Determination of the Sensitivity and Specificity of Prick Test Betula Verrucosa (T502)

Inmunotek

Status and phase: Completed; Phase 2

Conditions: Immune System Diseases

Treatments: Biological: 10 HEP/mL Betula verrucosa allergen extract; Biological: 25 HEP/mL Betula verrucosa allergen extract; Biological: 50 HEP/mL Betula verrucosa allergen extract; Biological: 100 HEP/mL Betula verrucosa allergen extract

Study type: Interventional

Funder types: Industry

Identifiers

NCT02527187

2013-005368-24 (EudraCT Number)

T502-SSP-007

Details and patient eligibility

About

The main objective is to evaluate the concentration of allergen extract of Betula verrucosa that elicit a papule equivalent to that produced by a solution of histamine dihydrochloride 10 mg / ml in size.

Full description

Open, prospective, unblinded and non-randomized biological assay. Each patient was tested with four concentrations of allergen and with a histamine and saline solution as positive and negative controls, respectively.

Enrollment: 201 patients

Sex: All

Ages: 5 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

General inclusion criteria for both groups:

• Positive skin prick test with the positive control (Histamine HCl at 10 mg/mL). The length of the largest diameter of the wheal induced by this control should be ≥ 3 mm.
• Negative skin prick test with the negative control. The length of the largest diameter of the wheal induced by this control should be < 3 mm.
• All ages and both genders.

For the group of patients CH+ (true positive to Betula verrucosa): All these patients had a previous diagnosis of allergy to the birch pollen:

• A positive case history with inhalant allergy related to exposure to birch pollen.
• A positive skin prick test (mean wheal diameter ≥ 3 mm) when tested with a biologically standardized extract prepared from birch pollen. This preparation, from another manufacturer, was the one used in the routine in the Hospital.
• Positive test for specific IgE (CAP value > 0.35 IU/mL). For the group of patients CH- (true negative to Betula verrucosa): All these patients had a previous diagnosis of allergy to agents unrelated to birch pollen.
• A negative case history with inhalant allergy related to exposure to birch pollen or to pollen with known cross-reactivity with the birch pollen. These patients could be allergic to other pollen or other allergens, such mites.
• A negative prick test (largest diameter of the wheal ≥ 3 mm) when tested with a standardized extract prepared from the allergen source in question.
• A negative test for specific IgE (CAP value < 0.35 IU/mL) to birch pollen or to pollen with known cross-reactivity with birch pollen: Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa.

Exclusion criteria for both groups:

• Patients that were using drugs that may interfere with the skin prick tests.
• Patients using the following drugs 24 hours before the test: theophylline, systemic corticosteroids.
• Patients in which the largest diameter of the wheal induced by the positive control was < 3 mm.
• Patients in which the largest diameter of the wheal induced by the negative control was ≥ 3 mm.
• Pregnancy, dermographism, atopic dermatitis (locally at the test site), urticaria.
• Patients who suffer disease in which the use of adrenaline is not allowed.
• Patients with any severe psychiatric disease.

For the patients CH+:

• Patients that received or are treated with immunotherapy with an allergenic extract of birch pollen and/or with allergen extracts with known cross-reactivity to birch pollen (Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa).

For the patients CH-:

• Patients sensitized to pollen with demonstrated cross-reactivity with the pollen of Betula verrucosa. These pollen included Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa.

Trial design

Primary purpose: Diagnostic

Allocation: Non-Randomized

Interventional model: Single Group Assignment

Masking: None (Open label)

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201 participants in 2 patient groups

Allergic patients to birch pollen

Experimental group

Description:

Allergic patients already diagnosed to be "true allergic" to birch pollen. A mean wheal diameter \>3 mm obtained in a prick test with histamine dihydrochloride 10 mg/ml.Also presence of serum specific IgE and clinical history of symptomatology related to exposure to birch pollen. Patients of both gender aged from 5 up to 70 years.

Treatment:

Biological: 100 HEP/mL Betula verrucosa allergen extract

Biological: 25 HEP/mL Betula verrucosa allergen extract

Biological: 50 HEP/mL Betula verrucosa allergen extract

Biological: 10 HEP/mL Betula verrucosa allergen extract

Non-allergic patients to birch pollen

Experimental group

Description:

Patients already diagnosed to be "true non-allergic" to birch pollen. Non clinical history of symptomatology related to the exposure to birch pollen. Previous skin prick test negative and absence or undetectable serum specific IgE to Betula verrucosa Patients of both gender aged from 5 up to 70 years.

Treatment:

Biological: 100 HEP/mL Betula verrucosa allergen extract

Biological: 25 HEP/mL Betula verrucosa allergen extract

Biological: 50 HEP/mL Betula verrucosa allergen extract

Biological: 10 HEP/mL Betula verrucosa allergen extract