Grastek, a sublingual allergen extract manufactured by Merck & Co Inc, has received FDA approval as an immunotherapy for the treatment of Timothy grass pollen-induced allergic rhinitis (with or without conjunctivitis) for patients age 5 to 65, according to Merck.

The drug is the second sublingual allergen immunotherapy approved by the FDA in as many weeks, after it approved Stallergenes SA’s Oralair earlier this month. However, Oralair was approved for ages 10-65, while Grastek is approved for children as young as 5, according to Merck.

Approximately 7.5 million US children and adults ages 5 to 64 have been diagnosed with moderate to severe allergic rhinitis and are sensitized to Timothy and cross-reactive grass pollens, according to Merck.

“The FDA approval of Grastek brings an important new sublingual tablet for allergy specialists treating adults and children with allergic rhinitis with or without conjunctivitis caused by Timothy or cross-reactive grass pollens,” said Sean Curtis, vice president, Respiratory and Immunology, Merck Research Laboratories. “This important milestone marks another opportunity for Merck to build on our respiratory heritage with allergy specialists.”

According to Merck, the recommended dose of Grastek is one tablet daily to be placed under the tongue, where it will dissolve in less than 10 seconds.1

The company noted that the first dose should be administered in a healthcare setting under the supervision of a physician, who should observe the patient for at least 30 minutes. If there is no adverse reaction, subsequent doses can be self-administered at home.

Merck emphasized that children must take Grastek under adult supervision and “the physician should prescribe auto-injectable epinephrine, and instruct and train the patient on its appropriate use.”

The product will be available in US pharmacies in late April, according to the company.

Medication guide and prescribing information for Grastek, including Boxed Warning, are available here: