CLASSES

Immunotherapy for Allergic Rhinitis

DEA CLASS

Rx

DESCRIPTION

Oral, sublingual immunotherapy
For allergic rhinitis with or without conjunctivitis that is induced by short ragweed pollens
First dose given in health care provider's office to allow for patient observation for potential adverse reactions

COMMON BRAND NAMES

RAGWITEK

HOW SUPPLIED

RAGWITEK Oral Tablet, SL

DOSAGE & INDICATIONS

MAXIMUM DOSAGE

1 tablet (12 Amb a 1-Unit)/day SL

65 years: 1 tablet (12 Amb a 1-Unit)/day SL
older than 65 years: Safety and efficacy have not been established.

1 tablet (12 Amb a 1-Unit)/day SL

5 to 12 years: 1 tablet (12 Amb a 1-Unit)/day SL
1 to 4 years: Safety and efficacy have not been established.

Safety and efficacy have not been established.

Safety and efficacy have not been established.

DOSING CONSIDERATIONS

Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.

Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.

ADMINISTRATION

STORAGE

RAGWITEK:
- Protect from moisture
- Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
- Store in original package until time of use

CONTRAINDICATIONS / PRECAUTIONS

Short ragweed pollen allergen extract can cause life-threatening allergic reactions, including a risk of serious hypersensitivity reactions or anaphylaxis. Use with great caution in patients with a history of atopy or sublingual allergen immunotherapy hypersensitivity; these patients may be predisposed to severe allergic reactions. The use of more than one type of immunotherapy (i.e. allergy shots, sublingual immunotherapy) may increase the likelihood of a severe allergic reaction. Short ragweed pollen allergen extract is contraindicated in patients with a history of severe local reaction to sublingual allergen immunotherapy and/or severe systemic allergic reactions of any type. Additionally, do not use the extract in patients with a hypersensitivity to any of the inactive ingredients present in the product, including those with mannitol hypersensitivity, gelatin hypersensitivity, or sodium hydroxide hypersensitivity. Systemic allergic reactions including life-threatening anaphylaxis and severe local reactions (e.g., laryngopharyngeal swelling) that may compromise breathing may occur; treatment with epinephrine may be required. Patients who experience a systemic reaction to short ragweed pollen allergen extract should stop taking the extract immediately. Those who have persistent or escalating local reactions in the mouth or throat should be reevaluated, and discontinuation of the extract should be considered to avoid potential airway compromise. Administration of the first dose requires a specialized care setting due to the risk of severe allergic reactions; give the first dose in a healthcare setting where acute allergic reactions can be recognized and treated by an experienced clinician. Observe the patient for at least 30 minutes post-dose for signs or symptoms of a severe systemic or local reaction. If the patient tolerates the first dose, subsequent doses may be administered outside of the healthcare setting. Auto-injectable epinephrine should be made available to patients; instruct patients to recognize symptoms of a severe allergic reaction, about the proper use of epinephrine, and to seek immediate medical care upon use. Short ragweed pollen allergen extract may not be suitable for patients with medical conditions that may decrease the patient's ability to survive a serious allergic reaction or increase the risk of adverse reactions after epinephrine administration. These conditions may include, but are not limited to, unstable angina, recent myocardial infarction, significant cardiac arrhythmias, and uncontrolled hypertension. Further, the extract may not be suitable for patients taking medications that can potentiate or inhibit the effects of epinephrine or decrease the effectiveness of inhaled bronchodilators; these medications include beta-adrenergic blockers, alpha-adrenergic blockers, ergot alkaloids, tricyclic antidepressants, levothyroxine, monoamine oxidase inhibitors, chlorpheniramine, diphenhydramine, cardiac glycosides, and diuretics. Concomitant use of short ragweed pollen allergen extract with other allergen immunotherapy has not been studied; concurrent use may increase the risk of local or systemic reactions to either subcutaneous or sublingual immunotherapy.

Short ragweed pollen allergen extract is contraindicated in patients with severe, unstable, or uncontrolled asthma (e.g., status asthmaticus or acute bronchospasm). Patients with recurrent asthma exacerbations should be reevaluated for appropriateness of therapy and discontinuation should be considered. The extract may not be suitable for patients who have acute or chronic compromised lung function (e.g., asthma, chronic lung disease (CLD), chronic obstructive pulmonary disease (COPD), or emphysema) that may reduce the patient's ability to survive a serious allergic reaction or increase the risk of adverse reactions after epinephrine administration. The extract has not been studied in patients with moderate or severe asthma.

Short ragweed pollen allergen extract is contraindicated in patients with a history of eosinophilic esophagitis. Discontinue the extract in patients who experience severe or persistent gastro-esophageal symptoms (e.g., dysphagia, chest pain) and consider a diagnosis of eosinophilic esophagitis.

Patients with any type of oral inflammation (e.g., oral lichen planus, mouth ulcers, or thrush) or oral wounds, such as those after dental work or oral surgery, should not receive short ragweed pollen allergen extract until complete healing of the oral cavity occurs.

Adequate and well-controlled studies with the short ragweed pollen allergen extract have not been conducted in pregnant women, and animal reproduction studies have not been performed. The short ragweed pollen allergen extract should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, as systemic and local adverse reactions to immunotherapy may be poorly tolerated during pregnancy.

According to the manufacturer, short ragweed pollen allergen extract should be used with caution in breast-feeding women. It is not known if the extract is excreted into human breast milk. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

ADVERSE REACTIONS

angioedema / Rapid / Incidence not known
serious hypersensitivity reactions or anaphylaxis / Rapid / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
anaphylactic shock / Rapid / Incidence not known

oral ulceration / Delayed / 6.8-8.4
edema / Delayed / 1.1-6.1
dysphagia / Delayed / 1.0-1.6
chest pain (unspecified) / Early / 1.0-1.0
esophagitis / Delayed / Incidence not known
dysphonia / Delayed / Incidence not known
erythema / Early / Incidence not known

throat irritation / Early / 7.6-48.3
pruritus / Rapid / 1.2-47.8
nausea / Early / 1.1-11.5
abdominal pain / Early / 10.1-10.1
paresthesias / Delayed / 1.9-10.0
dysgeusia / Early / 3.9-3.9
diarrhea / Early / 2.7-2.7
sneezing / Early / 1.6-1.6
xerostomia / Early / 1.4-1.4
vomiting / Early / 1.2-1.2
rhinorrhea / Early / 1.2-1.2
urticaria / Rapid / Incidence not known
gastroesophageal reflux / Delayed / Incidence not known
dyspepsia / Early / Incidence not known
hypoesthesia / Delayed / Incidence not known
cough / Delayed / Incidence not known

DRUG INTERACTIONS

There are no drug interactions associated with Short Ragweed Pollen Allergen Extract products.

PREGNANCY AND LACTATION

Adequate and well-controlled studies with the short ragweed pollen allergen extract have not been conducted in pregnant women, and animal reproduction studies have not been performed. The short ragweed pollen allergen extract should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, as systemic and local adverse reactions to immunotherapy may be poorly tolerated during pregnancy.

According to the manufacturer, short ragweed pollen allergen extract should be used with caution in breast-feeding women. It is not known if the extract is excreted into human breast milk. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

MECHANISM OF ACTION

When short ragweed pollen allergen extract is allowed to dissolve sublingually, allergens bind to epithelial cells and cross the oral mucosa, where they are taken up by tolerogenic antigen-presenting cells (i.e., Langerhans cells and myeloid dendritic cells). The allergens are then processed into small immunogenic peptides, and the antigen-presenting cells migrate into local regional lymph nodes (submaxillary, cervical, internal jugular). There, allergen peptide fragments are presented to naive CD4+ T cells. This interaction stimulates suppressive T helper (Th) 1 and regulatory T cells and inhibits the activation and proliferation of Th2 cells. Subsequently, T cells encourage B cells to produce protective antibody responses, including secretion of allergen-specific IgG4 and IgA and, later, inhibition of IgE. Regulatory T cells may also suppress other inflammatory cells (e.g., eosinophils, mast cells, basophils) either by cytokine secretion or direct cell-to-cell contact. CD4+ T cells eventually migrate into the blood and tissues, resulting in allergen tolerance.

PHARMACOKINETICS

Short ragweed pollen allergen extract is administered sublingually. The pharmacokinetics of the extract are not well defined. Limited pharmacokinetic data are available for sublingual immunotherapy in general. However, direct contact with the oral mucosa has been determined to be the critical step in ensuring adequate exposure.
 
Parietaria judaica is a perennial plant with highly allergenic pollen. Human pharmacodynamic studies of radiolabeled Parietaria judaica allergen have shown little systemic absorption into the bloodstream through the sublingual mucosa, despite its highly vascular nature. In one study, radioactivity was not detectable in the plasma until swallowing occurred, at which point the plasma radioactivity slowly rose and peaked at approximately 2 hours. In another study using Parietaria judaica, a small amount of the allergen (about 2% of the administered dose) was detected within the oral mucosa 20 hours after dosing. It has been suggested allergens bind to epithelial cells within a few minutes. In a biodistribution study of sublingual radiolabeled ovalbumin in mice, allergen crossed the oral mucosa within 15—30 minutes and was captured by antigen-presenting cells within 30—60 minutes. At 60 minutes, allergen began to disappear from the submucosa, perhaps coinciding with uptake and processing by the antigen-presenting cells. Within 12—24 hours after administration, the antigen-presenting cells migrate to the lymph nodes where they interact with CD4+ cells and further promote the desensitization process.
 
Affected cytochrome P450 isoenzymes: none