Grass allergy test study seeks better standardization
NCT ID NCT06957496
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study aimed to find the right strength of two grass allergen extracts (timothy and orchard grass) to cause a skin reaction similar to histamine. Thirty-one adults with grass pollen allergies received skin prick tests with different concentrations. The goal was to improve allergy testing accuracy, not to treat or cure allergies.
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Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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31 people
The number who actually took part.
- Started
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Dec 2024
- Finished
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Jan 2025
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 64 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Subjects who have signed and dated informed consent form. * Female or male aged 18 to 64 years, both included. * Subjects must reside in a geographical area where allergic problems caused by Phleum pratense and Dactylis glomerata are relevant. * Positive medical history of inhalant allergy (rhinitis and/or rhinoconjunctivitis and/or asthma) to Phleum pratense and Dactylis glomerata. * A positive prick-test (mean wheal diameter ≥ 3 mm) with extracts of the same allergens and/or presence of specific IgE against complete extract or any molecular component to the allergenic sources. * The area of the wheal obtained with 10 mg/mL histamine dihydrochloride should be ≥ 7 mm², which corresponds to a mean wheal diameter ≥ 3 mm. * The area of the wheal obtained with negative control should be \< 7 mm², which corresponds to a mean wheal diameter \< 3 mm. * Women of childbearing age (i.e following menarche and until postmenopause, defined as no menses for 12 months without an alternative medical cause, or non-subject to permanent sterilization methods, such as hysterectomy, bilateral salpingectomy, and bilateral oophorectomy) must present a negative urine pregnancy test at the time of enrollment in the trial, as well as a confirmed menstrual period. * Women of childbearing age must commit to using a highly effective and adequate contraception method during the trial and up to 72 hours after the end of treatment with the investigational medicinal product. Such methods include combined (estrogen and progestogen containing) hormonal; contraception associated with inhibition of ovulation (oral, intravaginal, or transdermal), progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable or implantable), intrauterine device, intrauterine hormone-releasing system, male condom, diaphragm used with spermicide, bilateral tubal occlusion, vasectomized partner or sexual abstinence. Exclusion Criteria: * Subjects outside the age range. * Subjects who have previously received immunotherapy within the last 5 years for the treatment of asthma or allergic rhinoconjunctivitis induced by allergens that may interfere with the extracts of Phleum pratense and Dactylis glomerata. * Subjects with significant symptoms of rhinoconjunctivitis and/or bronchial asthma in whom discontinuation of systemic antihistamine treatment is contraindicated. * Subjects who have previously exhibited a severe adverse reaction during diagnostic skin prick tests. * Subjects on treatment with ß-blockers. * Use of drugs that could interfere with skin prick test reactions (e.g., antihistamines) (See Section 5.2). * Clinically unstable subjects (acute asthma, febrile, etc.). * Subjects with active urticaria lesions, severe active dermographism, severe atopic dermatitis, sunburn, eczema, psoriasis lesions in the area where the prick test is performed (risk of false positives). * Subjects with active herpes simplex viral infection, or herpes varicella zoster in the area where the prick test is performed. * Subjects with any pathology in which the administration of adrenaline is contraindicated (hyperthyroidism, hypertension, heart disease, etc.). * States in which the subject is unable to offer cooperation and severe psychiatric disorders. * Pregnant or potentially pregnant women and breastfeeding women. * Subjects with known phenol allergy.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Clínica de Asma y Alergia Dres. Ojeda
Madrid, 28006, Spain
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