whether the modulatory effect of IL-16 on IgE production was mediated by interferon-gamma (IFN-gamma), anti-CD40/IL-4-stimulated PBMC were cultured in the presence of rIL-16 and neutralizing concentrations of anti-IFN-gamma antibody.

RESULTS

PBMC stimulated with rIL-4 (400 U/ml) and anti-CD40 monoclonal antibody (0.5 microg/ml) produced significant amounts of IgE (range: 1.3-46.0 ng/ml). The addition of rIL-16 twenty-four hours before stimulation significantly reduced the levels of IgE released by anti-CD40/IL-4-stimulated PBMC (0.5-29.6 ng/ml, p < 0.05). IL-16 reduced the expression of the Cepsilon transcript in stimulated PBMC. IL-16 induced the expression of IFN-gamma mRNA. However, the use of anti-IFN-gamma antibody did not alter the effect of IL-16 on IgE production. Rescue doses of IL-13 did not restore the production of IgE by PBMC treated with IL-16. IL-16 did not alter IgE production in CD14-depleted cell preparations suggesting that the IL-16-mediated effects on IgE production may be related to CD14+ cells.

CONCLUSION

These data show that IL-16 inhibits IgE production and therefore may play an important regulatory role in atopic disorders.

Promise and pitfalls in animal-based asthma research: building a better mousetrap

Asthma is one of the leading chronic diseases in the world today. An essential component of the asthma research endeavor is the animal-based experimental disease system, which provides knowledge that is not attainable through study of patients alone. Animal research is especially valuable for elucidating pathophysiology, drug testing, and as an adjunct for interpreting the results of human clinical trials. However, controversies surrounding animal systems data and at the interface between animal and human studies raise questions regarding the true utility of experimental asthma research. We consider here the considerable promise and important limitations of animal-based systems and their prospects for the future study asthma.

Omalizumab is effective and safe in the treatment of Japanese cedar pollen-induced seasonal allergic rhinitis

BACKGROUND

Seasonal allergic rhinitis (SAR) induced by Japanese cedar pollen is a substantial problem in Japan. Omalizumab, a novel humanized monoclonal anti-immunoglobulin E (IgE) antibody, has already been proven to reduce symptoms associated with SAR. We investigated the safety and efficacy of omalizumab in the treatment of patients with Japanese cedar pollen-induced SAR compared to placebo.

METHODS

A randomized, placebo-controlled, double-blind study was conducted in 100 Japanese patients with a history of moderate-to-severe SAR induced by Japanese cedar pollens. Omalizumab (150, 225, 300, or 375mg) or placebo was administered subcutaneously every 2 or 4 weeks based on serum total IgE and body weight at baseline. The primary efficacy variable was the mean of daily nasal symptom medication scores (sum of the daily nasal symptom severity score and daily nasal rescue medication score) during the treatment period. Secondary efficacy variables included the daily ocular symptom medication score and related variables.

RESULTS

Primary and all secondary efficacy variable scores were significantly lower in the omalizumab group than in the placebo group (P < .01). Serum free IgE levels markedly decreased in the omalizumab group and were associated with clinical efficacy. The overall incidence of injection site reactions was higher in the omalizumab group than in the placebo group; however, the adverse reaction profile was similar between the two groups when excluding injection site reactions. No anti-omalizumab antibodies were detected.

CONCLUSIONS

Omalizumab was effective and safe in the treatment of SAR induced by Japanese cedar pollen.

Improvement of asthma control with omalizumab in 2 obese pediatric asthma patients

BACKGROUND

Dosing of the anti-IgE antibody (omalizumab) in the treatment of allergic asthma depends on serum IgE concentration and body weight. It is unclear whether omalizumab is therapeutically effective in obese patients with difficult-to-control asthma whose body weights fall outside dosing guidelines.

OBJECTIVE

To report the efficacy of omalizumab in 2 obese pediatric patients with severe persistent asthma whose high body weights placed them outside current dosing guidelines.

METHODS

Omalizumab was given at maximum doses to both patients. Standard asthma therapy was continued throughout the treatment period. Multiple parameters of asthma disease activity were followed at every health encounter for approximately 1 year during and before omalizumab treatment. These parameters included asthma disease severity and activity, pulmonary functions, daily inhaled corticosteroid requirements, systemic steroid rescue, and urgent care and emergency department visits and hospitalizations.

RESULTS

While receiving omalizumab, both patients had improvements in asthma disease activity and reduction in systemic steroid requirements. One patient required fewer daily inhaled corticosteroids and achieved total asthma control.

CONCLUSION

Patients with difficult-to-treat asthma may benefit from receiving omalizumab even if they fall outside current dosing guidelines because of high body weight.

Novel molecular therapy

Anti-inflammatory treatment, mainly with inhaled corticosteroids, is the cornerstone of asthma therapy. There are a number of new more specific therapies based on a molecular approach. Despite some promising results from some novel molecular therapies there are also some studies which have shown no effect of these treatments.

Immunoglobulin E: role in asthma and allergic disease: lessons from the clinic

The role of immunoglobulin E (IgE) in allergic asthmatic disease is well established. Allergen-specific IgE binds to its cognate receptors, thus triggering a series of cellular events. These events include presentation of antigen by dendritic cells and the degranulation of mast cells and basophils to release numerous factors that play an integral part in potentiating the disease symptoms. Studies in the mouse indicate that a reduction in IgE levels could lead to significant attenuation of the allergic inflammatory response associated with diseases such as asthma, making IgE a target for the development of new therapeutic agents. Omalizumab (Xolair), a recombinant humanised monoclonal anti-IgE antibody that blocks the interaction of IgE with its receptors, is the first anti-IgE agent to undergo clinical development. Several clinical studies have been performed in adults and children with moderate-to-severe allergic asthma to evaluate the efficacy and safety of this agent, but which have also enabled an insight into the role of IgE in human disease. IgE plays a significant role in a number of allergic conditions including allergic rhinitis and allergies to various substances. Recent data suggests that local IgE production may occur in mucosal tissues and that locally significant concentrations of IgE, not reflected by serum IgE concentrations, indicate that it may play a role in non-atopic as well as atopic disease.

Therapy with immunoglobulin: applications for monoclonal antibodies

The ability of antibodies to recognize specific antigenic targets and trigger responses from the immune system has made them attractive candidates as therapeutic agents. Monoclonal and recombinant technology have made possible the development of a new class of therapeutic and diagnostic agents that combine the exquisite specificity of antibodies with biologic compatibility and protracted half-lives. This technology is just beginning to be explored and considerable evolution may be expected in the next few decades.

Novel and emerging therapies for asthma

At present, there are a wide variety of novel and emerging therapeutic approaches for the treatment of asthma. Here, we will summarize these state-of-the-art approaches, including specific and nonspecific mediator inhibition-- a quest that has been on going for more than 25 years-- together with cytokine modulation in asthma (primarily attempting to modulate the Th2-Th1 balance in asthma), targeting cell recruitment, angiogenesis, signal transduction and gene transduction pathways. Finally, we will discuss the recently approved anti-IgE therapy for the treatment of allergic asthma and immune modulation using CpG oligodeoxynucleotides.

Biologic therapies for the treatment of asthma

Asthma is a chronic disease of the airway whose pathogenesis involves the complex interplay between many cell types and inflammatory mediators. The mainstays of therapy, inhaled bronchodilators and corticosteroids, do not target the asthmatic airway specifically and therefore are associated with untoward side effects. Anti-IgE (omalizumab) is the only biologic therapy to have transitioned completely from bench to bedside. Other candidate therapies, such as those that alter the T-helper 1/T-helper 2 cytokine balance, interfere with inflammatory cell trafficking, or modify normal intracellular signaling cascades involved in inflammatory gene transcription, have had only limited success in human clinical trials. This article describes several potential novel biologic therapies that have been or could be investigated.

Targets in allergy-directed immunotherapy

Allergic diseases such as asthma, atopic dermatitis, rhinitis and urticaria are immunological disorders affecting almost one third of the population in industrialised countries. Therapeutic or prophylactic approaches to turn around the increasing prevalence of these diseases have been intensively investigated. Allergen-specific immunotherapy has been applied in clinical practice for many decades, although varying results and occasional severe side effects have called for more effective and safer vaccines. Recent advances in our knowledge of immunological mechanisms have created several options to comply with these demands. This article will focus on some of the most promising new developments.

Potential adverse events with biologic response modifiers

In recent years, an explosion of biologic response modifiers has entered the market to combat a variety of immune-mediated diseases. These can be in the form of recombinant cytokines, as in the case of interferon beta in the treatment of multiple sclerosis, or novel engineered antibodies constructed by combining non-human determinants with a human immunoglobulin scaffold, as in the case of omalizumab in the treatment of allergic asthma. More recently, completely human monoclonal antibodies have also been constructed. Adverse reactions related to these agents can be classified as expected or unexpected events. A number of case studies and a handful of randomized trials have demonstrated the potential toxicities with the use of biologic response modifiers. This article aims to review adverse event profiles of select biologic response modifiers for which the most data is available and are common to a rheumatology, allergy/immunology, and dermatology patient population.

Asthma severity and atopy: how clear is the relationship?

BACKGROUND

The relationship between asthma severity and atopy is complex. Many studies have failed to show significant relationships between clinical severity or lung function and markers of atopic sensitisation.

AIM

To determine whether increasing asthma severity is related to atopic sensitisation in a population of children with asthma.

METHODS

A total of 400 children (7-18 years) with asthma were recruited as part of a multicentre study of the genetics of asthma. Detailed phenotypic data were collected on all participants. Associations between measures of asthma severity and atopic sensitisation were sought using multilevel models allowing variation at the individual and family level.

RESULTS

Children recruited to the study had a range of asthma severities, with just over a third having mild persistent asthma. The logarithm of total serum IgE was associated with increased asthma severity score, decreased FEV1, increased airways obstruction, risk of hospital admission, and inhaled steroid use. Increasing skin prick test reactivity to a panel of seven aeroallergens was associated with increased risk of hospital admission, use of an inhaled steroid, and airways obstruction. The results remained highly significant after corrections for age, gender, and birth order.

CONCLUSIONS

In children with asthma, increasing atopy is associated with increasing asthma severity. However, the relationships between asthma severity and skin prick tests, and asthma severity and total serum IgE values, appear subtly different.

Omalizumab : other indications and unanswered questions

Omalizumab, a recombinant humanized monoclonal antibody against immunoglobulin (Ig)E, represents a unique therapeutic approach for the treatment of allergic diseases. This agent acts as a neutralizing antibody by binding IgE at the same site as the high-affinity receptor. Subsequently, IgE is prevented from sensitizing cells bearing high-affinity receptors. Inhibition of the biological effects of IgE targets an early phase of the allergic cascade before the generation of allergic symptoms. Currently, omalizumab has been approved for the treatment of persistent allergic asthma in patients who are poorly controlled with inhaled corticosteroids. However, other allergic disorders may be amenable to treatment with omalizumab because of its ability to inhibit effector functions of IgE. Studies of omalizumab in the treatment of allergic rhinitis comprise the greater part of the literature pertaining to the use of this agent for clinical indications other than asthma. This article summarizes clinical trials of omalizumab in allergic rhinitis and examines the evidence regarding the effects of omalizumab on the pathophysiological mechanisms underlying allergic rhinitis. Additionally, we consider the role of this novel therapeutic agent in combination with specific allergen immunotherapy and discuss other potential indications for omalizumab in IgE-mediated disorders, including food allergy, latex allergy, atopic dermatitis, and chronic urticaria.

Omalizumab in asthma: approval and postapproval experience

Omalizumab is a humanized mouse monoclonal antibody that binds specifically to the constant region of the immunoglobulin (Ig)E heavy chain. Omalizumab exerts its effects by reducing free serum IgE levels and FcepsilonRI expression on several cell types. These effects have been shown to result in decreased airway inflammation and clinical improvement. In multiple studies, omalizumab has been shown to be efficacious in the treatment of moderate-to-severe persistent asthma and is currently approved by the US Food and Drug Administration for the treatment of moderate-to-severe allergic asthma in patients age 12 yr and older. Moreover, omalizumab has been demonstrated to be effective in the treatment of children and adults with seasonal and perennial allergic rhinitis. Postmarketing surveillance has shown omalizumab to be a relatively safe and well-tolerated medication.

Anti-IgE for chronic asthma in adults and children

BACKGROUND

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (anti-IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes.

OBJECTIVES

To determine the efficacy of anti-IgE compared with placebo in patients with allergic asthma

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register for potentially relevant studies (February 2006).

SELECTION CRITERIA

Randomised controlled trials examining anti-IgE administered in any manner for any duration. Trials with co-interventions were included as long as they were the same in each arm.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

Fourteen trials (15 group comparisons) were included in the review, contributing a total of 3143 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab significantly reduced free IgE compared with placebo. Omalizumab led to a significant reduction in inhaled steroid (ICS) consumption compared with placebo (-119 mcg/day (95% CI -154 to -83, three trials)). There were significant increases in the number of participants who were able to reduce ICS by over 50% (odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10 (four trials)); or completely withdraw their daily ICS intake (OR 2.50 (95%CI 2.00 to 3.13; four trials)). Participants treated with Omalizumab were less likely to suffer an asthma exacerbation with treatment as an adjunct to ICS (OR 0.52, 95%CI 0.41 to 0.65, five trials), or as an ICS tapering agent (OR 0.47, 95% CI 0.37 to 0.60, four trials).

AUTHORS' CONCLUSIONS

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids, but the clinical value of the reduction in steroid consumption has be considered in the light of the high cost of Omalizumab. The impressive placebo effects observed in control groups bring into question the true effect of Omalizumab. Omalizumab was effective in reducing asthma exacerbations as an adjunctive therapy to inhaled steroids, and during steroid tapering phases of clinical trials. Omalizumab was generally well tolerated, although there were more injection site reactions with Omalizumab. Patient and physician assessments of the drug were positive. Further assessment in paediatric populations is necessary, as is direct double-dummy comparison with ICS.

Impact of omalizumab on quality-of-life outcomes in patients with moderate-to-severe allergic asthma

BACKGROUND

Moderate-to-severe allergic asthma has a substantial impact on patients' quality of life (QOL). Despite care consistent with treatment guidelines, many patients with moderate-to-severe asthma still experience variability in asthma control, signaling an unmet need within this population. Omalizumab has recently demonstrated clinical efficacy and safety in treating IgE-mediated asthma.

OBJECTIVE

To summarize asthma-related QOL outcomes associated with omalizumab therapy in moderate-to-severe allergic asthma.

METHODS

A systematic review and meta-analysis of asthma-related QOL on data from published clinical trials and unpublished clinical study reports were conducted on omalizumab. The Juniper Asthma Quality of Life Questionnaire (AQLQ) measured asthma-related QOL.

RESULTS

Statistically significant results for asthma-related QOL end points consistently favored omalizumab over placebo. Moderate to large effect sizes in the omalizumab groups were observed across the clinical trials and during study extension phases. A meta-analysis indicated a 1.6- to 2-fold increase in moderate (> or = 1 point) and a 1.8- to 2.1-fold increase in large (> or = 1.5 point) improvements in AQLQ overall scores in the omalizumab-treated group compared with placebo during the steroid-stabilization and steroid-reduction phases of the trials.

CONCLUSIONS

Significant differences and large effect sizes favoring omalizumab were observed despite the control group receiving active, guideline-consistent treatment. The meta-analysis findings demonstrate that omalizumab treatment provides QOL benefits in patients with moderate-to-severe allergic asthma.

Role of anti-IgE monoclonal antibody (omalizumab) in the treatment of bronchial asthma and allergic respiratory diseases

IgE molecules play a crucial role in allergic respiratory diseases and may cause chronic airway inflammation in asthma through activation of effector cells via high-affinity (FcepsilonRI) or low-affinity (FcepsilonRII) IgE receptors. Since the discovery of IgE antibodies our understanding of the mechanisms of allergy has improved to such an extent that we can differentiate allergic/atopic from intrinsic respiratory diseases. Therapeutic anti-IgE antibodies, able to reduce free IgE levels and to block the binding of IgE to FcepsilonRI without crosslinking IgE and triggering degranulation of IgE-sensitized cells have been developed. This non-anaphylactogenic anti-IgE monoclonal antibody (omalizumab) binds IgE at the same site as these antibodies bind FcepsilonRI and FcepsilonRII. Consequently, omalizumab inhibits IgE effector functions by blocking IgE binding to high-affinity receptors on IgE effector cells and does not cause mast cell or basophil activation because it cannot bind to IgE on cell surfaces where the FcepsilonR1 receptor already masks the anti-IgE epitope. Studies in patients with atopic asthma showed that omalizumab decreases serum IgE levels and allergen-induced bronchoconstriction during both the early and late-phase responses to inhaled allergen. In several clinical controlled trials omalizumab resulted effective in reducing asthma-related symptoms, decreasing corticosteroid use and improving quality of life of asthmatic patients. Recent studies show the benefits of omalizumab as add-on therapy in patients with severe persistent asthma who are inadequately controlled by optimal pharmacological therapy. The anti-IgE approach to asthma treatment has several advantages, including concomitant treatment of other IgE-mediated diseases such as allergic rhinitis, a favorable safety profile and a convenient dosing frequency.

Childhood asthma: breakthroughs and challenges

As we move forward, our goal is to control and eliminate asthma and other allergic disorders. This may come through broadly applied manipulation of environmental, dietary, and infectious risk factors, possibly during the perinatal period. Or we may learn to identify genetically susceptible children and to intervene with individualized genotype-specific treatment before the onset of disease. Maybe we'll learn how to block the mechanisms that give rise to chronic inflammation, or how to subdue Th2 activation. However, as the Swedish proverb says--Don't throw away the old bucket until you know whether the new one holds water. To continue using the old bucket, we have to fix the leaks. One approach to reducing asthma disparities is through traditional disease prevention stages. Primary prevention targets asthma incidence; secondary prevention mitigates established disease and involves disease detection, management, and control; and tertiary prevention is the reduction of complications caused by severe disease. Once causative factors at each level of disease prevention are understood, this knowledge can be translated into clinical practice and public health policy. We need reliable diagnostic criteria to provide correct treatment for infants and toddlers. This will require longitudinal cohort studies supported by assessment of pulmonary function and inflammatory markers. We must find ways to convince more physicians to embrace controller therapy for more severe disease, and to identify the patients with less severe disease who also require ongoing controller therapy. We need to close the gap between what we know and what we do in practice. We need to link basic research to healthcare delivery, and to gain acceptance and support from the intended recipients of new interventions. We need better strategies for improving adherence. We need accountability, foresight, and imagination.

Effect of omalizumab on adenosine 5'-monophosphate responsiveness in subjects with allergic asthma

BACKGROUND

The objective of this study was to evaluate the effects of omalizumab on bronchoconstriction induced by methacholine and adenosine 5'-monophosphate (AMP).

METHODS

Thirty-four subjects with mild to moderate allergic asthma were randomized to receive placebo (n = 16) or omalizumab (n = 18) subcutaneously during 12 weeks. Airway responsiveness to AMP was measured at baseline and after 4 and 12 weeks of treatment, whereas the response to methacholine was measured at baseline and after 12 weeks of treatment.

RESULTS

After 4 weeks of treatment, the increase in AMP PC(20) (provocative concentration required to produce a 20% fall in FEV(1)) was significantly greater in the omalizumab group than in the placebo group, the mean difference in the change between the groups being 1.52 doubling concentrations (95% CI, 0.25-2.79, p = 0.02). Compared with baseline, the mean AMP PC(20) values at 12 weeks were increased by 1.91 doubling concentrations with omalizumab (p < 0.001) and 1.01 doubling concentrations with placebo (p = 0.16), but changes were not significantly different between the treatment groups. Changes in methacholine PC(20) values were not significantly different between the omalizumab and placebo groups.

CONCLUSIONS

In subjects with allergic asthma, omalizumab reduces the response to AMP without decreasing the response to methacholine. These findings are consistent with the conclusion that the contribution of IgE to the development of AMP bronchoconstriction is more important than their role in the induction of methacholine hyperresponsiveness.

Effects of omalizumab and budesonide on markers of inflammation in human bronchial epithelial cells

BACKGROUND

Many patients with asthma have an IgE-mediated allergic component to the disease. Omalizumab, a monoclonal anti-IgE antibody, has demonstrated clinical efficacy in patients with allergic asthma. The effects of omalizumab on inflammation in asthma are not completely understood.

OBJECTIVES

To evaluate the effects of omalizumab on allergen- and growth factor-stimulated proinflammatory cytokine and nitric oxide (NO) production in human bronchial epithelial cells (BECs) and to compare them to the effects of budesonide, a corticosteroid with known anti-inflammatory properties.

METHODS

Human BECs were stimulated in duplicate with interleukin 1beta (IL-1beta), 100 U/mL; ragweed, 10 microg/mL; dust mite, 1000 AU; and epithelial growth factor, 40 ng/mL; and either 10(-7) M budesonide or 0.1 microg/mL of omalizumab in a 4% dust mite atopic serum medium for 6 and 24 hours in 5% carbon dioxide at 37 degrees C. Tumor necrosis factor alpha and transforming growth factor betaexpression and production and IL-4, IL-13, and NO production were assayed using gene-specific messenger RNA or sensitive enzyme-linked immunosorbent assays.

RESULTS

Omalizumab inhibited the expression and of production proinflammatory cytokines and growth factor in antigen-stimulated BECs at 6 and 24 hours. Production of NO was inhibited at 6 hours and increased at 24 hours by omalizumab and budesonide.

CONCLUSIONS

The effects of omalizumab were similar to those of budesonide. These results, consistent with previously reported evidence of anti-inflammatory effects of omalizumab, demonstrate that omalizumab may reduce airway inflammation and probably contributes to decreased airway remodeling in patients with asthma.

Immunotherapy: first do no harm

Immunotherapy continues to be a treatment modality that is used most exclusively by allergists. The acceptance of immunotherapy for treating children with allergic rhinitis or asthma has been limited by the lack of adequate numbers of pediatric double-blind, placebo-controlled trials of specific allergen immunotherapy; use of venom immunotherapy is more clearly supported by current data. Children represent a unique group of patients where allergic disease may not only be treated using immunotherapy resulting in reduction of symptoms, signs, and complications of disease, but may also hold the best potential for the evasive goal of prevention of the development of future allergic disease.

Allergens in the pathogenesis of asthma: potential role of anti-immunoglobulin E therapy

Evidence suggests that allergy is a significant triggering factor in asthma in children and adults alike. In immunoglobulin (Ig) E-mediated allergic reactions, sensitization occurs when allergen-specific B cells are stimulated and switched to IgE antibody production by interleukin (IL)-4 and IL-13 provided by helper T cells type 2 (Th2). The IgE antibodies act by arming cells bearing either the high-affinity (FcepsilonRI) or low-affinity (FcepsilonRII or CD23) receptor. The subsequent interaction of allergen with IgE-FcepsilonRI complexes on mast cells and basophils causes cross-linking of receptors that triggers the release of a variety of inflammatory mediators, cytokines and chemokines. Therefore, the ability to lower circulating free IgE levels is desirable because most individuals are exposed to multiple allergens to which they are sensitive at any given time. Omalizumab (formerly known as rhuMAb-E25) is a recently developed humanized monoclonal anti-IgE antibody directed at the FcepsilonRI binding domain of human IgE. It inhibits binding of IgE to mast cells without provoking mast cell activation. Preliminary clinical data from randomized controlled trials have shown that the addition of omalizumab to standard asthma therapy reduces asthma exacerbations and decreases inhaled corticosteroid and rescue medication use. The compound is also well tolerated. Omalizumab represents a novel therapeutic approach in the management of asthma.

Targeting immunoglobulin E as a novel treatment for asthma

Omalizumab is a recently developed monoclonal anti-IgE antibody. Clinical trials have demonstrated its efficacy in patients with moderate-to-severe and severe or poorly controlled allergic asthma, in patients with seasonal and perennial allergic disease, and in subjects with concomitant asthma and allergic rhinitis. Patients with more severe asthma appear to obtain the greatest benefit from omalizumab therapy. Omalizumab is well tolerated and has a good safety profile. Anti-inflammatory activity has been shown in both allergic asthma and allergic rhinitis. These results confirm the importance of IgE in allergic disease and support the rationale behind the development of a therapeutic anti-IgE antibody. Omalizumab is a significant addition to current asthma treatments and shows great promise as a therapy for allergic rhinitis, in particular for those patients with concomitant allergic disease.

Anti-IgE antibodies for the treatment of asthma

PURPOSE OF REVIEW

Allergic asthma is a hypersensitivity reaction initiated by immunologic mechanisms mediated by IgE antibodies. IgE plays a central role in the initiation and propagation of the inflammatory cascade and thus the allergic response. Targeting factors involved in the allergic response, such as IgE, is a novel strategy for new therapies. Attenuating allergic disease by specifically inhibiting IgE and the development of the monoclonal anti-IgE antibody, omalizumab, were major breakthroughs in asthma management.

RECENT FINDINGS

Several studies have shown that omalizumab has significant anti-inflammatory effects and that it may act on multiple components of the inflammatory cascade. Specific binding of IgE by omalizumab reduces both the early allergic response and the late allergic response and symptoms of IgE-mediated allergy. The long-term clinical efficacy of omalizumab has been demonstrated along with improvements in quality of life. As add-on therapy in severe asthma, omalizumab reduces the requirement for inhaled corticosteroids and improves disease control. Clinical studies have shown that the patients who benefit most from omalizumab therapy are those at high risk of exacerbations, those with poorly controlled and/or severe asthma, and those with IgE-mediated comorbidities.

SUMMARY

Omalizumab is a significant addition to current asthma treatments and shows great promise as a therapy for allergic asthma and for patients with concomitant allergic rhinitis. This is particularly true for difficult-to-treat patients with moderate to severe allergic asthma who have poorly controlled disease on conventional therapies, experience severe adverse effects secondary to high-dose or prolonged corticosteroid treatment, have frequent exacerbations, and/or are at high risk of hospitalization. Future studies will continue to investigate the anti-inflammatory mechanisms of anti-IgE therapy. Because many of these mechanisms are common to all IgE-mediated allergic diseases, the efficacy of omalizumab in other allergic diseases should be further explored.

Anti-immunoglobulin E treatment with omalizumab in allergic diseases: an update on anti-inflammatory activity and clinical efficacy

Omalizumab is a humanized monoclonal anti-IgE antibody developed for the treatment of allergic disease, with established efficacy in patients with moderate-to-severe allergic asthma and in patients with intermittent (seasonal) and persistent (perennial) allergic rhinitis (AR). Omalizumab is known to result in a marked reduction in serum levels of free IgE and down-regulation of IgE receptors on circulating basophils. Recent work has shed further light on its mechanism of action, showing significant and profound reductions in tissue (nasal and bronchial) eosinophils and in bronchial IgE+ cells (mast cells), as well as T cells and B cells. Omalizumab treatment was also shown to be associated with down-regulation of IgE receptors on circulating (precursor) dendritic cells, suggesting that blocking IgE may inhibit more chronic aspects of allergic inflammation involving T cell activation. Further work with omalizumab demonstrated it to have important benefits in patients with poorly controlled asthma despite high-dose inhaled corticosteroid therapy, and analysis of clinical data suggests that the patients who are the best 'responders' to anti-IgE treatment are those with asthma at the more severe end of the spectrum. Notably, systemic anti-IgE therapy with omalizumab has been shown to improve symptoms, quality of life and disease control (asthma exacerbations) in patients with concomitant asthma and persistent AR. These impressive clinical data and the studies elucidating the anti-inflammatory profile of omalizumab also serve to emphasize the fundamental importance of IgE in the pathogenesis of allergic diseases.

The effect of treatment with omalizumab, an anti-IgE antibody, on asthma exacerbations and emergency medical visits in patients with severe persistent asthma

BACKGROUND

Patients with severe persistent asthma who are inadequately controlled despite treatment according to current asthma management guidelines have a significant unmet medical need. Such patients are at high risk of serious exacerbations and asthma-related mortality.

METHODS

Here, we pooled data from seven studies to determine the effect of omalizumab, an anti-immunoglobulin E (IgE) monoclonal antibody, on asthma exacerbations in patients with severe persistent asthma. Omalizumab was added to current asthma therapy and compared with placebo (in five double-blind studies) or with current asthma therapy alone (in two open-label studies). The studies included 4308 patients (2511 treated with omalizumab), 93% of whom had severe persistent asthma according to the Global Initiative for Asthma (GINA) 2002 classification. Using the Poisson regression model, results were calculated as the ratio of treatment effect (omalizumab : control) on the standardized exacerbation rate per year.

RESULTS

Omalizumab significantly reduced the rate of asthma exacerbations by 38% (P < 0.0001 vs control) and the rate of total emergency visits by 47% (P < 0.0001 vs control). Analysis of demographic subgroups showed that the efficacy of omalizumab on asthma exacerbations was unaffected by patient age, gender, baseline serum IgE (split by median) or by 2- or 4-weekly dosing schedule, although benefit in absolute terms appeared to be greatest in patients with more severe asthma, defined by a lower value of percentage predicted forced expiratory volume in 1 s (FEV(1)) at baseline.

CONCLUSIONS

These results suggest that omalizumab may fulfil an important need in patients with severe persistent asthma, many of whom are not adequately controlled on current therapy.

[Asthma treatment in childhood: from guidelines to practice]

Aims for the management of asthma in children are to optimize quality of life and to maintain normal lung functions. International guidelines recommend rapid-acting inhaled beta2-agonist as needed in children with intermittent asthma. Once asthma is persistent, mild, moderate or severe, daily long-term therapy with inhaled corticosteroids should be started. Association with long-acting inhaled beta2-agonist or leukotriene inhibitors are required in children not enough controlled with inhaled corticosteroids alone. Management of the asthmatic child should not be restricted to antiasthmatic drug prescription but should include patient and patient's family education as well as adequate health of life.

Anti-IgE therapy

IgE has a central role in the initiation of allergic hypersensitivity reactions. Pioneered by the development of humanized monoclonal antibodies directed against IgE, anti-IgE therapy represents an original approach to the treatment of allergic disease and has demonstrated promise in preventing the symptoms of asthma, allergic rhinitis, and food allergy. The primary mechanism of action of anti-IgE therapy is the reduction in serum levels of IgE and FcepsilonRI expression on mast cells and basophils.

Anti-IgE therapy in allergic disease

PURPOSE OF REVIEW

Recombinant monoclonal humanized anti-IgE has put forward a fundamentally new concept for the control of allergic disorders. This review will present recent data from clinical studies with anti-IgE in asthma, allergic rhinitis, and food allergy and will examine the place of anti-IgE among current therapeutic options for the treatment of asthma.

RECENT FINDINGS

Therapy with anti-IgE depresses circulating free IgE to the limits of detection, inhibits early- and late-phase responses to allergens, suppresses inflammation and improves the control of allergic diseases. In moderate to severe asthma it results in fewer exacerbations and a lower requirement for both corticosteroids and beta-agonists. IgE appears to be an important regulator of high-affinity Fc receptors (FcepsilonRI) and, in the mouse, to enhance mast cell survival and activation. IgE receptors have been found on diverse inflammatory cells. Anti-IgE reduces the expression of FcepsilonRI on inflammatory cells. Current work has documented a marked decrease in tissue eosinophils, lymphocytes, and interleukin-4-positive cells by anti-IgE treatment and has provided insight into the mechanisms underlying improved control of asthma.

SUMMARY

Clinical studies with anti-IgE have promoted and will continue to advance the understanding of IgE-mediated disease mechanisms. They have documented its efficacy in the treatment of allergic diseases, but much remains to be learned about the most effective clinical strategies and the selection of patients for therapy.

Effect of anti-immunoglobulin E on nasal inflammation in patients with seasonal allergic rhinoconjunctivitis

BACKGROUND

Binding of allergens to IgE on mast cells and basophils causes release of inflammatory mediators in nasal secretions.

OBJECTIVE

The combined effect of specific immunotherapy (SIT) and omalizumab, a humanized monoclonal anti-IgE antibody, on release of eosinophilic cationic protein (ECP), tryptase, IL-6, and IL-8 in nasal secretion was evaluated.

METHODS

Two hundred and twenty five children (aged 6-17 years) with a history of seasonal allergic rhinoconjunctivitis induced by birch and grass pollen were randomized into four groups: either birch- or grass-pollen SIT in combination with either anti-IgE or placebo. Complete sets of nasal secretion samples before treatment Visit 1 (V1), during birch- (V2) and grass (V3)-pollen season and after the pollen season (V4) were collected from 53 patients.

RESULTS

A significant reduction in tryptase only was seen in the anti-IgE-treated group at V2 (P<0.05) and V4 (P<0.05) compared with the placebo group. During the pollen season, patients with placebo showed an increase of ECP compared with baseline (V2: +30.3 microg/L; V3: +134.2 microg/L, P< 0.005; V4: +79.0 microg/L, P< 0.05), and stable levels of tryptase, IL-6 and IL-8. Treatment with anti-IgE resulted in stable ECP values and a significant decrease of tryptase compared with V1 (baseline): V2: -80.0 microg/L (P< 0.05); V3: -56.3 microg/L, which persisted after the pollen season with V4: -71.6 microg/L (P< 0.05). After the pollen season, a decrease of IL-6 was observed in both groups (V4 placebo group: -37.5 ng/L; V4 anti-IgE group: -42.9 ng/L, P< 0.01).

CONCLUSION

The combination of SIT and anti-IgE is associated with prevention of nasal ECP increase and decreased tryptase levels in nasal secretions.

Effects of omalizumab, a humanized monoclonal anti-IgE antibody, on nasal reactivity to allergen and local IgE synthesis

BACKGROUND

Treatment with omalizumab has been shown to reduce serum free IgE concentrations and to have beneficial effects on allergic airway disease. However, its effect on IgE synthesis is unknown.

OBJECTIVE

To determine whether omalizumab therapy affects nasal reactivity to allergen and local IgE production.

METHODS

Nineteen patients with perennial allergic rhinitis were treated with intravenous omalizumab every 2 weeks for 26 weeks in an open-label study. Serum free and total IgE concentrations were measured at baseline and every 2 weeks throughout the study. Nasal challenge to dust mite allergen was performed at baseline and after 12 and 24 weeks of treatment. Nasal lavage fluid obtained before and after each nasal challenge was evaluated for mite-specific antibodies, plaque-forming cells, and productive epsilon messenger RNA (mRNA).

RESULTS

During treatment, serum free IgE concentrations were decreased by 97% to 99%, and the nasal response to allergen challenge was significantly reduced on days 80 and 164. The postchallenge increase in nasal lavage mite specific IgE was significantly reduced by treatment with omalizumab on day 168. IgE plaque-forming cells and productive epsilon mRNA were not significantly affected by omalizumab treatment.

CONCLUSIONS

Omalizumab treatment markedly reduced serum free IgE and the clinical response to nasal allergen challenge. However, the absence of an effect on IgE-secreting B cells and epsilon mRNA in nasal lavage fluid suggests that omalizumab treatment for 6 months does not significantly modulate synthesis of nasal IgE.

Cost-effectiveness analysis of omalizumab in adults and adolescents with moderate-to-severe allergic asthma

BACKGROUND

Omalizumab can reduce hospitalization and emergency department visits and improve quality of life in patients with moderate-to-severe, suboptimally controlled allergic asthma. Given the high cost and modest efficacy of this agent, it is not clear that it is cost-effective if given to a broad population with asthma.

OBJECTIVE

The purpose of this study was to evaluate the cost-effectiveness of omalizumab in adults and adolescents with moderate-to-severe allergic asthma.

METHODS

A retrospective economic analysis was performed to determine the cost-effectiveness of omalizumab using 52-week data from 2 randomized controlled clinical trials in adults and adolescents with moderate-to-severe allergic asthma. The analysis was conducted from a third-party payer's perspective, and only direct costs were considered.

RESULTS

The incremental cost-effectiveness ratios showed that the cost to achieve an additional successfully controlled day was $523, and the daily cost to achieve at least a 0.5-point increase in Asthma Quality of Life Questionnaire score was $378 in 2003 dollars.

CONCLUSION

From a pharmacoeconomic standpoint, omalizumab would be better used in allergic asthmatic patients with poorly controlled symptoms despite maximal therapy, given the high cost and modest efficacy of this agent. It could be cost saving if given to nonsmoking patients who are hospitalized 5 or more times or 20 days or longer per year despite maximal asthma therapy.

Is there a role for anti-IgE in combination with specific allergen immunotherapy?

PURPOSE OF REVIEW

A line of novel therapeutic approaches that try to interfere more specifically with the immunological mechanisms underlying allergen-induced pathology are currently undergoing clinical evaluation. The most advanced of these is anti-IgE, which directly targets IgE serum antibodies, thus inhibiting the central mechanism of immediate type hypersensitivity reactions. In addition, a lot of interest has recently been focused on allergen-specific immunotherapy due to its potential to cure allergic diseases. In the present review, state-of-the-art treatment of allergic diseases with anti-IgE and allergen-specific immunotherapy is summarized, and the potential of combination therapy with both treatment options is discussed.

RECENT FINDINGS

Application of anti-IgE antibodies effectively reduces IgE serum levels regardless of allergen specificity. This treatment has been successfully tested in patients with allergic rhinitis, asthma and food allergy, showing significant efficacy in reducing symptom scores and rescue medication use. Anti-IgE therapy is limited by high costs and the necessity for permanent or every-season treatment. The strongest argument in favor of allergen-specific immunotherapy is the potential to cure allergic diseases, which has been demonstrated in patients with allergic rhinitis, insect venom allergy and, to a lesser degree, asthma. The broader application of allergen-specific immunotherapy is restricted by sometimes life-threatening side effects. A combination of anti-IgE and allergen-specific immunotherapy was shown to be superior to each single treatment protocol in children and adolescents with allergic rhinitis, as demonstrated by efficacy of symptom scores and rescue medication use.

SUMMARY

There are strong arguments for a combination of anti-IgE plus allergen-specific immunotherapy for treatment of allergic diseases: improved efficacy, limited side effects, and potential curative effects.

Efficacy and safety of a recombinant anti-immunoglobulin E antibody (omalizumab) in severe allergic asthma

BACKGROUND

Patients with severe asthma are often inadequately controlled on existing anti-asthma therapy, constituting an unmet clinical need.

OBJECTIVE

This randomized, double-blind, placebo-controlled trial evaluated the ability of omalizumab, a humanized monoclonal anti-IgE antibody, to improve disease control sufficiently to enable inhaled corticosteroid reduction in patients with severe allergic asthma.

METHODS

After a run-in period when an optimized fluticasone dose (> or =1000 microg/day) was received for 4 weeks, patients were randomized to receive subcutaneous omalizumab [minimum 0.016 mg/kg/IgE (IU/mL) per 4 weeks; n=126] or matching placebo (n=120) at intervals of 2 or 4 weeks. The study comprised a 16-week add-on phase of treatment followed by a 16-week fluticasone-reduction phase. Short-/long-acting beta(2)-agonists were allowed as needed.

RESULTS

Median reductions in fluticasone dose were significantly greater with omalizumab than placebo: 60% vs. 50% (P=0.003). Some 73.8% and 50.8% of patients, respectively, achieved a > or =50% dose reduction (P=0.001). Fluticasone dose reduction to < or =500 microg/day occurred in 60.3% of omalizumab recipients vs. 45.8% of placebo-treated patients (P=0.026). Through both phases, omalizumab reduced rescue medication requirements, improved asthma symptoms and asthma-related quality of life compared to placebo.

CONCLUSION

Omalizumab treatment improves asthma control in severely allergic asthmatics, reducing inhaled corticosteroid requirements without worsening of symptom control or increase in rescue medication use.

Anti-IgE monoclonal antibody, omalizumab: a new treatment for allergic asthma

Omalizumab (Xolair Genentech, USA/Tanox, Inc., USA/Novartis Pharma AG, Switzerland) - a humanised antibody to IgE that reduces circulating free IgE - has been developed for the treatment of allergic asthma. It inhibits the early- and late-phase response to allergens, suppresses eosinophilic and T cell inflammation in asthmatic airways and reduces the levels of high-affinity IgE receptors on basophils. In clinical trials of moderate-to-severe asthma, omalizumab allowed a reduction in inhaled corticosteroid dosage while improving peak flows and reducing exacerbations, particularly in patients at high-risk of serious asthma-related morbidity and improved quality of life scores. When added to existing therapies of patients with more severe asthma, omalizumab also improved asthma control. Additionally, in asthma patients with concomitant perennial allergic rhinitis, omalizumab provides improvement in these comorbid conditions. Omalizumab is well-tolerated by asthma patients and represents a new approach to the treatment of the moderate-to-severe asthmatic patient. It is likely that it will first be used at the more severe end of the asthmatic diathesis.