Merck announces success of pill against ragweed allergy

By Dr. Ananya Mandal, MDMar 5 2012

Merck & Co. announced Monday that their experimental allergy tablet reduced allergic reactions to ragweed and helped patients use less medication to treat their symptoms.

The company announced that it will file for marketing approval of its allergy immunotherapy tablets in 2013. It plans to ask the Food and Drug Administration (FDA) to approve the tablets as treatments for ragweed and grass allergies. It is also studying a treatment for allergies brought on by house dust mites.

Merck's allergy immunotherapy tablet or AIT is an investigational, dissolvable oral tablet designed to treat the underlying cause of allergies. The drug is being studied to determine whether it may help to prevent allergy symptoms by generating an immune response to protect against targeted allergens. The tablets are designed to reduce the severity of allergies over time, and they could be an alternative to repeated allergy shots.

The multicenter Phase III trial that showed the drug’s efficacy involved 565 adults age 18 to 50. Most of them had multiple allergies. Patients were randomized to receive a once-daily tablet of Ambrosia artemisiifolia, or ragweed allergen extract, for about 16 weeks prior to and throughout the ragweed pollen season, for a total treatment period of 52 weeks.

In the study patients were given one of two doses of the allergy tablets or a placebo. They took the tablets for a full year, including about 16 weeks before ragweed allergy season began, and recorded their allergy symptoms and use of other allergy medications in a daily journal. Merck combined the symptoms and medication use into daily scores and compared results for the patients over the 15 days with the highest ragweed pollen count.

The results showed that patients who took the lower dose of the allergy tablet had a 21-percent reduction in symptoms and a 34-percent reduction in medication use compared to patients who took the placebo, and patients who took the larger dose had a 27-percent reduction in symptoms and used 45 percent less medication.

The company said that the most common side effects of its allergy tablet were itchiness of the mouth and ear, and throat irritation. It plans to report further results from the study Tuesday at a meeting of the American Academy of Allergy, Asthma and Immunology.

Rupert Vessey, senior vice president and franchise head of Respiratory & Immunology, Merck Research Laboratories said, “Merck is pleased that patients who took its AIT in this study experienced a significant reduction in the nasal and eye symptoms caused by ragweed allergies, and these positive results are an important step in the development of this investigational therapy.” He said pills would be far more convenient than allergy shots because patients would not have to make repeated visits to doctors or undergo injections. Moreover, he said shots given by allergists contain allergens that are not approved by the U.S. Food and Drug Administration.

Vassey said allergy shots typically are taken for about three years, after which many patients experience relief for years afterward. By the same token, he said Merck's pills, if approved, might also be taken for an extended period to tame immune responses, before patients stop treatment.