Clinical efficacy of 300IR 5-grass pollen sublingual tablet in a US study: The importance of allergen-specific serum IgE

Allergen immunotherapy (AIT) for the multiple-pollen sensitive patient

INTRODUCTION

The majority of allergic subjects are polysensitized. In Europe, allergy immunotherapy (AIT) in these patients is usually limited to their single clinically most troublesome allergy while in the U.S. the immunotherapy prescription usually includes all allergen extracts to which the patient has evidence of clinical sensitivity. Areas covered: This article will review the evidence supporting the U.S. practice. It will also review the major new development in the management of polysensitized patients, the introduction of component-resolved diagnosis (CRD). Expert commentary: This allows, in many cases, distinguishing in polysensitized patients between sensitization to the major allergens of several unrelated allergen extracts and to panallergens that cause broad patterns of cross-reactivity.

Applications and mechanisms of immunotherapy in allergic rhinitis and asthma

Clinical and immunologic tolerance are hallmarks of successful allergen immunotherapy (AIT). Clinical benefits such as reduced symptoms, pharmacotherapy intake and improvement of quality of life persist following cessation of treatment. Successful AIT is associated with suppression of allergic inflammatory cells such as mast cells, eosinophils and basophils in target organs. Furthermore, AIT down-regulates type 2 innate lymphoid cells and allergen-specific type 2 T-helper (Th2) cells. The immunologic tolerant state following AIT is associated with the induction of distinct phenotypes of regulatory T-cells (T-regs) including interleukin (IL)-10-, IL-35- and transforming growth factor (TGF)-β- producing T-regs and FoxP3⁺ T-regs. B-cell responses, including the induction of IL-10⁺ regulatory B-cells (B-regs) and the production of IgG4-associated blocking antibodies are also induced following successful AIT. These events are associated with the suppression of antigen-specific Th2 responses and delayed immune deviation in favour of Th1 type responses. Insight into the mechanisms of AIT has allowed identification of novel biomarkers with potential to predict the clinical response to AIT and also novel therapeutic strategies for more effective and safer AIT.

MK-8237: a house dust mite vaccine for treating allergic rhinitis, asthma and atopic dermatitis

INTRODUCTION

Since its introduction in clinical practice one century ago for the treatment of respiratory allergic diseases, allergen-specific immunotherapy (AIT) has exhibited a relevant clinical efficacy that was subsequently confirmed in controlled trials. Thus, AIT has been accepted worldwide, as testified by guidelines and international documents. AIT is considered pivotal in the management of allergic rhinitis with or without conjunctivitis and with or without asthma. These conditions, in addition to hymenoptera venom allergy, currently are the accepted indications. The use of AIT in house-dust mite allergy still remains debated, especially due to the methodological problems in assessing this form of respiratory allergy. The more recent experimental data on MK-8237 sublingual tablets provided evidence that AIT, in the sublingual form, is effective in dust mite allergy.

AREAS COVERED

At present, the evidence of the efficacy of AIT in conditions other than respiratory allergy are not conclusive, but encouraging results have been obtained in food allergy and atopic dermatitis. Herein, the authors discuss the data for these indications.

EXPERT OPINION

Not all patients respond to AIT in the same way. Accordingly, AIT represents a promising path to precision medicine and hopefully will be able to reduce this burden of non-responding patients.

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.

Comparison of six disease severity scores for allergic rhinitis against pollen counts a prospective analysis at population and individual level

BACKGROUND

Many different symptom (medication) scores are nowadays used as measures of allergic rhinoconjunctivitis severity in individual patients and in clinical trials. Their differences contribute to the heterogeneity of the primary end-point in meta-analyses, so that calls for symptom (medication) score harmonization have been launched.

OBJECTIVE

To prospectively compare six different severity scores for allergic rhinitis (AR) against pollen counts at both population and individual levels.

METHODS

Two groups of children with seasonal AR and grass pollen sensitization were recruited in Ascoli, Italy (n = 76) and Berlin, Germany (n = 29). Symptoms and drug intake were monitored daily for 40 and 30 days of the grass pollen season in 2011 (Ascoli) and 2013 (Berlin), respectively, through an Internet-based platform (AllergyMonitor(™) , TPS Production srl, Rome, Italy). From the gathered data, the informatics platform automatically generated one symptom score (RTSS) and five symptom-medication scores (RC-ACS(©) , ACS, RTSS[LOCF], RTSS[WC] and AdSS). Values were then statistically normalized for reciprocal comparison and matched against the daily variations of local grass pollen counts (Spearman's rank correlation).

RESULTS

The grass pollen counts were higher in Ascoli than in Berlin (peak values 194 vs. 59 grains/m(3) ). At population level, the trajectories of the normalized average values of the six scores differed only slightly in both studies and correlated well with the pollen counts (ranges r(2) : 0.38-0.50 in Ascoli, 0.41-0.56 in Berlin). By contrast, in individual patients, trajectories of different scores were often quite heterogeneous. The RTSS[WC] had a very low discriminatory power and generated in many patients long, flat horizontal segments.

CONCLUSIONS

Disease severity scores for seasonal AR, as evaluated via an Internet-based platform, tend to provide similar results at population level but can often produce heterogeneous slopes in individual patients. The choice of the disease severity score might have only a low impact on the outcome of a very large clinical trial, but it may be crucial in the management of individual patients.

Sublingual Immunotherapy: A Useful Tool for the Allergist in Private Practice

This is a review of the author's experience with Sublingual Immunotherapy in a private office setting. Sublingual Immunotherapy should be considered by any allergy practitioner as a useful tool. Sublingual Immunotherapy is safe while at the same time it is effective. It enables the practitioner to treat asthmatics and young children without the concerns implicit with allergy injections.

How does the efficacy and safety of Oralair(®) compare to other products on the market?

Due to differences between allergen immunotherapy (AIT) trials in patient populations, trial design (including primary efficacy variables), the definition of a pollen season, data analysis, and comparisons between AIT products with existing data, is not possible nor valid. The efficacy of two grass pollen AIT tablets, Oralair^® and Grazax^®/Grastek^®, should not be compared by looking at the percentage of score improvement in their respective trials. However, the evidence available concerning the efficacy and safety in trials can be compared by paying close attention to the scientific quality of the trials, details in the administration schedules, and safety issues. It can be concluded due to the high level of evidence available, that Oralair^® is effective in a pre (2-months)-coseasonal schedule to reduce symptoms and medication use, and improve a patients’ quality of life during the treatment season. For the long-term, where the quality of efficacy evidence is moderate at 2-year posttreatment due to a high dropout rate, the pre (4-months)-coseasonal schedule should be used. No clinical efficacy data exists for starting treatment in-season, but the clinical onset of action of Oralair^® is detectable after only 1 month of treatment. In the pivotal trials in Europe and the USA, no tablet-related epinephrine was needed, though some rare severe local reactions have been reported. Research for Grazax^®/Grastek^® showed that the long-term efficacy needs a continuous 3-year administration (moderate-low quality evidence available), and in two patients, tablet-related epinephrine was given. Further details on the comparative efficacy of both tablets would only be possible if both were evaluated in the same, adequately powered trial.

Relevance of a 5-grass sublingual tablet for immunotherapy of patients with grass pollen allergy in North America

Grass pollen allergy is common and clinically consequential in North America. While it is frequently treated with subcutaneous or sublingual immunotherapy, debate remains regarding whether allergen immunotherapy is best carried out using a single representative or multiple cross-reactive allergen(s). Patients are commonly exposed to pollens from multiple allergenic grass species belonging to the Pooideæ subfamily. Beyond the known IgE cross-reactivity, considerable molecular heterogeneity exists with respect to allergen content among grass species, with further evidence that these molecular variants can be detected by the patients' immune system. These observations provide a compelling scientific rationale for the use of mixed pollen allergen extracts to broaden the allergen repertoire, with the aim of reorienting inappropriate immune responses in allergic patients.

Clinical considerations in the use of sublingual immunotherapy for allergic rhinitis

BACKGROUND

Allergen immunotherapy (AIT) has been in practice for more than 100 years. However, research in novel routes and delivery methods of immunotherapy to treat allergic rhinitis (AR) and conjunctivitis has only recently occurred in the United States, where the predominant form of AIT provided is largely via a subcutaneous immunotherapy (SCIT) route. AIT may prevent new sensitizations, improve symptoms, decrease medication usage, and prevent allergic asthma. Although AIT is the only potentially curative treatment for AR, access and adherence continue to be problematic. Only a fraction of eligible patients actually undergo treatment, and attrition rates are high. An obvious limitation of SCIT includes the requirement of regular injections to be provided in the physician's office due to the potential for anaphylaxis. Sublingual immunotherapy (SLIT) for home administration has been investigated as a potential alternative to address this limitation of SCIT.

METHODS

A literature review was performed including the current findings from randomized clinical trials and meta-analyses with a discussion of the most recent evidence for the efficacy, safety, and dosing of allergen SLIT.

RESULTS

The current data suggest that SLIT is effective for treatment of seasonal allergies, can potentially prevent asthma, and has a favorable safety profile. Head-to-head studies, however, are few, and comparative effectiveness still remains to be answered. Optimal treatment algorithms for SLIT have not yet been established, with wide variation in dosage selection and schedules. Similarly to SCIT, only a few allergens such as ragweed and grass pollen have been found to be effective in large clinical trials.

CONCLUSION

Recent data indicate that SLIT is an effective treatment modality for seasonal AR, improve quality of life, and can potentially prevent asthma but head-to head studies comparing SLIT to SCIT are needed.

Allergen extracts for immunotherapy: to mix or not to mix?

Allergen immunotherapy (AIT) is established as a curative treatment for allergic rhinitis, asthma, as well as insect venom allergy. AIT is based on the administration of natural allergen extracts via the subcutaneous or sublingual routes to reorient the immune system towards tolerogenic mechanisms. In this regard, since many patients are poly-allergic, mixtures of allergen extracts are often used with a potential risk to cause allergen degradation, thereby affecting treatment efficacy. Herein, we discuss the advantages and drawbacks of mixing homologous (i.e., related) or heterogeneous (i.e., unrelated) allergen extracts. We provide evidence for incompatibilities between mixes of grass pollen and house dust mite extracts containing bodies and feces, and summarize critical points to consider when mixing allergen extracts for AIT.

Choosing the optimal dose in sublingual immunotherapy: Rationale for the 300 index of reactivity dose

Sublingual immunotherapy (SLIT) is an effective and well-tolerated method of treating allergic respiratory diseases associated with seasonal and perennial allergens. In contrast to the subcutaneous route, SLIT requires a much greater amount of antigen to achieve a clinical effect. Many studies have shown that SLIT involves a dose–response relationship, and therefore it is important to use a proven clinically effective dose from the onset of treatment, because low doses are ineffective and very high doses may increase the risk of side effects. A well-defined standardization of allergen content is also crucial to ensure consistent quality, potency and appropriate immunomodulatory action of the SLIT product. Several methods of measuring antigenicity are used by manufacturers of SLIT products, including the index of reactivity (IR), standardized quality tablet unit, and bioequivalent allergy unit. A large body of evidence has established the 300 IR dose of SLIT as offering optimal efficacy and tolerability for allergic rhinitis due to grass and birch pollen and HDM, and HDM-induced moderate, persistent allergic asthma. The 300 IR dose also offers consistency of dosing across a variety of different allergens, and is associated with higher rates of adherence and patient satisfaction. Studies in patients with grass pollen allergies showed that the 300 IR dose has a rapid onset of action, is effective in both adults and children in the short term and, when administered pre-coseasonally in the long term, and maintains the clinical benefit, even after cessation of treatment. In patients with HDM-associated AR and/or asthma, the 300 IR dose also demonstrated significant improvements in symptoms and quality of life, and significantly decreased use of symptomatic medication. The 300 IR dose is well tolerated, with adverse events generally being of mild or moderate severity, declining in frequency and severity over time and in the subsequent courses. We discuss herein the most important factors that affect the selection of the optimal dose of SLIT with natural allergens, and review the rationale and evidence supporting the use of the 300 IR dose.

Plant-based vaccines for animals and humans: recent advances in technology and clinical trials

It has been about 30 years since the first plant engineering technology was established. Although the concept of plant-based pharmaceuticals or vaccines motivates us to develop practicable commercial products using plant engineering, there are some difficulties in reaching the final goal: to manufacture an approved product. At present, the only plant-made vaccine approved by the United States Department of Agriculture is a Newcastle disease vaccine for poultry that is produced in suspension-cultured tobacco cells. The progress toward commercialization of plant-based vaccines takes much effort and time, but several candidate vaccines for use in humans and animals are in clinical trials. This review discusses plant engineering technologies and regulations relevant to the development of plant-based vaccines and provides an overview of human and animal vaccines currently under clinical trials.

Optimum treatment strategies for polyallergic patients - analysis of a large observational trial

OBJECTIVES

To document the effectiveness and safety of sublingual allergen immunotherapy (SLIT) with a five-grass pollen tablet (Oralair ) and compare different treatment options in a broad, non-selected population of patients in a real-world clinical setting.

RESEARCH DESIGN AND METHODS

This was a 2 year, open, prospective, multicenter, single-arm, non-interventional study. Patients with a history of clinically relevant allergic symptoms caused by grass pollen, confirmed by skin prick testing, received treatment with the five-grass pollen tablet. Concomitant treatment with symptomatic medication and/or additional SLIT or subcutaneous immunotherapy (SCIT) was permitted. Twelve-month data are presented here. Effectiveness was assessed comparing a combined rhinoconjunctivitis (RC) score derived from the severity of rhinitis and conjunctivitis symptoms under treatment with retrospective data of the previous year.

RESULTS

A total of 1408 patients participated in the study, of whom 434 were children/adolescents and 962 polyallergic. Compared with the grass pollen season preceding five-grass pollen tablet treatment, a statistically significant reduction of 49.9% was achieved in RC score for the total population (p < 0.001), and an improvement in overall health was perceived by 90.9% of patients. The overall population of polyallergic patients derived similar benefits from treatment with the five-grass pollen tablet as monoallergic patients. The percentage reduction in RC score was larger in polyallergic patients taking no additional therapy (60.2%) than in those taking concomitant symptomatic medication (38.1%) or allergen immunotherapy (AIT) (50.8%). Within the last of these groups, RC score improved by 47.6% among patients receiving additional SCIT, versus 54.8% with additional SLIT. Adverse drug reactions, reported in 15.3% of study participants, were mostly local in nature and mild or moderate in intensity.

CONCLUSIONS

After 1 year of treatment, polyallergic patients responded similarly to the five-grass pollen tablet as monoallergic patients. For polyallergic patients in whom additional treatment was needed, a second SLIT may be more beneficial than a SCIT or symptomatic co-medication.

Persistence of treatment with 5-grass pollen tablets in patients with allergic rhinitis: a real-life study

BACKGROUND

In patients with allergic rhinitis, treatment adherence to allergen immunotherapy varies greatly in randomized and real-life studies.

OBJECTIVE

To evaluate the use of a 5-grass pollen tablet as sublingual immunotherapy, its treatment persistence, and the reasons for discontinuation in a real-life clinical setting.

METHODS

This multicenter, prospective, open-label, noncontrolled observational study evaluated the use of sublingual immunotherapy with a 5-grass pollen tablet in a cross-sectional population of patients (≥5 years old) with grass pollen-induced allergic rhinitis with or without asthma. The primary objective was to determine the percentage of patients persisting with treatment across 1 season in a pre-co-seasonal scheme. Secondary objectives included evaluation of reasons for treatment discontinuation, safety and adverse events; effectiveness (based on physician and patient assessments), and treatment compliance.

RESULTS

The study included 196 patients (49.2% male, mean age 27.5 years, range 5.3-65.7 years), with treatment provided by 47 participating physicians. Sixty-seven percent of patients had polysensitivity and 32% had coexistent asthma. On average, patients were treated for 7 months with the 5-grass pollen tablet. After 1 month, 85% of all patients persisted with treatment, and 70% persisted after 7 months. Treatment discontinuation was due chiefly to known side effects (mild to moderate local allergic reactions). Most patients reported symptom improvement; 80% of all patients intended to continue treatment next season.

CONCLUSION

Most patients with allergic rhinitis treated pre-co-seasonally with a 5-grass pollen tablet persisted with treatment after the first pollen season. Patients were willing to continue their treatment in the following season owing to improvement of symptoms.

Pharmacodynamic and pharmacokinetic evaluation of house dust mite sublingually administered immunotherapy tablet in the treatment of asthma

INTRODUCTION

Sublingual immunotherapy (SLIT) for house dust mite (HDM) allergy has an evidence of efficacy demonstrated by meta-analyses, but marked differences are reported between the various SLIT products. The standardized quality (SQ) HDM sublingual tablet containing Dermatophagoides pteronyssinus and Dermatophagoides farinae in a 1:1 ratio (MK-8237) is a qualitative advance for SLIT products.

AREAS COVERED

The rationale for developing the HDM tablets is discussed against the other available SLIT products, analyzing the clinical data on efficacy and safety obtained by controlled trials.

EXPERT OPINION

Following preliminary Phase I and II studies, a double-blind, placebo-controlled trial on 604 patients with mite-induced asthma, aged more than 14 years and treated by inhaled budesonide, was performed using one of three active doses (1, 3 or 6 SQ) or placebo. The results showed a significant mean difference between 6 SQ-HDM and placebo in the reduction in daily budesonide dose of 81 µg (p = 0.004), with relative mean and median reductions of 42 and 50% for 6 SQ-HDM and 15 and 25% for placebo, respectively. Safety was very good, with no report of anaphylactic reaction. These findings suggest a role to the HDM SLIT tablets in the treatment of patients with mite-induced asthma.

The efficacy assessment of a self-administered immunotherapy protocol

Background

We previously reported the safety of a self‐administered subcutaneous immunotherapy (SCIT) protocol. Here we report the results of the retrospective efficacy trial of the United Allergy Service (UAS) self‐administered SCIT protocol. We hypothesized that by utilizing a slow SCIT buildup phase, designed to attain recommended allergen concentrations on a cumulative basis, efficacious outcomes and clinical relevance would be achieved.

Methods

We enrolled 60 SCIT patients and 56 control patients. The study contrasted baseline and treatment period combined symptom plus medication scores (CSMS) as the primary outcome measure and rhinoconjunctivitis quality of life questionnaire (RQLQ) scores as the secondary study outcome measure. Changes in pollen counts were also examined with regard to effects on these efficacy parameters.

Results

The treatment group showed significantly improved CSMS (standardized mean difference [SMD]: −1.57; 95% confidence interval [CI], −1.97 to −1.18; p < 0.001) and RQLQ (SMD: −0.91; 95% CI, −1.23 to −0.59; p < 0.001). These treatment group outcome measures were respectively improved by 33% and 29% compared to baseline and greater than 40% in comparison to the control group (p < 0.0001). Significant results were also shown when examining these outcome measures with regards to either monotherapy or poly‐allergen SCIT. Furthermore, a comparison to recent meta‐analyses of SCIT studies showed equivalent efficacy and clinical relevance. Assessment of pollen counts during the baseline and treatment periods further corroborated the efficacy of the UAS SCIT protocol.

Conclusion

These efficacy results, and our previous safety results, show that a carefully designed and implemented self‐administered SCIT protocol is efficacious and safe.

New developments in allergen immunotherapy

PURPOSE OF REVIEW

Allergic rhinitis, conjunctivitis, and asthma impact quality of life and cost billions of dollars in lost wages, productivity, and medical expenditures. Allergen immunotherapy is the only therapy that alters the allergen immune response, resulting in fewer symptoms upon natural exposure. This review summarizes recent immunotherapy developments.

RECENT FINDINGS

Subcutaneous immunotherapy (SCIT) remains a disease modifying treatment for allergic rhinoconjunctivitis and asthma with rare complications of therapy. Recent evidence suggests that SCIT may be effective in select cases of atopic dermatitis, particularly for patients with dust mite sensitivity. Sublingual immunotherapy (SLIT) tablets are now commercially available for grass and ragweed allergy and appear to have a superior safety profile to SCIT with similar long-term effectiveness, because as with SCIT, symptom improvement persists after the SLIT course is completed. SLIT tablets are administered daily at home (after initial supervised dosing) and may be used shortly before and during the target pollen seasons in a precoseasonal fashion (instead of perennial dosing). Research continues into experimental approaches using oral food allergen immunotherapy (OIT) to modify the natural history of food allergies. Although a proportion of patients in OIT trials experience sustained unresponsiveness, many do not and current recommendations limit the use of OIT to research protocols.

SUMMARY

Patients have new well tolerated and effective options for more convenient treatment of asthma and allergic rhinoconjunctivitis associated with grass and ragweed allergy. SCIT remains effective for polysensitized patients and may be an option for some patients with atopic dermatitis. Research continues into novel food allergy treatments.

Allergy immunotherapy: the future of allergy treatment

Allergic respiratory disease represents a significant and expanding health problem worldwide. Allergic symptoms, such as asthma and hay fever, cause sleep impairment and reduce school and work performance. The cost to society is substantial. Allergen avoidance and pharmacotherapy cannot control the disease. Only allergy immunotherapy has disease-modifying potential and should be included in optimal treatment strategies. Allergy immunotherapy was first administered as subcutaneous injections and has been practiced for the past 100 years or so. Recently, tablet-based sublingual allergy immunotherapy (SLIT) was introduced with comprehensive clinical documentation. SLIT tablets represent a more patient-friendly concept because they can be used for self-treatment at home.

Sublingual immunotherapy for asthma

BACKGROUND

Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. However, it is not clear whether the sublingual delivery route is safe and effective in asthma.

OBJECTIVES

To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov (www.ClinicalTrials.gov), the World Health Organization (WHO) trials portal (www.who.int/ictrp/en/) and reference lists of all primary studies and review articles. The search is up to date as of 25 March 2015.

SELECTION CRITERIA

We included parallel randomised controlled trials (RCTs), irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results for included trials, extracted numerical data and assessed risk of bias, all of which were cross-checked for accuracy. We resolved disagreements by discussion.We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We rated all outcomes using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) and presented results in the 'Summary of findings' table.

MAIN RESULTS

Fifty-two studies met our inclusion criteria, randomly assigning 5077 participants to comparisons of interest. Most studies were double-blind and placebo-controlled, but studies varied in duration from one day to three years. Most participants had mild or intermittent asthma, often with co-morbid allergic rhinitis. Eighteen studies recruited only adults, 25 recruited only children and several recruited both or did not specify (n = 9).With the exception of adverse events, reporting of outcomes of interest to this review was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence. Allocation procedures generally were not well described, about a quarter of the studies were at high risk of bias for performance or detection bias or both and participant attrition was high or unknown in around half of the studies.One short study reported exacerbations requiring a hospital visit and observed no adverse events. Five studies reported quality of life, but the data were not suitable for meta-analysis. Serious adverse events were infrequent, and analysis using risk differences suggests that no more than 1 in 100 are likely to suffer a serious adverse event as a result of treatment with SLIT (RD 0.0012, 95% confidence interval (CI) -0.0077 to 0.0102; participants = 2560; studies = 22; moderate-quality evidence).Within secondary outcomes, wide but varied reporting of largely unvalidated asthma symptom and medication scores precluded meaningful meta-analysis; a general trend suggested SLIT benefit over placebo, but variation in scales meant that results were difficult to interpret.Changes in inhaled corticosteroid use in micrograms per day (MD 35.10 mcg/d, 95% CI -50.21 to 120.42; low-quality evidence), exacerbations requiring oral steroids (studies = 2; no events) and bronchial provocation (SMD 0.69, 95% CI -0.04 to 1.43; very low-quality evidence) were not often reported. This led to many imprecise estimates with wide confidence intervals that included the possibility of both benefit and harm from SLIT.More people taking SLIT had adverse events of any kind compared with control (OR 1.70, 95% CI 1.21 to 2.38; low-quality evidence; participants = 1755; studies = 19), but events were usually reported to be transient and mild.Lack of data prevented most of the planned subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Lack of data for important outcomes such as exacerbations and quality of life and use of different unvalidated symptom and medication scores have limited our ability to draw a clinically useful conclusion. Further research using validated scales and important outcomes for patients and decision makers is needed so that SLIT can be properly assessed as clinical treatment for asthma. Very few serious adverse events have been reported, but most studies have included patients with intermittent or mild asthma, so we cannot comment on the safety of SLIT for those with moderate or severe asthma. SLIT is associated with increased risk of all adverse events.

Sublingual Immunotherapy with a Five-Grass Pollen Tablet in Adult Patients with Allergic Rhinitis: An Open, Prospective, Noninterventional, Multicenter Study

Background. Although the safety and efficacy of sublingual immunotherapy (SLIT) with a five-grass pollen tablet have been demonstrated in randomized clinical trials (RCTs), these outcomes must always be evaluated in real-life medical practice. Methods. In a prospective, open-label, noninterventional, “real-life” study in Germany, we evaluated the safety, tolerability, and effectiveness of SLIT with a five-grass pollen tablet in adults with grass-pollen-induced allergic rhinoconjunctivitis. Results. 808 adults were enrolled between September 2008 and December 2009. 35.3% of the participants experienced at least one adverse drug reaction (ADR), the most common of which were mild-to-moderate gastrointestinal and respiratory disorders. Serious ADRs considered causally related to SLIT treatment occurred in four patients. Overall, the five-grass pollen tablet was considered to have good or very good tolerability by most investigators and patients. Treatment was associated with the relief of nasal, ocular, and bronchial symptoms and decreased symptomatic medication use. However, interpretation of clinical improvements was limited by lower atmospheric grass pollen levels during the study season (relative to the preceding season). Conclusions. In a large population of patients treated in real-life medical practice, SLIT with a five-grass pollen tablet was safe and well tolerated. The patient-reported symptom relief suggests that SLIT was associated with clinical benefits.

Development and evaluation of a sublingual tablet based on recombinant Bet v 1 in birch pollen-allergic patients

BACKGROUND

Sublingual immunotherapy (SLIT) applied to type I respiratory allergies is commonly performed with natural allergen extracts. Herein, we developed a sublingual tablet made of pharmaceutical-grade recombinant Bet v 1.0101 (rBet v 1) and investigated its clinical safety and efficacy in birch pollen (BP)-allergic patients.

METHODS

Following expression in Escherichia coli and purification, rBet v 1 was characterized using chromatography, capillary electrophoresis, circular dichroism, mass spectrometry and crystallography. Safety and efficacy of rBet v 1 formulated as a sublingual tablet were assessed in a multicentre, double-blind, placebo-controlled study conducted in 483 patients with BP-induced rhinoconjunctivitis.

RESULTS

In-depth characterization confirmed the intact product structure and high purity of GMP-grade rBet v 1. The crystal structure resolved at 1.2 Å documented the natural conformation of the molecule. Native or oxidized forms of rBet v 1 did not induce the production of any proinflammatory cytokine by blood dendritic cells or mononuclear cells. Bet v 1 tablets were well tolerated by patients, consistent with the known safety profile of SLIT. The average adjusted symptom scores were significantly decreased relative to placebo in patients receiving once daily for 5 months rBet v 1 tablets, with a mean difference of 17.0-17.7% relative to the group treated with placebo (P < 0.025), without any influence of the dose in the range (12.5-50 μg) tested.

CONCLUSION

Recombinant Bet v 1 has been produced as a well-characterized pharmaceutical-grade biological drug. Sublingual administration of rBet v 1 tablets is safe and efficacious in patients with BP allergic rhinoconjunctivitis.

Oral/sublingual Phleum pretense grass tablet (Grazax/Grastek) to treat allergic rhinitis in the USA

With the approval of two grass tablets and one ragweed tablet for sublingual immunotherapy (SLIT) by the US FDA in April 2014, the practice of allergy immunotherapy (AIT) in the USA has dramatically changed. Until this time, there were no approved allergen extracts for sublingual administration and physicians who prescribed SLIT for their patients did so without full knowledge of proper dosing or assurance of its safety. Now sublingual allergen tablets are available that have proven safe and effective doses. This article describes, in detail, the studies that have been conducted with a timothy grass SLIT tablet and draws some comparisons to the alternative 5-grass SLIT tablet. It also attempts to predict what will be the impact of the introduction of these tablets on the practice of AIT in the USA over the next few years.

Specific IgE recognition of pollen allergens from subtropic grasses in patients from the subtropics

BACKGROUND

Pollens of subtropical grasses, Bahia (Paspalum notatum), Johnson (Sorghum halepense), and Bermuda (Cynodon dactylon), are common causes of respiratory allergies in subtropical regions worldwide.

OBJECTIVE

To evaluate IgE cross-reactivity of grass pollen (GP) found in subtropical and temperate areas.

METHODS

Case and control serum samples from 83 individuals from the subtropical region of Queensland were tested for IgE reactivity with GP extracts by enzyme-linked immunosorbent assay. A randomly sampled subset of 21 serum samples from patients with subtropical GP allergy were examined by ImmunoCAP and cross-inhibition assays.

RESULTS

Fifty-four patients with allergic rhinitis and GP allergy had higher IgE reactivity with P notatum and C dactylon than with a mixture of 5 temperate GPs. For 90% of 21 GP allergic serum samples, P notatum, S halepense, or C dactylon specific IgE concentrations were higher than temperate GP specific IgE, and GP specific IgE had higher correlations of subtropical GP (r = 0.771-0.950) than temperate GP (r = 0.317-0.677). In most patients (71%-100%), IgE with P notatum, S halepense, or C dactylon GPs was inhibited better by subtropical GP than temperate GP. When the temperate GP mixture achieved 50% inhibition of IgE with subtropical GP, there was a 39- to 67-fold difference in concentrations giving 50% inhibition and significant differences in maximum inhibition for S halepense and P notatum GP relative to temperate GP.

CONCLUSION

Patients living in a subtropical region had species specific IgE recognition of subtropical GP. Most GP allergic patients in Queensland would benefit from allergen specific immunotherapy with a standardized content of subtropical GP allergens.

Current developments for improving efficacy of allergy vaccines

Allergic diseases are prevalent worldwide. Allergen immunotherapy (AIT) is a current treatment for allergy, leading to modification of the natural course of disease. Mechanisms of efficacy include Treg through release of IL-10 and TGF-β and specific IgG4 blocking antibodies. Subcutaneous and sublingual routes are popular, but uptake is limited by inconvenience and safety concerns. Inclusion criteria limit application to a small proportion of allergic patients. New forms of immunotherapy are being investigated for more efficacious, convenient and safer options with promising advances in recent years. The rationale of reducing vaccine allergenicity to increase safety while improving immunogenicity led to investigation of T-cell epitope-based peptides and recombinant allergen derivatives. Additionally, different routes of administration and adjuvants and adjunct therapies are being explored. This review discusses the current status of AIT and recent advances to improve clinical efficacy, safety and long-term immune tolerance.

Prolonged efficacy of the 300IR 5-grass pollen tablet up to 2 years after treatment cessation, as measured by a recommended daily combined score

BACKGROUND

The 300IR (index of reactivity) 5-grass pollen tablet has favorable short-term and sustained clinical efficacy in patients with grass pollen-induced allergic rhinoconjunctivitis (ARC). Here, we report maintenance of efficacy and safety over 2 years following treatment discontinuation.

METHODS

Randomized, double-blind, placebo-controlled, parallel-group, multicenter Phase 3 trial in patients aged 18-50 years with ARC. During study years 1-3, patients received a daily sublingual tablet containing either 300IR 5-grass pollen extract or placebo, according to a discontinuous pre- and coseasonal protocol. Study years 4 and 5 were treatment-free. In response to health authorities' recommendations, the daily combined score (DCS) was assessed in a post-hoc analysis as the efficacy endpoint. Components of the DCS were daily rhinoconjunctivitis total symptom score (DRTSS) and daily rescue medication score (DRMS).

RESULTS

633 patients with ARC were randomized to placebo (n = 219) or 300IR 5-grass pollen tablet, beginning 4 months (4 M, n = 207) or 2 months (2 M, n = 207) prior to the estimated start of the grass pollen season and continuing until season's end. During the first post-treatment year, a statistically significant difference versus placebo in least squares (LS) mean DCS was noted in patients previously receiving active treatment (300IR (2 M) point estimate: -0.16, 95% confidence interval (CI95%): [-0.26, -0.06], p = 0.0019; -31.1%; 300IR (4 M) point estimate: -0.13, CI95%: [-0.23, -0.03], p = 0.0103, -25.3%). During the second post-treatment year, patients in the 300IR (4 M) group, but not the 300IR (2 M) group, showed a statistically significant difference in LS mean DCS versus placebo (point estimate: -0.11, CI95%: [-0.21; 0.00], p = 0.0478, -28.1%). This significant efficacy seen during the post-treatment years in patients previously treated with 5-grass pollen tablet compared favorably with that during the 3 prior years of active treatment. A statistically significant difference versus placebo was also noted in secondary efficacy measures in both post-treatment years (except for DRTSS in year 5). In the absence of any active treatment, the safety profile was similar in the active groups versus placebo group during either post-treatment year.

CONCLUSIONS

In adults with grass pollen-associated ARC, 5-grass pollen tablet therapy beginning 4 months before the pollen season and continuing to season's end demonstrated efficacy across all variables during active treatment, and this effect was prolonged for up to 2 years post-treatment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00418379.

Phenotypes and endotypes of rhinitis and their impact on management: a PRACTALL report

Rhinitis is an umbrella term that encompasses many different subtypes, several of which still elude complete characterization. The concept of phenotyping, being the definition of disease subtypes on the basis of clinical presentation, has been well established in the last decade. Classification of rhinitis entities on the basis of phenotypes has facilitated their characterization and has helped practicing clinicians to efficiently approach rhinitis patients. Recently, the concept of endotypes, that is, the definition of disease subtypes on the basis of underlying pathophysiology, has emerged. Phenotypes/endotypes are dynamic, overlapping, and may evolve into one another, thus rendering clear-cut definitions difficult. Nevertheless, a phenotype-/endotype-based classification approach could lead toward the application of stratified and personalized medicine in the rhinitis field. In this PRACTALL document, rhinitis phenotypes and endotypes are described, and rhinitis diagnosis and management approaches focusing on those phenotypes/endotypes are presented and discussed. We emphasize the concept of control-based management, which transcends all rhinitis subtypes.

Safety and tolerability of 5-grass pollen tablet sublingual immunotherapy: pooled analysis and clinical review

INTRODUCTION

The 5-grass pollen tablet (Oralair®, Stallergenes, Antony, France) is a once-daily preseasonal and coseasonal sublingual immunotherapy (SLIT) that is effective in controlling the symptoms of allergic rhinoconjunctivitis and in reducing the need for symptomatic medication.

AREAS COVERED

The body of safety data gathered from the 5-grass pollen tablet clinical development program, post-approval studies, and more than 6 years of real-life experience demonstrates the safety and tolerability profile of the 5-grass pollen tablet across all age groups. Adverse events (AEs) are generally mild or moderate in severity, and rarely lead to treatment discontinuation. AEs also tend to decline in frequency and severity over time and with repeated treatment. The most frequent treatment-emergent AEs are local-site oropharyngeal reactions (e.g., oral pruritus, throat irritation, tongue pruritus, mouth edema, ear pruritus), which are consistent with the sublingual route of administration.

EXPERT OPINION

The first dose of the 5-grass pollen tablet should be administered under the supervision of an experienced physician, to allow for optimal monitoring and timely management of AEs, should they occur. The 5-grass pollen tablet can be administered at home after the first dose, and patients and carers should be educated on how to manage adverse reactions, unplanned treatment interruptions and situations in which SLIT should be withheld.

Safety evaluation of standardized allergen extract of Japanese cedar pollen for sublingual immunotherapy

Japanese cedar (JC) pollinosis is caused by Japanese cedar pollen (JCP) and most common seasonal allergic disease in Japan. Subcutaneous immunotherapy (SCIT) with allergen extract of JCP (JCP-allergen extract) is well established for JC pollinosis treatment with improvement of symptoms. However, major drawbacks for SCIT are repeated painful injections, frequent hospital visits and anaphylactic risk. Currently, sublingual immunotherapy (SLIT) has received much attention as an advanced alternative application with lower incidence of systemic reactions because the liquid or tablet form of allergen is placed under the tongue. The aim of this study was safety evaluation of standardized JCP-allergen extract currently developed for SLIT in JC pollinosis. JCP-allergen extract showed no potential genotoxicity. No systemic effects were observed in rats administered JCP-allergen extract orally for 26 weeks followed by 4-week recovery period. Mild local reactions such as hyperplasia and increased globule leukocytes resulting from vehicle (glycerin)-induced irritation were observed in stomach. No-observed-adverse-effect level was greater than 10,000 JAU/kg/day for systemic toxicity, equivalent to 300-fold the human dose. No local irritation was found in rabbits oral mucosae by 7-day sublingual administration. These results demonstrate the safe profile of standardized JCP-allergen extract, suggesting it is suitable for SLIT in JC pollinosis.

Immunotherapy in all aspects

Allergen immunotherapy is a form of long-term treatment that decreases symptoms for many people with allergic rhinitis, allergic asthma, conjunctivitis (eye allergy) or stinging insect allergy. In this review, we presented the important topics in immunotherapy. The important aspects of immunotherapy are considered to be "Immunologıcal responses to immunotherapy"; "The principal types of immunotherapy"; "Effectiveness"; "Indications"; "Contraindications"; "Allergen immunotherapy in children"; "Safety"; and "Anaphylactic reactions after immunotherapy". The principal types of immunotherapy are subcutaneous immunotherapy (SCIT) and sublingual immunotherapy. Both of them can be used in indicated cases. When using SCIT, physicians must be more careful because of reported rare fatal cases. The risks and benefits of continuing allergen immunotherapy in patients who have experienced severe systemic reactions should be carefully considered.

Health economic comparison of SLIT allergen and SCIT allergoid immunotherapy in patients with seasonal grass-allergic rhinoconjunctivitis in Germany

BACKGROUND

Allergoids are chemically modified allergen extracts administered to reduce allergenicity and to maintain immunogenicity. Oralair® (the 5-grass tablet) is a sublingual native grass allergen tablet for pre- and co-seasonal treatment. Based on a literature review, meta-analysis, and cost-effectiveness analysis the relative effects and costs of the 5-grass tablet versus a mix of subcutaneous allergoid compounds for grass pollen allergic rhinoconjunctivitis were assessed.

METHODS

A Markov model with a time horizon of nine years was used to assess the costs and effects of three-year immunotherapy treatment. Relative efficacy expressed as standardized mean differences was estimated using an indirect comparison on symptom scores extracted from available clinical trials. The Rhinitis Symptom Utility Index (RSUI) was applied as a proxy to estimate utility values for symptom scores. Drug acquisition and other medical costs were derived from published sources as well as estimates for resource use, immunotherapy persistence, and occurrence of asthma. The analysis was executed from the German payer's perspective, which includes payments of the Statutory Health Insurance (SHI) and additional payments by insurants. Comprehensive deterministic and probabilistic sensitivity analyses and different scenarios were performed to test the uncertainty concerning the incremental model outcomes.

RESULTS

The applied model predicted a cost-utility ratio of the 5-grass tablet versus a market mix of injectable allergoid products of € 12,593 per QALY in the base case analysis. Predicted incremental costs and QALYs were € 458 (95% confidence interval, CI: € 220; € 739) and 0.036 (95% CI: 0.002; 0.078), respectively. Compared to the allergoid mix the probability of the 5-grass tablet being the most cost-effective treatment option was predicted to be 76% at a willingness-to-pay threshold of € 20,000. The results were most sensitive to changes in efficacy estimates, duration of the pollen season, and immunotherapy persistence rates.

CONCLUSIONS

This analysis suggests the sublingual native 5-grass tablet to be cost-effective relative to a mix of subcutaneous allergoid compounds. The robustness of these statements has been confirmed in extensive sensitivity and scenario analyses.

A milestone in house dust-mite-allergen immunotherapy: the new sublingual tablet S-524101 (actair)

Subcutaneous allergen-specific immunotherapy has long been used in the treatment of allergic rhinitis and/or asthma and its efficacy has been confirmed. However, due to the discomfort of injections and the risk of severe adverse reactions, alternative routes of allergen administration have emerged. Delivery of allergens through the mucosal route had been proposed and investigated thoroughly, confirming the sublingual route to be the most efficacious. Later, the efficacy and safety of this route have been documented by numerous controlled trials both for house dust mite (HDM) and pollens. Recently, sublingual orodispersable grass pollen allergen tablets were in use followed by the newly developed HDM allergen tablets with satisfactory clinical results: Moreover, very recently 1 year of HDM tablet treatment was demonstrated to exert its clinical efficacy 1 year after discontinuation of tablet IT. The persistence of efficacy after only 1 year of treatment is a new and promising era. Currently, Sublingual Immunotherapy is the most easily administered and safe treatment option until more immunogenic, less allergenic and more efficient allergen extracts are developed.

300IR 5-Grass pollen sublingual tablet offers relief from nasal symptoms in patients with allergic rhinitis

BACKGROUND

300IR 5-grass pollen sublingual immunotherapy tablets have been approved for the treatment of allergic rhinitis (AR) with or without conjunctivitis in adults and children >5 years with grass pollen allergy. This study was designed to review data on nasal symptoms with 300IR 5-grass pollen sublingual tablets in adults and children.

METHODS

We reviewed data from four double-blind, placebo-controlled, randomized clinical trials. Two groups of patients who received a daily dose of either placebo or 300IR 5-grass pollen sublingual tablets starting 4 months before the expected start of the pollen season and continuing through the season were compared (analysis of covariance) for scores of sneezing, rhinorrhea, nasal pruritus, nasal congestion, total nasal symptom score (TNSS), and adult Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores.

RESULTS

Data for 266 children (one pediatric trial) and 1036 adults (three trials) were analyzed. Compared with the placebo groups, mean TNSS in the 300IR groups was lower by 22% in children and 19-36% in adults. Among the four nasal symptoms, the lowest scores relative to placebo were for nasal congestion in children (31%) and adults (43%). Mean adult RQLQ scores were 21-31% lower in the 300IR group than in the placebo group.

CONCLUSION

Allergen immunotherapy with 300IR 5-grass pollen sublingual tablets was consistently associated with AR symptom relief in adults and children and provided a clinically meaningful improvement in quality of life.

Current status of sublingual immunotherapy in the United States

Sublingual immunotherapy (SLIT) use in the United States to date has been limited, despite common use and demonstrated efficacy elsewhere in the world. This is largely in part due to lack of FDA-approved SLIT products, lack of established dosing and administration guidelines, and cost concerns. Several recent studies have demonstrated efficacy and safety of two sublingual grass tablets and one ragweed tablet approved by the FDA, and one sublingual ragweed liquid currently pending FDA approval. With FDA approved SLIT products, there will be numerous challenges to the allergist and patient in deciding whether to pursue SLIT or SCIT (subcutaneous immunotherapy) for allergic rhinitis. This review highlights the current state of SLIT in the United States, and expected future directions.

Management of allergic rhinitis

In this paper, we review the current management of allergic rhinitis and new directions for future treatment. Currently, management includes pharmacotherapy, allergen avoidance and possibly immunotherapy. The simple washing of nasal cavities using isotonic saline provides a significant improvement and is useful, particularly in children. The most effective medication in persistent rhinitis used singly is topical corticosteroid, which decreases all symptoms, including ocular ones. Antihistamines reduce nasal itch, sneeze and rhinorrhea and can be used orally or topically. When intranasal antihistamine is used together with topical corticosteroid, the combination is more effective and acts more rapidly than either drug used alone. Alternative therapies, such as homeopathy, acupuncture and intranasal carbon dioxide, or devices such nasal air filters or intranasal cellulose, have produced some positive results in small trials but are not recommended by Allergic Rhinitis and its Impact on Asthma (ARIA). In the field of allergic immunotherapy, subcutaneous and sublingual routes are currently used, the former being perhaps more efficient and the latter safer. Sublingual tablets are now available. Their efficacy compared to standard routes needs to be evaluated. Efforts have been made to develop more effective and simpler immunotherapy by modifying allergens and developing alternative routes. Standard allergen avoidance procedures used alone do not provide positive results. A comprehensive, multi-trigger, multi-component approach is needed, including avoidance of pollutants such as cigarette smoke.

Five-grass-pollen sublingual immunotherapy tablet for the treatment of grass-pollen-induced allergic rhinoconjunctivitis: 5 years of experience

Oralair(®) (OA) (Stallergenes, Antony, France) is a unique pre- and co-seasonal 5-grass-pollen sublingual immunotherapy tablet launched in 2008, and now approved in 31 countries worldwide for the treatment of grass-pollen allergic rhinitis and rhinoconjunctivitis. OA is the first oral treatment with a consistent, well-balanced allergen extract that mimics natural exposure and sensitization. A wealth of data exists from over 5 years of clinical and real-world experience demonstrating the efficacy and safety of OA for grass-pollen-allergy treatment. OA is highly effective from the first pollen season in all patient subgroups, including children and those with comorbid mild asthma, irrespective of sensitization status and symptom severity. OA also has sustained long-term benefits for symptom control and quality of life. This article provides an overview of the pharmacodynamics and pharmacology of OA; its efficacy, safety, tolerability and cost-effectiveness for the treatment of allergic rhinitis and rhinoconjunctivitis and its role in clinical practice.

Safety and tolerability of sublingual immunotherapy in clinical trials and real life

PURPOSE OF REVIEW

Sublingual immunotherapy (SLIT) is effective in allergic rhinitis and asthma. Apart from its efficacy, safety is crucial as this treatment is usually self-administered at home. Tolerability also plays a pivotal role, as mild local reactions, although not life-threatening, may represent a risk for treatment withdrawal and can therefore negatively affect clinical outcomes. The present study addresses this issue by reviewing double-blind, placebo-controlled, randomized trials and real-life studies.

RECENT FINDINGS

The number of life-threatening SLIT-related reactions is negligible. SLIT-related adverse events are not always consistently reported nor uniformly classified in published studies. However, systemic reactions are rare and side effects mostly consist of mild, self-limiting local reactions. No treatment-related risk factors for adverse events have been clearly defined, as far as type of allergen, dose or schedule.

SUMMARY

SLIT provides an optimal safety profile both in children and in adults. Apart from life-threatening reactions, the lack of standardization of adverse events reporting may account for the wide variability of the prevalence of side effects in clinical trials and in real-life setting. It can lead to a possible underestimation of adverse events, concerning, in particular, local reactions. Since poor tolerability may affect adherence and cause treatment discontinuation, adopting shared strategies in order to recognize, grade and manage adverse events is mandatory.

Sublingual immunotherapy: the U.S. experience

PURPOSE OF REVIEW

It is likely that approval of allergen preparations for sublingual immunotherapy (SLIT) will soon occur in the United States. This article reviews experience with SLIT in this country, concentrating on the large, multicenter trials that will provide the evidence of safety and efficacy necessary to obtain that approval.

RECENT FINDINGS

Large multicenter trials have been conducted with both grass and short ragweed. In five single-season studies with sublingual grass tablets, usually starting 4 months prior to and continuing through the pollen season, the combined symptom medication score was improved 20-28% relative to placebo-treated individuals. Short ragweed tablets, initiated 4 months prior to and continued through the pollen season, reduced symptom/medication scores by 24-26%. Similar results have been reported with short ragweed aqueous extract administered sublingually. To date, there has been only one small study each with house dust mite and cat allergen extracts. All of these studies were conducted with a single allergen. One small study, comparing timothy alone to the same dose of timothy combined with nine other pollen extracts, raised still unanswered questions regarding the efficacy of SLIT with multiple allergen mixes.

SUMMARY

SLIT is coming to the United States. There will be approved allergen preparations for which the appropriate dosing for efficacy and safety has been established. It would be inappropriate to use the evidence generated by these large studies to justify off-label use of allergen extracts approved for injection or the administration of multiple allergen preparations sublingually.

A meta-analysis of sublingual allergen immunotherapy and pharmacotherapy in pollen-induced seasonal allergic rhinoconjunctivitis

BACKGROUND

The capacity of sublingual allergen immunotherapy (SLIT) to provide effective symptom relief in pollen-induced seasonal allergic rhinitis is often questioned, despite evidence of clinical efficacy from meta-analyses and well-powered, double-blind, placebo-controlled randomized clinical trials. In the absence of direct, head-to-head, comparative trials of SLIT and symptomatic medication, only indirect comparisons are possible.

METHODS

We performed a meta-analysis of classes of products (second-generation H1-antihistamines, nasal corticosteroids and grass pollen SLIT tablet formulations) and single products (the azelastine-fluticasone combination MP29-02, and the leukotriene receptor antagonist montelukast) for the treatment of seasonal allergic rhinitis in adults, adolescents and/or children. We searched the literature for large (n >100 in the smallest treatment arm) double-blind, placebo-controlled randomized clinical trials. For each drug or drug class, we performed a meta-analysis of the effect on symptom scores. For each selected trial, we calculated the relative clinical impact (according to a previously published method) on the basis of the reported post-treatment or season-long nasal or total symptom scores: 100 × (scorePlacebo - scoreActive)/scorePlacebo.

RESULTS

Twenty-eight publications on symptomatic medication trials and ten on SLIT trials met our selection criteria (total number of patients: n = 21,223). The Hedges' g values from the meta-analyses confirmed the presence of a treatment effect for all drug classes. In an indirect comparison, the weighted mean (range) relative clinical impacts were -29.6% (-23% to -37%) for five-grass pollen SLIT tablets, -19.2% (-6% to -29%) for timothy pollen SLIT tablets, -23.5% (-7% to -54%) for nasal corticosteroids, -17.1% (-15% to -20%) for MP29-02, -15.0% (-3% to -26%) for H1-antihistamines and -6.5% (-3% to -10%) for montelukast.

CONCLUSIONS

In an indirect comparison, grass pollen SLIT tablets had a greater mean relative clinical impact than second-generation antihistamines and montelukast and much the same mean relative clinical impact as nasal corticosteroids. This result was obtained despite the presence of methodological factors that mask the clinical efficacy of SLIT for the treatment of seasonal allergic rhinitis.