The anti-IgE antibody omalizumab reduces exacerbations and steroid requirement in allergic asthmatics

Identifying the child in need of asthma therapy

Based on the results of the long-term CAMP clinical trial in childhood asthma, the benefits of continuous long-term use of inhaled glucocorticoid on asthma control are clear. Studies are in progress to evaluate whether early intervention with inhaled glucocorticoids can alter the natural history of asthma. Indicators are now being defined to identify the patient at risk for persistent asthma and thus to identify candidates for early intervention. Given the right medication and the patient profile, it may be possible to induce remission or even a cure. Patients with severe asthma have low pulmonary function that is difficult to improve, however. It will be important to recognize patients at risk for severe asthma and to intervene more effectively to prevent asthma progression. None of these advances will be possible without a comprehensive approach to asthma care including the ready access to health care. Although it seems that the rise in asthma mortality and morbidity has reached a plateau, there are significant racial and ethic disparities in asthma health care use and mortality. The goal should now be to strive for a reduction in asthma morbidity and mortality. A high proportion of asthma morbidity among inner-city children may be related to nonadherence; therefore targeting management approaches to improve adherence could prove effective in reducing morbidity. Recommendations have been made to integrate available resources in the United States to improve overall asthma outcomes for children.

Immunological and clinical changes in allergic asthmatics following treatment with omalizumab

IgE plays a key role in allergic asthma. We investigated whether omalizumab treatment of patients with moderate to severe allergic asthma leads to changes in inflammatory mediators and clinical symptoms. This sub-study was conducted on 35 patients with a positive skin prick test (SPT) requiring daily administration of beclomethasone dipropionate (500-1,000 microg), who participated in a multicentre, randomised, double-blind, placebo-controlled study. Omalizumab or placebo was administered at 0.016 mg/kg/IgE every 4 weeks. Patients recorded peak expiratory flow, asthma symptom score and beta(2)-agonist use in daily diaries and spirometry was performed at each visit. beta(2)-Agonist use and SPT wheal reaction decreased significantly (p < 0.05). Circulating levels of IL-5, IL-6, IL-8, IL-10, IL-13 and s-ICAM were measured before and after 16 weeks of treatment. IL-13 and s-ICAM were measured before and after 16 weeks of treatment. IL-13 decreased significantly (p < 0.01). IL-5 and IL-8 decreased in the omalizumab group compared to baseline. The other circulating mediators did not demonstrate any changes. Histamine release was significantly reduced (p < 0.01). Airway resistance (p < 0.05) and the provocative concentration inducing a 20% decrease in FEV(1) (p < 0.05) were measured before, after 16 weeks, and 3 months after completion of treatment. Both parameters decreased significantly (p < 0.05). Peripheral eosinophil count decreased significantly compared to placebo (p < 0.01). These findings suggest that omalizumab has potential as a novel treatment for allergic asthma.

Management of asthma in adults: current therapy and future directions

Asthma is increasing in prevalence worldwide and results in significant use of healthcare resources. Although most patients with asthma can be adequately treated with inhaled corticosteroids, an important number of patients require additional therapy and an increasing number of options are available. A further minority of patients develop severe persistent asthma which remains difficult to manage despite current pharmacological therapies. This review discusses the various treatment options currently available for each stage of asthma severity, highlights some of the limitations of current management, and outlines directions which may improve the management of asthma in the future.

Anti-immunoglobulin E therapy for asthma

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 humanized 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. Treatment with omalizumab was well tolerated and showed clinical benefit in terms of a reduction in the frequency and number of asthma exacerbation episodes and lower usage of corticosteroids and other medications to control disease, along with improved quality of life. Such findings indicate that omalizumab represents a promising new treatment option for allergic asthma.

Omalizumab (Xolair) improves quality of life in adult patients with allergic asthma: a review

Physicians are increasingly aware that asthma causes significant impairment of the patients physical, psychological, and social well-being. Whilst standard clinical endpoints provide significant information on airway status during treatment, it is important to determine whether such improvements overcome the functional impairment that patients have to deal with on a daily basis. As such, assessment of health-related quality of life (QoL) is an important aspect of asthma management in clinical practice. Omalizumab (Xolair) is a recombinant humanized monoclonal anti-immunoglobulin E (IgE) antibody that represents a new therapeutic approach to IgE-mediated diseases such as allergic asthma. Clinical studies show that omalizumab improves the control of allergic asthma whilst reducing steroid consumption, and enhances long-term disease control in patients with recurrent symptoms. Using established and validated QoL methodology, two placebo-controlled clinical studies in adults with moderate-to-severe allergic asthma have shown that patients treated with omalizumab experience a clinically relevant improvement in all aspects of their asthma-related QoL, changes that were significantly superior to those observed for placebo. Such improvements were apparent when omalizumab was added to existing therapy with inhaled corticosteroids, and maintained during a subsequent steroid-reduction phase. Through effective disease control, omalizumab therefore leads to significant improvements in health-related QoL that are meaningful to patients with allergic asthma.

Is there a role for treatment of asthma with omalizumab?

The allergic response is distinct from other immune reactions in its reliance on IgE, its high affinity receptor, Fc epsilon RI, and the primary effector cell--the tissue mast cell. Positive skin tests or raised concentrations of specific immunoglobulin E (IgE) in the serum define IgE sensitisation or "atopy". IgE participates both in immediate hypersensitivity response and in the induction of chronic allergic inflammation. It enhances allergen capture and Th2 cell activation, and may trigger other immunoregulatory pathways. Considerable effort in therapeutic research has focused on interference with IgE function because of its position high in the allergic cascade. Therapy with anti-IgE is one such approach that shows much promise.

Pharmacodynamics of omalizumab: implications for optimised dosing strategies and clinical efficacy in the treatment of allergic asthma

OBJECTIVE

Omalizumab (Xolair), is a recombinant humanised monoclonal anti-immunoglobulin E (IgE) antibody, for the treatment of allergic asthma. This review describes how the correlation between clinical outcomes and a suitable surrogate marker (free serum IgE) led to the development of an individualised dosing strategy for omalizumab. It also demonstrates how subsequent studies using this dosing strategy were able to achieve low levels of IgE and clinical benefit.

DATA SOURCES

Published articles and data on file (Novartis Pharma AG, Genentech).

RESULTS

Studies in patients with IgE-mediated diseases of the airways have shown that clinical benefit with omalizumab is observed when free IgE levels in serum are reduced to 50 ng/ml (20.8 IU/ml) or less (target 25 ng/ml (10.4 IU/ml)). The ability of omalizumab to reduce free IgE levels to such levels is dependent on dose, the patient's weight and baseline IgE level. To simplify dosing, and ensure that free IgE reduction is achieved, an individualised tiered dosing table was developed from which patients with asthma, depending on weight and starting IgE level, receive omalizumab 150-375 mg by subcutaneous injection every 2 or 4 weeks. This dosing strategy has proved clinically efficacious for improving disease control in patients with allergic asthma, as shown by significantly lower exacerbation rates and decreased dependence on treatment with inhaled corticosteroids, along with improvements in symptoms, lung function and usage of rescue bronchodilators.

CONCLUSIONS

The clinical efficacy of omalizumab has been optimised through the development of an individualised dosing table that emerged from an understanding of the pharmacodynamics of this agent.

[The high-affinity IgE receptor: lessons from structural analysis]

The high affinity receptor for IgE, FcERI, is at the core of the allergic reaction. This receptor is expressed mainly on mast cells and basophils. Interaction of an allergen with its specific IgE bound to FcERI triggers cell activation, which induces the release of numerous mediators that are responsible for allergic manifestations. The recent increase in the prevalence of allergic diseases in developed countries has resulted in renewed efforts towards the development of new drugs. One of these is a humanised antibody directed against the IgE ligand. This antibody recognises specifically free but not FcERI-bound IgE thus preventing ligand binding and subsequent cell activation. This antibody has shown some efficacy in clinical trials involving patients with asthma and allergic rhinitis. The recent elucidation of the tridimensional structure of the complex between IgE and FcERI provides unexpected information regarding the mechanism of assembly of the complex, which now can be used to design small chemical compounds capable of specifically inhibiting this interaction.

Omalizumab, a recombinant humanized anti-IgE antibody, reduces asthma-related emergency room visits and hospitalizations in patients with allergic asthma

BACKGROUND

Prevention of serious asthma exacerbations is an important therapeutic goal in patients with asthma.

OBJECTIVE

The purpose of this study was to investigate the effect of omalizumab (Xolair), a recombinant humanized monoclonal anti-IgE antibody, on the rate of serious exacerbations during long-term therapy.

METHODS

A pooled analysis was completed of 3 multicenter, randomized, double-blind, placebo-controlled phase III studies with omalizumab in adults/adolescents aged > or =12 years (n = 1071) and in children aged 6 to 12 years (n = 334) who required treatment with inhaled corticosteroids for allergic asthma. Rates of serious asthma exacerbations were computed and compared between omalizumab- and placebo-treated patients. Serious exacerbations were those leading to unscheduled outpatient visits, emergency room treatment, or hospitalization during 1 year of treatment.

RESULTS

In all, 767 patients were treated with omalizumab (at least 0.016 mg/kg/IgE [IU/mL], administered subcutaneously every 4 weeks). Another 638 patients were treated with placebo. The rate of unscheduled, asthma-related outpatient visits was lower for the omalizumab-treated patients than for the placebo-treated patients (rate ratio [95% CI], 0.60 [0.44, 0.81]; P <.01), as were asthma-related emergency room visits (rate ratio [95% CI], 0.47 [0.24, 1.01]; P =.05). Importantly, hospitalizations for asthma were markedly reduced in patients receiving omalizumab (rate ratio [95% CI], 0.08 [0.00, 0.25]; P <.01).

CONCLUSION

Omalizumab reduces the rate of serious asthma exacerbations and the need for unscheduled outpatient visits, emergency room treatment, and hospitalization in patients with moderate-to-severe allergic asthma.

The effect of anti-IgE treatment on in vitro leukotriene release in children with seasonal allergic rhinitis

BACKGROUND

Binding of allergens with IgE to the IgE receptors on mast cells and basophils results in the release of inflammatory mediators as sulfidoleukotrienes (SLTs), triggering allergic cascades that result in allergic symptoms, such as asthma and rhinitis.

OBJECTIVE

We sought to investigate whether anti-IgE (Oma-lizumab), a humanized monoclonal anti-IgE antibody, in addition to specific immunotherapy (SIT) affects the leukotriene pathway.

METHODS

Ninety-two children (age range, 6-17 years) with sensitization to birch and grass pollens and with seasonal allergic rhinitis were included in a phase III, placebo- controlled, multicenter clinical study. All subjects were randomized to one of 4 treatment groups. Two groups subcutaneously received birch SIT and 2 groups received grass SIT for at least 14 weeks before the start of the birch pollen season. After 12 weeks of SIT titration, placebo or anti-IgE was added for 24 weeks. The primary clinical efficacy variable was symptom load (ie, the sum of daily symptom severity score and rescue medication score during pollen season). Blood samples taken at baseline and at the end of study treatment after the grass pollen season were used for separation of leukocytes in this substudy. After in vitro stimulation of the blood cells with grass and birch pollen allergens, SLT release (LTC4, LTD4, and LTE4) was quantified by using the ELISA technique.

RESULTS

Before the study treatment, SLT release to birch and grass pollen exposure did not differ significantly among the 4 groups. Under treatment with anti-IgE + SIT-grass (n = 23), a lower symptom load occurred during the pollen season compared to placebo + SIT-grass (n = 24, P =.012). The same applied to both groups receiving birch SIT (n = 23 and n = 22, respectively; P =.03). At the end of treatment, the combination of anti-IgE plus grass SIT, as well as anti-IgE plus birch SIT, resulted in significantly lower SLT release after stimulation with the corresponding allergen (416 ng/L [5th-95th percentile, 1-1168] and 207 ng/L [1-860 ng/L], respectively) compared with placebo plus SIT (2490 ng/L [384-6587 ng/L], P =.001; 2489 ng/L [1-5670 ng/L], P =.001). In addition, treatment with anti-IgE was also followed by significantly lower SLT releases to the allergens unrelated to SIT (grass SIT: 300 ng/L [1-2432 ng/L] in response to birch allergen; birch SIT: 1478 ng/L [1-4593 ng/L] in response to grass pollen) in comparison with placebo (grass SIT: 1850 ng/L [1-5499 ng/L], P =.001; birch SIT: 2792 ng/L [154-5839 ng/L], P =.04].

CONCLUSION

Anti-IgE therapy reduces leukotriene release of peripheral leukocytes stimulated with allergen in children with allergic rhinitis undergoing allergen immunotherapy independent of the type of SIT allergen used.

Asthma: future directions

Asthma continues to be a significant health care problem, as reflected by the increasing rise in disease morbidity and mortality. Because steroids are relatively safe, clinically effective, and easy to administer, they remain the gold standard of treatment. After many decades of use, however, it is apparent that inhaled corticosteroids have failed to halt the progression of the asthma epidemic. Newer, more effective drugs are being developed to combat this disease, and the interest in developing new medications to treat allergic disease and asthma has increased exponentially. The financial burden of asthma has also been a significant motivating factor in the development of new medications. It is estimated that in 1998 the total cost of asthma on society was $11 billion [175]. This consideration has further intensified the quest to develop more effective asthma medications. Table 1 reviews the wide array of drugs currently being investigated. With the development and approval of novel asthma treatments, millions of asthma sufferers will undoubtedly have increased therapeutic options for control of their disease in the near future.

The use of anti-IgE in the treatment of allergic asthma

Allergic sensitization plays a significant role in the development of asthma in many patients. IgE-mediated immune responses play a central role in the pathogenesis of this condition. The development of a treatment that interrupts this pathway is particularly desirable to prevent downstream events. Large-scale trials in patients ranging in age from 6 to 76 years have shown that omalizumab therapy is safe and effective in the treatment of severe allergic asthma. This is particularly true in patients who experience poor disease control despite high doses of inhaled steroids or need oral steroids for control of their disease. These patients are at risk for severe exacerbations despite recommended therapy, and anti-IgE therapy has proved to reduce these episodes. Early aggressive therapy of asthma is needed for maximum control in all age groups. Despite the efficacy of inhaled steroids there is a reluctance to use these agents, especially in younger children. Because of these concerns a long-acting treatment is especially desirable. Because of imperfect effort or technique limiting inhaled medications, introduction of an effective agent that could be administered parenterally at long intervals also is very important. Allergic rhinitis is a co-existing problem in many patients with allergic asthma. Immunotherapy trials have suggested that early intervention with immunotherapy and allergic rhinitis patients may actually prevent the development of asthma. Early treatment of patients with anti-IgE may also have benefits, particularly in those who have concomitant allergic rhinitis in addition to allergic asthma. Although omalizumab has not yet received Food and Drug Administration approval in the United States, it shows great promise in the management of patients requiring high doses of inhaled or oral corticosteroids for control of their disease and to prevent exacerbations of asthma in such patients. Reductions in high doses of inhaled or oral corticosteroids may prevent long-term complications of these treatments.

Omalizumab and the immune system: an overview of preclinical and clinical data

OBJECTIVE

This review discusses the role of immunoglobulin (Ig)E in allergic disease, inhibition of IgE with omalizumab, and the consequences of IgE inhibition (both clinically and in terms of the effect on the immune system).

DATA SOURCES

Relevant publications obtained from a literature review.

STUDY SELECTION

Relevant publications on IgE, allergic disease, and anti-IgE were critically evaluated.

RESULTS

IgE plays a key role in allergic diseases such as allergic asthma and allergic rhinitis. Its role in healthy individuals is less well defined. Treatment of allergic asthma and rhinitis with omalizumab, a humanized monoclonal anti-IgE antibody, causes a marked reduction in circulating free IgE levels. This has been shown to reduce symptoms and decrease the need for other medication in patients with these allergic diseases. Anti-IgE treatment with omalizumab did not cause any of the complications that might, in theory, be expected to result from reduction in circulating free IgE, such as adverse effects upon the immune system or other body systems.

CONCLUSIONS

The limited clinical data currently available suggest that this novel method of treatment for allergic asthma and rhinitis seems to be both effective and well tolerated in clinical use.

New asthma targets: recent clinical and preclinical advances

Current asthma therapy is directed at the relief of chronic inflammation or improving lung function through bronchodilation. These approaches treat the overt symptoms of asthma but do not approach underlying causes of the disease. Such therapies have limited efficacy and for a number of patients the disease remains poorly controlled. The short-term future of asthma therapy will probably focus on the treatment of multiple symptoms to provide improved lung function. Long-term approaches to asthma will have to focus on modulation of the mechanisms that are the underlying causes of the various asthmatic pathophysiologies. These targets include a number of TH2-type T-cell-generated cytokines and chemokines, G-protein-coupled receptors, TH2-related transcription factors, neurotrophins and adhesion molecules. Additional new targets and understanding of asthma may also arise from genetic analysis.

The effect of omalizumab on nasal allergic inflammation

BACKGROUND

In sensitized patients, coupling between IgE and FcepsilonRI receptors on mast cells leads to release of proinflammatory mediators and a subsequent influx of inflammatory cells to the affected organ. Omalizumab (Xolair; formerly rhuMAb-E25) binds to circulating IgE, thus preventing induction of the allergic process.

OBJECTIVE

We investigated the effect of treatment with omalizumab on seasonal allergic rhinitis and related changes in inflammatory cell numbers in nasal biopsy specimens.

METHODS

Patients were randomized to treatment with omalizumab or placebo before the pollen season; the treatment was started and continued during season. Symptoms and use of medication were recorded, and blood samples and nasal biopsy specimens were obtained before and during season. Immunocytochemistry was performed on biopsy sections through use of the following antibodies: anti-CD4, CD8 (T lymphocytes), EG2, and anti-eosinophil peroxidase (eosinophils), anti-tryptase (mast cells), human neutrophil lipocalin (neutrophils), and antibodies against IgE and FcepsilonRI.

RESULTS

During the season, blood eosinophils increased in placebo-treated patients but not in omalizumab-treated patients (P =.01); the difference between the treatment groups was significant (P =.04). Free IgE in serum decreased significantly (P =.0002) in omalizumab-treated patients but not in placebo-treated patients; the difference between the groups was significant (P =.0001). In nasal biopsy specimens, the number of eosinophil peroxidase-positive staining cells increased in the placebo-treated patients (P =.003) but not in the actively treated patients during the season; the difference between the groups was significant (P =.0001). The number of IgE(+) staining cells decreased significantly in the omalizumab group during the season in comparison with the placebo group (P =.04).

CONCLUSION

The clinical benefit of treatment with omalizumab is associated with an anti-inflammatory effect on cellular markers in blood and nasal tissue.

Omalizumab. A review of the new treatment of allergic asthma and seasonal allergic rhinitis

The causal role of immunoglobulin E (IgE) in triggering the cascade of biochemical events leading to allergic disease is well established. Treatments that selectively inhibit IgE activity are a logical approach in managing the allergic response. Omalizumab is a recombinant humanised monoclonal antibody which specifically binds to the Cε3 domain of immunoglobulin (Ig) E, the site of high-affinity IgE receptor binding. The clinical benefit and steroid-sparing effect of treatment with the anti-immunoglobulin-E (IgE) antibody, Omalizumab, was assessed in patients with moderate-to-severe allergic asthma and seasonal allergic rhinitis. Intravenous and subcutaneous administration of anti-IgE mAb reduces circulating levels of IgE in atopic patients to low levels commonly seen in non-atopic individuals. Anti-IgE therapy offers protection against allergen-induced bronchoconstriction, reduces the need for short acting inhaled beta 2-agonist and corticosteroids among asthmatic patients and reduces severity of symptoms of allergic rhinitis. Adverse events were infrequent in clinical trials of omalizumab, and not significantly different from placebo. The most frequent drug-related event was mild to moderate urticaria. They do not induce anaphylaxis and the occurrence of antibodies against anti-IgE mAb is sporadic. The results of cited studies suggest that humanized anti-IgE monoclonal antibodies may have important immunotherapeutic benefit for treatment of allergic disorders.

Efficacy of combination treatment with anti-IgE plus specific immunotherapy in polysensitized children and adolescents with seasonal allergic rhinitis

BACKGROUND

Specific immunotherapy (SIT) and treatment with monoclonal anti-IgE antibody have complementary modes of action.

OBJECTIVE

The purpose of this study was to determine whether combined therapy could provide better efficacy than either treatment alone.

METHODS

We conducted a randomized, double-blinded trial to assess the efficacy and safety of subcutaneously administered anti-IgE (omalizumab) or placebo in children and adolescents with seasonal allergic rhinitis in both a birch pollen season and a grass pollen season (sequential seasons together lasting an average of 84 days). There were 4 treatment arms. Each subject was started on SIT-birch or SIT-grass, and anti-IgE or placebo was started before and maintained during the anticipated pollen seasons (a total of 24 weeks). The primary efficacy variable was symptom load, the sum of daily symptom severity score plus rescue medication use.

RESULTS

A total of 221 subjects (intent-to-treat population) aged 6 to 17 years were analyzed for efficacy. Combination therapy reduced symptom load over the 2 pollen seasons by 48% (P <.001) over SIT alone. When analyzed separately by season, the 2 groups receiving unrelated SIT were considered placebo controls. In the grass season, symptom loads were as follows: unrelated (birch) SIT + placebo, 0.89 (reference value); unrelated (birch) SIT + anti-IgE, 0.49 (-45%); SIT-grass + placebo, 0.61 (-32%); SIT-grass + anti-IgE, 0.26 (-71%).

CONCLUSION

Anti-IgE therapy conferred a protective effect independent of the type of allergen. Additional clinical benefit was demonstrated in both pollen seasons, whether there was coverage by SIT or not. This combination might prove useful for the treatment of allergic rhinitis, particularly for polysensitized patients.

Monoclonal anti-IgE antibody: a novel therapy for allergic airways disease

LEARNING OBJECTIVES

To familiarize the practitioner with a novel (monoclonal anti-immunoglobulin [Ig]E antibody) form of therapy for allergic airways disease. To understand the relevance of IgE as a therapeutic target. To appreciate the concepts behind the design of the molecule. To learn how anti-IgE was used in clinical trials. To anticipate the likely effects (efficacy and safety) in clinical use in patients with allergic asthma and with allergic rhinitis. To characterize the types of patients who might benefit from this therapy.

DATA SOURCES

Published data for preclinical and clinical studies.

RESULTS

Omalizumab is a nonimmunogenic, nonanaphylactogenic monoclonal anti-IgE antibody. In clinical use, omalizumab reduces levels of serum-free IgE. Given subcutaneously in patients with moderate-severe allergic asthma, omalizumab reduced exacerbations compared with placebo, and at the same time it allowed inhaled corticosteroids to be reduced or withdrawn. In patients with allergic rhinitis, omalizumab reduced the severity of symptoms and rescue antihistamine usage versus placebo. In both settings, quality of life was improved with active treatment relative to placebo. The drug seems safe and well tolerated.

CONCLUSION

As the first clinical anti-IgE agent, omalizumab is an interesting new addition to the currently available therapies for allergic airways disease. The benefits demonstrated underline the importance of IgE in these conditions. The use of anti-IgE in other IgE-mediated allergic diseases warrants further research.