Sublingual immunotherapy in children with allergic polysensitization

IR (index of reactivity)-house dust mite sublingual immunotherapy liquid formulation for allergic rhinoconjunctivitis: Systematic review and meta-analysis of randomized and nonrandomized studies

Background

Although randomized controlled trials (RCT) are the reference standard of evidence in allergen immunotherapy (AIT), nonrandomized studies (NRS) are needed to confirm their results in more representative populations, particularly for treatment duration and persistence. However, when discrepancies are observed between RCT and NRS, NRS reliability decreases because these discrepant results are generally attributed to the methodologic flaws of NRS.

Objective

We compared the benefit of sublingual AIT (SLIT) for allergic rhinoconjunctivitis in NRS versus RCT focusing on a single product/allergen to reduce heterogeneity.

Methods

For meta-analysis, house dust mite (HDM) SLIT liquid formulation studies were sourced from computerized (Medline, Web of Science, and LILACS databases, to January 2023) and manual literature searches. Populations, treatments, and outcome data were combined (DerSimonian-Laird method). Noncomparative NRS were compared to RCT' SLIT arm before and after treatment. Efficacy was determined as the standardized mean difference (SMD) in symptom score (SS) and medication score (MS).

Results

Data from 12 NRS (682 patients) and 8 RCT (176 patients) were analyzed. The benefit with index of reactivity (IR)-HDM SLIT liquid formulation was found significant for, first, SS in both NRS (SMD = -1.27; 95% confidence interval [CI], -1.64, -0.90) and RCT (SMD = -0.56; 95% CI, -0.90, -0.21), and second, MS with SMD equal to -1.35 (95% CI, -1.77, -0.93) and -0.46 (95% CI, -0.67, -0.25), respectively. Metaregression showed that symptom improvement was correlated with treatment duration with consistent results in NRS and RCT with 12-month SS data: -0.87 (interquartile range, -1.02, -0.77) and -0.75 (interquartile range, -0.93, -0.41), respectively.

Conclusion

This meta-analysis showed comparable clinical benefit of IR-HDM SLIT liquid formulation increasing over time in both NRS and RCT, suggesting that NRS may reliably integrate RCT results and be considered for guidelines.

Planning and approach to allergen-specific immunotherapy in polyallergic patients

Allergy immunotherapy (AIT) is currently the only disease-modifying treatment for allergic-respiratory diseases. Polysensitization may increase the severity of current disease resulting in subsequent asthma development in patients with allergic rhinitis. Due to the absence of general recommendations for the practical approach to polysensitized patients, clinical management is not standardized. The correlation between sensitizations and clinical symptoms, elimination of possible pollen cross-reactivities and principles of homologous allergen groups will guide the allergists to deduce the most relevant allergens for AIT. In the highlight of the previously proposed approach strategies to polyallergic patients, hereby we propose a revised practical stepwise approach based on the current European Medicine Agency (EMA) guidelines. However, more supporting data from well-designed, controlled, future studies are needed to improve clinical management recommendations for AIT in polyallergic patients.

EAACI Allergen Immunotherapy User's Guide

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

An analysis of factors related to the effect of sublingual immunotherapy on Japanese cedar pollen induced allergic rhinitis

BACKGROUND

Sublingual immunotherapy (SLIT) can improve the symptoms of allergic rhinitis and modify its natural history; however, its efficacy varies among patients. This study aimed to determine which factors modify the effect of SLIT through post hoc analysis of a previous phase 3 trial of standardized Japanese cedar (JC) pollen extract (CEDARTOLEN^®).

METHODS

The study included 482 patients who had previously completed a phase 3 trial during two seasons. The SLIT and placebo groups each contained 241 subjects. Because pollen dispersal differed in the two seasons, we identified good and poor responders from the SLIT group in the 2nd season. We compared patient baseline characteristics, changes in serum immunoglobulin, and severity of symptoms in the 1st season between good and poor responders, as well as between SLIT and placebo groups.

RESULTS

When we compared the baseline characteristics of good and poor responders, a significant difference was observed in body mass index (BMI) such that the patients with BMI ≥25 presented with lower treatment efficacy. No significant difference was observed in correlation with any other factors or treatment-induced alterations of serum immunoglobulin levels. We found that 75.3% of the patients with moderate symptoms and 50.9% of the patients with severe or very severe symptoms in the 1st season met our criteria for good responders in the 2nd season.

CONCLUSIONS

BMI might modify the effect of SLIT; however, other factors were not related clearly. The severity of symptoms in the 1st season of treatment does not predict that in the 2nd season.

Management of the polyallergic patient with allergy immunotherapy: a practice-based approach

Background

The great majority (60–80 %) of patients consulting specialist physicians for allergic respiratory disease are polysensitized and thus may be potentially clinically polyallergic. However, management approaches to allergen immunotherapy (AIT) in polysensitized and polyallergic patients are not standardized.

Methods

An international group of clinicians with in-depth expertise in AIT product development, clinical trials and clinical practice met to generate up-to-date, unambiguous, pragmatic guidance on AIT in polysensitized and polyallergic patients. The guidance was developed after reviewing (1) the current stance of regulatory bodies and learned societies, (2) the literature data on single- and multi-AIT and (3) the members’ confirmed clinical experience with polysensitized patients.

Results

AIT is safe and effective in polysensitized and polyallergic patients, and should always be based on the identification of one or more clinically relevant allergens (based on the type and severity of symptoms, the duration of induced symptoms, the impact on quality of life and how difficult an allergen is to avoid). Single-AIT is recommended in polyallergic patients in whom one of the relevant allergens is nevertheless clearly responsible for the most intense and/or bothersome symptoms. Parallel 2-allergen immunotherapy or mixed 2-allergen immunotherapy is indicated in polyallergic patients in whom two causal relevant allergens have a marked clinical and QoL impact. In parallel 2-allergen immunotherapy (whether subcutaneous or sublingual), high-quality, standardized, single-allergen formulations must be administered with an interval of 30 min. Mixing of allergen extracts may be considered, as long as (1) the mixture is technically feasible, (2) the mixture is allowed from a regulatory standpoint, (3) the allergen doses are reduced in proportion to the number of components but are still at concentrations with demonstrated efficacy.

Conclusions

Physicians can prescribe AIT (preferably with high-quality, standardized, single-allergen formulations) with confidence in polysensitized and polyallergic patients by focusing on clinical/QoL relevance and safety.

Guiding principles of sublingual immunotherapy for allergic rhinitis in Japanese patients

OBJECTIVE

Sublingual immunotherapy (SLIT) appears to offer practical advantages for the treatment of allergic rhinitis (AR). Based on a review of the scientific literature, we present recommendations as guiding principles to administer SLIT safely.

METHODS

Clinical questions concerning SLIT were prepared. Literature published between January 2003 and December 2012 was searched from PubMed, the Cochrane Library, and Japana Centra Revuo Medicina. Qualified studies were analyzed and the results were evaluated, consolidated, and codified. We answered 17 clinical questions and, based on this, presented evidence-based recommendations.

RESULTS

Sublingual immunotherapy improved symptoms (e.g., quality of life [QOL]) and reduced medication scores in seasonal AR and perennial AR. Most SLIT-induced adverse effects were local oral reactions, although systemic adverse effects such as gastrointestinal symptoms, urticaria, and asthma are occasionally reported. There have been no reports of lethal anaphylactic reactions by SLIT. When SLIT is continued for 3-4 years, its effect persists long after discontinuation.

CONCLUSION

A correct diagnosis of AR and sufficient informed consent from patients are required before initiating SLIT. Sublingual immunotherapy should be continued for 3 years or longer. The initial administration of SLIT during the uptitration of an allergen vaccine and the general condition of patients are critical for the safe performance of SLIT.

Sublingual immunotherapy for allergic rhinitis: where are we now?

Sublingual immunotherapy (SLIT) was introduced in the 1980s as a safer option to subcutaneous immunotherapy and in the latest decade achieved significant advances. Its efficacy in allergic rhinitis is supported by a number of meta-analyses. The development of SLIT preparations in tablets to fulfill the requirements of regulatory agencies for quality of allergen extracts made available optimal products for grass-pollen-induced allergic rhinitis. Preparations of other allergens based on the same production methods are currently in progress. A notable outcome of SLIT, that is shared with subcutaneous immunotherapy, is the evident cost–effectiveness, showing significant cost savings as early as 3 months from starting the treatment, that become as high as 80% compared with drug treatment in the ensuing years.

Allergen immunotherapy, routes of administration and cytokine networks: an update

Allergen immunotherapy is a disease-modifying therapy, effective for the treatment of allergic rhinitis, allergic asthma, conjunctivitis or stinging insect allergy. Allergen immunotherapy involves the administration of increasing doses of allergens with the aim of ameliorating the allergic response. Although precise underlying mechanisms of the induction of immune tolerance remain unclear, immunotherapy has been associated with the induction of distinct subsets of Tregs that eventually lead to peripheral tolerance by inducing a deviation from Th2 to Th1 immune responses. This review focuses on the current knowledge of the mechanisms of immunotherapy in relationship to different routes of administration and also provides a unifying view.

Efficacy and safety of house dust mite sublingual immunotherapy in monosensitized and polysensitized children with respiratory allergic diseases

BACKGROUND

The efficacy of single-allergen-specific immunotherapy in polysensitized subjects is a matter of debate. This study aimed to investigate the efficacy of house dust mite (HDM) sublingual immunotherapy (SLIT) in monosensitized and polysensitized children.

METHODS

A total of 112 children, aged 4 to 13 years old, with HDM-induced respiratory allergic diseases were allocated to a monosensitized group (n = 56) or a polysensitized group (n = 56). Both groups were treated by standard pharmacotherapy and SLIT with Dermatophagoides farinae (American HDM) extracts for 52 weeks. Symptoms, medications, visual analogue scale (VAS), and presence of adverse events (AEs) were assessed once a month. Skin-prick test (SPT) was done before and after treatment. After treatment, subjects in the polysensitized group who completed the study were further analyzed as subgroup 1 (n = 20) and subgroup 2 (n = 15) according to the number of coexisting allergens.

RESULTS

Forty-one subjects in the monosensitized group and 35 subjects in the polysensitized group completed the study. The global clinical parameters had significantly improved after treatment, with no significant difference between the monosensitized and polysensitized group throughout this period (all p > 0.05). The comparison among the monosensitized group, subgroup 1, and subgroup 2 indicated that there was no significant difference in symptoms scores and VAS at each scheduled follow-up visit. There was also no significant difference in total medications score (TMS) in the monosensitized group, subgroup 1, and subgroup 2 after week 24 (all p > 0.05). No severe systemic AEs were reported.

CONCLUSION

No significant difference was observed in the clinical effects of HDM SLIT between polysensitized and monosensitized children with respiratory allergic diseases.

Types of sensitization to aeroallergens: definitions, prevalences and impact on the diagnosis and treatment of allergic respiratory disease

The type of allergic sensitization is of central importance in the diagnosis and treatment of respiratory allergic diseases. At least 10% of the general population (and more than 50% of patients consulting for respiratory allergies) are polysensitized. Here, we review the recent literature on (i) the concepts of polysensitization, paucisensitization, co-sensitization, co-recognition, cross-reactivity, cross-sensitization, and polyallergy, (ii) the prevalence of polysensitization and (iii) the relationships between sensitization status, disease severity and treatment strategies. In molecular terms, clinical polysensitization can be divided into cross-sensitization (also known as cross-reactivity, in which the same IgE molecule binds to several allergens with common structural features) and co-sensitization (the simultaneous presence of different IgEs binding to allergens that may not necessarily have common structural features). There is a strong overall association between sensitization in skin prick tests and total IgE values but there is debate as to whether IgE thresholds are useful guides to the presence or absence of clinical symptoms in individual cases. Molecular information from component-resolved techniques appears to be of value for diagnosis and treatment decisions. Polysensitization develops over time and is a risk factor for respiratory allergy (being associated with disease severity) and therefore has clinical relevance for treatment decisions. The subterm polysensitization has been defined as polysensitization to between two and four allergens. Polyallergy is defined as clinically confirmed allergy to two or more allergens. Single-allergen grass pollen allergen immunotherapy (AIT) is safe and effective in polysensitized patients, whereas multi-allergen AIT requires more supporting evidence. Given that AIT may be more efficacious in moderate-to-severe disease than in mild disease, polysensitization could be an indication for this type of treatment. There is a need for flowcharts or decision trees for choosing the allergens for AIT in polysensitized patients and polyallergic patients.

Pollen-induced allergic rhinitis in 1360 Italian children: comorbidities and determinants of severity

BACKGROUND

Pollen-induced allergic rhinoconjunctivitis (AR) is highly prevalent and rapidly evolving during childhood. General practitioners may not be fully aware of the nature and severity of symptoms experienced by patients and might underestimate the prevalence of moderate or severe disease. Thus, the relevance of early diagnosis and intervention may be overlooked.

OBJECTIVES

To investigate the severity of pollen-induced AR and its determinants in Italian children referred to allergy specialists and who had never received specific immunotherapy (SIT).

METHODS

Children (age 4-18 yr) affected by pollen-induced AR who had never undergone SIT were recruited between May 2009 and June 2011 in 16 pediatric outpatient clinics in 14 Italian cities. Recruited children's parents answered standardized questionnaires on atopic diseases (International Study of Allergy and Asthma in Childhood, Allergic Rhinitis and its Impact on Asthma, Global Initiative for Asthma). The children underwent skin-prick test (SPT) with several airborne allergens and six food allergens. Information on socio-demographic factors, parental history of allergic diseases, education, perinatal events, breastfeeding, nutrition and environmental exposure in early life was collected through an informatics platform shared by the whole network of clinical centers (AllergyCARD™).

RESULTS

Among the 1360 recruited patients (68% males, age 10.5 ± 3.4 yr), 695 (51%) had moderate-to-severe AR, 533 (39%) asthma, and 325 (23.9%) oral allergy syndrome (OAS). Reported onset of pollen-induced AR was on average at 5.3 ± 2.8 yr, and its mean duration from onset was 5.2 ± 3.3 yr. Only 6.2% of the patients were pollen-monosensitized, and 84.9% were sensitized to ≥3 pollens. A longer AR duration was significantly associated with moderate-to-severe AR symptoms (p 0.004), asthma (p 0.030), and OAS comorbidities (p < 0.001).

CONCLUSIONS

This nationwide study may raise awareness of the severity of pollen-induced AR among Italian children who have never received pollen SIT. The strong association between pollen-induced AR duration and several markers of disease severity needs replication in longitudinal studies, while suggesting that countrywide initiatives for earlier diagnosis and intervention should be planned.

Multiallergen-specific immunotherapy in polysensitized patients: where are we?

Allergen-specific immunotherapy administered by the subcutaneous route was introduced a century ago and has been shown to be effective in the management of allergic rhinitis and asthma. More recently, the sublingual administration of allergen extracts has become popular, especially in European countries, and has also demonstrated efficacy in respiratory allergic diseases. Both modes of allergen administration during immunotherapy have been shown not only to reduce symptoms and the need for medication, but also to prevent the development of additional sensitivities in monosensitized patients, as well as asthma development in patients with allergic rhinitis, with a long-lasting effect after the completion of several years of treatment. Almost all of the well-designed and double-blinded, placebo-controlled studies evaluated treatment with single-allergen extracts. Therefore, most meta-analyses published to date evaluated immunotherapy with single allergen or extracts containing several cross-reactive allergens. As a result, in general, multiallergen immunotherapy in polysensitized patients (mixture of noncross-reactive allergens) is not recommended owing to lack of evidence. Although some guidelines have recommended against the use of multiallergen mixtures, allergists commonly use mixtures to which the patient is sensitive with the rationale that effective immunotherapy should include all major sensitivities. Literature on this subject is scarce in spite of the widespread use worldwide. Here, this issue will be extensively discussed based on currently available literature and future perspectives will also be explored.

Asthma in children and adolescents: a comprehensive approach to diagnosis and management

Asthma is a chronic disease that has a significant impact on quality of life and is particularly important in children and adolescents, in part due to the higher incidence of allergies in children. The incidence of asthma has increased dramatically during this time period, with the highest increases in the urban areas of developed countries. It seems that the incidence in developing countries may follow this trend as well. While our knowledge of the pathophysiology of asthma and the available of newer, safer medication have both improved, the mortality of the disease has undergone an overall increase in the past 30 years. Asthma treatment goals in children include decreasing mortality and improving quality of life. Specific treatment goals include but are not limited to decreasing inflammation, improving lung function, decreasing clinical symptoms, reducing hospital stays and emergency department visits, reducing work or school absences, and reducing the need for rescue medications. Non-pharmacological management strategies include allergen avoidance, environmental evaluation for allergens and irritants, patient education, allergy testing, regular monitoring of lung function, and the use of asthma management plans, asthma control tests, peak flow meters, and asthma diaries. Achieving asthma treatment goals reduces direct and indirect costs of asthma and is economically cost-effective. Treatment in children presents unique challenges in diagnosis and management. Challenges in diagnosis include consideration of other diseases such as viral respiratory illnesses or vocal cord dysfunction. Challenges in management include evaluation of the child’s ability to use inhalers and peak flow meters and the management of exercise-induced asthma.

Allergen specificity is relevant for immunotherapy prescription in polysensitised children

The sensitization to more allergens, such as polysenitization, is becoming a frequent characteristic of allergic patients, since the childhood. However, this phenomenon is considered an obstacle to prescribe immunotherapy by many doctors. This study investigated the relevance of polysensitization in a cohort of allergic children and evaluated the number of allergen extracts prescribed for these children. There are allergens that are frequent, but not prescribed. This issue should be matter of adequate debate for Italian paediatricians.

Sublingual immunotherapy not effective in house dust mite-allergic children in primary care

BACKGROUND

Sublingual immunotherapy (SLIT) as a therapy for the treatment of allergic rhinitis in children might be acceptable as an alternative for subcutaneous immunotherapy. However, the efficacy of SLIT with house dust mite extract is not well established.

OBJECTIVE

To investigate whether SLIT in house dust mite-allergic children recruited in primary care is effective and safe.

METHODS

Children aged 6-18 years (n = 251) recruited in primary care with a house dust mite-induced allergic rhinitis received either SLIT or placebo for 2 years. Symptoms and medication use were assessed throughout the study. Primary outcome parameter was the mean total nose symptom score (scales 0-12) during the autumn of the second treatment year. Safety was assessed by recording any adverse event.

RESULTS

Overall, the mean nose symptom score ± s.d. after 2 years of treatment showed no significant effect of SLIT (symptom score intervention group 2.26 ± 1.84 vs. placebo group, 2.02 ± 1.67; p = 0.08). There were no significant differences in secondary outcomes, nor in subgroup analyses. The number of patients reporting adverse events was comparable between both groups.

CONCLUSIONS

Sublingual immunotherapy with house dust mite allergen was not better than placebo in reducing rhinitis symptoms in house dust mite-allergic children in primary care. SLIT as administered in this study can be considered safe.

The Pediatric Asthmatic

The incidence of allergies and asthma in the Western world has been increasing over the past 30 years. However, more recent data suggests that over the past 5–10 years, the overall global trends of asthma incidence have begun to stabilize (1). Urbanization and industrialization has contributed to the increase in developed countries, but the reasons for this are still unclear. Asthma is estimated to be responsible for 1 in every 250 deaths worldwide. Many of these deaths are preventable, and specific issues have been identified that may contribute to this high mortality rate. Factors that contribute to high ­mortality and morbidity include slow access to care and medications, inadequate environmental control of allergens and irritants, dietary changes, genetic variations, cultural barriers, lack of education amongst patients and providers, insufficient resources, and improper use of health care dollars.

Subcutaneous and sublingual immunotherapy for allergic rhinitis: what is the evidence?

BACKGROUND

Increasing interest in sublingual immunotherapy (SLIT) among practitioners and patients has resulted in numerous publications and clinical trials in recent years. With the clinical growth of SLIT, discussions of its efficacy, safety, and immunologic effects have intensified, as have comparisons to subcutaneous immunotherapy (SCIT). In the United States, SCIT has been the traditional form of immunotherapy for inhalant allergy and is the only immunotherapy method approved by the U.S. Food and Drug Administration at this time. The similarities and differences between SLIT and SCIT are often discussed, yet clinical studies directly comparing these immunotherapy methods are scarce.

METHODS

A literature review of specific issues and controversies between SLIT and SCIT for allergic rhinitis was conducted.

RESULTS

Safety, efficacy, and immunologic effects of these two immunotherapy techniques are reviewed.

CONCLUSION

Unanswered questions relating to SLIT are examined.

Sublingual immunotherapy in patients with allergic rhinoconjunctivitis

Sublingual immunotherapy (SLIT) is a well-established treatment option for allergic rhinitis in several European countries, but it is considered investigational in the United States. Studies conducted in Europe provided a large body of evidence supporting the safety and efficacy of SLIT, but those studies used allergen products that are different from those that are likely to be approved in the United States, and many of them were not controlled, randomized, double-blinded trials. This review summarize research conducted on the efficacy, safety, and mechanisms of SLIT published during the past year, with a focus on ragweed and grass antigens. Results of recent US studies document the safety and efficacy of SLIT and have started to yield insight into the mechanisms of SLIT.

Polysensitization as a challenge for the allergist: the suggestions provided by the Polysensitization Impact on Allergen Immunotherapy studies

INTRODUCTION

Polysensitization, that is, sensitization to more than one allergen family, is a common feature of patients with allergic rhinitis (AR) and significantly impairs their quality of life (QoL). Allergen-specific immunotherapy is the only causal treatment for AR. However, the polysensitization phenomenon may represent a crucial obstacle as far as it concerns the choice of the allergen extract to be used for immunotherapy.

AREAS COVERED

A series of real-life based multi-center studies, named POLISMAIL (Polysensitization Impact on Allergen Immunotherapy), have been designed with the aim of evaluating the behavior of allergists in managing polysensitized AR patients. The effect of immunotherapy treatment in these patients was also evaluated. A single allergen extract was used in two-thirds of patients, whereas a mix of two allergens was chosen in the remaining. The severity grade of AR and the QoL were significantly improved by immunotherapy. Both outcomes confirmed that immunotherapy with one or two allergen extracts achieves a significant improvement in polysensitized patients.

EXPERT OPINION

In conclusion, POLISMAIL studies demonstrate that polysensitization should not represent a counter-indication for prescribing immunotherapy. The choice of limiting sublingual immunotherapy to one to two allergen extracts, preferably separated and at high dosages, is sufficient and effective in improving symptoms and QoL.