An evaluation of the cost-effectiveness of omalizumab for the treatment of severe allergic asthma

Fisetin alleviates chronic urticaria by inhibiting mast cell activation via MRGPRX2

OBJECTIVES

The activation of mast cell (MC) plays an important part in the pathogenesis of chronic urticaria (CU), and the expression of MRGPRX2 (Mas-related G-protein coupled receptor X2) and the circulating levels of SP (substance P) in skin MC of CU patients increased. Fisetin is a natural flavonoid with anti-inflammatory and antiallergic pharmacological effects. This study aimed to investigate the inhibitory effect of fisetin on CU via MRGPRX2 and its possible molecular mechanisms.

METHODS

OVA/SP co-stimulated and SP-stimulated CU like murine models were used to evaluate the effect of fisetin on CU. MRGPRX2/HEK293 cells and LAD2 cells were used to perform the antagonism effect of fisetin on MC via MRGPRX2.

KEY FINDINGS

The results indicated that fisetin prevented urticaria-like symptoms in murine CU models, and inhibited MCs activation by suppressing calcium mobilization and degranulation of cytokines and chemokines via binding to MRGPRX2. The bioinformatics analysis showed that fisetin might have an interaction relationship with Akt in CU. The western blotting experiments showed that fisetin downregulated the phosphorylation levels of Akt, P38, NF-κB, and PLCγ in C48/80 activated LAD2 cells.

CONCLUSIONS

Fisetin alleviates CU progression by inhibiting mast cell activation via MRGPRX2, which may be a novel therapeutic candidate for CU.

Cost-Effectiveness Analysis of Omalizumab for Severe Allergic Asthma in Japan Using Real-World Evidence

OBJECTIVES

Omalizumab is a recommended add-on therapy for patients with severe allergic asthma who remain uncontrolled despite treatment with standard of care (SoC). This study evaluated the cost-effectiveness of omalizumab compared with SoC applying real-world clinical outcomes in adult patients with severe allergic asthma in Japan.

METHODS

A validated Markov model was adapted for Japan and compared the cost-effectiveness of omalizumab as an add-on therapy to SoC versus SoC alone using the most recently updated price of omalizumab. A Japanese real-world postmarketing surveillance and a pivotal randomized clinical trial were used as inputs for clinical effectiveness. Japanese life tables and literature were accessed for mortality data and unit costs were extracted from a Japanese insurance claims database. Quality of life data were retrieved from the clinical trial.

RESULTS

In the base case, the incremental cost-effectiveness ratio for omalizumab add-on therapy was ¥2.85 million per quality-adjusted life-year gained (approximately €21 000; 1€ = ¥133.26) compared with SoC alone. The model appeared to be most sensitive to changes in clinically significant severe exacerbation fatality, day-to-day asthma symptom utilities for SoC, discount rates for benefits, day-to-day asthma symptom utilities for omalizumab responders, time horizon, and the annual cost of omalizumab. The results of the probabilistic sensitivity analysis showed that the probability of omalizumab being cost-effective was 93% to 98% at a threshold of ¥5 to ¥6 million (willingness-to-pay for 1 quality-adjusted life-year).

CONCLUSIONS

Omalizumab add-on therapy is cost-effective compared with SoC alone in Japan in severe allergic asthma population who are uncontrolled with high-dose inhaled corticosteroid and other controllers.

Biologics for Severe Asthma: Treatment-Specific Effects Are Important in Choosing a Specific Agent

Patients with uncontrolled severe persistent asthma have greater morbidity, greater use of health care resources, and more impairment in health-related quality of life when compared with their peers with well-controlled disease. Fortunately, since the introduction of biological therapeutics, patients with severe eosinophilic asthma now have beneficial treatment options that they did not have just a few years ago. In addition to anti-IgE therapy for allergic asthma, 3 new biological therapeutics targeting IL-5 and 1 targeting IL-4 and IL-13 signaling have recently been approved by the Food and Drug Administration for the treatment of severe eosinophilic asthma, and approval of more biological therapeutics is on the horizon. These medications decrease the frequency of asthma exacerbations, improve lung function, reduce corticosteroid usage, and improve health-related quality of life. This article reviews the mechanisms of action, specific indications, benefits, and side effects of each of the approved biological therapies for asthma. Furthermore, this article reviews how a clinician could use specific patient characteristics to decide which biologic treatment may be optimal for a given patient.

Add-On Omalizumab for Inadequately Controlled Severe Pollinosis Despite Standard-of-Care: A Randomized Study

BACKGROUND

Cedar pollinosis (CP), a common form of seasonal allergic rhinitis (AR), is a substantial medical problem in Japan due to its high prevalence and severe symptoms. Omalizumab (anti-IgE therapy) has previously proven to be effective in CP/AR, but no studies for inadequately controlled severe CP/AR despite standard-of-care (SoC) have been conducted.

OBJECTIVE

To determine the efficacy of omalizumab added to SoC in patients with inadequately controlled severe CP in a randomized, double-blinded, placebo-controlled, phase III study.

METHODS

Adult/adolescent patients with severe CP whose symptoms were inadequately controlled despite nasal corticosteroids plus 1 or more oral medications in the previous 2 seasons were randomized to receive omalizumab (n = 162) or placebo (n = 175). All patients received concomitant antihistamines and nasal corticosteroids as SoC. The primary endpoint was the mean nasal symptom score during the severe symptom period. Secondary endpoints included mean ocular symptom score, quality of life (QoL), and safety.

RESULTS

The SoC + omalizumab treatment had statistically significantly and clinically important lower nasal (least squares mean difference, -1.03, P < .001) and ocular (-0.87, P < .001) symptom scores compared with SoC + placebo, respectively. Differences in scores for individual components of nasal and ocular symptoms were also statistically and clinically significant. SoC + omalizumab also improved QoL scores as overall and in all domains. No unexpected safety signals were observed.

CONCLUSIONS

In patients with severe CP, omalizumab added to SoC demonstrated consistent efficacy in improving symptoms and QoL, and was well tolerated. These results indicate that omalizumab could be a promising therapeutic option for severe CP/AR.

The use of biologic therapies for the management of pediatric asthma

With better understanding of the role of type 2 inflammation in allergic asthma, there has been progress made in the development of new biologic therapies targeting these specific pathways. This review will consider diagnostic criteria for using biologic therapies for pediatric asthma with special emphasis on populations that are likely to benefit the most from particular therapies. With the exception of the anti-immunoglobulin E, omalizumab, very few studies have been published on the efficacy and safety of biologic therapies in children, particularly anti-interleukin-5 (IL5) and anti-IL4/IL13 therapies. The review will highlight the scarcity of published data in pediatric-specific populations. In addition, we will consider the cost-effectiveness as well as potential long-term consequences of biologic therapies in pediatric asthma.

Use of Natural Products in Asthma Treatment

Asthma, a disease classified as a chronic inflammatory disorder induced by airway inflammation, is triggered by a genetic predisposition or antigen sensitization. Drugs currently used as therapies present disadvantages such as high cost and side effects, which compromise the treatment compliance. Alternatively, traditional medicine has reported the use of natural products as alternative or complementary treatment. The aim of this review was to summarize the knowledge reported in the literature about the use of natural products for asthma treatment. The search strategy included scientific studies published between January 2006 and December 2017, using the keywords "asthma," "treatment," and "natural products." The inclusion criteria were as follows: (i) studies that aimed at elucidating the antiasthmatic activity of natural-based compounds or extracts using laboratory experiments (in vitro and/or in vivo); and (ii) studies that suggested the use of natural products in asthma treatment by elucidation of its chemical composition. Studies that (i) did not report experimental data and (ii) manuscripts in languages other than English were excluded. Based on the findings from the literature search, aspects related to asthma physiopathology, epidemiology, and conventional treatment were discussed. Then, several studies reporting the effectiveness of natural products in the asthma treatment were presented, highlighting plants as the main source. Moreover, natural products from animals and microorganisms were also discussed and their high potential in the antiasthmatic therapy was emphasized. This review highlighted the importance of natural products as an alternative and/or complementary treatment source for asthma treatment, since they present reduced side effects and comparable effectiveness as the drugs currently used on treatment protocols.

Economic Impact and Clinical Outcomes of Omalizumab Add-On Therapy for Patients with Severe Persistent Asthma: A Real-World Study

BACKGROUND

Omalizumab is a fully humanized monoclonal antibody indicated as add-on therapy to improve asthma control in patients with severe persistent allergic asthma.

AIMS

The aim of this study was to evaluate social, healthcare expenditure and clinical outcomes changes after incorporating omalizumab into standard treatment in the control of severe asthma.

METHODS

In this multicentre retrospective study, a total of 220 patients were included from 15 respiratory medicine departments in the regions of Andalusia and Extremadura (Spain). Effectiveness was calculated as a 3-point increase in the Asthma Control Test (ACT) and a reduction in the annual number of exacerbations. The economic evaluation included both direct and indirect costs. Incremental cost-effectiveness ratio (ICER) was calculated. Results from the year before and the year after incorporation of omalizumab were compared.

RESULTS

After adding omalizumab, improvement of lung function, asthma and rhinitis according to patient perception, as well as the number of exacerbations and asthma control measured by the ACT score were observed. Globally, both healthcare resources and pharmacological costs decreased after omalizumab treatment, excluding omalizumab cost. When only direct costs were considered, the ICER was €1712 (95% CI 1487-1995) per avoided exacerbation and €3859 (95% CI 3327-4418) for every 3-point increase in the ACT score. When both direct and indirect costs were considered, the ICER was €1607 (95% CI 1385-1885) for every avoided exacerbation and €3555 (95% CI 3012-4125) for every 3-point increase.

CONCLUSIONS

Omalizumab was shown to be an effective add-on therapy for patients with persistent severe asthma and allowed reducing key drivers of asthma-related costs.

Strategies to reduce corticosteroid-related adverse events in asthma

PURPOSE OF REVIEW

Severe asthmatics, despite the chronic use of high inhaled corticosteroids (ICS) doses and frequent intake of systemic corticosteroids, remains clinically and/or functionally uncontrolled. These patients are also often affected by rhinitis or chronic rhinosinusitis requiring frequent use of intranasal corticosteroids. Therefore, severe asthmatics are exposed to an overload of corticosteroids that is frequently associated with relevant and costly adverse events. This clinical problem and the strategies to overcome it are here summarized.

RECENT FINDINGS

Different therapeutic options may help in reducing the corticosteroid load in asthmatics, ranging from allergy immunotherapy (nonsuitable for severe uncontrolled patients), immunosuppressant agents like methotrexate or cyclosporine, novel biologic drugs (mainly anti-IgE, anti-IL5 and anti-IL4-receptor-alpha), and aspirin desensitization (for patients with anti-inflammatory drugs exacerbated respiratory disease).

SUMMARY

The evidence of even serious corticosteroid-related adverse events associated with consistent health-care costs, should prompt the entire scientific community and health regulatory authorities to promote actions to increase the use of well tolerated and effective strategies to reduce the corticosteroid need in asthmatics; the most promising option seems to be the add-on use of biologic agents.

Cost-effectiveness of fractional exhaled nitric oxide (FeNO) measurement in predicting response to omalizumab in asthma

Purpose: To use a modeled analysis to examine the cost-effectiveness of utilizing fractional exhaled nitric oxide (FeNO) as a biomarker to aid in the identification of omalizumab responders in patients with moderate-to-severe allergic asthma. Omalizumab is a biological drug used to treat asthma in adults and children 12 years and older. Patients and methods: We conducted a decision analysis in which two alternative strategies for predicting omalizumab response were assessed: 1) testing response via a 12-week trial of omalizumab and 2) using FeNO measurement to screen patients for likely omalizumab response prior to initiating a 12-week trial of omalizumab. In the standard of care arm, trial omalizumab responders continue on to receive 12 months of continuous omalizumab therapy. In the FeNO measurement predictor arm, patients with FeNO measurements >19.5 ppb are started on a trial of omalizumab. Trial omalizumab responders in this arm are then also tracked for 12 months of continuous omalizumab therapy. Results: Per-patient costs during the trial and initial treatment periods total $10,943 for FeNO + omalizumab and $13,703 for omalizumab only. The expected cost per responder during the trial period is $4,326 for FeNO + omalizumab and $7,786 for omalizumab only. Conclusion: Use of FeNO measurement to identify omalizumab responders decreases the expected per-patient cost by nearly 50% during the trial period and continues to show cost savings through the initial treatment period of 12 months. Our analysis may serve as a model for policy and clinical practice regarding the use of FeNO to determine omalizumab response and has widespread implications for health care payers, who may choose to require FeNO measurement and prespecify a minimum FeNO value to determine patient eligibility for omalizumab trial.

Shadow cost of oral corticosteroids-related adverse events: A pharmacoeconomic evaluation applied to real-life data from the Severe Asthma Network in Italy (SANI) registry

BACKGROUND

Asthma is one of the most common non-communicable respiratory diseases, affecting about 6% of the general population. Severe asthma, even if afflicts a minority of asthmatics, drives the majority of costs of the disease. The aim of this study is to create a pharmacoeconomic model to predict the costs of corticosteroid-related adverse events in severe asthmatics and applying it to the first published epidemiologic data from the Severe Asthma Network in Italy (SANI) registry.

METHODS

The analysis was conducted from the perspective of the Italian National Healthcare System (INHS). Model inputs, derived from literature, included: asthma epidemiology data, frequency of adverse events, percentage of severe asthma treated with OCS and adverse event cost (Diagnosis-Related Group (DRG) national tariffs). We estimated costs per different patient groups: non-asthma controls, mild/moderate and severe asthmatics. Final results report estimated direct cost per patient and total direct cost for overall target population, showing economic impact related to corticosteroid complication.

RESULTS

Based on epidemiological data input, in Italy, asthmatic subjects resulted about 3,999,600, of which 199,980 with severe asthma. The number of patients with severe asthma OCS-treated was estimated at 123,988. Compared to the non-asthma control cohort and to that with moderate asthma annual cost per severe asthmatic patient resulted respectively about €892 and €606 higher, showing a corticosteroids shadow cost ranging from 45% to 30%.Applying the cost per patient to the target population identified for Italy, the budget impact model estimated a total annual cost related to OCS-related adverse events of €242.7 million for severe asthmatics. In respect with non-asthmatic and moderate population, an incremental expenditure of about € 110.6 million and €75.2, respectively, were shown.

CONCLUSIONS

Our study provides the first estimates of additional healthcare costs related to corticosteroid induced adverse events in severe asthma patient. Budget impact model results highlighted the relevant economic impact of OCS-related adverse events in severe asthma patients. The future extrapolation of additional data from SANI registry will support the development of a model to investigate the role of corticosteroids sparing drugs.

Two decades with omalizumab: what we still have to learn

From its availability for clinical use nearly two decades ago for severe asthma, omalizumab has gained strong evidence of efficacy and safety in the treatment of severe asthma not controlled by standard-of-care therapy. It has been acknowledged by Global Initiative on Asthma guidelines as add-on therapy against severe uncontrolled asthma. Thanks to controlled trials supporting its efficacy, omalizumab has also been licensed for the treatment of chronic spontaneous urticaria. The optimal duration of treatment in either disease has not been established. Despite its high price, omalizumab appears to be cost-effective in severe uncontrolled asthma as well as in chronic urticaria. The literature suggests a wide range of applications for omalizumab in various disorders regardless of allergic or non-allergic pathophysiology.

A cost-effectiveness analysis of reslizumab in the treatment of poorly controlled eosinophilic asthma

Introduction: Poorly controlled severe eosinophilic asthma is difficult and costly to manage. Reslizumab, an add-on treatment for adults with severe eosinophilic asthma, reduces the number of exacerbations and improves the quality of life (QoL). The objective of this study was to evaluate the cost-effectiveness of reslizumab. Methods: A Markov model was used to compare the cost-effectiveness of add-on reslizumab with the standard-of-care (SOC) from the US societal perspective over a five-year time horizon. Efficacy and safety inputs for the model were based on data from two clinical trials (NCT01287039 and NCT01285323). Other model inputs, including mortality rates, costs, and utility, were estimated from literature, the Centers for Disease Control and Prevention (CDC), the US Department of Veterans Affairs (VA) and the Centers for Medicare and Medicaid Services (CMS). One-way, threshold, and probabilistic sensitivity analyses (PSA) were performed. Adherence, treatment response, and the placebo effect were evaluated in separate scenario analyses. Results: The base case incremental cost-effectiveness ratio (ICER) was $697 403 (2017 USD) per quality-adjusted life-years (QALYs). In the PSA, reslizumab becomes cost-effective in 50% of the iterations at a willingness-to-pay (WTP) threshold of $689 000. The model is most sensitive to the QoL improvement with reslizumab treatment in the one-way and threshold analyses. The response and adherence models had lower ICERs than the base model but still above $500 000. The ICER of the placebo effect model was $29 820. Conclusions: The improvement in QoL and exacerbation rates with reslizumab are associated with high costs, making reslizumab unlikely to be cost-effective at the $200 000 WTP threshold.

Targeting IgE in allergic disease

Immunoglobulin E (IgE) represents the least abundant antibody isotype in human serum. Nevertheless, it has the ability to induce potent allergic reactions. As a key component in the development and manifestation of hypersensitivity responses against usually non-hazardous foreign substances, IgE has become a major target of investigation and the subject of multiple therapeutic approaches for the treatment of allergies. Recent advances in the understanding of pathophysiologic mechanisms underlying IgE-associated allergic disorders have led to the generation of new drug candidates that are currently in development or under clinical evaluation. In this review, we highlight molecular and structural mechanisms underlying the different anti-IgE molecules and suggest a concept of multi-level targeting using a new class of disruptive IgE inhibitors to potentially optimize treatment efficacy.

Drug repurposing to treat asthma and allergic disorders: Progress and prospects

Allergy and atopic asthma have continued to become more prevalent in modern society despite the advent of new treatments, representing a major global health problem. Common medications such as antihistamines and steroids can have undesirable long-term side-effects and lack efficacy in some resistant patients. Biologic medications are increasingly given to treatment-resistant patients, but they can represent high costs, complex dosing and management, and are not widely available around the world. The field needs new, cheap, and convenient treatment options in order to bring better symptom relief to patients. Beyond continued research and development of new drugs, a focus on drug repurposing could alleviate this problem by repositioning effective and safe small-molecule drugs from other fields of medicine and applying them toward the treatment for asthma and allergy. Herein, preclinical models, case reports, and clinical trials of drug repurposing efficacy in allergic disease are reviewed. Novel drugs are also proposed for repositioning based on their mechanism of action to treat asthma and allergy. Overall, drug repurposing could become increasingly important as a way of advancing allergy and atopic asthma therapy, filling a need in treatment of patients today.

The real world effect of omalizumab add on therapy for patients with moderate to severe allergic asthma: The ASTERIX Observational study

Background

Omalizumab is a non-steroidal medication indicated for the treatment of poorly controlled moderate-to-severe allergic asthmatics. This observational study examines the “real world” effectiveness of omalizumab in this population.

Methods

This is a one year open-label observational study that compared clinical outcomes including total oral corticosteroid use, exacerbation history, measures of quality of life and inflammation in patients with moderate-to-severe allergic asthma, who were prescribed omalizumab as part of their treatment with the year prior to therapy.

Results

A total of 99 patients were enrolled at 25 sites in Canada. During the study period, the mean total annual OCS dose was reduced from 2301.5 mg (prednisone equivalents) in the year prior to omalizumab to 1130.0 mg (p<0.0001). There was a 71% reduction in asthma exacerbations and 56% of patients on omalizumab remained exacerbation free when compared to the year prior to study entry. Associated with this was reduced health care utilization. There were significant improvements in the Asthma Control Questionnaire (ACQ) and Asthma Quality of Life questionnaire (AQLQ) Patients with an elevated FeNO at baseline showed a better response to treatment. No new safety issues were identified during the study period.

Conclusion

Our study demonstrates that in “real world” clinical practice, after initiating omalizumab, there is a reduction in total OCS use and exacerbation frequency in patients with moderate-to-severe allergic asthma. Patients on treatment reported improved asthma control and quality of life. FeNO may be a useful biomarker to identify patients who may benefit with omalizumab treatment.

Assessing the value of mepolizumab for severe eosinophilic asthma: a cost-effectiveness analysis

BACKGROUND

Adding mepolizumab to standard treatment with inhaled corticosteroids and controller medications could decrease asthma exacerbations and use of long-term oral steroids in patients with severe disease and increased eosinophils; however, mepolizumab is costly and its cost effectiveness is unknown.

OBJECTIVE

To estimate the cost effectiveness of mepolizumab.

METHODS

A Markov model was used to determine the incremental cost per quality-adjusted life year (QALY) gained for mepolizumab plus standard of care (SoC) and for SoC alone. The population, adults with severe eosinophilic asthma, was modeled for a lifetime time horizon. A responder scenario analysis was conducted to determine the cost effectiveness for a cohort able to achieve and maintain asthma control.

RESULTS

Over a lifetime treatment horizon, 23.96 exacerbations were averted per patient receiving mepolizumab plus SoC. Avoidance of exacerbations and decrease in long-term oral steroid use resulted in more than $18,000 in cost offsets among those receiving mepolizumab, but treatment costs increased by more than $600,000. Treatment with mepolizumab plus SoC vs SoC alone resulted in a cost-effectiveness estimate of $386,000 per QALY. To achieve cost effectiveness of approximately $150,000 per QALY, mepolizumab would require a more than 60% price discount. At current pricing, treating a responder cohort yielded cost-effectiveness estimates near $160,000 per QALY.

CONCLUSION

The estimated cost effectiveness of mepolizumab exceeds value thresholds. Achieving these thresholds would require significant discounts from the current list price. Alternatively, treatment limited to responders improves the cost effectiveness toward, but remains still slightly above, these thresholds. Payers interested in improving the efficiency of health care resources should consider negotiations of the mepolizumab price and ways to predict and assess the response to mepolizumab.

Omalizumab Improves Quality of Life and Asthma Control in Chinese Patients With Moderate to Severe Asthma: A Randomized Phase III Study

Purpose

Omalizumab is the preferred add-on therapy for patients with moderate-to-severe persistent allergic asthma and has demonstrated efficacy and safety in various ethnicities. This study evaluated the efficacy and safety of omalizumab in Chinese patients with moderate-to-severe allergic asthma.

Methods

This randomized, double-blind, parallel-group, placebo-controlled, phase III study assessed lung function, quality of life, asthma control, and safety of omalizumab after 24-week therapy in Chinese patients (18-75 years of age).

Results

A total of 616 patients were randomized (1:1) to omalizumab or placebo. The primary endpoint, least squares mean treatment difference (LSM-TD) in morning peak expiratory flow (PEF) (omalizumab vs placebo), at Weeks >20-24 was 8.85 L/min (Full analysis set; P=0.062). Per-protocol analysis set showed significant improvements with LSM-TD of 11.53 L/min in mean mPEF at Weeks >20-24 (P=0.022). The FEV1 % predicted was significantly improved with omalizumab vs placebo from 8 to 24 weeks (after 24-week treatment: LSM-TD=4.12%; P=0.001). At Week 24, a higher proportion of omalizumab-treated patients achieved clinically relevant improvements in standardized AQLQ (58.2% vs 39.3%; LSM=0.51 vs 0.10; P<0.001) and ACQ (49.5% vs 35.5%; LSM=-0.51 vs -0.34; P=0.002) scores vs placebo. Total and nighttime symptom scores reduced significantly with omalizumab vs placebo (LSM-TD=-0.21, P=0.048 and -0.12, P=0.011, respectively). Although the study was not powered to study differences in exacerbation rates (P=0.097), exacerbations in winter months were less frequent in the omalizumab vs placebo group (2 vs 21). Adverse event and severe adverse event rates were comparable between omalizumab and placebo.

Conclusions

Omalizumab improves lung function, quality of life, and asthma control in Chinese patients with moderate-to-severe persistent allergic asthma and has a good safety profile.

Local immunoglobulin e in the nasal mucosa: clinical implications

Immunoglobulin E (IgE) can be highly elevated in the airway mucosa independently of IgE serum levels and atopic status. Mostly, systemic markers are assessed to investigate inflammation in airway disease for research or clinical practice. A more accurate but more cumbersome approach to determine inflammation at the target organ would be to evaluate markers locally. We review evidence for local production of IgE in allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP). Diagnostic and therapeutic consequences in clinical practice are discussed. We describe that the airway mucosa has the intrinsic capability to produce IgE. Moreover, not only do IgE-positive B cells reside within the mucosa, but all tools are present locally for affinity maturation by somatic hypermutation (SHM), clonal expansion, and class switch recombination to IgE. Recognizing local IgE in the absence of systemic IgE has diagnostic and therapeutic consequences. Therefore, we emphasize the importance of local IgE in patients with a history of AR or CRSwNP.

Long-term efficacy and safety of omalizumab in patients with persistent uncontrolled allergic asthma: a systematic review and meta-analysis

Currently, limited information is available to clinicians regarding the long-term efficacy of omalizumab treatment for allergic asthma. In this report, we aimed to (i) systematically review the evidence regarding the long-term efficacy of omalizumab in patients with persistent uncontrolled allergic asthma, and to (ii) discuss the cost-effectiveness evidence published for omalizumab in this patient population. A comprehensive search for randomized controlled trials (RCTs; ≥52 weeks) was performed, and six studies met our final inclusion criteria (n = 2,749). Omalizumab was associated with significant improvements in quality of life and the Global Evaluation of Treatment Effectiveness. Omalizumab also allowed patients to completely withdraw from inhaled corticosteroid therapy and did not increase the overall incidence of adverse events. However, there was insufficient evidence that omalizumab reduced the incidence of exacerbations, and the cost-effectiveness of omalizumab varied across studies. Our data indicated that omalizumab use for at least 52 weeks in patients with persistent uncontrolled allergic asthma was accompanied by an acceptable safety profile, but it lacked effect on the asthma exacerbations. Use of omalizumab was associated with a higher cost than conventional therapy, but these increases may be cost-effective if the medication is used in patients with severe allergic asthma.

The "e" in cost-effectiveness analyses. A case study of omalizumab efficacy and effectiveness for cost-effectiveness analysis evidence

This article is a call for increased use of real-world evidence in health technology assessment and related policy and decision making. There is currently a disconnect between evidence used to guide regulatory approval of therapies and evidence used to inform therapeutic coverage and reimbursement decisions. Public and private payers need to understand not only whether an intervention works but also whether it offers good value compared with licensed alternatives (not placebo) as they are used in the real-world practice and population (not in a controlled trial environment). Addressing such concerns requires evidence to be drawn from a wide range of study designs, but with consideration and weighting given to their relative strengths and weaknesses, as well as their position on the pragmatic-explanatory (i.e., effectiveness-efficacy) continuum. The potential impact of using different types of evidence to inform cost-effectiveness analysis (CEA) is discussed for omalizumab, comparing and contrasting a CEA model informed by an omalizumab efficacy trial to a CEA model drawing primarily on evidence from effectiveness observational studies of omalizumab. There was reasonable agreement between the two omalizumab CEA models, although the incremental cost-effectiveness ratio generated by the effectiveness observational study-driven model was more favorable for omalizumab. Health technology assessment bodies and payers must use their judgment to determine which components of efficacy-based and effectiveness-based CEA evidence are most closely aligned with their goals. For each CEA evidence component, perhaps the two E's form bounds of the truth as well as a fuller picture of the uncertainty surrounding the truth.

Asthma control in severe asthmatics under treatment with omalizumab: a cross-sectional observational study in Italy

Few data are available on the proportion of asthmatics achieving a good asthma control (according GINA guidelines) and on the level of airway inflammation during omalizumab treatment. The aim of this cross-sectional national observational study was to assess the level of control (according to GINA guidelines) achieved in a group of asthmatics on omalizumab treatment, and to characterize the factors that influence the lack of control. We studied 306 asthmatics under omalizumab treatment for a median of 32 months (range 4-120). The level of control according to GINA was good in 25.2%, partial in 47.1% and poor in 24.5% of patients (data were missing for the remaining 3.2%). Comparison between poorly controlled and partially or well controlled asthmatics showed a statistically significant higher prevalence of some comorbidities in the first group, namely obesity, gastro-oesophageal reflux disease (GORD), aspirin intolerance and mental disorders (all p < 0.001). Similarly, asthmatics with at least one exacerbation in the last year showed a significantly higher prevalence of obesity, chronic rhinosinusitis, nasal polyps, GORD, and aspirin intolerance (all p < 0.05) than patients without exacerbations. When we selected patients without relevant comorbidities (upper airways disease, GORD, obesity, aspirin intolerance) and not currently smoking (N = 73), the percentage of well or partially controlled asthmatics was significantly higher than in patients with comorbidities (84.9% vs 71.1%, p = 0.02); the rate of asthmatics without exacerbations in the last year was also higher (73.6% vs 51.1%, p = 0.001). During omalizumab treatment, a high percentage of asthmatics obtain a good or partial control of asthma. Comorbidities are associated with the lack of asthma control and persistence of exacerbations.

A budget impact analysis of bronchial thermoplasty for severe asthma in clinical practice

INTRODUCTION

Fully 80% of asthma-related deaths occur in patients with uncontrolled disease and 50% of all costs are attributable to this subgroup. Although asthma is costly, direct costs and loss of productivity have only recently been extensively studied, partly as a result of the introduction of new and more costly treatment options. A 5-year population-based budget impact model in the perspective of the Emilia Romagna of Italy regional healthcare service compared the impact of adding adjuvant bronchial thermoplasty (BT) for a population of patients with severe, uncontrolled asthma treated with standard care (SC) with or without adjuvant omalizumab (OMAL).

METHODS

The model compared the budget impact of two scenarios: the first examined a population treated either with SC alone or with administration of OMAL concurrent to SC; the second examined a population treated either with SC alone or with either the concurrent administration of OMAL or BT.

RESULTS

The cost for treating asthmatics patients in Emilia Romagna with BT would require 17.7 million Euros during the initial year; these costs would be offset by savings of 1 million Euros, 10.5 million Euros, and up to 19.2 million Euros during third, fourth, and fifth years, respectively.

CONCLUSION

Despite the increase in direct costs, the complementary treatment of patients with either BT or OMAL in addition to SC may not only help the clinician to meet the needs of a greater number of patients, but also decreases emergency room visits and hospitalizations, as well as generates economic savings in the longer term.

Loss of asthma control after cessation of omalizumab treatment: real life data

INTRODUCTION

Many clinical and observational studies have demonstrated effectiveness of omalizumab (OMA) in the treatment of severe asthma, but the optimal duration of the therapy remains unknown.

AIM

The article presents the authors' clinical experience on OMA cessation in routine practice.

MATERIAL AND METHODS

Due to new reimbursement criteria, OMA therapy has been interrupted in 11 subjects (6 women/5 men). The mean age of patients was 50.73 ±14.16 years, the mean time of severe asthma duration was 13.54 ±6.05 years. All of them had an excellent/good response to OMA. The duration of OMA therapy was 67.73 ±11.64 months.

RESULTS

Nine out of 11 patients had severe asthma exacerbation within the first 5 months after the OMA withdrawal. The mean time to the first severe exacerbation was 7.56 ±2.67 weeks. Between the time of OMA cessation and the time of reassessment, the mean score of Asthma Control Questionnaire increased from 2.58 ±0.71 to 3.63 ±1.26 points and the mean score of Asthma Quality of Life Questionnaire decreased from 4.3 ±1.91 to 3.18 ±1.17 points. The mean oral corticosteroids (OCS) dose increased from 4.61 ±3.0 mg/day to 33.33 ±13.12 mg/day. The number of exacerbations within the last 12 months increased from 1.6 ±0.67 to 5.2 ±1.4, and the number of hospitalizations or emergency room (ER) attendence increased from 0.11 ±0.31 to 1.56 ±1.26.

CONCLUSIONS

These data indicate that the withdrawal of OMA therapy after the successful long-term therapy may cause severe asthma exacerbations. Therefore, the decision regarding cessation of OMA treatment should be undertaken individually after careful weighing benefits and risks, especially in patients with a long history of severe asthma, treated with high doses of OCS before OMA introduction, near-fatal asthma events and/or aggravation of asthma during previous episodes of interruptions in OMA treatment.

Fungi: the neglected allergenic sources

Allergic diseases are considered the epidemics of the twentieth century estimated to affect more than 30% of the population in industrialized countries with a still increasing incidence. During the past two decades, the application of molecular biology allowed cloning, production and characterization of hundreds of recombinant allergens. In turn, knowledge about molecular, chemical and biologically relevant allergens contributed to increase our understanding of the mechanisms underlying IgE-mediated type I hypersensitivity reactions. It has been largely demonstrated that fungi are potent sources of allergenic molecules covering a vast variety of molecular structures including enzymes, toxins, cell wall components and phylogenetically highly conserved cross-reactive proteins. Despite the large knowledge accumulated and the compelling evidence for an involvement of fungal allergens in the pathophysiology of allergic diseases, fungi as a prominent source of allergens are still largely neglected in basic research as well as in clinical practice. This review aims to highlight the impact of fungal allergens with focus on asthma and atopic dermatitis.

Novel therapies in asthma: leukotriene antagonists, biologic agents, and beyond

Asthma is one of the most common conditions seen in clinical practice and carries both a significant disease burden in terms of patient morbidity and a high economic burden in both direct and indirect costs. Despite this, it remains a comparatively poorly understood disease, with only modest advances in treatment over the past decade. Corticosteroids remain the cornerstone of therapy. Both patient compliance with medications and physician adherence to evidence-based guidelines are often poor, and a high percentage of patients continue to have inadequately controlled disease even with optimal therapy. Following a contextual overview of the current treatment guidelines, this review focuses on novel asthma therapies, beginning with the introduction of the leukotriene receptor antagonist zafirlukast in the 1990s, continuing through advanced endoscopic therapy and into cytokine-directed biologic agents currently in development. Along with clinically relevant biochemistry and pharmacology, the evidence supporting the place of these therapies in current guidelines will be highlighted along with data comparing these agents with more conventional treatment. A brief discussion of other drugs, such as those developed for unrelated conditions and subsequently examined as potential asthma therapies, is included.

[Targeted therapies in severe asthma: the discovery of new molecules]

The pathophysiological mechanisms involved in the chronicity and phenotypic heterogeneity of asthma offer the prospect of new therapeutic opportunities. A better clinical and biological characterisation of selected patients has led to the development of targeted therapies. Studies are under way to demonstrate their efficacy and tolerance and also their impact on the natural history of the disease. This revue aims to examine the therapies, developed during the last ten years, that are based on the immunological mechanisms involved in the pathophysiology of asthma, essentially in its severe form. The rapid expansion of human monoclonal antibodies has allowed testing of various immunological pathways. Anti-IgE, anti- IL-5, and anti-IL-13 strategies seem the most promising. Antagonists to TNF-alpha and I'IL-4 have not succeeded in reducing the events related to severe asthma in a convincing manner. Molecules targeted against thymic stromal lymphopoietin (TSLP) and I'IL-9 are under development. These approaches are involved in the development of therapeutic programmes adapted to the patient's phenotype, that is to say a personalised approach to care.

Cost-Effectiveness Analysis of Omalizumab for the Treatment of Severe Asthma in Japan and the Value of Responder Prediction Methods Based on a Multinational Trial

OBJECTIVES

Omalizumab improves health outcomes for patients with severe asthma. The purpose of this study was to conduct a cost-utility analysis of omalizumab from a societal perspective by using the results from a randomized controlled trial in Japan, and explore the efficient use of omalizumab.

METHODS

We developed a Markov model to compare omalizumab add-on therapy with standard therapy. Patients transitioned between symptom-free, day-to-day, and exacerbation states. Our model had a lifetime horizon in which 5-year omalizumab add-on therapy was followed by standard therapy. Preference-based utilities were extracted from another study. We estimated the expected value of perfect information for patients' response to omalizumab.

RESULTS

In the base case, incremental cost-effectiveness ratio (ICER) for omalizumab add-on therapy was US $755,200 (95% credible interval [CI] $614,200-$1,298,500) per quality-adjusted life-year gained, compared with standard therapy alone. One-way sensitivity analyses indicated that the results were sensitive to asthma-related mortality, exacerbation risk, and omalizumab cost. The ICER for a responder subgroup was 22% lower than that in the base case. Individual and population expected value of perfect informations for the response were $4100 (95% CI $2500-$6000) and $28 million (95% CI $17 million-$42 million) per year, respectively.

CONCLUSIONS

With a willingness-to-pay of $45,000 per quality-adjusted life-year, omalizumab was not cost-effective in Japan. Confining omalizumab therapy to previously predicted responders, however, may be a reasonable strategy to reduce the ICER, as the cost-effectiveness was observed to improve for these patients. Further studies should be conducted to explore responder prediction methods. Decreasing the price of omalizumab would improve cost-effectiveness.

EAACI: A European Declaration on Immunotherapy. Designing the future of allergen specific immunotherapy

Allergy today is a public health concern of pandemic proportions, affecting more than 150 million people in Europe alone. In view of epidemiological trends, the European Academy of Allergy and Clinical Immunology (EAACI) predicts that within the next few decades, more than half of the European population may at some point in their lives experience some type of allergy.

Not only do allergic patients suffer from a debilitating disease, with the potential for major impact on their quality of life, career progression, personal development and lifestyle choices, but they also constitute a significant burden on health economics and macroeconomics due to the days of lost productivity and underperformance. Given that allergy triggers, including urbanization, industrialization, pollution and climate change, are not expected to change in the foreseeable future, it is imperative that steps are taken to develop, strengthen and optimize preventive and treatment strategies.

Allergen specific immunotherapy is the only currently available medical intervention that has the potential to affect the natural course of the disease. Years of basic science research, clinical trials, and systematic reviews and meta-analyses have convincingly shown that allergen specific immunotherapy can achieve substantial results for patients, improving the allergic individuals’ quality of life, reducing the long-term costs and burden of allergies, and changing the course of the disease. Allergen specific immunotherapy not only effectively alleviates allergy symptoms, but it has a long-term effect after conclusion of the treatment and can prevent the progression of allergic diseases.

Unfortunately, allergen specific immunotherapy has not yet received adequate attention from European institutions, including research funding bodies, even though this could be a most rewarding field in terms of return on investments, translational value and European integration and, a field in which Europe is recognized as a worldwide leader. Evaluation and surveillance of the full cost of allergic diseases is still lacking and further progress is being stifled by the variety of health systems across Europe. This means that the general population remains unaware of the potential use of allergen specific immunotherapy and its potential benefits.

We call upon Europe’s policy-makers to coordinate actions and improve individual and public health in allergy by:

Promoting awareness of the effectiveness of allergen specific immunotherapy

Updating national healthcare policies to support allergen specific immunotherapy

Prioritising funding for allergen specific immunotherapy research

Monitoring the macroeconomic and health economic parameters of allergy

Reinforcing allergy teaching in medical disciplines and specialties

The effective implementation of the above policies has the potential for a major positive impact on European health and well-being in the next decade.

Immunologic therapeutic interventions in asthma: impact on natural history

The discovery of new pathobiological pathways involved in asthma chronicity and reliefs offers novel therapeutic avenues. Enhanced phenotyping criteria associated with simple biologic characterization allowed to test targeted interventions in selected patients. Long-term studies are de facto lacking but required to address their impact on the natural history of the disease. Here, the authors review all potential available therapeutics based on immunologic pathways involved in asthma pathophysiology during the last decade.

Inhibition of ongoing allergic reactions using a novel anti-IgE DARPin-Fc fusion protein

BACKGROUND

Aggregation of the high-affinity IgE receptor (FcεRI) with the low-affinity IgG receptor (FcγRIIb) on basophils or mast cells has been shown to inhibit allergen-induced cell degranulation. Molecules cross-linking these two receptors might therefore be of interest for the treatment of allergic disorders. Here, we demonstrate the generation of a novel bispecific fusion protein efficiently aggregating FcεRI-bound IgE with FcγRIIb on the surface of basophils to prevent pro-inflammatory mediator release.

METHODS

Alternative binding molecules recognizing receptor-bound human IgE were selected from DARPin (designed ankyrin repeat protein) libraries. One of the selected DARPins was linked to the Fc-part of a human IgG(1) antibody for binding to FcγRIIb.

RESULTS

The resulting anti-IgE DARPin-Fc fusion protein was not anaphylactogenic and inhibited allergen-induced basophil activation in whole blood assays. Both binding moieties of the fusion protein, namely the anti-IgE DARPin as well as the IgG(1) Fc-part, were required to achieve this inhibitory effect. Most importantly, inhibition was faster and more efficient than with Omalizumab, a humanized anti-IgE antibody currently used for the treatment of severe asthma.

CONCLUSION

This novel anti-IgE DARPin-Fc fusion protein might represent a potential drug candidate for preventive or immediate treatment of allergic reactions.

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.

The costs and consequences of omalizumab in uncontrolled asthma from a USA payer perspective

BACKGROUND

Omalizumab, an anti-immunoglobulin E antibody, reduces exacerbations and symptoms in uncontrolled allergic asthma. The study objective was to estimate the costs and consequences of omalizumab compared to usual care from a US payer perspective.

METHODS

We estimated payer costs, quality-adjusted survival (QALYs), and the incremental cost-effectiveness ratio (ICER) of omalizumab compared to usual care using a state-transition simulation model that included sensitivity analyses. Every 2 weeks, patients could transition between chronic asthma and exacerbation health states. The best available evidence informed the clinical and cost input estimates. Five years of omalizumab treatment followed by usual care was assumed to estimate a lifetime horizon. Omalizumab responders (60.5% of treated) were modeled as a separate scenario where nonresponders reverted back to usual care after 16 weeks of active treatment.

RESULTS

The mean lifetime discounted costs and QALYs were $83,400 and 13.87 for usual care and $174,500 and 14.19 for omalizumab plus usual care resulting in $287 200/QALY (95% interval: $219,300, $557, 900). The ICER was $172 300/QALY when comparing omalizumab to usual care in the responder scenario. One-way sensitivity analyses indicated that the results were sensitive to the difference in treatment-specific utilities for the chronic state, exacerbation-associated mortality, omalizumab price, exacerbation rates, and response definition.

CONCLUSIONS

The results suggest that adding omalizumab to usual care improves QALYs at an increase in direct medical costs. The cost-effectiveness of omalizumab is similar to other chronic disease biologics. The value increases when omalizumab response is used to guide long-term treatment.

IgE in the human placenta: why there?

Immunoglobulin E (IgE) antibodies are key effector molecules in the allergic inflammatory response and are also involved in the protection against extracellular parasites. Allergic symptoms often develop early in life, and the intrauterine environment has been proposed to play an important role in affecting the risk of later allergy development. The placenta constitutes a selective barrier between the maternal and foetal circulation. Recently, we reported that maternal IgE antibodies are present on foetal macrophages in the villous tissue of the human placenta irrespective of maternal allergy status. This review discusses the presence of IgE antibodies in the human placenta and its possible roles in normal and pathologic pregnancy. It also deals with the relationship between placental IgE and development of allergy during childhood. A better understanding of the role of IgE in placenta could give us clues on how to prevent allergy development in the future generations.

[GA2LEN (Global Allergy and Asthma European Network), the perspective of the German speaking centers]

Allergic diseases represent a major health problem in Europe. They are increasing in prevalence, severity and costs. GA2LEN (Global Allergy and Asthma European Network), an FP6 Network of Excellence, was created in 2005 as a vehicle to ensure excellence in research bringing together research and clinical institutions to combat fragmentation in the European research area and to tackle allergy as a whole. GA2LEN benefited greatly from the voluntary efforts of researchers who are strongly committed to this model of pan-European collaboration. The network was organized in order to increase networking for scientific projects in allergy and asthma around Europe and to make GA2LEN the world leader in the field. Besides these activities, research has been jointly made and the first papers are being published. GA2LEN achievements in general can be grouped as those for a durable infrastructure built up during the project phase those which are project-related work based on these novel infrastructures, and the development and implementations of guidelines. The major achievements of GA2LEN are reported in this paper.

Adding omalizumab to the therapy of adolescents with persistent uncontrolled moderate--severe allergic asthma

OBJECTIVE

This study aimed to evaluate the effectiveness of omalizumab among adolescents with moderate-severe allergic asthma inadequately controlled with inhaled corticosteroids.

PATIENTS AND METHODS

Data from patients 12 to 17 years of age were pooled from 5 placebo-controlled registration trials of omalizumab. Impact on asthma control was assessed by need for rescue bursts of oral corticosteroids, lung function, symptom scores, and unscheduled office visits.

RESULTS

In adolescents (n = 146), addition of omalizumab decreased mean number of rescue bursts (0.3 vs 0.9) versus placebo; relative risk 0.47 (95% confidence interval [CI], 0.22-0.99; P = .047). At study conclusion, mean forced expiratory volume in 1 second increased 268 mL (13.8%) in omalizumab-treated subjects versus 98 mL (5.5%) for placebo (least squares mean treatment difference 146 mL [95% CI, 19.4-272.6; P = .024]). Omalizumab significantly improved asthma symptom scores and reduced unscheduled office visits.

CONCLUSION

Omalizumab added to baseline therapy improves measures of asthma control in adolescents with persistent moderate-severe allergic asthma.

[GA2LEN (Global Allergy and Asthma European Network)]

Allergic diseases represent a major health problem in Europe. They are increasing in prevalence, severity and costs. GA2LEN (Global Allergy and Asthma European Network), an FP6 Network of Excellence, was created in 2005 as a vehicle to ensure excellence in research bringing together research and clinical institutions to combat fragmentation in the European research area and to tackle Allergy in its globality. GA2LEN benefited greatly from the voluntary efforts of researchers who are strongly committed to this model of pan-European collaboration. The network was organized in order to increase networking for scientific projects in allergy and asthma around Europe and to make GA2LEN the world leader in the field. Besides these activities, research has been jointly made and the first papers are being published. GA2LEN achievements in general can be grouped as those for a durable infrastructure built up during the project phase those which are project-related work based on these novel infrastructures, and the development and implementations of guidelines. The major achievements of GA2LEN are reported in this paper.

Omalizumab: overview of pharmacology and efficacy in asthma

BACKGROUND

Omalizumab is a monoclonal, humanized antibody specific for the region of IgE that binds to the high affinity IgE receptor on basophils and mast cells. Subcutaneous administration of omalizumab reduces the serum IgE concentration within hours and reduces the number of high affinity IgE receptors expressed on basophils and mast cells over 8 - 12. weeks.

METHODS

A literature search of PubMed was performed using terms omalizumab or monoclonal and asthma.

RESULTS/CONCLUSION

Asthma exacerbations are reduced by 19 - 75% with omalizumab therapy added to inhaled corticosteroid therapy, with or without long acting beta agonists and leukotriene modifiers. Approximately 60% of treated subjects show a response and 12 - 16 weeks are generally needed to evaluate response. Omalizumab is cost-effective if high-risk responders are treated. Side effects include 0.2% frequency of systemic reactions to the injections and 2% of subjects with local injection reactions, which do not usually require treatment.

GA2LEN (Global Allergy and Asthma European Network) addresses the allergy and asthma 'epidemic'

Allergic diseases represent a major health problem in Europe. They are increasing in prevalence, severity and costs. The Global Allergy and Asthma European Network (GA(2)LEN), a Sixth EU Framework Program for Research and Technological Development (FP6) Network of Excellence, was created in 2005 as a vehicle to ensure excellence in research bringing together research and clinical institutions to combat fragmentation in the European research area and to tackle allergy in its globality. The Global Allergy and Asthma European Network has benefited greatly from the voluntary efforts of researchers who are strongly committed to this model of pan-European collaboration. The network was organized in order to increase networking for scientific projects in allergy and asthma around Europe and to make GA(2)LEN the world leader in the field. Besides these activities, research has also been carried out and the first papers are being published. Achievements of the Global Allergy and Asthma European Network can be grouped as follows: (i) those for a durable infrastructure built up during the project phase, (ii) those which are project-related and based on these novel infrastructures, and (iii) the development and implementation of guidelines. The major achievements of GA(2)LEN are reported in this paper.

Omalizumab in the management of patients with allergic (IgE-mediated) asthma

Immunoglobulin E (IgE) is central to the pathophysiology of allergic asthma. Omalizumab, an anti-IgE monoclonal antibody, binds to the FcɛRI binding site on free IgE. As a result, circulating free IgE is reduced, IgE is prevented from attaching to mast cells and basophils, and FcɛRI receptor expression is down-regulated. The inflammatory response to allergens and the acute and chronic effector phases of allergic inflammation are thereby attenuated. In clinical trials in adults and adolescents, omalizumab reduced asthma exacerbations, severe asthma exacerbations, inhaled corticosteroid requirements, and emergency visits, as well as significantly improving asthma-related quality of life, morning peak expiratory flow and asthma symptom scores in patients with severe allergic (IgE-mediated) asthma. Results from clinical trials in children (<12 years) are consistent with those in the adult population. It is difficult to predict which patients will respond to omalizumab. Responders to omalizumab should be identified after a 16-week trial of therapy using the physician's overall assessment. When treatment is targeted to these responders, omalizumab provides a cost-effective therapy for inadequately controlled severe allergic (IgE-mediated) asthma. Long-term therapy with omalizumab shows the potential for disease-modification in asthma. Ongoing studies are also evaluating the use of omalizumab in other non-asthma IgE-mediated conditions.

Clinical Immunology Review Series: An approach to the patient with allergy in childhood

Allergic conditions are common, with asthma being the most common chronic illness in childhood in most developed countries. Some 80% of asthmatic children are sensitized to aeroallergens, usually indoor animal dander and house dust mite. Some 80% of asthmatics also have rhinitis. Rhinitis and eczema receive less medical attention than asthma, but they can cause longterm morbidity and have substantial direct and indirect economic costs. Food allergy and anaphylaxis are increasingly recognised and are usually easily diagnosed and managed.Clinicians can use in vivo and in vitro measurements of allergen-specific immunoglobulin E to better time reintroduction of implicated foods. Specific parenteral and sublingual immunotherapy is widely practiced internationally but is uncommon in the UK. It may alter the natural history of aeroallergen reactive diseases in the upper and lower airways. Specific oral tolerance induction represents the current cutting edge in clinical allergy research. It remands resource intensive at present and cannot be adopted into routine clinical practice at this time.

Acute exacerbations of asthma: epidemiology, biology and the exacerbation-prone phenotype

Asthma is a highly prevalent chronic respiratory disease affecting 300 million people world-wide. A significant fraction of the cost and morbidity of asthma derives from acute care for asthma exacerbations. In the United States alone, there are approximately 15 million outpatient visits, 2 million emergency room visits, and 500,000 hospitalizations each year for management of acute asthma. Common respiratory viruses, especially rhinoviruses, cause the majority of exacerbations in children and adults. Infection of airway epithelial cells with rhinovirus causes the release of pro-inflammatory cytokines and chemokines, as well as recruitment of inflammatory cells, particularly neutrophils, lymphocytes, and eosinophils. The host response to viral infection is likely to influence susceptibility to asthma exacerbation. Having had at least one exacerbation is an important risk factor for recurrent exacerbations suggesting an 'exacerbation-prone' subset of asthmatics. Factors underlying the 'exacerbation-prone' phenotype are incompletely understood but include extrinsic factors: cigarette smoking, medication non-compliance, psychosocial factors, and co-morbidities such as gastroesophageal reflux disease, rhinosinusitis, obesity, and intolerance to non-steroidal anti-inflammatory medications; as well as intrinsic factors such as deficient epithelial cell production of the anti-viral type I interferons (IFN-alpha and IFN-beta). A better understanding of the biologic mechanisms of host susceptibility to recurrent exacerbations will be important for developing more effective preventions and treatments aimed at reducing the significant cost and morbidity associated with this important global health problem.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Siglec-8 on human eosinophils and mast cells, and Siglec-F on murine eosinophils, are functionally related inhibitory receptors

Siglecs (sialic acid-binding, Ig-like lectins) are a family of single-pass transmembrane cell surface proteins found predominantly on leucocytes. Their unique structural characteristics include an N-terminal carbohydrate-binding ('lectin') domain that binds sialic acid, followed by a variable number of Ig-like domains, hence these structures are a subset of the Ig gene superfamily. Another unique feature of Siglecs is that most, but not all, possess so-called immunoreceptor tyrosine-based inhibitory motifs in their cytoplasmic domains, suggesting that these molecules function in an inhibitory capacity. Siglec-8, the eighth member identified at the time, was discovered as part of an effort initiated almost a decade ago to identify novel human eosinophil and mast cell proteins. Since that time, its selective expression on human eosinophils and mast cells has been confirmed. On eosinophils, Siglec-8 engagement results in apoptosis, whereas on mast cells, inhibition of FcepsilonRI-dependent mediator release, without apoptosis, is seen. It has subsequently been determined that the closest functional paralog in the mouse is Siglec-F, selectively expressed by eosinophils but not expressed on mast cells. Despite only modest homology, both Siglec-8 and Siglec-F preferentially recognize a sulphated glycan ligand closely related to sialyl Lewis X, a common ligand for the selectin family of adhesion molecules. Murine experiments in normal, Siglec-F-deficient mice and hypereosinophilic mice have resulted in similar conclusions that Siglec-F, like Siglec-8, plays a distinctive and important role in regulating eosinophil accumulation and survival in vivo. Given the resurgent interest in eosinophil-directed therapies for a variety of disorders, plus its unique additional ability to also target the mast cell, therapies focusing on Siglec-8 could some day prove to be a useful adjunct to our current armamentarium for the treatment of asthma, allergies and related disorders where overproduction and overactivity of eosinophils and mast cells is occurring.

Omalizumab in the treatment of severe asthma: efficacy and current problems

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 their interactions 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 relevant improvements in respiratory symptoms and quality of life, paralleled by a marked 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.