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Study of Grass Pollen Extract and Olive Pollen Extract for Patients with Hay Fever and Asthma caused by Grass and Olive Pollen Allergies

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What is this trial about?

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

This study is being conducted to evaluate the efficacy and safety of Depigoid DUO in individuals living with allergic rhinoconjunctivitis, which is an allergic reaction affecting the nose and eyes, and potentially asthma, a condition that affects the breathing passages. These symptoms are caused by a sensitivity to grass pollen and olive pollen. The treatment involves subcutaneous injection, which means the medicine is administered via a small needle into the layer of tissue just under the skin. The study compares this treatment to a placebo.

The research aims to determine how well the immunotherapy works compared to a placebo during the periods when pollen levels are highest. Participants will receive a series of injections. During the course of the study, information regarding symptoms such as sneezing, a runny nose, itchy eyes, or breathing difficulties will be recorded. The study also considers the use of other medications, such as antihistamines or intranasal corticoids, which are sprays used to reduce inflammation in the nose.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    <b>provocation tests</b>

    Eye drops containing grass-mix and olive pollen extracts are applied to the eyes to perform a conjunctival provocation test. this test is used to observe how the eyes react to these specific substances.

  2. Step 2

    <b>treatment phase</b>

    A series of subcutaneous injections, which are injections administered under the skin, is performed. these injections consist of either the test medication, known as depigoid duo grass-mix/olea at a dose of 0.5 ml, or a placebo, which is a substance without active medication.

    The effectiveness of the treatment is evaluated after at least 8 injections have been administered.

    During the period of grass and olive pollen peaks, symptoms and the use of medications are recorded using a mobile application.

    The symptom score tracks the severity of a runny nose, sneezing, itchy nose, nasal congestion, itchy eyes, and tearing on a scale from 0 (none) to 3 (severe).

    The medication score tracks the use of antihistamine eye drops, oral antihistamines, or intranasal corticoids (nasal sprays) on a scale from 0 to 1.5.

  3. Step 3

    <b>additional monitoring</b>

    For those with asthma, additional monitoring includes measurements of lung function and assessments of asthma control and asthma severity.

    Blood tests may be conducted to measure levels of specific antibodies, such as IgE and IgG4, which are proteins used by the immune system to respond to allergens like grass and olive pollen.

Who can join the trial?

11 criteria

  • You must be at least 6 years old when you sign the permission forms.
  • You must have moderate or severe allergic rhinoconjunctivitis, which is a condition involving sneezing, nasal congestion, and itchy or watery eyes caused by allergies.
  • If you have asthma, a condition where your airways narrow making it hard to breathe, your asthma must be well-controlled according to medical guidelines.
  • If you have asthma, you must not have had any severe asthma exacerbations, which are sudden worsening of asthma symptoms, during the last pollen season.
  • If you have asthma, your forced expiratory volume in 1 second (FEV1), which is a measurement of how much air you can forcefully breathe out in one second, must be at least 70% of the normal amount.
  • You or your legal guardian must understand and sign the informed consent, which is a formal document explaining the study details and your rights.
  • You or your guardian must own a mobile phone that can run the specific study app and has internet access.
  • You must be able to stay in your usual home for most of the time when pollen levels are high.
  • You must be able to follow the rules and steps required by the study plan.
  • You may have preexisting stable disease, meaning a health condition that has not required new medicine or hospital visits in the 28 days before joining the study.
  • You must agree to stay in regular contact with the medical team throughout the study to ensure your safety.

Who cannot join the trial?

23 criteria

  • You have received any form of allergy immunotherapy (treatment designed to reduce allergic reactions by exposing the body to small amounts of an allergen) within the last 5 years.
  • You have any medical reason that makes it unsafe for you to receive subcutaneous allergen-specific immunotherapy (allergy shots given under the skin).
  • You have used systemic corticosteroids (strong medicines used to reduce inflammation throughout the entire body) in the 12 weeks before joining the study.
  • You have had a serious secondary reaction during a skin prick test (a test where a small amount of an allergen is placed on the skin to check for a reaction).
  • You are currently clinically unstable, meaning your health condition is changing or worsening, such as having a sudden asthma attack, a respiratory infection, a fever, or acute urticaria (a sudden outbreak of hives).
  • You have any other health condition that the doctor believes might put you at extra risk during the study.
  • You have chronic urticaria (long-lasting hives), severe dermographism (a condition where skin becomes raised or swollen after being lightly scratched), severe atopic dermatitis (a long-term skin condition causing itchiness and redness), sunburn, active psoriasis (a skin disease causing red, scaly patches) in areas being tested, or a history of hereditary angioedema (a genetic condition causing sudden swelling under the skin).
  • You have any condition that prevents you from safely receiving adrenaline (a medicine used to treat severe allergic reactions), such as certain heart diseases.
  • You are currently taking immunosuppressive treatment (medicines that lower the body's ability to fight infections), unless it is a cream applied directly to the skin.
  • You have any other serious disease not related to your allergies or asthma, such as epilepsy (a disorder causing seizures), problems with mental or physical movement, physical malformations, kidney diseases, or having had many major surgeries.
  • You have a confirmed or suspected immunodeficiency (a condition where your immune system does not work properly).
  • You are sensitive to Alternaria alternata (a specific type of common mold).
  • You have a severe mental health disorder or any condition that prevents you from being able to cooperate with the study requirements.
  • You have a known allergy to any ingredients in vaccines other than the grass or olive extracts used in this study.
  • You have chronic lung diseases other than asthma, such as emphysema (damage to the air sacs in the lungs) or bronchiectasis (a condition where the airways become permanently widened and damaged).
  • You are a direct relative of the person conducting the study.
  • You are sensitive to dust mites (tiny organisms that live in household dust).
  • You are sensitive to epithelia (proteins found in animal skin or dander) and live with or frequently contact animals.
  • You are sensitive to other allergens that are active at the same time of year as grass and olive pollen.
  • You are currently receiving treatment with biologics (advanced medicines made from living organisms to target specific parts of the immune system).
  • Your asthma is currently uncontrolled or unstable according to medical guidelines.
  • You are a woman who is breastfeeding.
  • Women of childbearing potential who are not using reliable contraception (methods to prevent pregnancy) or who test positive for pregnancy.
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Investigated drugs

Depigoid DUO Grass-Mix/Olea is an allergy treatment given by injection under the skin. It contains processed extracts from various types of grass pollen and olive pollen, designed to help the body become less sensitive to these specific allergens.

What is already known about the treatment

  • Phleum pratense pollen extract, Lolium perenne pollen extract, Poa pratensis pollen extract, Festuca elatior pollen extract, and Dactylis glomerata pollen extract

    This solution is applied directly to the eye during medical testing to check for allergies. These extracts are used in clinical settings to identify sensitivities to various types of grass pollen. When they come into contact with the eye, they trigger a biological response from the immune system to confirm if a person is allergic. This substance is classified as a diagnostic allergen used for provocation testing.

  • Olea europaea pollen extract

    This solution is administered through the eye to help doctors identify olive pollen allergies. It is used as a specialized tool in medical examinations to see how the eye reacts to specific plant particles. By stimulating the local immune cells, it allows for the clear detection of an allergic reaction. This product serves as a diagnostic extract for ocular provocation tests.

  • Depigoid DUO Grass-Mix/Olea

    This medication is given as an injection under the skin to treat allergies caused by grass and olive pollen. It is currently being studied in clinical trials to see how well it can help manage symptoms like hay fever and asthma. The treatment works by exposing the immune system to small, processed amounts of pollen, which helps train the body to stop overreacting to these triggers. It is classified as an allergen immunotherapy designed to build long-term tolerance.

Investigated diseases

Allergic rhinoconjunctivitis with or without asthma due to clinically relevant sensitisation to grass and olive pollen - This condition occurs when the immune system overreacts to specific proteins found in grass and olive pollen. It causes inflammation of the nasal passages and the lining of the eyes. Common symptoms include sneezing, a runny nose, nasal congestion, itchy eyes, and tearing. In some individuals, this allergic response can also involve the airways, leading to asthma symptoms. The condition typically progresses or worsens during periods when pollen levels are high in the air.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-521709-42-00Protocol code060018-PG-PSC-217Estimated enrolment343 patientsSponsorLETI Pharma S.L.U.

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