Economic evaluation of sublingual immunotherapy vs symptomatic treatment in adults with pollen-induced respiratory allergy: the Sublingual Immunotherapy Pollen Allergy Italy (SPAI) study

Efficacy of Sublingual Immunotherapy in Allergic Rhinitis Patients with Asthma: A Systematic Review and Meta-Analysis

OBJECTIVE

Sublingual immunotherapy (SLIT) has been widely applied to treat patients with allergic rhinitis (AR). However, meta-analyses on the efficacy of SLIT in AR patients with asthma are still limited.

METHODS

Literature without language limitation published before October 28, 2022, were retrieved from PubMed, EMBASE, and Cochrane Library. STATA 16.0 software was used for the meta-analysis of the extracted data. The results reported were symptom scores, drug scores, adverse effects rates, and cost of treatment.

RESULTS

Ten studies involving 1722 patients met the inclusion criteria. The total rhinitis score (TRSS) (weighted mean difference [WMD] = -1.23, 95% CI: -1.39--1.06, P < .001) and total asthma symptom score (TASS) (WMD = -1.00, 95% CI: -1.12-0.89, P < .001) were significantly lower in the SLIT group than the placebo group. The SLIT group had higher rates of treatment-related adverse events (relative risk [RR] = 2.82, 95% CI: 1.77-4.48, P < .001) and total costs of treatment (standardized mean difference [SMD] = 0.71, 95% CI: 0.45-0.97, P < .001). There was no significant difference in inhaled corticosteroids (ICS) dose (P = .195), fractional exhaled nitric oxide (FeNO) (P = .158), forced expiratory volume in 1 s (FEV1) (P = .237), and direct costs of treatment (P = .630) between the SLIT and placebo groups.

CONCLUSION

SLIT may be a therapeutic method for improving rhinitis symptoms and asthma symptoms in AR patients with asthma. However, as there was significant heterogeneity in results, more high-quality and well-designed studies are needed in the future to elucidate the efficacy of SLIT.

Pharmacoeconomics of allergy immunotherapy versus pharmacotherapy

Introduction: The purpose of this review is to evaluate the cost-effectiveness of allergy immunotherapy (AIT) in the treatment of allergic rhinitis, asthma, and other allergic conditions.Area covered: An extensive search of the PubMed and Medline database (January 1996 up to June of 2020) was conducted using the search terms allergy immunotherapy, pharmacoeconomics, cost-effectiveness, allergic rhinitis, and asthma. Studies were included if they included information on the economics of AIT in comparison to pharmacotherapy in the treatment of allergic rhinitis or asthma either as actual costs or based on theoretical models. Systematic reviews were included if they included information about the cost-effectiveness of AIT.Most clinical trials found significant cost-savings with AIT. The cost-effective time-point ranged from a few months to several years after treatment initiation.. Cost savings were demonstrated as early as 3 months after treatment initiation and were as great as 80% less than SDT in some studies.Expert opinion: There is strong evidence in the collective literature that AIT is cost-effective as compared to SDT alone. The magnitude of AIT's cost-effectiveness is likely underestimated because most of the studies considered during treatment costs and not AIT's long-term benefits or preventive/prophylactic effects or its impact on co-morbid conditions.

[Allergic immunotherapy in children and adolescents]

L’immunothérapie spécifique allergénique nécessite l’administration répétée d’allergènes dans le but de provoquer une tolérance clinique et immunologique. C’est la seule thérapeutique à visée étiologique qui permet de modifier l’évolution de la maladie en assurant une rémission après l’interruption de la procédure. La prévention de nouvelles sensibilisations par l’immunothérapie reste discutée. Nous envisagerons dans cette revue les principaux mécanismes immunologiques et les indications de l’immunothérapie chez l’enfant et l’adolescent.

The Cost-Effectiveness of Allergen Immunotherapy Compared with Pharmacotherapy for Treatment of Allergic Rhinitis and Asthma

This article evaluates the cost-effectiveness of allergy immunotherapy (AIT) in the treatment of allergic rhinitis, asthma, and other allergic conditions. An extensive search of the PubMed and Medline databases (up to December 2018) was conducted. There is strong evidence in the collective literature, which included individual studies and systematic reviews, that AIT is cost-effective in the management of allergic rhinitis and asthma as compared with standard drug treatment alone. The magnitude of AIT's cost-effectiveness is likely underestimated because most of the studies considered during-treatment costs and not the long-term benefits or preventive or prophylactic effects of AIT.

30 years of sublingual immunotherapy

Allergen Immunotherapy (AIT) was introduced in clinical practice on an empirical basis more than 100 years ago. Since the first attempts, AIT was administered subcutaneously. Indeed, other routes of administration were proposed and studied, in particular to improve the safety, but only the sublingual route (SLIT) achieved a credibility based on evidence and was then accepted as a viable "alternative" option to the subcutaneous route. SLIT was largely used in clinical trials and clinical practice in this last 30 years. Thus, a large amount of data is available, coming from either controlled trials and postmarketing surveillance studies. It is clear that SLIT is overall effective, but it is also clear that the efficacy is not "class-related," as derived from meta-analyses, but restricted to each specific product. The 30-year lasting use of SLIT allowed to clarify many clinical aspects, such as efficacy, safety, use in asthma, regimens of administration, and optimal doses. In parallel, the mechanisms of action of AIT were elucidated, and new indications were proposed (eg food allergy, atopic dermatitis). In addition, the introduction of molecular-based diagnosis, allowed to better refine the prescription of SLIT, based on specific sensitization profiles. The present article will describe the origin and evolution of SLIT for respiratory allergy, taking into account the clinical context that suggested this form of treatment, the recently developed aspects, the future perspectives and unmet needs, This is not, therefore, a systematic review, rather a narrative historical description of the past history, and a look forward to the future opportunities.

EAACI Guidelines on Allergen Immunotherapy: Allergic rhinoconjunctivitis

Allergic rhinoconjunctivitis (AR) is an allergic disorder of the nose and eyes affecting about a fifth of the general population. Symptoms of AR can be controlled with allergen avoidance measures and pharmacotherapy. However, many patients continue to have ongoing symptoms and an impaired quality of life; pharmacotherapy may also induce some side-effects. Allergen immunotherapy (AIT) represents the only currently available treatment that targets the underlying pathophysiology, and it may have a disease-modifying effect. Either the subcutaneous (SCIT) or sublingual (SLIT) routes may be used. This Guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on AIT for AR and is part of the EAACI presidential project "EAACI Guidelines on Allergen Immunotherapy." It aims to provide evidence-based clinical recommendations and has been informed by a formal systematic review and meta-analysis. Its generation has followed the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included involvement of the full range of stakeholders. In general, broad evidence for the clinical efficacy of AIT for AR exists but a product-specific evaluation of evidence is recommended. In general, SCIT and SLIT are recommended for both seasonal and perennial AR for its short-term benefit. The strongest evidence for long-term benefit is documented for grass AIT (especially for the grass tablets) where long-term benefit is seen. To achieve long-term efficacy, it is recommended that a minimum of 3 years of therapy is used. Many gaps in the evidence base exist, particularly around long-term benefit and use in children.

Health economic analysis of allergen immunotherapy for the management of allergic rhinitis, asthma, food allergy and venom allergy: A systematic overview

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is developing guidelines for allergen immunotherapy (AIT) for the management of allergic rhinitis, allergic asthma, IgE-mediated food allergy and venom allergy. To inform the development of clinical recommendations, we undertook systematic reviews to critically assess evidence on the effectiveness, safety and cost-effectiveness of AIT for these conditions. This study focusses on synthesizing data and gaps in the evidence on the cost-effectiveness of AIT for these conditions.

METHODS

We produced summaries of evidence in each domain, and then, synthesized findings on health economic data identified from four recent systematic reviews on allergic rhinitis, asthma, food allergy and venom allergy, respectively. The quality of these studies was independently assessed using the Critical Appraisal Skills Programme tool for health economic evaluations.

RESULTS

Twenty-three studies satisfied our inclusion criteria. Of these, 19 studies investigated the cost-effectiveness of AIT in allergic rhinitis, of which seven were based on data from randomized controlled trials with economic evaluations conducted from a health system perspective. This body of evidence suggested that sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT) would be considered cost-effective using the (English) National Institute for Health and Clinical Excellence (NICE) cost-effectiveness threshold of £20 000/quality-adjusted life year (QALY). However, the quality of the studies and the general lack of attention to characterizing uncertainty and handling missing data should be taken into account when interpreting these results. For asthma, there were three eligible studies, all of which had significant methodological limitations; these suggested that SLIT, when used in patients with both asthma and allergic rhinitis, may be cost-effective with an incremental cost-effectiveness ratio (ICER) of £10 726 per QALY. We found one economic modelling study for venom allergy which, despite being based largely on expert opinion and plausible assumptions, suggested that AIT for bee and wasp venom allergy is only likely to be cost-effective for very high-risk groups who may be exposed to multiple exposures to venom/year (eg bee keepers). We found no eligible studies investigating the cost-effectiveness of AIT for food allergy.

CONCLUSIONS

Overall, the evidence to support the cost-effectiveness of AIT is limited and of low methodological quality, but suggests that AIT may be cost-effective for people with allergic rhinitis with or without asthma and in high-risk subgroups for venom allergy. We were unable to draw any conclusions on the cost-effectiveness of AIT for food allergy.

Allergen immunotherapy for allergic rhinoconjunctivitis: A systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis. To inform the development of clinical recommendations, we undertook a systematic review to assess the effectiveness, cost-effectiveness, and safety of AIT in the management of allergic rhinoconjunctivitis.

METHODS

We searched nine international biomedical databases for published, in-progress, and unpublished evidence. Studies were independently screened by two reviewers against predefined eligibility criteria and critically appraised using established instruments. Our primary outcomes of interest were symptom, medication, and combined symptom and medication scores. Secondary outcomes of interest included cost-effectiveness and safety. Data were descriptively summarized and then quantitatively synthesized using random-effects meta-analyses.

RESULTS

We identified 5960 studies of which 160 studies satisfied our eligibility criteria. There was a substantial body of evidence demonstrating significant reductions in standardized mean differences (SMD) of symptom (SMD -0.53, 95% CI -0.63, -0.42), medication (SMD -0.37, 95% CI -0.49, -0.26), and combined symptom and medication (SMD -0.49, 95% CI -0.69, -0.30) scores while on treatment that were robust to prespecified sensitivity analyses. There was in comparison a more modest body of evidence on effectiveness post-discontinuation of AIT, suggesting a benefit in relation to symptom scores.

CONCLUSIONS

AIT is effective in improving symptom, medication, and combined symptom and medication scores in patients with allergic rhinoconjunctivitis while on treatment, and there is some evidence suggesting that these benefits are maintained in relation to symptom scores after discontinuation of therapy.

Chinese Guideline on allergen immunotherapy for allergic rhinitis

The present document is based on a consensus reached by a panel of experts from Chinese Society of Allergy (CSA) and Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G). Allergen immunotherapy (AIT), has increasingly been used as a treatment for allergic rhinitis (AR) globally, as it has been shown to provide a long-term effect in improving nasal and ocular symptoms, reducing medication need, and improving quality of life. AIT is currently the only curative intervention that can potentially modify the immune system in individuals suffering from AR and prevent the development of new sensitization and the progression of disease from AR to asthma. Although the use of AIT is becoming more acceptable in China, to date no AR immunotherapy guideline from China is available for use by the international community. This document has thus been produced and covers the main aspects of AIT undertaken in China; including selection of patients for AIT, the allergen extracts available on the Chinese market, schedules and doses of allergen employed in different routes of AIT, assessment of effect and safety, patients' administration and follow-up, and management of adverse reactions. The Chinese guideline for AR immunotherapy will thus serve as a reference point by doctors, healthcare professionals and organizations involved in the AIT of AR in China. Moreover, this guideline will serve as a source of information for the international community on AIT treatment strategies employed in China.

Sublingual immunotherapy in patients with latex allergy: systematic review and meta-analysis of randomized controlled trials

Latex allergy (LA) is a commonly observed entity for which sublingual immunotherapy (SLIT) has been shown to be effective in many small randomized clinical trials. The present study was conducted with an aim of systematically reviewing the existing literature on the efficacy and safety of SLIT in patients with LA and to apply the principles of meta-analysis. A search for randomized controlled trials with appropriate search strategy in PubMed and CENTRAL was conducted. Studies with documented clinical history of LA and SLIT administered in any dose, duration and regimen compared with placebo were included. Outcome measures were symptom scores, glove provocation test score, serum IgE levels, induration following latex skin prick test, medication scores and adverse effects. Random effects model was used when moderate to severe heterogeneity was observed and fixed effects model when there was mild heterogeneity. Forest plots for standardized mean difference (95% confidence interval) for all the continuous outcome measures were created. A total of 152 records were identified from the electronic databases and four studies were finally included in the meta-analysis. A statistically significant reduction for induration following glove provocation test (pooled results from two studies) was observed in the SLIT group with SMD of -0.9 [-1.71, -0.08]. No significant differences were observed in any other outcome measures between the interventions. We did not identify significant reduction in most of the outcome measures with SLIT in patients with LA except for glove provocation test score wherein only two studies were included. Large and more randomized controlled trials are required to ascertain and confirm the utility of SLIT in such patients.

Allergen-Specific Immunotherapy

Allergen-specific immunotherapy remains the only causal treatment of allergic disease to date. Its efficacy in symptom reduction was demonstrated in double blind, placebo-controlled studies of allergic rhinoconjunctivitis, allergic asthma, and Hymenoptera venom hypersensitivity, including long-term effects after discontinuation of treatment. In addition, immunotherapy decreases the risk of developing new sensitisations to aeroallergens in monosensitised patients and allergic asthma in patients with mere allergic rhinitis. The mechanism of immunotherapy entails redirection of the T lymphocyte response from a T helper cell Type 2 phenotype in favour of induction of regulatory T cells and/or immune deviation toward a T helper cell Type 1 phenotype, with resulting inhibition of downstream effector pathways and induction of immunoglobulin G-associated blocking antibodies. Two main application forms are used in clinical practice: subcutaneous immunotherapy and sublingual immunotherapy. The advantage of subcutaneous immunotherapy is its proven efficacy over a broad range of indications. Disadvantages are systemic allergic reactions and inconvenience for the patient due to frequent doctor visits. Sublingual immunotherapy has been shown to result in less systemic allergic reactions and may be more convenient due to home application; however, efficacy has only been proven for allergic rhinitis. For clinicians, the adherence to practice guidelines and thorough knowledge of allergen products, application routes, indications, immunomodulatory mechanisms, efficacy, safety, and cost-effectiveness is important for successful treatment and will be addressed in this review article.

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

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

Allergy immunotherapy in reducing healthcare cost

PURPOSE OF REVIEW

To evaluate the cost-effectiveness of allergen immunotherapy (AIT) in the treatment of allergic rhinitis and asthma. Individual studies and systematic reviews that included information on AIT economic outcomes as compared with symptomatic drug treatment (SDT) were evaluated.

RECENT FINDINGS

One systematic review that included 14 studies concluded that subcutaneous and sublingual immunotherapy may be cost-effective compared with SDT from around 6 years. Another systematic review of 24 studies comparing economic outcomes of subcutaneous allergy immunotherapy and/or sublingual allergy immunotherapy with SDT found compelling evidence for cost-savings with both forms of AIT over SDT. There was no strong evidence indicating superior cost-efficacy of subcutaneous allergy immunotherapy or sublingual allergy immunotherapy over SDT in either of these systematic reviews. Individual studies have demonstrated AIT cost-savings as high as 80% compared with SDT. Significant cost-savings were reported as early as 3 months after AIT initiation. In some studies, cost-efficacy time-point was not established until after treatment discontinuation - presumably due to time required for the clinical benefits to outweigh the AIT treatment costs. Although some economic modeling studies included the costs of 'asthma prevented', the collective literature of AIT economics provides very little to no information about the cost benefits of the preventive aspect of AIT.

SUMMARY

Overall, individual studies and systematic reviews provide strong evidence for the cost-effectiveness of AIT over SDT. The magnitude of cost-efficacy is likely underestimated in that few studies consider the cost-savings due to AIT's long-term benefits or preventive effect.

Timothy grass pollen therapeutic vaccine: optimal dose for subcutaneous immunotherapy

AIMS

To establish the optimal dose of Phleum pratense subcutaneous immunotherapy (SCIT) in patients with allergic rhinoconjunctivitis with/without asthma.

MATERIALS & METHODS

One hundred and fifty-one patients were randomized to receive SCIT 0.25, 0.5, 1.0, 2.0 or 4.0 skin-prick test units (SPT) or placebo. The primary end point was the variation in the concentration of Phleum pratense extract needed to produce a positive nasal provocation test from baseline (V0) to final visit (FV).

RESULTS

After 17 weeks, a dose-dependent trend was apparent in the concentration of P. pratense extract needed to produce a positive nasal provocation response. Systemic adverse reactions occurred with 3.2% of administered doses. Grade III (n = 2) and IV (n = 2) events were observed only at the two highest doses.

CONCLUSION

P. pratense depot SCIT showed signs of clinical and immunological efficacy by dose-dependently decreasing the allergen sensitization rate. Risk-benefit favored doses below 1.0 SPT units for confirmatory trials.

Allergy immunotherapy: what is the evidence for cost saving?

PURPOSE OF REVIEW

Given the widespread prevalence of allergic disease, its substantially associated clinical and economic burden, the unique disease-modifying benefits of allergy immunotherapy (AIT), and increased availability of sublingual immunotherapy (SLIT), a critical update of the evidence for AIT-related cost savings [for both subcutaneous immunotherapy (SCIT) and SLIT] is particularly relevant and timely. The present article reviews the evidence for SCIT-related and SLIT-related cost savings derived from a systematic review of the published literature.

RECENT FINDINGS

Examined were 24 publications pertaining to the health economics of AIT. Except for one early study comparing the costs of AIT to symptomatic drug treatment (SDT), the remainder provide compelling evidence for AIT cost savings (whether SCIT or SLIT) over SDT. Furthermore, of the six studies comparing cost outcomes of SLIT to SCIT, four reported cost savings favoring SLIT.

SUMMARY

This review, spanning research from Southern Europe, Scandinavia, Northern Europe, North America, and the Czech Republic, encompasses a range of perennial and seasonal allergic conditions, including allergic asthma, allergic rhinitis with or without asthma, and rhinoconjunctivitis with or without allergic rhinitis due to house dust mite, grass or ragweed pollen, or a mixture of various allergens. All but one study compellingly demonstrate cost savings conferred by AIT over SDT.

Economic evaluation of SQ-standardized grass allergy immunotherapy tablet (Grazax(®)) in children

Background

Grass pollen-induced rhinoconjunctivitis is a common allergic respiratory disorder affecting over 20% of the UK population in terms of quality of life and sleep, work, and school patterns. The SQ-standardized grass allergy immunotherapy tablet (AIT) has been demonstrated as a disease-modifying treatment which gives a sustained effect even after completion of a treatment course. The objective of this study was to provide an economic assessment of whether treatment with the SQ-standardized grass AIT, Grazax^® (Phleum pratense) in combination with symptomatic medications is preferable to the standard of care using symptomatic medications only. The analysis was performed for children with grass pollen-induced rhinoconjunctivitis, with or without concomitant asthma, in the UK.

Methods

The model evaluated the two treatment regimens in a cohort of 1,000 children from a payer’s perspective. Treatment was modeled in terms of management of symptoms, impact on resource use, and development of allergic asthma. The analysis modeled the use of SQ-standardized grass AIT and the sustained effects of treatment over a 9-year time horizon (ie, 3 years of treatment, with modeled long-term benefits). Data inputs were drawn from a recent clinical trial, published studies, and databases.

Results

SQ-standardized grass AIT improves patient outcomes, generating an incremental cost per quality-adjusted life year gained of £12,168. This is below commonly accepted thresholds in the UK.

Conclusion

The resulting incremental cost per QALY falls below commonly accepted willingness to pay thresholds. Therefore, the SQ-standardized grass AIT is a cost-effective option for the treatment of grass pollen-induced rhinoconjunctivitis in the UK pediatric population.

Economic evaluation of 5-grass pollen tablets versus placebo in the treatment of allergic rhinitis in adults

Background

Allergen immunotherapy (AIT) is aimed at modifying the immune response to a causative allergen, thereby reducing clinical symptoms and symptomatic medication intake and improving quality of life. Long-term AIT research has led to the development of 5-grass pollen tablets, currently indicated for the treatment of grass pollen-induced allergic rhinitis (AR).

Methods

A post-hoc analysis was conducted using the Average Adjusted Symptom Score (AAdSS) to compare the effect of treatment of AR with 5-grass pollen tablets versus placebo treatment. Using the results of the VO34.04 and VO53.06 trials and economic data, cost-effectiveness analysis of 5-grass pollen tablet treatment was performed from the Italian third-party payer perspective with cost data derived from a study of 2008 updated to 2011. Also a societal perspective was considered by using the costs related to the losses of productivity by following the human capital approach. Using the results of the analysis, the estimated receiver-operating characteristic curve was plotted to evaluate medication effectiveness in terms of quality-adjusted life years (QALYs) and a decision tree constructed to model the possible outcomes and costs for adults and paediatric patients with a low, medium, and high AAdSS. Finally, probabilistic sensitivity analysis was conducted to test the robustness of the results as well as their consistency at an assumed cost-effectiveness threshold of € 30,000/QALY.

Results

The results indicate that compared to the placebo, the 5-grass pollen tablet treatment provides a benefit of 0.127 QALYs in medium AAdSS patients and of 0.143 QALYs in high AAdSS patients. The 5-grass pollen tablet treatment was found to cost € 1,024/QALY for patients with a medium AAdSS and € 1,035/QALY for patients with a high AAdSS. Of all the simulations performed in the probabilistic sensitivity analysis, 99 % indicated that the incremental cost-effectiveness ratio of the 5-grass pollen tablet treatment was below the threshold of € 30,000/QALY in patients with medium and high AAdSS, whereas it was found to be dominated in 67 % of simulations related to patients with low AAdSS.

Conclusion

The 5-grass pollen tablet is a cost-effective treatment for adult AR patients with a medium or high AAdSS. This finding should be carefully considered when deciding the management strategy for these patients.

The cost-effectiveness of immunotherapy for respiratory allergy: a review

This article reviews the international literature on the cost-effectiveness of immunotherapy for respiratory allergy. Included studies conducted an economic evaluation of immunotherapy for allergic rhinoconjunctivitis, allergic conjunctivitis, allergic rhinitis, asthma or allergic rhinitis in combination with asthma. Although there were few economic evaluations and these suffered from methodological shortcomings, the evidence appears to support the cost-effectiveness of immunotherapy as compared with pharmacotherapy for allergic rhinoconjunctivitis, subcutaneous immunotherapy as compared with pharmacotherapy for allergic rhinitis and immunotherapy as compared with pharmacotherapy for allergic rhinitis and asthma. One economic evaluation suggested that immunotherapy as compared with pharmacotherapy is unlikely to be cost-effective for asthma. The questions of the cost-effectiveness of sublingual vs subcutaneous immunotherapy and of the cost-effectiveness of immunotherapy for allergic conjunctivitis have not been resolved to date. The cost-effectiveness of immunotherapy depends on the duration of the clinical benefit of immunotherapy following treatment cessation, and on the break-even point of cumulative costs between immunotherapy and pharmacotherapy. There is a need for economic evaluations based on high-quality prospective and long-term clinical studies comparing immunotherapy with pharmacotherapy in real-life practice and comparing sublingual with subcutaneous immunotherapy.

Allergen immunotherapy in allergic respiratory diseases: from mechanisms to meta-analyses

Allergen-specific immunotherapy (SIT) involves the repeated administration of allergenic extracts to atopic individuals over a period of 3 to 5 years either subcutaneously (SCIT) or sublingually (SLIT) for the treatment of allergic respiratory diseases, including asthma and allergic rhinitis (AR). In studies, SCIT and SLIT have been shown to improve existing symptoms of asthma and AR and to also have the capability to cause disease-modifying changes of the underlying atopic condition so as to prevent new allergic sensitization as well as arrest progression of AR to asthma. Recent evidence suggests that immunotherapy brings about these effects through actions that use T-regulatory cells and blocking antibodies such as IgG(4) and IgA(2,) which can then result in an "immune deviation" from a T-helper (Th) 2 cell pattern to a Th1 cell pattern. Numerous meta-analyses and studies have been performed to evaluate the existing data among these studies, with the consensus recommendation favoring the use of immunotherapy because of its potential to modify existing diseases. Significant adverse reactions can occur with immunotherapy, including anaphylaxis and, very rarely, death. A primary factor in considering SIT is its potential to provide long-lasting effects that are able to be sustained well after its discontinuation. Given the significant burden these allergic diseases impose on the health-care system, SIT appears to be a cost-effective adjunctive treatment in modifying the existing disease state.

The health economics of allergen immunotherapy

In contrast to symptomatic drug treatment, which only temporarily relieves allergy symptoms, allergen-specific immunotherapy (SIT) has the potential to alter the course of allergic disease, thereby reducing the need for long-term treatment, the progression of allergic rhinitis (AR) to asthma, and the development of new allergies. The clinical benefits of SIT have been shown to persist for an additional 3 to 12 years after discontinuation of a 2.5- to 5.0-year treatment. It therefore stands to reason that the clinical benefits of SIT also extend to economic benefits. A growing number of studies have evaluated the economic benefits of SIT in patients with AR and/or asthma. The authors critically examine each of these studies published from 1995 to present.

Specific immunotherapy: beyond the clinical scores

OBJECTIVE

The efficacy of specific immunotherapy always has been evaluated by clinical scores (symptoms or medication intake). Nonetheless, specific immunotherapy possesses some special or "additional" effects, including the carryover effect and the preventive actions, which are unique. Those effects are the consequence of the complex mechanism of action, which induces profound and persistent modifications in the immune response to allergens. The literature is reviewed to evaluate the available experimental data on this.

DATA SOURCES

The main databases (EmBase, Medline, Scopus) were searched.

STUDY SELECTION

Clinical trials of immunotherapy, either randomized or not, including placebo-controlled trials, were selected.

RESULTS

Currently, the carryover effect (persistence of the benefit after stopping the treatment) is well ascertained for injection immunotherapy, whereas fewer data are available for the sublingual route. On the contrary, the demonstration of the prevention of asthma onset relies on 2 randomized studies for sublingual immunotherapy, and 1 single study for subcutaneous immunotherapy.

CONCLUSION

Although additional confirmatory data are needed, possibly obtained with a rigorous methodology, the long-lasting and preventive effects of specific immunotherapy always should be taken into account when the efficacy is evaluated. The additional effects also may have relevant socioeconomic implications.

How to design and evaluate randomized controlled trials in immunotherapy for allergic rhinitis: an ARIA-GA(2) LEN statement

Specific immunotherapy (SIT) is one of the treatments for allergic rhinitis. However, for allergists, nonspecialists, regulators, payers, and patients, there remain gaps in understanding the evaluation of randomized controlled trials (RCTs). Although treating the same diseases, RCTs in SIT and pharmacotherapy should be considered separately for several reasons, as developed in this study. These include the severity and persistence of allergic rhinitis in the patients enrolled in the study, the problem of the placebo, allergen exposure (in particular pollen and mite), the analysis and reporting of the study, the level of symptoms of placebo-treated patients, the clinical relevance of the efficacy of SIT, the need for a validated combined symptom-medication score, the differences between children and adults and pharmacoeconomic analyses. This statement reviews issues raised by the interpretation of RCTs in sublingual immunotherapy. It is not possible to directly extrapolate the rules or parameters used in medication RCTs to SIT. It also provides some suggestions for the research that will be needed. Interestingly, some of the research questions can be approached with the available data obtained from large RCTs.

Specific immunotherapy by the sublingual route for respiratory allergy

Specific immunotherapy is the only treatment able to act on the causes and not only on the symptoms of respiratory allergy. Sublingual immunotherapy (SLIT) was introduced as an option to subcutaneous immunotherapy (SCIT), the clinical effectiveness of which is partly counterbalanced by the issue of adverse systemic reactions, which occur at a frequency of about 0.2% of injections and 2-5% of the patients and may also be life-threatening. A large number of trials, globally evaluated by several meta-analyses, demonstrated that SLIT is an effective and safe treatment for allergic rhinitis and allergic asthma, severe reactions being extremely rare. The application of SLIT is favored by a good compliance, higher than that reported for SCIT, in which the injections are a major factor for noncompliance because of inconvenience, and by its cost-effectiveness. In fact, a number of studies showed that SLIT may be very beneficial to the healthcare system, especially when its effectiveness persists after treatment withdrawal because of the induced immunologic changes.

Development of a sublingual allergy vaccine for grass pollinosis

Grass pollen is a very common cause of allergic rhinitis and asthma. The only treatment targeting the underlying causes of allergy is immunotherapy (IT). Sublingual immunotherapy (SLIT) has been introduced to solve the problem of systemic reactions to subcutaneous IT (SCIT). This article evaluates the characteristics of the allergen extract, Staloral, in terms of practical administration, effectiveness, safety, and mechanism of action. Efficacy data were obtained from double-blind, placebo-controlled studies using Staloral in patients sensitized to grass pollen, while practical administration, cost-effectiveness, and mechanism of action data were provided by well designed studies. The efficacy and safety of Staloral, as demonstrated by review of published studies which used doses up to 1125 times those administered with SCIT, shows that this allergen extract has optimal characteristics for treating patients with seasonal allergies due to grass pollens. The main mechanism of action is the interaction between dendritic cells of the oral mucosa and the subsequent tolerance induced in T-cells.

Evidence of adherence to allergen-specific immunotherapy

PURPOSE OF REVIEW

The main feature of allergen-specific immunotherapy is its capacity to modify the natural history of the disease, reducing the development of asthma and new sensitizations after 3-4 years of treatment. For this reason, adherence to the therapy is mandatory, as happens for all chronic medical treatment.

RECENT FINDINGS

Though subcutaneous immunotherapy is administered directly by physicians, the rate of adherence is surprisingly low, at less than 70%. The explanations for a poor subcutaneous immunotherapy adherence include inconvenience, lack of efficacy, costs and loss of working hours.Local nasal immunotherapy has a very low adherence rate (27%), due to the local nasal side effects.For sublingual immunotherapy, data are available from clinical trials and postmarketing surveys, which are favourable overall (rates of compliance >75%). Cost was the most common reason for discontinuation, followed by inconvenience, feeling of inefficacy and side effects.

SUMMARY

Studies addressing the adherence to allergen-specific immunotherapy in literature are lacking. In real life, costs and patient education are crucial issues in conditioning adherence to this treatment. Reduction of costs and more efforts in education of patients and also specialists may improve the adherence to immunotherapy.

Development of an allergen extract for sublingual immunotherapy--evaluation of Staloral

BACKGROUND

Specific immunotherapy (IT) is an effective treatment for rhinitis and asthma caused by aeroallergens sensitization. Sublingual IT (SLIT) was introduced to solve the problem of systemic reactions to subcutaneous IT (SCIT) and developed to represent an actual treatment option. It is now generally accepted that allergen doses much higher than those administered by SCIT must be used to achieve clinical efficacy on allergic symptoms.

OBJECTIVE

To evaluate the characteristics of Staloral, an allergen extract produced by Stallergenes (Antony, France) in terms of practical administration, efficacy, safety and mechanism of action.

METHODS

Data were obtained from 20 double-blind, placebo-controlled studies using Staloral in patients sensitized to pollens and house-dust mites, and also from open studies concerning practical administration and the mechanism of action.

RESULTS/CONCLUSION

Efficacy and safety of Staloral, as demonstrated by the revision of the studies, which used doses up to 1125 times those administered with SCIT, are very satisfactory and confer to this allergen extract optimal characteristics for treating patients with seasonal allergies due to pollens or with perennial symptoms induced by dust mites. The main mechanism of action is the interaction with dendritic cells of the oral mucosa and the subsequent tolerance induced in T cells.

Economic evaluation of sublingual immunotherapy vs. symptomatic treatment in allergic asthma

BACKGROUND

The worldwide increased prevalence of allergic diseases, and especially of respiratory allergy, is paralleled by increased health costs. This requires consideration of the cost to efficacy ratio of the available treatment to identify the optimal choice.

OBJECTIVE

To compare the different economic relevance, over a long evaluation time, of symptomatic pharmacologic therapy and sublingual immunotherapy (SLIT) in patients with allergic asthma.

METHODS

Seventy patients with perennial allergic asthma, sensitized to dust mites, were enrolled; 50 of these patients were treated with SLIT against house dust mites and 20 were treated with symptomatic drugs. The patients were evaluated for 2 years after discontinuing immunotherapy, which was performed for 3 years, to obtain a more complete follow-up. Symptom scores, medication scores, and all other direct medical costs were evaluated with a specific questionnaire.

RESULTS

Patients treated with SLIT plus drugs had a higher mean annual cost in the first year of SLIT treatment compared with patients only receiving drug treatment, but the mean annual cost became significantly lower since the end of SLIT both in the whole population and in the subgroups defined by disease severity.

CONCLUSION

The economic advantage measured alongside this prospective observational study was long lasting and still present at the fifth year of the follow-up (2 years after discontinuing SLIT) and could positively be related to the persistent good clinical control of patients.

Economic studies of immunotherapy: a review

PURPOSE OF REVIEW

To analyse and discuss the growing body of evidence on the economic advantages offered by immunotherapy for allergic rhinitis and asthma, in the various perspectives (society, national healthcare system, patients, etc) and according to the various types of standardized economic evaluations.

RECENT FINDINGS

This review shows that the economic studies of allergic rhinitis and asthma focus on three main research areas: studies aimed at determining the cost of illness and studies focused either on a simple cost comparison amongst available therapeutic alternatives, or directly comparing alternatives using full economic evaluations (cost-effectiveness, cost-utility measures, etc).

SUMMARY

Studies exploring the full cost of allergic rhinitis and asthma are still lacking; on the contrary, studies on immunotherapy (in its many administration forms, subcutaneous, sublingual, tablet, etc) in comparison with standard pharmaceutical treatment, have shown that immunotherapy may be very beneficial to the healthcare systems, in that either it could bring more clinical outcome at a reduced cost, versus standard therapy alone, or it could bring extra benefit at a very acceptable extra cost. This is even more correct under the societal perspective, that is, when indirect costs of lost productivity are considered and included in the economic analysis.

Perception and practice of sublingual immunotherapy among practicing allergists

BACKGROUND

Currently, little information is available regarding who is using sublingual immunotherapy (SLIT) in the United States, what product they may be using, how they are dosing that product, and what perceived effect it may be having on patients.

OBJECTIVE

To gather information regarding the perception and use of SLIT among practicing allergists in the United States.

METHODS

On behalf of the American College of Allergy, Asthma and Immunology (ACAAI) Immunotherapy and Diagnostics Committee, an electronic survey was sent to all practicing allergists of the ACAAI in March 2007.

RESULTS

The survey response rate was 25.7% (828/3,217) in which 92.5% of the respondents (766/828) practiced in the United States. For 61.7% (471/763) the most cited reason for not using SLIT was lack of approval by the Food and Drug Administration (FDA). If SLIT were an FDA-approved form of immunotherapy, 65.7% would use it to treat allergic rhinitis, 45.5% would use SLIT to treat patients younger than 5 years, and 40.9% would use it to treat moderate to severe asthma. A total of 5.9% (45/766) of US allergists reported using SLIT. Most perceived SLIT to be as effective (44.7%) or more effective (10.5%) than subcutaneous immunotherapy (SCIT). Most allergists who used SLIT (65.9%) had it reimbursed by patients paying out of pocket. The most commonly used extract (79.1%) was a commercially available extract used for SCIT. Some practitioners (53.5%) required their patients to administer doses of SLIT in their office, but 81.8% only required that this be done with the first dose. Practitioners gave epinephrine injectors to 41.5% of their patients receiving SLIT.

CONCLUSIONS

Although only 5.9% of US allergists reported using SLIT, most of the 828 surveyed (766 US allergists) viewed SLIT as safe and effective and would consider using SLIT if it were an FDA-approved therapy.

Cost-effectiveness of specific subcutaneous immunotherapy in patients with allergic rhinitis and allergic asthma

BACKGROUND

Specific immunotherapy is the only potentially curative treatment in patients with allergic rhinitis and allergic asthma. Health economic evaluations on this treatment, particularly in a German context, are sparse.

OBJECTIVE

To evaluate the cost-effectiveness of specific subcutaneous immunotherapy (SCIT) in addition to symptomatic treatment (ST) compared with ST alone in a German health care setting.

METHODS

The analysis was performed as a health economic model calculation based on Markov models. In addition, we performed a concomitant expert board composed of allergy experts in pediatrics, dermatology, pneumology, and otolaryngology. The primary perspective of the study was societal. Additional sensitivity analyses were performed to prove our results for robustness.

RESULTS

The SCIT and ST combination was associated with annual cost savings of Euro140 per patient. After 10 years of disease duration, SCIT and ST reach the breakeven point. The overall incremental cost-effectiveness ratio (ICER) was Euro-19,787 per quality-adjusted life-year (QALY), with a range that depended on patient age (adults, Euro-22,196; adolescents, Euro-14,747; children, Euro-12,750). From a third-party payer's perspective, SCIT was associated with slightly additional costs. Thus, the resulting ICER was Euro8,308 per QALY for all patients.

CONCLUSIONS

Additional SCIT was associated with improved medical outcomes and cost savings compared with symptomatic treatment alone according to a societal perspective. Taking a European accepted ICER threshold of up to Euro50,000 per QALY into account, additional SCIT is considered clearly cost-effective compared with routine care in Germany. The degree of cost-effectiveness is strongly affected by costs related to SCIT and the target population receiving such treatment.

Is sublingual immunotherapy the final answer? Implications for the allergist

Sublingual immunotherapy (SLIT) is now accepted as a viable alternative to the traditional injection route based on more than 40 clinical trials and several meta-analyses of efficacy. In addition, the safety profile is very favorable, also in younger children. Although some aspects need to be further clarified (eg, optimal doses, patient selection, and mechanisms of action), SLIT can be currently regarded as an additional therapeutic option that allergists have available. The main distinctive feature of SLIT is certainly its tolerability, safety, and convenience for the patient. Nonetheless, as happens with injection immunotherapy, it is mandatory that the prescription of SLIT is made by a trained specialist, and that a detailed diagnosis is made before prescribing it.

Immunotherapy: clinical trials--optimal trial and clinical outcomes

PURPOSE OF REVIEW

The methodology of randomized clinical trials is essential to assess and register treatment interventions. Although specific immunotherapy was introduced a century ago, very few trials meet the criteria for pivotal studies. The paper reviews the methods which should be used to investigate specific immunotherapy.

RECENT FINDINGS

Large pivotal trials on specific immunotherapy were published within the last year and made sublingual immunotherapy an accepted treatment in Europe. Moreover, a study proposed the guidelines for conducting trials on immunotherapy. Phase I studies were also published on sublingual immunotherapy. A large trial on subcutaneous immunotherapy confirmed its efficacy, but showed that this form of treatment is associated with side effects.

SUMMARY

The clinical efficacy of subcutaneous and sublingual immunotherapy with pollen and mites is well established for both rhinitis and asthma, but the methodology of many specific immunotherapy trials was found to be insufficient until recent large pivotal studies. The present paper reviews the requirements for conducting trials in allergen-specific immunotherapy including allergen standardization, patient inclusion and exclusion criteria, phase I trials to assess safety, dose-ranging studies, and pivotal trials. These need to be randomized, parallel group, placebo-controlled designs. The number of patients should be sufficient. Primary and secondary outcome measures are listed. Trials for asthma need specific requirements. In all trials, safety should be carefully monitored. Studies in children are required.

Allergy immunotherapy among Medicaid-enrolled children with allergic rhinitis: patterns of care, resource use, and costs

BACKGROUND

Although research demonstrates that allergy immunotherapy (IT) improves allergic rhinitis (AR) outcomes, little is known about IT patterns of care and associated resource use and costs among US children with diagnoses of AR.

OBJECTIVE

We sought to examine characteristics associated with receiving IT, patterns of IT care, and health care use and costs incurred in the 6 months before versus after IT.

METHODS

We performed retrospective Florida Medicaid claims data (1997-2004) analysis of children (<18 years of age) given new diagnoses of AR.

RESULTS

Of 102,390 patients with new diagnoses of AR, 3048 (3.0%) received IT. Male patients, Hispanic patients, and those with concomitant asthma were significantly more likely to receive IT. Approximately 53% completed less than 1 year and 84% completed less than 3 years of IT. Patients who received IT used significantly less pharmacy (12.1 vs 8.9 claims, P < .0001), outpatient (30.7 vs 22.9 visits, P < .0001), and inpatient (1.2 vs 0.4 admissions, P = .02) resources in the 6 months after versus before IT. Pharmacy ($330 vs $60, P < .0001), outpatient ($735 vs $270, P < .0001), and inpatient ($2441 vs $1, P < .0001) costs (including costs for IT care) were significantly reduced after IT.

CONCLUSION

Despite suboptimal treatment persistence (only 16% of patients completed 3 years of IT), resource use and costs after treatment were significantly reduced from pre-IT levels.

Sublingual immunotherapy in pediatric allergic rhinitis and asthma: efficacy, safety, and practical considerations

Specific allergen immunotherapy (SIT) is the only disease-modifying treatment for allergic rhinitis and asthma. Subcutaneous immunotherapy (SCIT) is the only method with a US Food and Drug Administration (FDA)-approved formulation, but safety concerns limit administration to medical facilities. Sublingual immunotherapy (SLIT), under investigation in the United States, appears to have a more favorable safety profile, which may expand its use to populations generally not treated with SIT (eg, young children). This paper reviews SLIT studies that were specifically limited to the pediatric population. Most demonstrated evidence of clinical efficacy, but approximately 29% failed to demonstrate efficacy in symptom and medication scores in the first treatment year. Efficacy was seen in a broad range of allergen doses, but optimal dose range has not been established. SLIT appeared to be well tolerated in children as young as 2 years, but serious adverse reactions, including anaphylaxis, were reported. SLIT is a promising immunotherapy that may expand the population receiving SIT because of the convenience of home administration due to its favorable safety profile. However, questions remain unanswered, including optimal therapeutic dose.

Comparison of costs of sublingual immunotherapy and drug treatment in grass-pollen induced allergy: results from the SIMAP database study

OBJECTIVES

This analysis is focused on the comparison of costs of allergic rhinitis (R) alone or with allergic asthma (R + A) in grass pollen allergy, for subjects treated with sublingual immunotherapy (SLIT) and symptomatic drugs, versus standard care controls.

METHODS

The SIMAP (Sublingual IMmunotherapy in Allergic Patients) study is a longitudinal observational database operated by a network of Allergy centers. Patients suffering from grass pollen allergy were included in this analysis and assigned to SLIT (plus drugs as needed) or to treatment with drugs alone. Outcome measures included use of medications, SLIT, visits and tests. Costs were assessed from the perspective of the Italian National Health Service; unit costs were obtained from published sources to produce an average cost/patient for the first year after enrolment.

RESULTS

One hundred and two patients were analyzed. Demographics were comparable in the two groups. Overall per patient yearly cost of treatment was higher in SLIT patients, both in the whole sample (euro311 vs. euro180/patient), in the R (euro288 vs. euro116) and R + A (euro362 vs. euro230) subpopulations, with R + A patients generating more costs than R patients in both groups. Nevertheless considerable savings were obtained in the cost of symptomatic drugs (-22% for R; -34% for R + A) in SLIT patients.

CONCLUSIONS

Other studies have shown that SLIT can reduce the use of drugs for asthma and rhinitis, but this is the first time this outcome has been demonstrated in a routine care population (in the medical practice environment of an observational study) within the first year of treatment.

Cost-effectiveness of GRAZAX for prevention of grass pollen induced rhinoconjunctivitis in Southern Europe

BACKGROUND

Allergic rhinoconjunctivitis is a global health problem. Around 14 million people in Spain, France, Italy, and Austria suffer from grass pollen induced allergic rhinitis. Standard care only provides symptoms relief, while allergen specific immunotherapy (SIT) treats the underlying cause of the disease. Grazax from ALK-Abelló is a new, tablet-based, effective route of SIT for home treatment. The objective was to assess the cost-effectiveness of Grazax in four Southern European countries.

METHODS

A prospective pharmacoeconomic analyses was carried out alongside a multinational, clinical trial measuring the efficacy of Grazax. Pooled data on resource use and health outcomes were collected. A societal perspective was adopted, and the analysis had a nine-year time horizon. The primary outcome measure was quality adjusted life years (QALYs).

RESULTS

Grazax was superior to standard care for all efficacy endpoints, including QALYs gained, and resulted in significantly less use of rescue medication and fewer hours missed from work. Grazax was cost-effective for all countries for an annual price in the range of 1500 euros - 1900 euros. The result was improved by inclusion of future costs of asthma and exclusion of Spanish trial centers which experienced an exceptionally low pollen season.

CONCLUSION

The analysis illustrates that allergen SIT with Grazax for grass pollen induced rhinoconjunctivitis is a cost-effective intervention in Southern Europe.