Ragweed Vaccine for Allergic Rhinitis

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allergic rhinitisAllergen immunotherapy is a powerful and effective treatment option for patients with allergic rhinitis, allergic asthma, and allergy to stinging insects. Allergen immunotherapy (ie, "allergy shots") has been used for nearly 100 years, and has been shown to provide both short-term and often long-term relief from allergic symptoms. It may also help prevent the development of asthma, and may reduce the incidence of new allergic sensitivities. Creticos and colleagues evaluated an experimental alternative to the traditional approach to immunotherapy.

The study authors conducted a double-blind, randomized, placebo-controlled, phase 2 trial with a ragweed antigen (Amb a 1), conjugated to a phosphorothioate oligodeoxyribonucleotide immunostimulatory sequence of DNA (AIC) in 25 ragweed-allergic adults. Patients were given injections once weekly for 6 weeks. Their allergic rhinitis symptoms were then followed for 2 years.

The primary endpoint for assessing the efficacy of the experimental vaccine was measurement of the level of albumin in nasal lavage fluid in response to nasal challenge with ragweed antigen. There was no difference in this endpoint between those treated with the experimental (AIC) vaccine and those treated with placebo, although those treated with the AIC vaccine had improved rhinitis scores, peak-season daily nasal symptoms diary scores, and midseason overall quality of life. AIC treatment caused a transient increase in Amb a 1-specific immunoglobulin (Ig)G, and also blocked the seasonal increase in ragweed-specific IgE, just as conventional immunotherapy does currently. Of interest, the benefits of this treatment persisted into the second year. The study authors concluded that this form of treatment offered long-term clinical efficacy in treating ragweed-associated allergic rhinitis.

Viewpoint

Allergen immunotherapy is a very powerful treatment modality for the management of allergic disease. For a number of years, researchers have investigated simpler ways to administer allergy shots. This study is promising, although this method of treatment needs additional research before it is ready for more widespread use. This was a small study; by the time the second season was completed, there were only 9 patients in the placebo group and 6 patients in the active treatment group. The study needs to be replicated and with the inclusion of different antigens. It does, however, allow a glimpse over the horizon of a possible, exciting future for more efficient immunomodulatory treatment for allergic disease.

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