American house dust mite allergenic extract 10000 AU/ML Injectable Solution

INDICATIONS AND USAGE Greer Standardized Mite ( Dermatophagoides farinae and/or Dermatophagoides pteronyssinus ) Extracts are allergenic extracts indicated for: skin test diagnosis of mite allergy treatment of patients with mite-induced allergic asthma, rhinitis and conjunctivitis. For immunotherapy, patients must show hypersensitivity to Dermatophagoides farinae ( D. farinae ) or Dermatophagoides pteronyssinus ( D. pteronyssinus ) based on their clinical history, allergen exposure history, and skin test reactivity. Greer Standardized Mite Extracts are allergenic extracts indicated for: Diagnosis of skin test reactivity to dust mite allergen (1) Treatment of mite-induced allergic asthma, rhinitis and conjunctivitis in patients that show hypersensitivity to dust mites based on clinical history, allergen exposure history, and skin test reactivity (1)

DOSAGE AND ADMINISTRATION Do not inject intravenously. Greer Standardized Mite extracts are diluted with sterile diluent for allergenic extracts when used for intradermal testing or subcutaneous immunotherapy. Dosages vary by mode of administration, and by individual response and tolerance. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Greer Standardized Mite Extracts should be a light brown solution that is free of particulate matter. If particulate matter is observed then the solution should be discarded. 2.1 Diagnostic Testing For diagnosis of a patient with a suspected allergy to either species of dust mite ( D. farinae or D. pteronyssinus ), diagnostic skin testing should include the standardized mite mixture or the single-species mite extracts. If a skin test with the standardized mite mixture elicits a positive reaction, then the single-species mite extracts can be used to determine the degree of sensitivity to each, and to guide in the selection of extracts and their concentration for immunotherapy, if indicated. A positive skin test reaction to any allergen must be interpreted in light of the patient's history of symptoms, the time of year, and known exposure to environmental allergens. 2.1.1 Percutaneous Skin Testing For percutaneous (scratch, prick, or puncture) testing, use 10,000 Allergy Units/mL Greer Standardized Mite Extract stock concentrate in dropper vials. If patient is suspected of having exquisite sensitivity, such as anaphylaxis, to certain foods and drugs, initiate percutaneous testing with several serial 10-fold dilutions of the usual test concentration. For scratch tests, scarify the skin, and then apply one drop of the extract to the scratch. For prick tests, place one drop of extract on the skin and pierce through the drop into the skin with a slight lifting motion. For puncture tests, place one drop of extract on the skin and pierce through the drop perpendicular to the skin. When using percutaneous test devices, follow the directions provided with the test devices. Include a positive control to detect false negative responses to skin testing, which may occur if serum levels of antihistamines remain from prior medication administration [see Drug Interactions (7.2)]. A glycerinated histamine phosphate diluted to 10 mg/mL (6 mg/mL histamine base) may be used as the positive control. Include a negative control to detect false positive responses, which can occur when the patient has a non-specific reaction to the diluent. A 50% glycerosaline solution may be used as the negative control. Read skin tests 15-20 minutes after exposure. Record the induration (wheal) and erythema (flare) response by noting the longest diameter of each, or by the sum of the longest erythema diameter and the mid-point orthogonal diameters of erythema (ΣE). Percutaneous testing devices often have their own grading systems, as these devices may cause different degrees of trauma to the skin and deliver different volumes of allergenic extract. Follow grading instructions for the device used. 2.1.2 Intradermal Skin Testing Intradermal tests are commonly used when the reaction to percutaneous testing is negative or equivocal but the patient has a strong clinical history of symptoms triggered by exposure to a specific allergen. Because immediate systemic reactions are more common with intradermal testing, prescreening with percutaneous testing is a practical safety measure. 1 Dilute the stock concentrate with sterile diluent. Use saline with human serum albumin (HSA), buffered saline, or saline. If prescreening is not done, or if patients are expected to be high risk, precautions should be observed since some patients have experienced anaphylaxis and death. Patients who do not react to percutaneous skin testing should be tested intradermally at a starting dose of 0.02 to 0.05 mL of a 50 Allergy Units/mL extract dilution. Patients suspected of being highly allergic should first receive a test dose of 0.02 to 0.05 mL of a 0.05 Allergy Units/mL extract dilution. If the initial dose test is negative, subsequent intradermal tests using increasingly stronger doses may be performed up to the maximum recommended strength of 200 Allergy Units/mL. If percutaneous skin testing was not performed, include a positive control to detect false negative responses to skin testing, which may occur if serum levels of antihistamines remain from prior medication administration [see Drug Interactions (7.2)]. A glycerinated histamine phosphate diluted to 0.5 mg/mL (0.18 mg/mL histamine base) or aqueous histamine phosphate 0.275 mg/mL (0.1 mg/mL histamine base) may be used as the positive control. If percutaneous skin testing was not performed, include a negative control to detect false positive responses, which can occur when the patient has a non-specific reaction to the diluent. A 1% glycerin in 0.9% saline solution may be used as the negative control. Measure the wheal-and-flare response after 15-20 minutes, which may be graded using variou methods as described in the instructions for the device used. The mean dose of Greer dust mite allergen required to elicit a positive intradermal test result (ΣE > 50 mm) in a total of 83 mite puncture test positive (ΣE > 20 mm) persons is shown in Table 1. Table 1. Intradermal Reactivity to Mite Allergens Allergen Number of Persons Dose to Elicit 50 mm Sum of Diameter Erythema Reaction Mean (AU*/mL) Range (AU/mL) D. farinae 46 0.00856 0.00004 - 1.75935 D. pteronyssinus 37 0.00570 0.00002 - 1.36341 ** * Allergy Units ** Data is available on file with Greer 2.2 Immunotherapy Subcutaneous injection only. Subcutaneous injections for immunotherapy should be prepared by dilution of stock concentrate based on patient's reactivity. Stock concentrations of Greer Standardized Mite Extract are available in 5,000 Allergy Units/mL, 10,000 Allergy Units/mL, 30,000 Allergy Units/ mL for immunotherapy. See Table 2 for dilution preparation. Also see Dosage Modification Guidelines 2.2.1). The initial dose of the extract should be based on the percutaneous test reactivity. In patients who appear to be exquisitely sensitive by history and skin test, the initial dose of the extract should be 0.1 mL of a 0.005 to 0.05 Allergy Units/mL dilution. Patients with lesser sensitivity may be started at a 0.5 to 5 Allergy Units/mL dilution. The dose of allergenic extract is increased at each injection by no more than 50% of the previous dose, and the next increment is governed by the response to the last injection. Large local reactions which persist for longer than 24 hours are generally considered an indication for repeating the previous dose or reducing the dose at the next administration. Any evidence of a systemic reaction is an indication for a significant reduction (at least 75%) in the subsequent dose. Repeated systemic reactions, even of a mild nature, are sufficient reason for the cessation of further attempts to increase the reaction-causing dose. Severe reactions require a decrease in the next dose by at least 50%. Proceed cautiously in subsequent dosing. A maximum tolerated maintenance dose should be selected based on the patient's clinical response and tolerance. Doses larger than 0.2 mL of the concentrate are rarely administered because an extract in 50% glycerin may cause discomfort upon injection. Since the two mite species tend to cross-react, consider the total Allergy Units content in determining the maximum maintenance dose of the mixture. 2.2.1 Dosage Modifications Guidelines for Immunotherapy The following conditions may indicate a need to withold or reduce the dosage of immunotherapy. In situations prompting dose reduction, once the reduced dose is tolerated, a cautious increase in dosage can be attempted. Immunotherapy should be withheld or reduced in dosage if the following concurrent conditions exist: Severe symptoms of rhinitis an

WARNINGS AND PRECAUTIONS 5.1 Serious Systemic Reactions All concentrates of Greer Standardized Mite Extracts have the ability during skin testing and immunotherapy to elicit serious systemic reactions including anaphylactic shock and death [see Adverse Reactions (6)]. A review of the literature indicates that the incidence of near-fatal reactions to immunotherapy, defined as severe respiratory compromise, hypotension, or both, and requiring emergency treatment with epinephrine, has been estimated as 5.4 events per million injections in a 10-year retrospective survey of allergists. 3 Fatalities from immunotherapy injections have been estimated to occur at a rate of approximately one death per 2.0 to 2.8 million injections in 4-, 10- and 12-year retrospective surveys of allergists. 4-6 Because of the danger of serious reactions, caution is required in testing and treating high risk patients and those with medical conditions that reduce their ability to survive a serious systemic adverse event. High-risk patients are defined as those patients: with labile or steroid-dependent asthma, particularly in those suffering an exacerbation of their symptoms at the time of extract administration; with extreme sensitivity to a particular allergen(s); who are currently using beta blockers; who are receiving an accelerated immunotherapy build-up schedule (e.g., rush immunotherapy); who are being changed from one allergenic extract to another; who are receiving high doses of allergenic extracts. High risk patients have had fatal reactions. In addition, patients not high-risk but on beta blockers have had fatal reactions because beta blockers interfere with beta adrenergics such as epinephrine used in treatment or anaphylaxis. Patients should be kept under observation for a minimum of 30 minutes after receiving allergenic extracts so that any adverse reaction can be observed and properly handled. 2 Medications to treat systemic reactions, as well as emergency equipment should be available for immediate use. Extracts must only be administered by persons who are aware of the risk of systemic reactions, including anaphylaxis; are capable of handling such reactions; and have the necessary drugs and equipment on hand to do so. 5.2 Patients on Beta Blockers Patients receiving beta blockers may be unresponsive to the usual doses of epinephrine used to treat serious systemic reactions, including anaphylaxis. Inhalant allergy immunotherapy should be approached with caution in patients taking beta blockers. The risks of anaphylaxis in these patients should be carefully weighed against the benefits of immunotherapy [see Drug Interactions (7.1)]. 5.3 Autoimmune Disease Immunotherapy should be given cautiously to patients with other immunologic diseases and only if the risk from exposure to the allergen is greater than the risk of exacerbating the underlying disorder. 2 All concentrates of Greer Standardized Mite Extracts can cause serious systemic reactions of varying degrees of severity, including anaphylactic shock and death, particularly in patients: With labile or steroid-dependent asthma (5.1) With extreme sensitivity to allergen(s) (5.1) Who are currently using beta blockers (5.2) Who are on an accelerated immunotherapy build-up schedule (5.1) Who are being changed from one allergenic extract to another (5.1) Who are receiving high doses of allergen extracts (5.1)

CONTRAINDICATIONS None. None (4)

CLINICAL PHARMACOLOGY Dust mites belonging to the genus Dermatophagoides are indoor allergens found in humid geographic locations worldwide. D. farinae and D. pteronyssinus occur widely with most homes in the United States coinhabited by both species. 11 12.1 Mechanism of Action The complete mechanisms of allergen immunotherapy are not clear and remain the subject of investigation. The allergic reaction is dependent on the presence of allergen-specific immunoglobulin E (IgE) antibodies that are bound to specific receptors on mast cells and basophils. The presence of IgE antibodies sensitizes these cells, and upon interaction with the appropriate allergens, histamine and other mediators are released which produce local or systemic responses in sensitive individuals, and characteristic symptoms of atopic diseases, such as allergic rhinitis and allergic asthma. Changes in serum antibody and T-lymphocyte responses resulting from immunotherapy have been demonstrated, and these changes often correlate closely with clinical (symptom) improvements. Specific mechanisms may vary depending on the nature of the allergic disease, the allergenic specificities of patients and populations, extract formulations, route of administration, dose and duration of treatment. 2 Subcutaneous administration of allergenic extracts is known to elicit numerous immunological changes that are both time and dose-dependent. Many of these changes appear to be related to (or a precursor to) improvements in symptoms and other clinical parameters, as noted above. Specific changes found after immunotherapy with dust mite extracts include significant increases in mite-specific IgG4 antibodies 12 , interleukin-10-positive T cells, and several T-cell receptors, and significant decreases in serum nitric oxide, eosinophil catonic protein, interleukin-4-positive T cells and IgE-mediated basophil histamine release. 13