A pilot study of omalizumab to facilitate rapid oral desensitization in high-risk peanut-allergic patients

Pharmacoeconomics of Biologic Therapy

Novel biologic agents have allowed clinicians to achieve improved patient outcomes. Appropriate pharmacoceconomic analyses demand evaluation of all relevant costs, including the treatments, the disease and comorbidities, and costs of alternative treatments, including their short- and long-term side effects. Only with complete data can the value of therapies be correctly estimated. By assessing costs, pharmacoeconomic studies complement studies of efficacy and safety, helping to determine the relationships of treatment and outcome. This article provides a broad framework for understanding and evaluating published economic analyses and identifying the key costs and benefits caring for patients with asthma and other immune diseases.

[Omalizumab: Beyond anti-IgE properties]

INTRODUCTION

Omalizumab is used as a treatment for severe allergic asthma. Its intended mechanism of action is based on its anti-IgE proprieties. However, recent studies have highlighted other mechanisms of action.

STATE OF THE ART

Omalizumab treatment is associated with a decrease in the number of dendritic cells, T and B lymphocytes and eosinophils. This anti-inflammatory activity is characterized by a decrease in the levels of several cytokines involved in the recruitment, activation and survival of eosinophils and mastocytes, and in a Th2 orientation of the immune response. A modulation of bronchial remodeling by omalizumab has recently been shown. A decrease in the production of extracellular matrix components and in the proliferation of smooth muscle cells could be involved in this modulation. These mechanisms of action could explain in part the clinical efficiency of omalizumab in non-allergic conditions such as non-allergic asthma, non-allergic urticaria or nasal polyposis.

CONCLUSION

A precise knowledge of the mechanisms of action of omalizumab could allow the identification of biomarkers predictive of efficacy of this treatment. These could be useful tools in the phenotyping of severe asthma.

Update on Potential Therapies for IgE-Mediated Food Allergy

PURPOSE OF REVIEW

Food allergy is common, affecting up to 8% of children in the USA. Currently, therapy is limited to avoidance of the implicated allergen and availability of self-injectable epinephrine. However, several new approaches to food allergy are under investigation. This article reviews the published data on these new approaches.

RECENT FINDINGS

Oral immunotherapy, in which allergic subjects are exposed to increasing amounts of antigen, can be accomplished in the majority of allergic individuals. However, this approach is not a cure as most patients will react after cessation of regular intake. In addition, there is a high rate of side effects. Other approaches include epicutaneous immunotherapy, therapy with anti-IgE medications, and use of Chinese herbs. Several novel approaches on food allergy are under study. At the current time, these approaches show promise for preventing severe reactions to accidental exposures. However, there is little evidence that current approaches will represent a true cure for food allergy.

Biological Modulators in Eosinophilic Diseases

Eosinophils can regulate local and systemic inflammation, and their presence in higher numbers appears to play an important role in the pathology of various atopic and inflammatory diseases. Eosinophil maturation, recruitment, and survival depend on several cytokine regulators, including interleukin (IL)-5, IL-4, and IL-13 as well as growth factors such as GM-CSF. Over the last decade, the approach to treating eosinophilic diseases has changed greatly. A number of biologic modulators have been developed to target eosinophilic inflammatory pathways, and their usage has resulted in variable clinical improvement in the treatment of eosinophilic-associated conditions. Novel targeted therapies that are safe and effective for treating these disorders are being investigated. This review summarizes the clinical use of biologic agents that have been studied in clinical trials or approved for treating eosinophilic diseases.

From IgE to Omalizumab

IgE is the least abundant Ig isotype, yet it plays a critical role in allergic reactions and host protection from helminth infection. Although IgE was discovered 50 years ago, the ultimate evidence for its role in human allergic diseases was obtained by the efficacy of anti-IgE therapy in many clinical trials on asthma and other allergic diseases. Beginning from the discovery of IgE 50 y ago, followed by studies of IgE receptors and activation mechanisms, this review provides a historic perspective of allergy research that has led to the development of anti-IgE therapy and other strategies targeting IgE and its receptors. Current IgE studies toward future precision medicine are also reviewed.

Specific oral tolerance induction in childhood

Food allergy continues to be a significant public health concern for which there are no approved treatments and management strategies primarily include allergen avoidance and pharmacological measures for accidental exposures. Food allergy is thought to result from either a failure to establish oral tolerance or the breakdown of existing oral tolerance, and therefore, experimental preventative and treatment strategies are now aimed at inducing specific oral tolerance. This may occur in infancy prior to the development of food allergy through the optimal timing of dietary exposure (primary oral tolerance induction) or as a treatment for established food allergy through oral immunotherapy (secondary oral tolerance induction). Trials examining the effectiveness of early dietary allergen exposure to prevent food allergy have yielded promising results for peanut allergy but not so for other allergens, although the results of several trials are yet to be published. Although infant feeding guidelines no longer advise to avoid allergenic foods and exposure to food allergens orally is an important step in inducing food tolerance by the immune system, evidence regarding the optimal timing, dose and form of these foods into the infant's diet is lacking. Likewise, oral immunotherapy trials appear promising for inducing desensitization; however, the long-term efficacy in achieving sustained desensitization and optimal protocols to achieve this is unknown. More research is needed in this emerging field.

Food allergy: immune mechanisms, diagnosis and immunotherapy

Food allergy is a pathological, potentially deadly, immune reaction triggered by normally innocuous food protein antigens. The prevalence of food allergies is rising and the standard of care is not optimal, consisting of food-allergen avoidance and treatment of allergen-induced systemic reactions with adrenaline. Thus, accurate diagnosis, prevention and treatment are pressing needs, research into which has been catalysed by technological advances that are enabling a mechanistic understanding of food allergy at the cellular and molecular levels. We discuss the diagnosis and treatment of IgE-mediated food allergy in the context of the immune mechanisms associated with healthy tolerance to common foods, the inflammatory response underlying most food allergies, and immunotherapy-induced desensitization. We highlight promising research advances, therapeutic innovations and the challenges that remain.

Food Allergy: What We Know Now

Food allergy is an adverse immune reaction that occurs reproducibly on exposure to a given food. Prevalence rates of food allergy continue to increase worldwide, sparking continual research efforts in finding a suitable and safe cure. Food avoidance, the current standard of care, can be difficult to achieve. This review aims to provide a broad overview of immunoglobulin E-mediated food allergy, highlighting its epidemiology, masqueraders, immunopathophysiology, clinical presentation, diagnostic work-up and available preventative and treatment strategies. This review also discusses novel, investigative therapies that offer promising therapeutic options, yet require continued research efforts to determine safety effects. Inducing tolerance, whether by immunotherapy or by the administration of monoclonal antibodies, allows us to move toward a cure for food allergy, which could vastly change this field of allergic diseases in the coming decades.

Off-Label Uses of Omalizumab

The off-label use of medicines is a common and extensive clinical practice. Omalizumab has been licensed for use in severe allergic asthma and chronic urticaria. Omalizumab dosing was based on body weight and baseline serum IgE concentration. All patients are required to have a baseline IgE between 30 and 700 IU/ml and body weight not more than 150 kg. The use of off-label drugs may lead to several problems including adverse effects and an increased risk/benefit balance. In this article, there are summarized off-label uses of omalizumab in the last recent years in diseases in which IgE maybe or certainly has a corner role such as allergic rhinitis, allergic bronchopulmonary aspergillosis, anaphylaxis, keratoconjunctivitis, food allergy, drug allergy, urticaria, angioedema, non-atopic asthma, atopic dermatitis, nasal polyps, Churg-Strauss syndrome, eosinophilic otitis media, chronic rhinosinusitis, bullous pemphigoid, contact dermatitis, and others. Use in pregnancy asthmatic women and pre-co-administration with specific immunotherapy will also be revised.

Treatment of allergic children - Where is the progress (for the practicing allergist)?

For any kind of therapeutic intervention in allergic diseases such as environmental control, pharmacological, or immunomodulating treatment including educational programs, children are addressed separately from adults. Health authorities like the Food and Drug Administration in the United States of America or the European Medicine Agency in Europe request a specific 'Pediatric investigational plan' with studies addressing dose-response relationship, safety, and efficacy for infants, children, and adolescents. During the last 2 years, promising advances have been reported for the treatment of a variety of allergic and immunologic disorders. This review summarizes the progress in the treatment of pediatric asthma and allergic diseases, based on publications of approximately the last 2.5 years (end of 2013 until May 2016) in and beyond this journal. Meanwhile, it highlights areas with promising novel therapeutic approaches, which are likely to change treatment for allergic children in the near future.

Epicutaneous immunotherapy for the treatment of peanut allergy in children and young adults

BACKGROUND

Peanut allergy is common, life-threatening, and without therapeutic options. We evaluated peanut epicutaneous immunotherapy (EPIT) by using Viaskin Peanut for peanut allergy treatment.

OBJECTIVE

We sought to evaluate the clinical, safety, and immunologic effects of EPIT for the treatment of peanut allergy.

METHODS

In this multicenter, double-blind, randomized, placebo-controlled study, 74 participants with peanut allergy (ages 4-25 years) were treated with placebo (n = 25), Viaskin Peanut 100 μg (VP100; n = 24) or Viaskin Peanut 250 μg (VP250; n = 25; DBV Technologies, Montrouge, France). The primary outcome was treatment success after 52 weeks, which was defined as passing a 5044-mg protein oral food challenge or achieving a 10-fold or greater increase in successfully consumed dose from baseline to week 52. Adverse reactions and mechanistic changes were assessed.

RESULTS

At week 52, treatment success was achieved in 3 (12%) placebo-treated participants, 11 (46%) VP100 participants, and 12 (48%) VP250 participants (P = .005 and P = .003, respectively, compared with placebo; VP100 vs VP250, P = .48). Median change in successfully consumed doses were 0, 43, and 130 mg of protein in the placebo, VP100, and VP250 groups, respectively (placebo vs VP100, P = .014; placebo vs VP250, P = .003). Treatment success was higher among younger children (P = .03; age, 4-11 vs >11 years). Overall, 14.4% of placebo doses and 79.8% of VP100 and VP250 doses resulted in reactions, predominantly local patch-site and mild reactions (P = .003). Increases in peanut-specific IgG₄ levels and IgG₄/IgE ratios were observed in peanut EPIT-treated participants, along with trends toward reduced basophil activation and peanut-specific T_H2 cytokines.

CONCLUSIONS

Peanut EPIT administration was safe and associated with a modest treatment response after 52 weeks, with the highest responses among younger children. This, when coupled with a high adherence and retention rate and significant changes in immune pathways, supports further investigation of this novel therapy.

Advances in food allergy oral immunotherapy: toward tolerance

The incidence of food allergy, a disease characterized by adverse immune responses that can render common foods life-threatening, is rising. Yet our current standard of care is simply avoidance of allergenic foods and administration of emergency medications upon accidental exposure. Significant advances have been made in food allergy oral immunotherapy, which is emerging as a potential preventive and curative treatment for this disease. The fundamental strategy of oral immunotherapy is to mitigate adverse immune responses to allergenic food proteins through repeated exposure; reduced reactivity to food allergens (desensitization) often results, but the establishment of sustained immune unresponsiveness or of permanent resolution (tolerance) is not certain. This review examines exciting recent developments in oral immunotherapy for food allergy.

Active treatment for food allergy

Food allergy has grown in rapidly in prevalence, currently affecting 5% of adults and 8% of children. Management strategy is currently limited to 1) food avoidance and 2) carrying and using rescue intramuscular epinephrine/adrenaline and oral antihistamines in the case of accidental ingestion; there is no FDA approved treatment. Recently, oral, sublingual and epicutaneous immunotherapy have been developed as active treatment of food allergy, though none have completed phase 3 study. Efficacy and safety studies of immunotherapy have been variable, though there is clearly signal that immunotherapy will be a viable option to desensitize patients. The use of bacterial adjuvants, anti-IgE monoclonal antibodies, and Chinese herbal formulations either alone or in addition to immunotherapy may hold promise as future options for active treatment. Active prevention of food allergy through early introduction of potentially offending foods in high-risk infants will be an important means to slow the rising incidence of sensitization.

Peanut Allergy: New Developments and Clinical Implications

Food allergies have increased in prevalence over the past 20 years, now becoming an important public health concern. Although there are no therapies currently available for routine clinical care, recent reports have indicated that immunotherapies targeting the mucosal immune system may be effective. Oral immunotherapy is conducted by administering small, increasing amounts of food allergen; it has shown promise for desensitizing individuals with peanut, egg, or milk allergies. Sublingual immunotherapy also desensitizes allergic patients to foods-two major studies have examined the effects of sublingual immunotherapy in subjects with peanut allergies. We review the complex nature of IgE-mediated food allergies and the therapies being evaluated in clinical trials. We focus on the diagnosis and management of food allergies and investigational therapies.

Omalizumab facilitates rapid oral desensitization for peanut allergy

BACKGROUND

Peanut oral immunotherapy is a promising approach to peanut allergy, but reactions are frequent, and some patients cannot be desensitized. The anti-IgE medication omalizumab (Xolair; Genentech, South San Francisco, Calif) might allow more rapid peanut updosing and decrease reactions.

OBJECTIVE

We sought to evaluate whether omalizumab facilitated rapid peanut desensitization in highly allergic patients.

METHODS

Thirty-seven subjects were randomized to omalizumab (n = 29) or placebo (n = 8). After 12 weeks of treatment, subjects underwent a rapid 1-day desensitization of up to 250 mg of peanut protein, followed by weekly increases up to 2000 mg. Omalizumab was then discontinued, and subjects continued on 2000 mg of peanut protein. Subjects underwent an open challenge to 4000 mg of peanut protein 12 weeks after stopping study drug. If tolerated, subjects continued on 4000 mg of peanut protein daily.

RESULTS

The median peanut dose tolerated on the initial desensitization day was 250 mg for omalizumab-treated subjects versus 22.5 mg for placebo-treated subject. Subsequently, 23 (79%) of 29 subjects randomized to omalizumab tolerated 2000 mg of peanut protein 6 weeks after stopping omalizumab versus 1 (12%) of 8 receiving placebo (P < .01). Twenty-three subjects receiving omalizumab versus 1 subject receiving placebo passed the 4000-mg food challenge. Overall reaction rates were not significantly lower in omalizumab-treated versus placebo-treated subjects (odds ratio, 0.57; P = .15), although omalizumab-treated subjects were exposed to much higher peanut doses.

CONCLUSION

Omalizumab allows subjects with peanut allergy to be rapidly desensitized over as little as 8 weeks of peanut oral immunotherapy. In the majority of subjects, this desensitization is sustained after omalizumab is discontinued. Additional studies will help clarify which patients would benefit most from this approach.

Oral Immunotherapy for Food Allergy

Food allergy is a potentially life-threatening condition with no approved therapies, apart from avoidance and injectable epinephrine for acute allergic reactions. Oral immunotherapy (OIT) is an experimental treatment in which food-allergic patients consume gradually increasing quantities of the food to increase their threshold for allergic reaction. This therapy carries significant risk of allergic reactions. The ability of OIT to desensitize patients to particular foods is well-documented, although the ability to induce tolerance has not been established. This review focuses on recent studies for the treatment of food allergies such as cow's milk, hen's egg, and peanut.

Desensitization for Peanut Allergies in Children

Immunotherapy for peanut allergy has been an exploding topic of study within the last few years. Sublingual, epicutaneous, and oral immunotherapy are being investigated and show promise in the treatment of peanut allergy. Oral immunotherapy has shown the most clinical benefit; however, sublingual and epicutaneous immunotherapy appear to have the most favorable safety profiles. Most studies to date suggest that only a minority of subjects achieve sustained unresponsiveness to peanut after discontinuation of immunotherapy. Recent efforts have been focused on identifying adjunct therapies, such as omalizumab, that may assist patients in achieving peanut desensitization more quickly and with greater success. Several underlying immunologic mechanisms, including a switch from IgE to IgG4 production and induction of T regulatory cells, have been studied although more research is needed to identify reliable biomarkers. This article will describe the immunotherapy approaches that are being investigated to induce peanut desensitization, and highlight the benefits and risks of these therapies that need to be considered before they are ready for routine clinical practice.

Molecular and cellular mechanisms of food allergy and food tolerance

Ingestion of innocuous antigens, including food proteins, normally results in local and systemic immune nonresponsiveness in a process termed oral tolerance. Oral tolerance to food proteins is likely to be intimately linked to mechanisms that are responsible for gastrointestinal tolerance to large numbers of commensal microbes. Here we review our current understanding of the immune mechanisms responsible for oral tolerance and how perturbations in these mechanisms might promote the loss of oral tolerance and development of food allergies. Roles for the commensal microbiome in promoting oral tolerance and the association of intestinal dysbiosis with food allergy are discussed. Growing evidence supports cutaneous sensitization to food antigens as one possible mechanism leading to the failure to develop or loss of oral tolerance. A goal of immunotherapy for food allergies is to induce sustained desensitization or even true long-term oral tolerance to food allergens through mechanisms that might in part overlap with those associated with the development of natural oral tolerance.

Local Side Effects of Sublingual and Oral Immunotherapy

Sublingual immunotherapy (SLIT) is increasingly used worldwide, and several products have been recently registered as drugs for respiratory allergy by the European Medicine Agency and the Food and Drug Administration. Concerning inhalant allergens, the safety of SLIT is overall superior to that of subcutaneous immunotherapy in terms of systemic adverse events. No fatality has been ever reported, and episodes of anaphylaxis were described only exceptionally. Looking at the historical and recent trials, most (>90%) adverse events are "local" and confined to the site of administration. For this reason, a specific grading system has been developed by the World Allergy Organization to classify and describe local adverse events. There is an increasing amount of literature concerning oral desensitization for food allergens, referred to as oral immunotherapy. Also, in this case, local side effects are predominant, although systemic adverse events are more frequent than with inhalant allergens. We review herein the description of local side effects due to SLIT, with a special focus on large trials having a declared sample size calculation. The use of the Medical Dictionary for Regulatory Activities nomenclature for adverse events is mentioned in this context, as recommended by regulatory agencies. It is expected that a uniform classification/grading of local adverse events will improve and harmonize the surveillance and reporting on the safety of SLIT.

Current and Emerging Therapies for IgE-Mediated Food Allergy

Food allergies are a growing clinical problem leading to increased health care utilization and decreases in patient quality of life. Current treatment recommendations include strict dietary avoidance of the offending food as well as use of self-injectable epinephrine in case of accidental exposure with allergic reaction. Although many individuals will eventually outgrow their food allergies, a substantial number will not. Significant effort has been made to find novel treatments that protect patients from food-triggered reactions as well as to develop immune-modulating therapies that could lead to tolerance. In this review, three therapies that have shown the most promise for the treatment of food allergies are highlighted: oral immunotherapy, sublingual immunotherapy, and epicutaneous immunotherapy.

International Consensus on Allergen Immunotherapy II: Mechanisms, standardization, and pharmacoeconomics

This article continues the comprehensive international consensus (ICON) statement on allergen immunotherapy (AIT). The initial article also recently appeared in the Journal. The conclusions below focus on key mechanisms of AIT-triggered tolerance, requirements in allergen standardization, AIT cost-effectiveness, and regulatory guidance. Potential barriers to and facilitators of the use of AIT are described in addition to future directions. International allergy specialists representing the European Academy of Allergy and Clinical Immunology; the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma and Immunology; and the World Allergy Organization critically reviewed the existing literature and prepared this summary of recommendations for best AIT practice. The authors contributed equally and reached consensus on the statements presented herein.

Anti-hIgE gene therapy of peanut-induced anaphylaxis in a humanized murine model of peanut allergy

BACKGROUND

Peanuts are the most common food to provoke fatal or near-fatal anaphylactic reactions. Treatment with an anti-hIgE mAb is efficacious but requires frequent parenteral administration.

OBJECTIVE

Based on the knowledge that peanut allergy is mediated by peanut-specific IgE, we hypothesized that a single administration of an adeno-associated virus (AAV) gene transfer vector encoding for anti-hIgE would protect against repeated peanut exposure in the host with peanut allergy.

METHODS

We developed a novel humanized murine model of peanut allergy that recapitulates the human anaphylactic response to peanuts in NOD-scid IL2Rgamma^null mice transferred with blood mononuclear cells from donors with peanut allergy and then sensitized with peanut extract. As therapy, we constructed an adeno-associated rh.10 serotype vector coding for a full-length, high-affinity, anti-hIgE antibody derived from the Fab fragment of the anti-hIgE mAb omalizumab (AAVrh.10anti-hIgE). In the reconstituted mice peanut-specific IgE was induced by peanut sensitization and hypersensitivity, and reactions were provoked by feeding peanuts to mice with symptoms similar to those of human subjects with peanut allergy.

RESULTS

A single administration of AAVrh.10anti-hIgE vector expressed persistent levels of anti-hIgE. The anti-hIgE vector, administered either before sensitization or after peanut sensitization and manifestation of the peanut-induced phenotype, blocked IgE-mediated alterations in peanut-induced histamine release, anaphylaxis scores, locomotor activity, and free IgE levels and protected animals from death caused by anaphylaxis.

CONCLUSION

If this degree of persistent efficacy translates to human subjects, AAVrh.10anti-hIgE could be an effective 1-time preventative therapy for peanut allergy and possibly other severe, IgE-mediated allergies.

[Allergen-specific immunotherapy for food allergies in childhood. Current options and future perspectives]

During recent years increasing research has been conducted on casual treatment options for food allergy, with focus on oral immunotherapy (OIT) for hen's egg, cow's milk and peanut allergy. Several studies could show that OIT leads to desensitization or an increase of threshold. However, severe adverse events during this treatment are not uncommon. Whether OIT leads to a sustained, 'robust' development of tolerance in patients has not yet been thoroughly investigated. Besides OIT, some studies on sublingual (SLIT) and epicutaneous immunotherapy (EPIT) were performed, aiming to improve the safety profile. Furthermore, there are some pilot studies investigating a combined treatment of SLIT and OIT or a combined use of anti-IgE treatment or probiotic supplementation with OIT. Further placebo-controlled trials with larger sample size are needed in order to develop standardized protocols before immunotherapy may be used as a therapeutic option for food allergy outside of clinical trials.

The Cloning and Expression of Human Monoclonal Antibodies: Implications for Allergen Immunotherapy

Allergic responses are dependent on the highly specific effector functions of IgE antibodies. Conversely, antibodies that block the activity of IgE can mediate tolerance to allergen. Technologies that harness the unparalleled specificity of antibody responses have revolutionized the way that we diagnose and treat human disease. This area of research continues to advance at a rapid pace and has had a significant impact on our understanding of allergic disease. This review will present an overview of humoral responses and provide an up-to-date summary of technologies used in the generation of human monoclonal antibodies. The impact that monoclonal antibodies have on allergic disease will be discussed, with a particular focus on allergen immunotherapy, which remains the only form of treatment that can modulate the underlying immune mechanisms and induce long-term clinical tolerance.

Food specific oral immunotherapy: a potential treatment for food allergy

Food allergy is a potentially life-threatening condition affecting up to 8% of children and up to 2% of adults in westernized countries. There are currently no approved treatments for food allergy apart from avoidance. The apparent increase in incidence of food allergies over the past few decades calls attention to the need for effective, disease-modifying therapies for food allergies. Oral immunotherapy (OIT) is a promising experimental treatment in which food allergic patients consume increasing quantities of food in attempt to increase their threshold for allergic reaction. Studies are ongoing to determine whether OIT is capable of safely inducing not only desensitization but also tolerance to the allergenic foods. This article focuses on recent relevant studies of OIT for the treatment of common food allergies.

Bortezomib treatment diminishes hazelnut-induced intestinal anaphylaxis in mice

Food allergy is a common health problem and can cause anaphylaxis. Avoidance of the offending food allergen is still the mainstay therapeutic approach. In this study, we investigated the role of plasma cell reduction by proteasome inhibition in a murine model of food allergy and examined the impact of this treatment on the systemic and local immune response. For this purpose, intestinal anaphylaxis was induced in BALB/c mice with the food allergen hazelnut, in conjunction with different adjuvants (alum and Staphylococcal enterotoxin B SEB) and different administration routes (oral and intraperitoneal). In both models, allergy symptoms were observed, but the clinical severity was more pronounced in the hazelnut-alum model than in the hazelnut-SEB model. Accordingly, allergen-specific immunoglobulin E (IgE) against hazelnut was detectable, and mast cell protease-1 in serum was increased after allergen provocation. Treatment with the proteasome inhibitor bortezomib reduced plasma cells and resulted in an abolishment of hazelnut allergen-specific IgE, which was associated with amelioration of clinical symptoms as well as a significant decrease in both CD19(+) and follicular B lymphocytes. Our data demonstrate the importance of allergen-specific IgE in food allergy and point to B cells as potential therapeutic targets for its treatment.

Assessing the efficacy of oral immunotherapy for the desensitisation of peanut allergy in children (STOP II): a phase 2 randomised controlled trial: a critical appraisal

AIM

Anagnostou et al. investigated the efficacy of oral immunotherapy (OIT) in treating peanut allergy.

SETTING AND DESIGN

An unmasked randomized controlled crossover trial of 7-16 year olds with double-blind placebo-controlled food challenge (DBPCFC)-proven peanut allergy. The first phase compared an active group undergoing 26 weeks of OIT with daily ingestion of peanut protein vs. a control group avoiding peanuts. Both groups underwent DBPCFC to peanut at 26 weeks. In the second phase the control group was then offered OIT for 26 weeks.

STUDY EXPOSURE

Participants undergoing OIT attended hospital every 2 weeks to initiate and increase their daily peanut protein dose through nine stages (2, 5, 12·5, 25, 50, 100, 200, 400 and 800 mg - about five peanuts), subsequently maintaining consumption at the highest tolerated dose. Primary outcome The primary outcome compared the proportions of active- and control-group participants able to ingest a cumulative dose of 1400 mg of peanut protein (about 10 peanuts) during their DBPCFC at the end of the first phase without reacting. Secondary outcomes Further outcomes included the proportion of participants who tolerated the top maintenance dosage of 800 mg protein up to 26 weeks; the proportion of the control group who were desensitized or tolerated daily ingestion of 800 mg protein in the second phase; threshold changes in no observed adverse effect level after OIT (NOAEL: defined as the highest dose of peanut protein tolerated in milligrams of protein during challenge or immunotherapy); change in quality of life; number and type of adverse events; and immunological parameters (basophil reactivity, peanut-specific IgE, total IgE and skin-prick test).

RESULTS

Primary outcome Twenty-four of 39 (62%) of the active group were able to tolerate the 1400 mg of peanut protein during their DBPCFC after 26 weeks of OIT, compared with none of the 46 control participants (P < 0·001). Secondary outcomes Twenty-five of 46 (54%) of the control group had a negative 1400-mg peanut protein challenge at the end of phase 2. Combining the two groups, 49 of 85 children (58%) were desensitized. Thirty-three of 39 (85%) active participants in phase one and 42 of 46 (91%) control participants in phase two tolerated 800 mg of OIT daily - a combined result of 75 of 85 (88%) trial participants. The median absolute change in NOAEL between baseline and 26 weeks was 1345 mg (P = 0·002), or a 25·5-fold increase (P < 0·001) for the active group. Both the active and control groups demonstrated a significant improvement (decrease) in Food Allergy Quality of Life scores after OIT in the under-13-year-old participants: -1·61 and -1·41, respectively (both P < 0·001). Mild side-effects predominated, with 54 (57%) reporting abdominal pain and 31 (33%) reporting vomiting. However, 21 (22%) also reported wheezing and one (1%) laryngeal oedema. One participant received adrenaline by self-administration on two occasions for wheezing.

CONCLUSIONS

Anagnostou et al. concluded that OIT successfully induced desensitization in challenge-proven peanut-allergic children and resulted in a clinically and socially meaningful increase in tolerated peanut protein. Quality of life improved after intervention and there was a good safety profile.

Improving the safety of oral immunotherapy for food allergy

Food allergy is a major public health problem in children, impacting upon the affected individual, their families and others charged with their care, for example educational establishments, and the food industry. In contrast to most other paediatric diseases, there is no established cure: current management is based upon dietary avoidance and the provision of rescue medication in the event of accidental reactions, which are common. This strategy has significant limitations and impacts adversely on health-related quality of life. In the last decade, research into disease-modifying treatments for food allergy has emerged, predominantly for peanut, egg and cow's milk. Most studies have used the oral route (oral immunotherapy, OIT), in which increasing amounts of allergen are given over weeks-months. OIT has proven effective to induce immune modulation and 'desensitization' - that is, an increase in the amount of food allergen that can be consumed, so long as regular (typically daily) doses are continued. However, its ability to induce permanent tolerance once ongoing exposure has stopped seems limited. Additionally, the short- and long-term safety of OIT is often poorly reported, raising concerns about its implementation in routine practice. Most patients experience allergic reactions and, although generally mild, severe reactions have occurred. Long-term adherence is unclear, which rises concerns given the low rates of long-term tolerance induction. Current research focuses on improving current limitations, especially safety. Strategies include alternative routes (sublingual, epicutaneous), modified hypoallergenic products and adjuvants (anti-IgE, pre-/probiotics). Biomarkers of safe/successful OIT are also under investigation.

Update on food allergy

Food allergies are a global health issue with increasing prevalence. Allergic reactions can range from mild local symptoms to severe anaphylactic reactions. Significant progress has been made in diagnostic tools such as component-resolved diagnostics and its impact on risk stratification as well as in therapeutic approaches including biologicals. However, a cure for food allergy has not yet been achieved and patients and their families are forced to alter eating habits and social engagements, impacting their quality of life. New technologies and improved in vitro and in vivo models will advance our knowledge of the pathogenesis of food allergies and multicenter-multinational cohort studies will elucidate interactions between genetic background, lifestyle, and environmental factors. This review focuses on new insights and developments in the field of food allergy and summarizes recently published articles.

Current Options for the Treatment of Food Allergy

Food allergy is increasing in prevalence; as a result, there is intense focus on developing safe and effective therapies. Current methods of specific immunotherapy include oral, sublingual, and epicutaneous, while nonspecific methods that have been investigated include: Chinese herbal medicine, probiotics, and anti-IgE antibodies. Although some studies have demonstrated efficacy in inducing desensitization, questions regarding safety and the potential for achieving immune tolerance remain. Although some of these therapies demonstrate promise, further investigation is required before their incorporation into routine clinical practice.

Early sustained unresponsiveness after short-course egg oral immunotherapy: a randomized controlled study in egg-allergic children

BACKGROUND

No studies have evaluated the potential of egg oral immunotherapy (egg-OIT) to induce sustained unresponsiveness after discontinuing therapy following short-term treatments.

OBJECTIVE

We assessed the efficacy of short-course egg-OIT to induce sustained unresponsiveness.

METHODS

Sixty-one egg-allergic children, 5 to 17 years old, with positive double-blind placebo-controlled food challenge (DBPCFC) to dehydrated egg white (EW) were randomized to receive egg-OIT (OITG) for 3 months (maintenance dose one undercooked egg every 48 hours) or to continue egg avoidance diet (control group, CG) for 4 months. Children who completed egg-OIT avoided egg for 1 month. At 4 months, both groups underwent a DBPCFC. OITG participants who passed this challenge were instructed to add egg to their diet ad libitum. Immune markers were studied at different time points.

RESULTS

Ninety-three percent (28/30) of OITG children were desensitized in a median of 32.5 days (IQR, 14 days). At 4 months, 1/31 (3%) in CG passed DBPCFC and 11/30 (37%) of OITG (95% CI, 14 to 51%; P = 0.003), all of them were consuming egg at 36 months. A decrease in EW, OVA and OVM skin test results and OVA-specific IgE (sIgE) levels was observed on OITG at 4 months (P = 0.001). EW-, OVA- and OVM-sIgE levels prior to the start of egg avoidance diet were lower in OITG children who passed DBPCFC at 4 months than in those who did not pass it. EW- and OVM-sIgE showed the best diagnostic performance in predicting DBPCFC result at 4 months. Levels above optimal EW-sIgE cut-off of 7.1 kU/L indicated 90% probability of failing DBPCFC.

CONCLUSION

This is the first demonstration of sustained unresponsiveness with a three-month egg-OIT protocol. Almost all treated subjects were desensitized and 37% achieved sustained unresponsiveness. EW-sIgE levels at the end of treatment predicted sustained unresponsiveness. This protocol shows a new approach to OIT for egg-allergic children.

A randomized, double-blind, placebo-controlled study of omalizumab combined with oral immunotherapy for the treatment of cow's milk allergy

BACKGROUND

Although studies of oral immunotherapy (OIT) for food allergy have shown promise, treatment is frequently complicated by adverse reactions and, even when successful, has limited long-term efficacy because benefits usually diminish when treatment is discontinued.

OBJECTIVE

We sought to examine whether the addition of omalizumab to milk OIT reduces treatment-related reactions, improves outcomes, or both.

METHODS

This was a double-blind, placebo-controlled trial with subjects randomized to omalizumab or placebo. Open-label milk OIT was initiated after 4 months of omalizumab/placebo with escalation to maintenance over 22 to 40 weeks, followed by daily maintenance dosing through month 28. At month 28, omalizumab was discontinued, and subjects passing an oral food challenge (OFC) continued OIT for 8 weeks, after which OIT was discontinued with rechallenge at month 32 to assess sustained unresponsiveness (SU).

RESULTS

Fifty-seven subjects (7-32 years) were randomized, with no significant baseline differences in age, milk-specific IgE levels, skin test results, or OFC results. At month 28, 24 (88.9%) omalizumab-treated subjects and 20 (71.4%) placebo-treated subjects passed the 10-g "desensitization" OFC (P = .18). At month 32, SU was demonstrated in 48.1% in the omalizumab group and 35.7% in the placebo group (P = .42). Adverse reactions were markedly reduced during OIT escalation in omalizumab-treated subjects for percentages of doses per subject provoking symptoms (2.1% vs 16.1%, P = .0005), dose-related reactions requiring treatment (0.0% vs 3.8%, P = .0008), and doses required to achieve maintenance (198 vs 225, P = .008).

CONCLUSIONS

In this first randomized, double-blind, placebo-controlled trial of omalizumab in combination with food OIT, we found significant improvements in measurements of safety but not in outcomes of efficacy (desensitization and SU).

Oral immunotherapy for food allergy: mechanisms and role in management

With the emergence of food allergy as an important public health problem, it has become clear that there is an unmet need in regard to treatment. In particular, IgE-mediated food allergy that is associated with risk of fatal anaphylaxis has been the subject of multiple studies in the past decade. The growing body of evidence derived from multiple centres and various study designs indicates that for IgE-mediated food allergy, immunomodulation through food immunotherapy is possible; however, the extent of protection afforded by such treatment is highly variable. At this time, the capacity for food immunotherapy to restore permanent tolerance to food has not been demonstrated conclusively. This review will discuss these topics as they apply to the most important studies of food oral immunotherapy.

[Omalizumab: What have we learned after ten years of prescription?]

INTRODUCTION

Omalizumab, an anti-immunoglobulin E monoclonal antibody, has now been used for ten years as an add-on therapy for severe adult atopic asthma, poorly controlled by high-doses inhaled steroids and long-acting beta-agonists.

BACKGROUND

This innovative therapy has been the first biotherapy used on a large scale in severe asthma. It has shown clinical benefits, especially in the prevention of severe exacerbation, with a satisfactory safety profile. Despite its cost, it is an interesting alternative to continuous oral steroids, which cause more long-term side effects.

PERSPECTIVES

After ten-years of prescription of omalizumab, we review here the mechanism of action, the benefits, the main side effects, the cost-effectiveness and also the alternative indications of this interesting molecule. We also consider the practicalities of using omalizumab, particularly the importance a rigorous assessment of its efficacy after 16 weeks of treatment, and possible future therapeutic indications.

CONCLUSION

Omalizumab has proven its efficacy in large randomized studies but also in real life practice in severe allergic asthma.

Immunoglobulin E in irritable bowel syndrome: another target for treatment? A case report and literature review

Irritable bowel syndrome (IBS) is notoriously difficult to treat and this situation is unlikely to change until the pathophysiology is better understood. There is no doubt that IBS is a multifactorial condition but it is likely that the relative contribution of the various factors involved varies from patient to patient. Consequently, in some individuals one mechanism may have such a strong effect that its elimination may lead to a substantial improvement in symptoms. This paper describes a patient with severe asthma and IBS where the administration of an anti-Immunoglobulin E (IgE) monoclonal antibody not only improved her asthma but also resulted in an almost complete resolution of her IBS symptoms. This observation suggests that some form of allergic process, which may be mediated by IgE, might be driving IBS in some patients and there is evidence from the literature that atopy is more common in this condition. Therefore, in patients with IBS and atopy where the response to standard treatment is poor, it may be worth considering targeting the allergic diathesis. Possible approaches include skin testing with food antigens followed by an appropriate exclusion diet or pharmacological mast cell stabilization.

Recent advances in immunotherapy and vaccine development for peanut allergy

Peanut allergy is a common problem and can be the cause of severe, life-threatening allergic reactions. It rarely resolves, with the majority of patients carrying the disease onto adulthood. Peanut allergy poses a significant burden on the quality of life of sufferers and their families, which results mainly from the fear of accidental peanut ingestion, but is also due to dietary and social restrictions. Current standard management involves avoidance, patient education and provision of emergency medication, for use in allergic reactions, when they occur. Efforts have been made to develop a vaccine for peanut allergy. Recent developments have also highlighted the use of immunotherapy, which has shown promise as an active form of treatment and may present a disease-modifying therapy for peanut allergy. So far, results, especially from oral immunotherapy studies, have shown good efficacy in achieving desensitization to peanut with a good safety profile. However, the capacity to induce long-term tolerance has not been demonstrated conclusively yet and larger, phase III studies are required to further investigate safety and efficacy of this intervention. Peanut immunotherapy is not currently recommended for routine clinical use or outside specialist allergy units.