Ragweed sublingual-liquid immunotherapy curbs rhinoconjunctivitis

By David Douglas

NEW YORK (Reuters Health) - Sublingual use of ragweed liquid extract can ease allergic rhinoconjunctivitis, according to U.S. and Canadian researchers.

In a paper online December 13 in the Journal of Allergy and Clinical Immunology, Dr. Peter S. Creticos and colleagues note that although sublingual immunotherapy has been espoused in Europe, it is not approved by the U.S. Food and Drug Administration (FDA).

In fact, Dr. Creticos told Reuters Health by email, "this study is the first successful confirmatory clinical trial in North America to demonstrate that ragweed immunotherapy, when administered as a sublingual liquid extract, was capable of providing highly effective clinical improvement in patient symptoms and medication requirements during the fall allergy season."

Dr. Creticos of the Creticos Research Group in Crownsville, Maryland, and his team note that subcutaneous immunotherapy has been the conventional mode of therapy in the U.S. and Canada for patients with seasonal allergic rhinoconjunctivitis.

The researchers conducted a phase 3 trial to determine the efficacy and tolerability of standardized glycerinated short ragweed sublingual allergen immunotherapy liquid (SAIL, Greer Laboratories).

In all, 429 subjects with or without asthma were randomized to self-administer the maximum tolerated dose of the liquid or placebo. They began 8 to 16 weeks before and continued until the end of the ragweed pollen season.

The subjects were provided with self-injectable epinephrine in case of a severe allergic reaction to treatment and as-needed antiallergy medications.

Compared to placebo, during the whole season there was a 43% reduction in subject-assessed total combined daily rhinoconjunctivitis symptom and medication scores. There were similar decreases during peak season and in daily scores over the peak and entire season. There was also a reduction in rescue medication use in the active treatment group.

There were no serious adverse events although mild and moderate adverse events overall were slightly higher in the active treatment compared to the placebo group.

The study, continued Dr. Creticos, is pivotal "in that its results provide us with the first conclusive evidence that this form of treatment can be safely tolerated at effective doses that provide meaningful clinical benefit."

"Hopefully," he concluded, "this and similar studies will provide the needed clinical safety and efficacy data that will lead to approval of this form of immunotherapy in the U.S., as it could potentially offer patients who suffer from allergic rhino-conjunctivitis a safe, convenient, and effective alternative to allergy injections."

Dr. Creticos is a consultant to Greer Laboratories, which funded the study and employed three of the authors.

SOURCE: http://bit.ly/1d6mZlQ

J Allergy Clin Immunol 2013.

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