The FDA approved the ragweed allergy treatment Ragwitek, the third sublingual immunotherapy (SLIT) approval last month. The announcement followed that of Merck’s other SLIT agent, the Timothy grass pollen allergy tablet Grastek, on Tuesday and that of Greer’s multi-grass pollen immunotherapy tablet Oralair earlier in April.  While under-the-tongue drops made off-label from subcutaneous allergy shot extracts have been used by some practitioners, no SLIT agents had been FDA approved before. The liquid extracts manufactured for injections have generally been too weak to have clinical effectiveness when administered sublingually, but the new sublingual tablets are high dose and are proven effective.

Ragwitek gained approval for treatment of short ragweed pollen-induced allergic rhinitis, confirmed by a positive skin test or in vitro testing for pollen-specific immunoglobulin-E antibodies, with or without conjunctivitis, in adults ages 18 through 65. That upper age limit had been the source of some dissension on the FDA advisory panel that recommended approval. The pivotal trials included no patients over age 51, so a few panel members felt the evidence wasn’t sufficient for older patients.

The other two SLIT agents approved have gained an indication for pediatric use, but that wasn’t sought or studied with Ragwitek. But the Ragwitek approval otherwise followed closely with that of the grass allergy SLIT agents. It was approved for once daily use starting 12 weeks before the start and continued through the offending pollen season, which typically runs from late summer to early fall. The first dose should be taken in-office and the patient observed for at least 30 minutes for potential adverse reactions.

The most common adverse reactions reported with Grastek and Ragwitek have been itching in the mouth and ears and throat irritation, but the drug carries a boxed warning of the risk of severe allergic reactions. Due to that risk, patients should be prescribed auto-injectable epinephrine and trained in its use.

Patients with severe, unstable, or uncontrolled asthma or a history of any severe systemic allergic reaction, eosinophilic esophagitis, or any severe local reaction after taking any SLIT agent shouldn’t get Ragwitek.

Dr. Kenneth Backman of Allergy & Asthma Care of Fairfield County comments: “This adds two more options to the new category of sublingual immunotherapy tablets, the first under-the-tongue allergen immunotherapy that has proven effectiveness to the satisfaction of the FDA. It is exciting to have this new treatment option available, and look forward to discussing this and other options with our patients.”