Subcutaneous specific immunotherapy for seasonal allergic rhinitis: a review of treatment practices in the US and Europe

BACKGROUND

Subcutaneous specific immunotherapy (SCIT) is claimed to be successful both in the US and Europe, yet treatment methodology differs.

METHODS

The authors review current literature surrounding guidelines and clinical trials in Europe and the US and contrast the treatment approach to SCIT for allergic rhinitis. Search methodology employs MEDLINE and PubMed, selecting articles on SCIT and allergic rhinitis, limited between 1990-2009. They focus on the safety and efficacy of vaccines, and the differences in formulations. Also mentioned are: standardization, new approaches in SCIT and sublingual immunotherapy (SLIT).

RESULTS

SCIT treatment differs in many respects regarding availability of SCIT products, regulatory controls, guidelines (e.g. multiple allergen vaccines in US, single allergen vaccines in Europe) and in location of formulation (US, clinician's office; Europe, manufacturers).

CONCLUSIONS

SCIT is an effective and safe therapy, but major evidence for efficacy is provided from European studies of single allergen extract vaccines; these vaccines may gain more acceptance because of increasing regulatory approval and lower numbers of injections. The potential impact upon public health (e.g. arrest of the 'allergic march') should not be overlooked.

The diagnosis and management of anaphylaxis practice parameter: 2010 update

These parameters were developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma and Immunology. The AAAAI and the ACAAI have jointly accepted responsibility for establishing "The Diagnosis and Management of Anaphylaxis Practice Parameter: 2010 Update." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, or the Joint Council of Allergy, Asthma and Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Pathogenicity and molecular characterization of emerging porcine reproductive and respiratory syndrome virus in Vietnam in 2007

In 2007, Vietnam experienced swine disease outbreaks causing clinical signs similar to the 'porcine high fever disease' that occurred in China during 2006. Analysis of diagnostic samples from the disease outbreaks in Vietnam identified porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV-2). Additionally, Escherichia coli and Streptococcus equi subspecies zooepidemicus were cultured from lung and spleen, and Streptococcus suis from one spleen sample. Genetic characterization of the Vietnamese PRRSV isolates revealed that this virus belongs to the North American genotype (type 2) with a high nucleotide identity to the recently reported Chinese strains. Amino acid sequence in the nsp2 region revealed 95.7-99.4% identity to Chinese strain HUN4, 68-69% identity to strain VR-2332 and 58-59% identity to strain MN184. A partial deletion in the nsp2 gene was detected; however, this deletion did not appear to enhance the virus pathogenicity in the inoculated pigs. Animal inoculation studies were conducted to determine the pathogenicity of PRRSV and to identify other possible agents present in the original specimens. Pigs inoculated with PRRSV alone and their contacts showed persistent fever, and two of five pigs developed cough, neurological signs and swollen joints. Necropsy examination showed mild to moderate bronchopneumonia, enlarged lymph nodes, fibrinous pericarditis and polyarthritis. PRRSV was re-isolated from blood and tissues of the inoculated and contact pigs. Pigs inoculated with lung and spleen tissue homogenates from sick pigs from Vietnam developed high fever, septicaemia, and died acutely within 72 h, while their contact pigs showed no clinical signs throughout the experiment. Streptococcus equi subspecies zooepidemicus was cultured, and PRRSV was re-isolated only from the inoculated pigs. Results suggest that the cause of the swine deaths in Vietnam is a multifactorial syndrome with PRRSV as a major factor.

Allergen immunotherapy: immunomodulatory treatment for allergic diseases

Allergen immunotherapy is currently the only immune-modifying treatment for allergic disease. At the present time it is indicated for the treatment of allergic rhinitis, asthma and venom hypersensitivity. Efficacy appears to be dose dependent, and the immunological mechanisms responsible for the clinical efficacy of immunotherapy are still being elucidated. Immunological changes associated with immunotherapy include induction of T regulatory cells, increase in allergen-specific immunoglobulin G4, increase in interleukin-10 production and downregulation of the T helper 2 response. The disadvantages of allergen immunotherapy include risk of adverse events and patient time and inconvenience. Risks of immunotherapy range from large local reactions to mild systemic reactions, such as rhinitis. Fatalities from immunotherapy injections have been reported at a rate of approximately one fatality per 2.5 million injections. Conventional subcutaneous immunotherapy build-up schedules involve administration of a single-dose increase each visit and it may take several months before a patient achieves the therapeutic maintenance dose. Accelerated schedules, such as rush and cluster, will allow the patient to achieve the maintenance dose sooner but there may be a greater risk of a systemic reaction. The current focus of immunotherapy research is to develop safer and more effective vaccines. Another approach to enhancing immunotherapy safety is through an alternative delivery method. Sublingual immunotherapy is clearly safer than subcutaneous immunotherapy, but further investigation is needed to determine optimal dose and appropriate patient selection.

Standardized allergen extracts: past, present and future

Consistent high-quality allergen extracts are essential for accurate diagnosis and effective treatment of allergic disease. Allergens represent complex heterogenous mixtures of allergenic and nonallergenic proteins, glycoproteins and polysaccharides. They are derived from natural sources (i.e., collected pollen) or cultures (dust mites and fungi). The goal of allergen standardization is to produce well-characterized extracts of known biologic potency and composition. This process requires the selection of an appropriate reference extract and methods to compare the test extract with the reference. Two methods are currently used in the standardization of these complex allergen extracts: marking and functional assays. Marking assays, which include allergen-specific, qualitative monoclonal antibody assays, indicate the presence of an individual protein but do not confer information regarding the biologic action of the protein. Functional assays, such as allergen skin tests, will provide information about the biologic function, but not about the specific composition of the extract.

Allergen immunotherapy and health care cost benefits for children with allergic rhinitis: a large-scale, retrospective, matched cohort study

BACKGROUND

Children with allergic rhinitis (AR) often experience significant impairment in quality of life and health, which increases health care utilization.

OBJECTIVE

To determine whether allergen immunotherapy reduces health care utilization and costs in children newly diagnosed as having AR using a retrospective matched cohort design.

METHODS

Among children (age <18 years) with a Florida Medicaid paid claim between 1997 and 2007, immunotherapy-treated patients were selected who had newly diagnosed AR, who had not received immunotherapy before their first (index) AR diagnosis, who had received at least 2 immunotherapy administrations after their index AR diagnosis, and who had at least 18 months of data after their first immunotherapy administration. A control group of patients with newly diagnosed AR who had not received immunotherapy either before or subsequent to their index AR diagnosis also were identified, and up to 5 were matched with each immunotherapy-treated patient by age at first AR diagnosis, sex, race/ethnicity, and diagnosis of asthma, conjunctivitis, or atopic dermatitis.

RESULTS

Immunotherapy-treated patients had significantly lower 18-month median per-patient total health care costs ($3,247 vs $4,872), outpatient costs exclusive of immunotherapy-related care ($1,107 vs $2,626), and pharmacy costs ($1,108 vs $1,316) compared with matched controls (P < .001 for all). The significant difference in total health care costs was evident 3 months after initiating immunotherapy and increased through study end.

CONCLUSIONS

This study demonstrates the potential for early and significant cost savings in children with AR treated with immunotherapy. Greater use of this treatment in children could significantly reduce AR-related morbidity and its economic burden.

Comparison of allergen immunotherapy practice patterns in the United States and Europe

OBJECTIVE

To discuss important differences and similarities in the allergen specific immunotherapy (SIT) treatment practices for aeroallergen sensitivity in the United States and Europe.

DATA SOURCES

Information on regulation and standardization in the United States and Europe was obtained from a Food and Drug Administration Allergenic Products Advisory Committee meeting, published literature, personal communications, and information obtained from the extract manufacturers.

STUDY SELECTION

Information from the published literature included articles known to the authors and acknowledged consultants, textbooks, and PubMed, with search terms dependent on the particular subtopic.

RESULTS

Key differences between Europe and the United States include allergen extract regulation, standardization, formulation, types of allergen extracts, routes of administration, and reimbursement. Most SIT is formulated in US allergists' offices, whereas virtually all SIT is formulated by extract manufacturers in Europe. Sublingual immunotherapy represents a significant percentage of SIT treatment in Europe (approximately 45%), but only a small percentage of US allergists (approximately 5.9%) prescribe sublingual immunotherapy. Similarities between European and US allergist specialists lie in their perception of SIT and approach to providing optimal SIT care, which is detailed in their practice guidelines.

CONCLUSION

Significant differences and similarities exist in SIT practice patterns of US and European allergy specialists. The differences lie primarily in the availability of allergen extracts and how these extracts are formulated. A key similarity is that both recognize the need for ongoing research focused on developing safer and more effective SIT.

Comparison of allergen immunotherapy practice patterns in the United States and Europe

OBJECTIVE

To discuss important differences and similarities in the allergen specific immunotherapy (SIT) treatment practices for aeroallergen sensitivity in the United States and Europe.

DATA SOURCES

Information on regulation and standardization in the United States and Europe was obtained from a Food and Drug Administration Allergenic Products Advisory Committee meeting, published literature, personal communications, and information obtained from the extract manufacturers.

STUDY SELECTION

Information from the published literature included articles known to the authors and acknowledged consultants, textbooks, and PubMed, with search terms dependent on the particular subtopic.

RESULTS

Key differences between Europe and the United States include allergen extract regulation, standardization, formulation, types of allergen extracts, routes of administration, and reimbursement. Most SIT is formulated in US allergists' offices, whereas virtually all SIT is formulated by extract manufacturers in Europe. Sublingual immunotherapy represents a significant percentage of SIT treatment in Europe (approximately 45%), but only a small percentage of US allergists (approximately 5.9%) prescribe sublingual immunotherapy. Similarities between European and US allergist specialists lie in their perception of SIT and approach to providing optimal SIT care, which is detailed in their practice guidelines.

CONCLUSION

Significant differences and similarities exist in SIT practice patterns of US and European allergy specialists. The differences lie primarily in the availability of allergen extracts and how these extracts are formulated. A key similarity is that both recognize the need for ongoing research focused on developing safer and more effective SIT.

Speaking the same language: The World Allergy Organization Subcutaneous Immunotherapy Systemic Reaction Grading System

Subcutaneous allergen immunotherapy (SCIT) is an effective treatment for allergic rhinitis, asthma and venom hypersensitivity and has the potential of producing serious life-threatening anaphylaxis. Adverse reactions are generally classified into 2 categories: local reactions, which can manifest as redness, pruritus, and swelling at the injection site, and systemic reactions (SRs). SRs can range in severity from mild rhinitis to fatal cardiopulmonary arrest. Early administration of epinephrine, which is the treatment of choice to treat anaphylaxis, may prevent the progression of an SR to a more serious life-threatening problem. Although there is little debate about using epinephrine to treat a SCIT SR, there is a lack of consensus about when it should be first used. A uniform classification system for grading SCIT SRs will be helpful in assessing more accurately when epinephrine should be administered. The primary purpose of this article is to discuss the proposed grading system for SCIT SRs.

Recommendations for appropriate sublingual immunotherapy clinical trials

Sublingual immunotherapy is gaining widespread attention as a viable alternative to subcutaneous immunotherapy for the treatment of allergic rhinoconjunctivitis. In addition, sublingual immunotherapy has been studied in other allergic disorders including asthma. However, a review of published studies indicates that there are deficiencies and considerable heterogeneity in both design and data interpretation of sublingual immunotherapy studies. These deficiencies have made it somewhat difficult to assess the appropriate place of sublingual immunotherapy in guidelines for the therapy of allergic diseases. Moreover, several unpublished oral and sublingual immunotherapy studies in the United States failed to meet primary endpoints. This article reviews data from sublingual immunotherapy trials and makes recommendations about appropriate designs of future sublingual immunotherapy studies. It is hoped that these recommendations will result in more adequately designed sublingual immunotherapy trials to facilitate the appropriate placement of this therapy to treat patients with allergic rhinoconjunctivitis and other allergic diseases.

Effectiveness of glyphosate and imazamox on the control of the invasive cordgrass Spartina densiflora

The south-American cordgrass, Spartina densiflora, has become the dominant plant species on recent tidal marsh restorations in the Doñana National Park (SW Spain). We examined the effect of different doses of glyphosate (720-7200 g a.i. ha(-1)) and imazamox (20-68 g a.i. ha(-1)) on growth and photosynthetic apparatus of S. densiflora. Imazamox had no effect on neither on growth nor photosynthetic apparatus of S. densiflora. On the contrary, glyphosate inhibited photochemical efficiency of photosynthesis from day one. Net photosynthetic rate, stomatal conductance and photosynthetic pigments and the number of new tillers were reduced. Glyphosate at high doses (ca. 7200 g a.i. ha(-1)) could be an appropriate method of control, since it has a negative effect over the photosynthetic apparatus and growth of S. densiflora. Furthermore, glyphosate and its main metabolite, AMPA, were not extracted from the soil, since they were retained by the very high iron and aluminum oxide content of this soil.

Feto-placental adaptations to maternal obesity in the baboon

Maternal obesity is present in 20-34% of pregnant women and has been associated with both intrauterine growth restriction and large-for-gestational age fetuses. While fetal and placental functions have been extensively studied in the baboon, no data are available on the effect of maternal obesity on placental structure and function in this species. We hypothesize that maternal obesity in the baboon is associated with a maternal inflammatory state and induces structural and functional changes in the placenta. The major findings of this study were: 1) decreased placental syncytiotrophoblast amplification factor, intact syncytiotrophoblast endoplasmic reticulum structure and decreased system A placental amino acid transport in obese animals; 2) fetal serum amino acid composition and mononuclear cells (PBMC) transcriptome were different in fetuses from obese compared with non-obese animals; and 3) maternal obesity in humans and baboons is similar in regard to increased placental and adipose tissue macrophage infiltration, increased CD14 expression in maternal PBMC and maternal hyperleptinemia. In summary, these data demonstrate that in obese baboons in the absence of increased fetal weight, placental and fetal phenotype are consistent with those described for large-for-gestational age human fetuses.

Allergen immunotherapy and asthma: efficacy, safety, and other considerations

The efficacy of allergen immunotherapy (AIT) for allergic asthma is often debated despite multiple controlled trails and three meta-analyses that have established a significant effect on subjective and objective outcomes. Indications for AIT in allergic asthma include suboptimal control with medications, adverse effect of medications, and/or environmental control measures; patient's desire to avoid long-term pharmacotherapy; and presence of comorbid allergic conditions. Symptomatic asthma is a risk factor for AIT systemic reactions (SRs) and asthma should be controlled at the time of the AIT administration. The vast majority of studies in AIT for asthma have used single allergens although the majority of allergic patients in the United States are not monosensitized. There have been conflicting results in the limited number of studies that have investigated the effect of multiallergen AIT or as add-on therapy to asthmatic patients who are optimally controlled with medications and environmental controls. Several studies have suggested that AIT may prevent the development of asthma in subjects with allergic rhinitis and new allergen sensitizations. The recently updated Allergen Immunotherapy Practice Parameters lists possible prevention of asthma in patients with allergic rhinitis as one of the indications for AIT. Currently, subcutaneous immunotherapy is the only route with Federal Drug Administration approved formulations in the United States but sublingual immunotherapy is currently under investigation. This review examines the efficacy, safety, and preventive effects of these two routes of immunotherapy.

Sublingual immunotherapy and allergic rhinitis

This paper reviews the safety and efficacy of sublingual immunotherapy (SLIT) in the treatment of allergic rhinitis. The literature from 1986 through 2007 shows approximately a 6000-fold range in doses found to be effective with SLIT. However, recent studies in large patient populations have demonstrated a clear dose response with an effective dose range that appears to be equivalent to one to two times the monthly subcutaneous immunotherapy dose administered daily or weekly (ie, 15 to 30 microg of major allergen). Further study is needed to establish the optimal dose and dosing schedule for each formulation. Local reactions (eg, oral itchiness) are common, and serious adverse reactions, although rare, have been reported. Cost-effective analysis cannot be made until the effective dose is established. SLIT appears to be a promising treatment for allergic rhinitis, but it is currently considered investigational in the United States until a formulation approved by the US Food and Drug Administration is available.

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.