Officials with the US FDA today approved Merck, Sharp & Dohme Corporation's Odactra, the first allergen extract to be administered sublingually to treat house dust mite-induced nasal inflammation (allergic rhinitis), with or without eye inflammation, in adults aged 18 through 65.

In a press release, the administration noted that Odactra is a once-daily tablet that exposes patients to house dust mite allergens, gradually training the immune system to reduce the frequency and severity of nasal and eye allergy symptoms. The first dose is taken under the supervision of a health care professional with experience in the diagnosis and treatment of allergic diseases. The patient is to be observed for at least a half hour for potential adverse reactions. Provided the first dose is well tolerated, patients can then take Odactra at home. It can take about 8 to 14 weeks of daily dosing after initiation of Odactra for the patient to begin to experience a noticeable benefit.

The safety and efficacy of Odactra was evaluated in studies conducted in the United States, Canada and Europe, involving approximately 2,500 people. Some participants received Odactra, while others received a placebo pill. Participants reported their symptoms and the need to use symptom-relieving allergy medications. During treatment, participants taking Odactra experienced a 16% to 18% reduction in symptoms and the need for additional medications compared to those who received a placebo.

The most commonly reported adverse reactions were nausea, itching in the ears and mouth, and swelling of the lips and tongue. The prescribing information includes a boxed warning that severe allergic reactions, some of which can be life-threatening, can occur. As with other FDA-approved allergen extracts administered sublingually, patients receiving Odactra should be prescribed auto-injectable epinephrine. Odactra also has a Medication Guide for distribution to the patient.

FDA approves Odactra for house dust mite allergies [news release]. Gaithersburg, MD. FDA newsroom. Accessed March 1, 2017.