Economic evaluation of specific immunotherapy versus symptomatic treatment of allergic rhinitis in Germany

Efficacy and tolerability of short-term specific immunotherapy with pollen allergoids adjuvanted by monophosphoryl lipid A (MPL®) for children and adolescents

BACKGROUND

Specific immunotherapy (SIT) with pollen allergoids formulated with the Th1-inducing adjuvant 3-deacylated monophosphoryl lipid A (MPL adjuvant, Corixa) has shown good efficacy and tolerability in the treatment of pollen allergies in adults. The aim of this study was to evaluate this treatment in children and adolescents aged 6-17 years old who were sensitive to grass/rye or tree pollens.

METHODS

An open, multicenter study was performed using 90 children and adolescents. The patients received four subcutaneous injections of grass/rye (n = 64) or tree pollen allergoids (n = 26) adsorbed to L-tyrosine and containing MPL adjuvant. Efficacy was measured by symptom and medication scoring, skin prick test reactivity and IgG/IgE antibody responses. Tolerability was monitored by recording adverse events.

RESULTS

Both grass/rye and tree pollen treatment groups showed significant reductions in symptom scores and anti-allergic medication use compared with the previous pollen seasons (p < 0.01 in all cases). After therapy, skin prick test reactivity was significantly reduced in both groups and pollen-specific IgG was significantly increased in both groups whereas little change was apparent in pollen-specific IgE. Overall tolerability was similar to results obtained in previous studies in adults.

CONCLUSION

Short-term SIT using four injections of grass/rye or tree pollen allergoids adsorbed to L-tyrosine and with MPL adjuvant was shown to be effective with good tolerability. The treatment compared favorably with previous studies in adults.

Allergen immunotherapy for asthma

BACKGROUND

Allergen specific immunotherapy has long been a controversial treatment for asthma. Although beneficial effects upon clinically relevant outcomes have been demonstrated in randomised controlled trials, there remains a risk of severe and sometimes fatal anaphylaxis. The recommendations of professional bodies have ranged from cautious acceptance to outright dismissal. With increasing interest in new allergen preparations and new methods of delivery, it was time to conduct another systematic review of allergen specific immunotherapy for asthma.

OBJECTIVES

The objective of this review was to assess the effects of allergen specific immunotherapy for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register up to June 2001, MEDLINE, Dissertation Abstracts, Current Contents and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials using various forms of allergen specific immunotherapy to treat asthma and reporting at least one clinical outcome.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed eligibility of studies for inclusion. Two reviewers independently performed quality assessment of studies.

MAIN RESULTS

Seventy-five trials were included (52 of 54 previously included trials and 23 new trials). A total of 3,506 participants (3,188 with asthma) were involved. There were 36 trials of immunotherapy for house mite allergy; 20 pollen allergy trials; ten animal dander allergy trials; two Cladosporium mould allergy, one latex and six trials looking at multiple allergens. Concealment of allocation was assessed as clearly adequate in only 15 of these trials. Significant heterogeneity was present in a number of comparisons. Overall, there was a significant reduction in asthma symptoms and medication and improvement in bronchial hyper-reactivity following immunotherapy. There was a significant improvement in asthma symptom scores (standardised mean difference -0.72, 95% confidence interval -0.99 to -0.33) and it would have been necessary to treat 4 (95%CI 3 to 5) patients with immunotherapy to avoid one deterioration in asthma symptoms. Overall it would have been necessary to treat 5 (95%CI 4 to 6) patients with immunotherapy to avoid one requiring increased medication. Allergen immunotherapy significantly reduced allergen specific bronchial hyper-reactivity, with some reduction in non-specific bronchial hyper-reactivity as well. There was no consistent effect on lung function.

REVIEWER'S CONCLUSIONS

Immunotherapy reduces asthma symptoms and use of asthma medications and improves bronchial hyper-reactivity. One trial found that the size of the benefit is possibly comparable to inhaled steroids. The possibility of adverse effects (such as anaphylaxis) must be considered.

A well-tolerated grass pollen-specific allergy vaccine containing a novel adjuvant, monophosphoryl lipid A, reduces allergic symptoms after only four preseasonal injections

BACKGROUND

We present data showing that a Th1-inducing adjuvant can reduce the number of injections required for allergy vaccination. Allergy vaccination is the only treatment for type 1 hypersensitivity that can alter the underlying disease process. A switch of specific T-cell activity from Th2 >Th1 to Th1 >Th2 is believed to be an important change seen after long-term vaccination therapy. An immunologic adjuvant that enhances such a switch could be used to reduce the number of injections required. This would improve compliance with the treatment and provide pharmacoeconomic advantages. Such an adjuvant is 3-deacylated monophosphoryl lipid A (MPL adjuvant, Corixa).

METHODS

A multicentre, placebo-controlled, randomized, double-blind clinical study was performed with a new standardized allergy vaccine comprising a tyrosine-adsorbed glutaraldehyde-modified grass pollen extract containing MPL adjuvant. Four subcutaneous injections of the active product were given preseasonally to 81 grass pollen-sensitive subjects, and 60 received placebo injections (tyrosine alone). Diary cards were used to record symptoms and medication taken during approximately 30 days of the grass pollen season.

RESULTS

There was a statistical advantage in favour of the active treatment for nasal (P = 0.016) and ocular (P = 0.003) symptoms and combined symptom and medication scores (P=0.013). Titrated skin prick testing revealed a significant reduction of skin sensitivity in the active group compared to placebo (P = 0.04). Grass-pollen-specific IgG antibody was raised by active treatment (P < 0.01). A rise in IgE antibody was seen in the placebo group during the season (P < 0.01). The first year's treatment rise of IgE was not seen in the active group, and no rise occurred during the pollen season. More local adverse events were seen in the active group. There was no difference in generalized adverse events.

CONCLUSION

A new, well-tolerated allergy vaccine, incorporating a Th1-inducing adjuvant, MPL, was efficacious and after only four preseasonal injections produced antibody changes normally associated with long injection schedules. This may encourage wider application of allergy vaccination. The vaccine is now available in a number of countries as Pollinex Quattro.

Health economics of asthma and rhinitis. II. Assessing the value of interventions

Health care providers and payers are being asked to weigh data on the economic impact of new interventions along with clinical evidence when making decisions about the care of patients. The notion of incorporating formal health economic assessments into clinical and resource decisions is a difficult concept for many in the health care sector. However, it is the reality in today's environment. To effectively participate in these ongoing discussions, clinicians and other decision makers must be able to understand and critically assess the evidence on economic impact of medical interventions. This second of 2 articles describes the elements of comparative economic evaluations, reviewing the published literature on asthma and rhinitis in an attempt to critically appraise the studies from the perspective of one who might use data for decision making. Unfortunately, the quality of the economic evidence in these two disease states is not extensive. Until better economic analyses are conducted and made available, the allocation of resources for asthma and allergic rhinitis will continue to primarily rely on expert opinion rather than evidence-based literature.

Cost effectiveness of ramipril in patients with non-diabetic nephropathy and hypertension: economic evaluation of Ramipril Efficacy in Nephropathy (REIN) Study for Germany from the perspective of statutory health insurance

BACKGROUND

In the Ramipril Efficacy In Nephropathy (REIN) trial, ramipril significantly lowered the rate of reaching the combined end-point of doubling of baseline serum creatinine levels or end-stage renal failure (ESRF).

OBJECTIVE

To determine the additional cost per patient-year of chronic (long term) dialysis avoided (PYCDA) when the ACE inhibitor, ramipril, was added to conventional treatment of patients with non-diabetic nephropathy and hypertension.

STUDY PERSPECTIVE

Statutory Health Insurance (SHI) provider in Germany.

DESIGN AND SETTING

Data from the REIN Study were used in a cost-effectiveness analysis (CEA). A modelling approach was used, which was based on secondary analysis of published data, and costs were those incurred by the SHI provider (i.e. SHI expenses). In the base-case analysis, average case-related SHI expenses were applied and PYCDA were quantified using the cumulative incidence of ESRF as observed in the REIN trial.

MAIN OUTCOME MEASURES AND RESULTS

The incremental cost-effectiveness ratios (ICERs) of ramipril varied between about -76,700 deutschmarks (DM) and -DM81,900 per PYCDA (DM 1 approximately equals 0.55 US dollars; 1999 values), according to the treatment periods of 1 year and 3 years, respectively. In the sensitivity,analysis, the robustness of the model and its results were shown when the extent of influence of different model variables on the base-case results was investigated. First, probabilities of ESRF and PYCDA were estimated according to the Weibull method. Second, the influence of the model variables on the target variable was quantified using a deterministic model. Third, the dependency of the target variable (ICER) on random variables was described in a simulation. The cost for chronic dialysis had by far the greatest impact on the target variable, which was 28 times greater than the impact of clinical effectiveness of ramipril, i.e. the number of PYCDA. There were net savings per PYCDA with ramipril treatment after 1, 2 and 3 years: 95% of the 10,000 simulation steps resulted in savings of between DM69 500 and D94,600 per PYCDA after 3 years.

CONCLUSIONS

Results from this evaluation show that ramipril offers enormous savings from the perspective of the SHI provider (third-party payer) in Germany when added to the conventional treatment of patients with non-diabetic nephropathy and hypertension.

Immunotherapy of asthma and allergic diseases

The goals of therapy for allergic disease and asthma, which have increased dramatically during the past 2 decades, are to relieve and prevent symptoms. Currently, allergen immunotherapy is the only available treatment that can reduce symptoms, alter the natural course of disease, and induce long-term clinical remission effectively and safely in patients with allergic rhinitis, asthma, and insect venom anaphylaxis. Allergen immunotherapy may even prevent the evolution towards polysensitization and prevent the development of asthma in allergic children. In the long run, it is more cost-effective than pharmacotherapy and environmental control measures alone. Future developments, such as using alternate routes of administration, peptide fragments of allergen, adjuvants, and DNA vaccines, may improve its efficiency in inducing long-term clinical relief of symptoms.

Effect of allergist intervention on patient-centered and societal outcomes: allergists as leaders, innovators, and educators

Atopic disorders, which afflict millions of Americans and hundreds of millions worldwide, are at epidemic levels with concomitant increases in morbidity and mortality. Environmental and lifestyle changes over the past three to five decades are proposed causes for this pandemic and as such present major burdens to reverse. The scope of allergy practice bridges directly on this challenge. Allergy as a specialty is a major leader in developing effective strategies to confront this epidemic. Allergists have made major contributions to the understanding of the risk factors, immunology, pathophysiology, immunomodulation, and prevention of atopic and immunologic disorders. Allergist epidemiologists and clinicians have helped develop and implement national and international guidelines in the recognition, management, and prevention of asthma and rhinitis. Allergist clinical researchers are active in (1) outcomes research that demonstrates convincingly the value of allergy as a specialty in asthma, allergic rhinitis, anaphylaxis, drug and food allergy, and other atopic disorders, (2) National Institutes of Health clinical trials that will form the basis for the future treatment of asthma and allergic disease, and (3) pharmaceutical trials that evaluate new, effective, and safe medication to treat atopic disease. Allergist educators, comprising academic and practicing allergists, supported by allied health professionals, national associations, and affiliated lay organizations, provide comprehensive education to fellows, residents, colleague physicians, media, the public, and patients. Documentation of the value of allergists in improving patient-centered and societal outcomes in their core domain, allergy, is the appropriate final topic contribution in the important series "New millennium: The conquest of allergy."