Is Oraltek (sublingual immunotherapy) 30,000 TU/mL solution indicated for the treatment of weed pollen allergy?

Sublingual Immunotherapy with Oraltek for Weed Pollen Allergy

Oraltek 30,000 TU/mL sublingual solution can be used for weed pollen allergy if it contains the appropriate weed allergen extracts (such as ragweed, mugwort, or plantain) at therapeutic doses, as sublingual immunotherapy is conditionally recommended for pollen allergies in adults and children. 1

Evidence Supporting Sublingual Immunotherapy for Weed Pollen

Guideline Recommendations

• The ARIA 2010 guidelines suggest sublingual allergen-specific immunotherapy in adults with rhinitis caused by pollen (conditional recommendation, moderate-quality evidence). 1

• For children with allergic rhinitis caused by pollens, sublingual allergen-specific immunotherapy is also suggested (conditional recommendation, moderate-quality evidence). 1

• The 2015 AAO-HNS clinical practice guideline recommends that clinicians should offer, or refer to a clinician who can offer, immunotherapy (sublingual or subcutaneous) for patients with allergic rhinitis who have inadequate response to pharmacologic therapy with or without environmental controls. 1

Critical Considerations for Weed Pollen Immunotherapy

The specific weed allergen content matters significantly. The major allergenic weeds in Europe and North America include:

• Ragweed (Ambrosia artemisiifolia) - with Amb a 1 as the major allergen 2, 3
• Mugwort (Artemisia vulgaris) - with Art v 1 as the marker allergen 2, 4
• English plantain (Plantago lanceolata) - with Pla l 1 as the marker allergen 2, 4
• Pellitory (Parietaria judaica) - with Par j 2 as the marker allergen 2, 4

Dosing Requirements

For ragweed specifically, the probable effective dose range is 6-12 mg of Amb a 1 or 1000-4000 AU per injection for subcutaneous immunotherapy. 1 While sublingual immunotherapy typically requires 20 to 200 times the parenteral injected dosage, the 30,000 TU/mL concentration in Oraltek could potentially deliver therapeutic doses depending on the volume administered and specific allergen content. 1

Safety Profile

Sublingual immunotherapy has demonstrated excellent safety, even at very high doses (up to 500 times the usual monthly subcutaneous dose), with a lower incidence of serious side effects compared to subcutaneous immunotherapy. 1 However, local adverse effects are relatively frequent (approximately 35%), including oral and gastrointestinal reactions. 1

Clinical Decision Algorithm

1. Confirm weed pollen sensitization through specific IgE testing (skin or blood) to identify the relevant weed allergen(s). 1

2. Verify that Oraltek contains the specific weed allergen(s) to which the patient is sensitized (ragweed, mugwort, plantain, or pellitory). 2

3. Ensure inadequate response to pharmacologic therapy (antihistamines, intranasal corticosteroids) before initiating immunotherapy. 1

4. Consider patient age and preferences: The evidence is stronger for adults (moderate-quality) than children, though both populations can benefit. 1

Important Caveats

• There is currently no FDA-approved formulation for sublingual immunotherapy for weed pollens in the United States (as of the 2007 guidelines), making this treatment investigational in that jurisdiction. 1 However, FDA-approved sublingual tablets for grass and ragweed pollen became available in 2014. 1

• A consistent relationship among allergen dose, treatment duration, and clinical efficacy has not been established for sublingual immunotherapy, unlike subcutaneous immunotherapy. 1

• Approximately 35% of randomized, double-blind, placebo-controlled studies did not demonstrate efficacy in either symptom or medication scores during the first year of sublingual immunotherapy treatment. 1

• Component-resolved diagnostics using marker allergens (Amb a 1 for ragweed, Art v 1 for mugwort, Pla l 1 for plantain, Par j 2 for pellitory) can help identify the primary sensitizer and enable appropriate allergen selection. 2