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Study on Allergy to Phleum pratense and Dactylis glomerata: Testing Reactions to Phleum pratense and Dactylis glomerata Pollen Extracts in Patients with Allergies

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying allergies caused by two types of grass pollen: Phleum pratense and Dactylis glomerata. These allergies can lead to symptoms like sneezing, runny nose, and itchy eyes. The study will use a skin test called a "prick test" to see how the body reacts to these pollen extracts. The prick test involves applying a small amount of the allergen solution to the skin to check for a reaction. The solutions used in this study include enriched extracts of Phleum pratense pollen and Dactylis glomerata pollen, as well as a positive control solution containing histamine dihydrochloride and a negative control solution with sodium chloride.

The purpose of the study is to determine the concentration of each pollen extract that causes a skin reaction similar in size to the reaction caused by the histamine solution. Histamine is a substance that naturally occurs in the body and is known to cause a reaction when applied to the skin, which helps in comparing the reactions to the pollen extracts. Participants will undergo the prick test with different concentrations of the pollen extracts, as well as the positive and negative controls, to measure the size of the skin reaction, known as a wheal.

The study will monitor the reactions at the test site on the skin and any other reactions that might occur. It will also track any side effects or adverse events that participants might experience during the study. The trial aims to provide valuable information about the sensitivity of individuals to these specific pollen allergens, which can help in understanding and managing allergies more effectively.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and initial assessment

    Upon joining the study, the participant will undergo an initial assessment to confirm eligibility. This includes signing an informed consent form and verifying age between 18 and 64 years.

    A medical history review will be conducted to confirm a positive history of inhalant allergy to Phleum pratense and Dactylis glomerata.

  2. Step 2

    Skin prick test preparation

    Participants will be prepared for the skin prick test, which involves applying solutions to the skin to test for allergic reactions.

    The solutions include enriched extracts of Phleum pratense and Dactylis glomerata, a positive control with histamine dihydrochloride, and a negative control with sodium chloride.

  3. Step 3

    Administration of skin prick test

    The skin prick test will be administered by applying the solutions to the skin using a small needle. This is done to assess the size of the wheal (a raised, red area) that forms in response to each solution.

    The primary goal is to determine the concentration of each allergen extract that produces a wheal size equivalent to that of the histamine solution.

  4. Step 4

    Observation and measurement

    After the test, the size of the wheals will be measured to evaluate the skin's reaction to each allergen extract and control solution.

    The primary endpoint is the measurement of the wheal area in square millimeters for each allergen and control.

  5. Step 5

    Monitoring for adverse reactions

    Participants will be monitored for any adverse reactions at the test site or systemically. This includes any unexpected reactions or side effects.

    Any medication required to treat adverse reactions will be documented.

  6. Step 6

    Completion and follow-up

    The trial is expected to conclude by April 30, 2025. Participants will be informed of the results and any necessary follow-up actions.

    Participants are required to use effective contraception methods during the trial and for 72 hours after the end of treatment if applicable.

Who can join the trial?

9 criteria

  • Participants must have signed and dated an informed consent form, which means they agree to take part in the study after understanding what it involves.
  • Participants can be either female or male and must be between 18 and 64 years old.
  • Participants must live in an area where allergies caused by **Phleum pratense** and **Dactylis glomerata** are common.
  • Participants should have a history of inhalant allergies, such as sneezing, runny nose, itchy eyes, or asthma, specifically to **Phleum pratense** and **Dactylis glomerata**.
  • Participants must have a positive skin test, known as a prick-test, showing a reaction (a wheal or bump) of at least 3 mm in size when exposed to the allergens or have specific IgE antibodies against these allergens. IgE antibodies are proteins in the blood that indicate an allergic reaction.
  • The reaction size from a histamine test, which is a standard test to measure allergic response, should be at least 7 mm², meaning the wheal should be at least 3 mm in diameter.
  • The reaction size from a negative control test, which is a test to ensure the skin is not reacting to non-allergenic substances, should be less than 7 mm², meaning the wheal should be less than 3 mm in diameter.
  • Women who can have children must have a negative urine pregnancy test when joining the trial and must have had a recent menstrual period.
  • Women who can have children must agree to use a highly effective birth control method during the trial and for 72 hours after the treatment ends. These methods include hormonal birth control (like pills, patches, or injections), intrauterine devices (IUDs), condoms, diaphragms with spermicide, surgical sterilization, or choosing not to have sex.

Who cannot join the trial?

1 criterion

  • If you have an allergy to certain types of grass, specifically Phleum pratense and Dactylis glomerata, you cannot participate. An allergy is when your body reacts negatively to something that is usually harmless to most people.
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Investigated drugs

  • Phleum pratense allergen extract

    is used in this trial to determine how much of the extract is needed to cause a skin reaction similar in size to the reaction caused by a standard histamine solution. This helps in understanding the potency of the allergen extract.

  • Dactylis glomerata allergen extract

    is also tested in the trial to find out the concentration required to produce a skin reaction equivalent to that of a histamine solution. This is important for evaluating the strength of the allergen extract.

  • Histamine dihydrochloride solution

    is used as a reference in the trial. It is a standard solution that causes a known skin reaction, which is used to compare the reactions caused by the allergen extracts.

What is already known about the treatment

  • Phleum pratense allergen extract

    This medication is administered through a skin prick test to evaluate allergic reactions. It is currently being studied in clinical trials to determine its effectiveness in diagnosing allergies to Phleum pratense, commonly known as Timothy grass. The main therapeutic indication is to identify allergic sensitivity in individuals. The mechanism of action involves triggering an immune response that results in a wheal, similar to the reaction caused by histamine. It is classified as an allergen extract used for diagnostic purposes.

  • Dactylis glomerata allergen extract

    This medication is also administered via a skin prick test to assess allergic reactions. It is under investigation in clinical trials to determine its ability to diagnose allergies to Dactylis glomerata, also known as Orchard grass. The primary therapeutic use is to detect allergic sensitivity in patients. The mechanism of action involves inducing an immune response that produces a wheal, akin to the reaction from histamine. It is categorized as an allergen extract for diagnostic use.

Investigated diseases

Allergic Rhinitis – This condition is characterized by an allergic reaction to specific allergens, such as pollen from grasses like Phleum pratense (timothy grass) and Dactylis glomerata (orchard grass). When exposed to these allergens, the immune system overreacts, leading to symptoms such as sneezing, itching, nasal congestion, and runny nose. The reaction occurs when the allergens come into contact with the mucous membranes of the nose and eyes. Over time, repeated exposure can lead to chronic symptoms and discomfort. The severity of symptoms can vary depending on the concentration of allergens in the environment.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-514215-98-00Protocol codeG110-STD-071Estimated enrolment30 patientsSponsorInmunotek S.L.

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