Sublingual Immunotherapy

What is Sublingual Immunotherapy?

Sublingual Immunotherapy is a new treatment for patients with grass pollen allergies.

Sublingual immunotherapy (SLIT) is an alternative way to treat allergies without injections. It was first proposed as a method of treatment for allergic disease in the early 1900. In the 1980s, properly designed clinical trials first demonstrated a dose-dependent therapeutic response with specific and well-characterized aeroallergens. In 1998, the World Health Organization recognized that SLIT was a promising alternate mode of immunotherapy and encouraged continued clinical investigation into this form of treatment. In 2009, the World Allergy Organization (WAO) published their opinion that the cumulative evidence showed SLIT represented a viable alternative to subcutaneous immunotherapy (SCIT). Several types of allergen preparations have been studied in oral immunotherapy. Among the different approaches to oral immunotherapy, studies using sublingual tablets (SLIT-tablets) of grass and weed pollen extracts have yielded some of the best results. The effectiveness and convenience of this self-administered treatment and its low potential for severe side effects have helped SLIT gain popularity in several countries. SLIT, like conventional subcutaneous immunotherapy, is disease-modifying therapy, which may prevent new sensitization and progression of asthma. On 04/14/2014 the U.S. Food and Drug Administration (FDA) approved GRASTEK (Timothy Grass Pollen Allergen Extract) tablet for sublingual use. In its pivotal studies, compared to placebo GRASTEK was superior in reducing allergy symptoms associated with grass pollen exposure by about 34% during treatment for one grass pollen season and by about 41% during treatment for two grass pollen seasons.

Indications and Usage for GRASTEK

GRASTEK is an allergen extract indicated as immunotherapy for the treatment of grass pollen-induced allergic rhinitis with or without conjunctivitis confirmed by positive skin or blood (ImmunoCAP) test for pollen-specific IgE antibodies for Timothy grass or cross-reactive grass pollens (sweet vernal, orchard/cocksfoot, perennial rye, Kentucky blue/June grass, meadow fescue, or redtop). This is an effective therapy for those who have been sensitized to a single allergen (grass pollen) ONLY. It is estimated that approximately 7.5 million U.S. 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. 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 (May – August).

• GRASTEK is approved for use in persons 5 through 65 years of age.
• GRASTEK is not indicated for the immediate relief of allergic symptoms.

Dosage and Administration

The recommended dose of GRASTEK is one tablet daily to be placed under the tongue and held there until fully dissolved (at least 1 minute). No food or beverages should be ingested for five minutes following administration. The first dose is to be taken at the allergist’s office followed by at least 30-minute observation period for signs or symptoms of a severe systemic or a severe local allergic reaction. Subsequent doses are to be administered once a day at home. Children must take GRASTEK under adult supervision. If you choose this treatment option, you will be prescribed auto-injectable epinephrine, as well as instructed and trained on its appropriate use. Treatment should be started three months (12 weeks) prior to the expected onset of the respective pollen season and continued through the grass pollen season (May-August). It may be taken throughout the year (including the intervals between the grass pollen season) and for three consecutive years. If you miss one or more weeks of treatment, your next dose should be administered under medical supervision.

Contraindications

• Severe, unstable, or uncontrolled asthma
• History of any severe systemic allergic reaction
• History of any severe local reaction after taking sublingual allergen immunotherapy
• History of Eosinophilic Esophagitis
• Hypersensitivity to any of the inactive ingredients (gelatin, mannitol and sodium hydroxide)

May Not Be Suitable (risks vs benefits will be discussed at your appointment)

• History of a medical condition that may reduce the ability to survive a serious allergic reaction or increase the risk of adverse reactions after epinephrine administration (markedly compromised lung function, unstable angina, recent heart attack, significant irregular heartbeat, and uncontrolled hypertension)
• Use of beta-blockers, alpha-blockers, tricyclic antidepressants, levothyroxine sodium, monoamine oxidase inhibitors, certain antihistamines, cardiac glycosides and diuretics.
• Those who are receiving concomitant subcutaneous allergen immunotherapy
• Those who are pregnant and nursing mothers

In case of oral inflammation or wounds, GRASTEK should be stopped to allow complete healing of the oral cavity.

Most Common Adverse Reactions (commonly observed within the first seven daily doses):\

• Oral itching (27%)
• Throat irritation (23%)
• Ear itching (13%)
• Mouth swelling (11%)

SLIT: Pros and Cons

PROS:

• Causes fewer systemic side effects than subcutaneous immunotherapy (SCIT); serious side effects with SLIT are rare, but a few have been documented
• Greater convenience due to self-administration, no need for a waiting period in a medical office, and no discomfort of injection
• A great treatment option for those, who are monosensitized to grass pollen
  • Do not have the ability to commit to 3-5 years of SCIT due to their busy lifestyle
  • Needle phobic
• Possible quicker onset of efficacy, usually within 3-4 months, whereas SCIT may take 6-9 months

CONS:

• – SLIT is NOT effective if you are poly-sensitized (have multiple environmental allergies)
• – Compliance-related issues due to self-administration (daily administration is a MUST in order to obtain the
• maximum benefit)
• – Costs may be quite high and may not yet be covered by some insurance companies