cat hair extract 10000 BAU/ML Injectable Solution

INDICATIONS AND USAGE Studies have shown that skin tests with cat extract are useful in the diagnosis of cat allergy. As a rule, persons with cat allergy have positive skin reactions when tested with cat extract, and non-allergic individuals rarely react (7, 8, 9). However, the relationship between a positive skin test and the appearance of clinical symptoms after exposure to a cat is not absolute, i.e., some skin-test positive persons do not experience allergic symptoms after exposure (10). Failure to experience symptoms may be dose related, since it is known that cats vary significantly in the amount of Fel d1 they produce (11). The efficacy of cat extract immunotherapy in the treatment of bronchial asthma has been shown in two studies (12, 13) A reduction in bronchial sensitivity was observed in five patients with cat allergy, whereas no reduction was observed in placebo treated, cat-allergic patients.

DOSAGE AND ADMINISTRATION Diagnosis: Concentrated extract (10,000 BAU/mL) may be used for scratch or prick-puncture testing. Puncture tests performed with a bifurcated needle in ten cat allergic persons showed a mean wheal diameter of 6.6 mm (S.D. 1.3) with a mean sum of erythema of 57.3 mm (S.D. 10.4). Intradermal tests with serial three-fold dilution of the 10,000 BAU/mL showed the following results: Serial 3-Fold Dilutions of 10,000 BAU/mL Extract Subject 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X The mean three-fold dilution eliciting a response of 50 mm sum of erythema diameters was 11.120 (S.D. 2,38). The number of BAU/mL required to elicit this response was 0.05 (range 0.0003 to 9.24 BAU/mL). This concentration is approximately a 1:200,000 v/v dilution of the 10,000 BAU/mL extract. Extract for intradermal testing should be used as follows: Patients with a positive scratch or prick test to Standardized Cat Hair Extract. It is not advisable to perform an intradermal skin test in these patients. Patients with a negative scratch or prick test to Standardized Cat Hair Extract. Patients who do not react to a scratch or prick test with the 10,000 BAU/mL concentrate maybe tested intradermally with 0.05 mL of a 1:2,000 v/v dilution of the concentrate (5 BAU/mL). If the test is negative, a second test should be performed with 0.05 mL of a 1:200 v/v dilution of concentrate (50 BAU/mL). Patients tested only by the intradermal method with Standardized Cat Hair Extract. Patients suspected of being highly allergic to cats should be tested with 0.05 mL of a 1:200,000 v/v dilution (0.05 BAU/mL) of the concentrate. A negative test should be followed by repeat tests using 10 fold stronger concentrations until the maximum dose of 0.05 mL of a 1:200 v/v dilution (50 BAU/mL) is reached. Interpretation Of Skin Tests: The interpretation of skin tests should be based on the size of the erythema and wheal response to the allergen compared to a negative saline control. A suggested method of scoring skin tests is shown below. Measurements refer to the longest (single), diameter of erythema and wheal response. Scratch and Prick Test A negative test shows only a slight red area at the site of scarification or prick penetration. Positive tests are scored as follows: 1 + Erythema with a 5 mm wheal 2 + Erythema with a 5 -10 mm wheal 3 + Erythema with a 10 - 15 mm wheal 4 + Erythema with a wheal 15 mm (or larger) with pseudopodia Intradermal Test A negative test shows no change in the appearance and size of the 5mm wheal created by the 1.D. injection of 0.05 mL of extract. Positive tests are scored as follows: 1 + Erythema 10 - 20 mm with a 5 -10 mm wheal 2 + Erythema 20 - 30 mm with a 5 -10 mm wheal 3 + Erythema 30 - 40 mm with a 10 - 15 mm wheal 4 + Erythema greater than 40 mm with a 15 mm wheal (or larger) with pseudopodia Immunotherapy Allergenic extract should be administered subcutaneously in the outer aspect of the upper arm using a sterile tuberculin syringe and needle. The skin should be cleaned with 70% alcohol and aseptic technique should be observed in removing the extract from the vial. Care must be taken to avoid injecting the extract into a blood vessel because of the potential hazard of anaphylaxis. Standardized Cat Hair Extract must be diluted before administration to new patients. As a precaution against overdose, a skin test with the intended starting dose should be done to help evaluate the patient's sensitivity to the product. If the skin response is larger than 5/15 mm (edema/erythema), the extract should be diluted before it is given subcutaneously. The doses shown in the Dosage Schedule may be followed unless the patient's skin test response and allergic history indicate that more dilute extract should be used. Little is known about the required accumulated dosage of Fel d 1 (and other allergens that may be present in cat extract) that is needed to relieve symptoms. However, studies with other allergenic substances have shown that high dose immunotherapy is most efficacious in the treatment of allergic rhinitis and asthma. The amount of cat extract that is tolerated during immunotherapy depends upon the sensitivity of the patient. In one study in which patients with cat asthma were treated for a period of one year, the accumulated dose of Fel d 1 varied from 3.6 to 115.8 (median 46.2) units (13). A burning sensation immediately following the injection of extract from the concentrate is due to the glycerol in the extract. It should not be interpreted as an adverse allergic response. Patients who have received allergenic extract for maintenance therapy SHOULD NOT be given the same dose from a fresh vial of extract. IT IS ADVISABLE TO REDUCE THE DOSAGE OF FRESH EXTRACT TO ONE-FOURTH THE AMOUNT GIVEN FROM A PREVIOUS LOT. Dosage Schedule for Standardized Cat Hair Extract (The safety and efficacy of this schedule has not been determined by well-controlled clinical trials.) [BAU = Bioequivalent Allergy Units per mL] Vial #1 0.05 BAU Vial #2 0.5 BAU Vial #3 5 BAU Vial #4 50 BAU Vial #5 500 BAU Vial #6 5,000 BAU frequency twice weekly No. mL mL mL mL mL mL 1 0.05 0.05 0.05 0.05 0.05 0.05 2 0.1 0.1 0.1 0.1 0.1 0.1 3 0.2 0.2 0.2 0.2 0.2 0.2 4 0.3 0.3 0.3 0.3 0.3 0.3 5 0.4 0.4 0.4 0.4 0.4 0.4 v/v dilutions of concentrate containing 10,000 BAU per mL required to make the above concentrations. BAU per mL v/v Dilution of Concentrate 0.05 1:200,000 0.5 1:20,000 5.0 1:2,000 50.0 1:200 500.0 1:20 5,000.0 1:2

WARNINGS Standardized Cat Hair Extract may cause local or severe life-threatening reactions when administered to highly sensitive individuals. Physicians who use this product should be familiar with the clinical use of allergenic extract and have the necessary emergency equipment and medications available to treat systematic allergic reactions See Precautions, Adverse Reactions and Overdosage . Standardized Cat Hair Extract should not be used interchangeably with Standardized Cat Pelt Extracts or previously standardized cat extracts labeled in Allergy Units per mL. Cat hair extracts labeled in BAU/mL made by other manufacturers should be tested for bioequivalency by serial titration skin testing before these products are used in patients who have previously received Allermed Standardized Cat Hair Extract. The dosage of Standardized Cat Hair Extract must be reduced when starting a patient on a new lot of Standardized Cat Hair Extract containing the same amount of Fel d1 units per mL. This is necessary due to a possible loss of potency during storage in the physician's office. The dose of the new lot of extract should not exceed 1/4 the last dose given from the old lot of extract. Any evidence of a strong local reaction or systemic reaction following the administration of Standardized Cat Hair Extract requires a reduction in dosage during the initial stages of immunotherapy, as well as during maintenance therapy.

CONTRAINDICATIONS Standardized Cat Hair Extract should not be used for immunotherapy in persons who do not have cat related allergic symptoms and a positive skin test to the extract.

CLINICAL PHARMACOLOGY Positive skin tests with allergenic extract are the result of histamine release from mast cells sensitized with allergen specific IgE. The exact mechanisms by which immunotherapy relieves symptoms of allergy are still under investigation. Elevations in allergen-specific IgG antibodies and an increase in the activity of T suppressor lymphocytes appear to be some of the immunologic changes that occur from hyposensitization (4, 5, 6).