NEW YORK, June 30 (Reuters) -- People with allergies may be miserable as pollen counts rise, often coughing, sneezing, and having watery eyes throughout the spring or fall. A series of injections containing the offending allergen can help reduce hayfever symptoms, but the shots may be uncomfortable and carry a small risk of causing a severe, even life-threatening immune reaction -- in about 1 in 2.5 million injections.
Now, a new study suggests that allergens may be successfully given in an oral dose, according to a report in the Annals of Allergy, Asthma and Immunology. Encapsulated pH-sensitive gelcaps were used to protect the medication from harsh digestive enzymes, which had rendered previous oral doses ineffective.
The investigational study suggests that taking an allergen orally is safe and moderately effective at reducing hayfever symptoms, according to senior investigator Dr. David Skoner, of the Children's Hospital of Pittsburgh in Pennsylvania. The study was conducted with researchers from Allergenics, Inc, in Cincinnati, Ohio.
In the study, 23 patients who were allergic to ragweed were given either an inactive placebo, or a gelcap containing ragweed extract once a day for six days a week.
Those given the active ragweed extract had fewer symptoms, such as sneezing or a runny nose, when exposed to ragweed compared with those given a placebo. And those given the active medication were no more likely than other study participants to have side effects, such as nausea, vomiting or cramps, or hives, rash or difficulty breathing. Such coated capsules release the allergen in the small intestine, which can irritate the digestive system causing diarrhea, cramps or other symptoms.
However, much larger studies are needed to determine if such a therapy is indeed safe and effective, the authors noted.
"The information gleaned from this clinical trial will aid greatly in designing future pivotal trials of this novel allergy therapy," they concluded.
SOURCE: Annals of Allergy, Asthma and Immunology (1997;78:573-580)
