Timothy Grass Pollen Allergen Extract approved by FDA

FDA has approved the Timothy Grass Pollen Allergen Extract (Grastek, Merck) sublingual tablet as immunotherapy to treat grass pollen-induced allergic rhinitis with or without conjunctivitis in children as young as 5 years of age and adults up to the age of 65. The tablet is a new option for patients who decline allergy shots.

Grastek is not indicated for the immediate relief of allergic symptoms. Symptoms of grass pollen-induced allergic rhinitis with or without conjunctivitis may include sneezing, runny or itchy nose, stuffy or congested nose, or itchy and watery eyes, and typically intensify during the grass pollen season.

The grass-pollen season varies regionally across the United States, including for Timothy grass, one of the most common grasses in the country. Use of Grastek should begin at least 12 weeks before the grass-pollen season is expected to begin, and treatment should continue throughout the season. Safety and efficacy have not been established for use of Grastek when it is begun after the grass pollen season.

“With the FDA approval of Grastek, allergy specialists now have a new sublingual approach to offer appropriate patients to help treat their grass allergies, meeting a current unmet need,” said Bob Consalvo, director, global communications, Merck. “Prior to the recent FDA approval of sublingual tablets, allergy immunotherapy traditionally has been given as injections administered in the physician’s office.”

Some patients, including pediatric patients, who may be candidates for allergy immunotherapy, decline allergy shots, Consalvo said. The recommended dose of Grastek is 1 tablet daily to be placed under the tongue, where it will dissolve.

“In addition, the first dose of Grastek is given under the supervision of a physician with experience in the diagnosis and treatment of allergic diseases,” he said. “If the patient tolerates the first dose, the patient may take subsequent doses at home. This may offer convenience for pediatric patients and their caregivers.”

The prescribing information for Grastek includes a boxed warning regarding severe allergic reactions. Grastek is contraindicated for patients with severe, unstable or uncontrolled asthma; a history of any severe systemic allergic reaction; a history of any severe local reaction after taking any sublingual allergen immunotherapy; a history of eosinophilic esophagitis; or hypersensitivity to any of the inactive ingredients contained in the product.

The efficacy of Grastek was supported by 2 studies of approximately 24 weeks’ treatment duration over one grass-pollen season each for patients 5 through 65 years of age, and one 5-year grass-pollen-season study in patients 18 through 65 years of age. The most common adverse reactions reported in clinical studies for patients between the ages of 18 and 65 who have allergic rhinitis induced by Timothy grass pollen, with or without conjunctivitis and treated with Grastek vs placebo, included oral pruritus (26.7% vs 3.5%), throat irritation (22.6% vs 2.8%), ear pruritus (12.5% vs 1.1%), and mouth edema (11.1% vs 0.8%).

The most common adverse reactions for Grastek versus placebo in clinical studies for pediatric patients between 5 and 17 years of age with grass pollen-induced allergic rhinitis, with or without conjunctivitis, included oral pruritus (24.4% vs 2.1%), throat irritation (21.3% vs 2.5%), and mouth edema (9.8% vs 0.2%).