FDA Approves Sublingual Grastek for Timothy Grass Pollen Allergy

On Monday, Merck announced that the US Food and Drug Administration (FDA) has approved Grastek (Timothy Grass Pollen Allergen Extract) tablet for sublingual use for the treatment of grass pollen-induced allergic rhinitis with or without conjunctivitis confirmed by positive skin test or in vitro testing for pollen-specific IgE antibodies for Timothy grass or cross-reactive grass pollens.

Grastek is approved for use in patients age 5 to 65, making it the first sublingual allergy immunotherapy product approved for use in children as young as age 5. The recommended dose is one tablet daily.

According to the Merck news release, Timothy grass “is the most common allergy-provoking grass in North America. Current treatment consists of allergen avoidance and pharmacotherapies including antihistamines, leukotriene antagonists, and intranasal corticosteroids.”

Grastek is not indicated for the immediate relief of allergic symptoms. The prescribing information for the drug includes a boxed warning regarding severe allergic reactions. Grastek is contraindicated in 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.

Therapy with Grastek should be initiated at least 12 weeks before the start of the grass pollen season, and should be administered in a healthcare setting under the supervision of a physician with experience in the diagnosis and treatment of allergic diseases. Treatment should be continued throughout the season.

Patients should be observed by their physician for at 30 minutes after the first dose of Grastek to monitor for signs or symptoms of a severe systemic or a severe local allergic reaction. If the patient tolerates the first dose, the patient may take subsequent doses at home.

Physicians prescribing Grastek should also prescribe auto-injectable epinephrine, and instruct and train the patient on its appropriate use. Children should take Grastek only under adult supervision.

According to Merck, “For sustained effectiveness for one grass pollen season after cessation of treatment, GRASTEK may be taken daily for three consecutive years (including the intervals between the grass pollen seasons). The safety and efficacy of in-season initiation have not been established.”

Grastek will be available in pharmacies in late April.