Merck says pill tames allergic response to ragweed

Sun Mar 4, 2012 5:29am EST

* Says pill may be alternative to allergy shots

* Says cut allergy symptoms, need for other drugs

* Says pill trains immune system to overlook ragweed

By Ransdell Pierson

March 4 (Reuters) - Merck & Co on Sunday said it would seek U.S. approvals next year for separate allergy pills that help tame the immune system's reaction to ragweed and grass, and the drugmaker released favorable data from a late-stage trial of the ragweed medicine.

The pills are meant to be an alternative to traditional allergy shots given in doctors' offices, which include a mixture of proteins that gradually weaken the immune system's response to ragweed, grass, foods and other allergy triggers.

The Phase III study involved 565 patients 18 to 50 years old prone to ragweed-induced allergies, with or without asthma. Patients took Merck's once-daily tablet for 52 weeks, at one of two available doses, or took placebos.

The active ingredient of the pill is Ambrosia artemisifolia, the chemical name of the ragweed allergen, or protein, that causes runny noses, sneezing and other miseries for millions of Americans.

The study assessed relief of nasal and eye symptoms as well as reductions in the need for other allergy medications, which together were considered in the total combined score.

During peak ragweed season, patients taking Merck's pill experienced 27 percent and 21 percent reductions in the total combined score, respectively, at the higher and lower doses, compared with patients taking placebos. Merck said the results were highly statistically significant.

Specifically, the pill reduced allergy symptoms during peak ragweed season by 17 percent and 14 percent, respectively, at the higher and lower doses. It reduced the need for standard allergy medications -- including antihistamines and nasal steroids such as Nasonex -- by 45 percent and 34 percent, respectively, at the two doses.

SIDE EFFECTS INCLUDE ITCHINESS, THROAT IRRITATION

The most frequent side effects of the treatment were itchiness of the mouth and ear and throat irritation, Merck said, with no reports of death, systemic allergic reactions or life-threatening events.

But two patients during the trial received epinephrine, an injectable hormone often used to treat serious allergic reactions to drugs, foods or other substances. Additional details about the treatments with epinephrine were not immediately available.

Merck sells many of the world's most widely used standard allergy treatments, including Nasonex and Claritin, an antihistamine sold over the counter by the U.S. drugmaker and other companies under the chemical name loratadine.

Rupert Vessey, head of respiratory and immunology research at Merck, said favorable data have also been seen in separate studies of the company's medicine to moderate grass allergies. It and the ragweed product are the first pills to attack the underlying cause of allergy attacks, while current drugs just treat allergy symptoms, he said in an interview.

"Immune therapy actually modifies the disease. It educates the immune system to get rid of allergic responder cells, and to become tolerant of allergens," Vassey said.

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.

When asked how symptom relief with the pills compares with relief seen with Claritin and other standard therapies, Vessey declined to provide statistics. He said it would be inappropriate to compare effectiveness of the Merck pills with other classes of allergy medicines because they had not been tested against each other.

Merck is developing the allergy immunotherapies with Danish drugmaker ALK-Abello. Data from the ragweed trial were to be presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology being held in Orlando.

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