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Study on the Effectiveness and Safety of Sublingual Immunotherapy with Betula Pendula Pollen Extract for Patients with Birch Pollen Allergy

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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 the effects of a treatment for people who have been suffering from allergic rhinitis or rhinoconjunctivitis due to birch pollen for at least two years. These conditions are characterized by symptoms like sneezing, runny or blocked nose, and itchy or watery eyes. The treatment being tested is called SULGEN® Spray Betula verrucosa, which is a sublingual spray, meaning it is used under the tongue. The study aims to find the most effective and well-tolerated dose of this spray.

Participants in the study will receive either the SULGEN® Spray Betula verrucosa or a placebo. The study will compare the effects of the spray with the placebo to see how well it works in reducing symptoms and improving the quality of life for those with birch pollen allergies. The trial will also monitor any side effects to ensure the treatment is safe. The study will last for a period that includes the peak birch pollen season, allowing researchers to assess the treatment's effectiveness during the time when symptoms are usually at their worst.

Throughout the study, participants will be asked to keep a diary of their symptoms and any medication they take. This information will help researchers understand how the treatment affects daily life and symptom management. The goal is to determine if the SULGEN® Spray Betula verrucosa can provide a better balance of benefits and risks compared to not using the active treatment. The study is expected to conclude by August 2025.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, you will be required to sign and date an informed consent form. This confirms your understanding and agreement to participate in the clinical trial.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to confirm your eligibility. This includes verifying your medical history of moderate-to-severe allergic rhinitis or rhinoconjunctivitis due to birch pollen for at least two years.

    A skin prick test will be performed to check for sensitization to Betula verrucosa pollen. A positive result is indicated by a wheal diameter of at least 3 mm.

  3. Step 3

    Baseline measurements

    Baseline measurements will be taken, including a nasal provocation test with Betula verrucosa pollen allergen extract to assess your response.

  4. Step 4

    Treatment phase

    You will receive the SULGEN® Spray Betula verrucosa in one of three doses: low, mid, or high. This is a sublingual spray, meaning it is administered under the tongue.

    The spray will be used daily throughout the birch pollen season. The exact duration will be specified by the study team.

  5. Step 5

    Symptom tracking

    You will be required to maintain an electronic diary to record your symptoms and any use of rescue medication. This helps in evaluating the effectiveness of the treatment.

  6. Step 6

    Follow-up assessments

    Regular follow-up assessments will be conducted to monitor your health and the treatment's impact. This includes repeating the nasal provocation test to measure any changes in your response.

  7. Step 7

    End of study

    At the end of the study, a final assessment will be conducted to evaluate the overall effectiveness and safety of the treatment. Your participation will contribute to determining the best dose of the SULGEN® Spray Betula verrucosa.

Who can join the trial?

11 criteria

  • Patients must have signed and dated the informed consent form before any study-specific examination.
  • Patients must be between 18 and 65 years old at the time of signing the informed consent form.
  • Patients must have had moderate-to-severe allergic rhinitis/rhinoconjunctivitis due to birch pollen for at least two years, as per the ARIA guideline.
  • Patients must have well-controlled mild-to-moderate asthma or no asthma, as defined by the GINA guideline.
  • For patients with asthma, the forced expiratory volume (FEV1) in one second must be more than 70% of the predicted normal value. FEV1 is a measure of how much air you can forcefully exhale in one second.
  • Patients must be sensitized to Betula verrucosa pollen, confirmed by:
    • A positive skin prick test (a small skin test to check for allergies).
    • Serum allergen-specific IgE to Betula verrucosa must be 0.7 kU/L or higher (CAP EAST class 2 or higher). IgE is a type of antibody that indicates an allergic reaction.
    • A Retrospective Rhinoconjunctivitis Total Symptom Score (RRTSS) of 2 or higher on a 0-3 scale, based on the most severe days during one of the two birch pollen seasons before enrollment.
    • A positive response to nasal provocation with Betula verrucosa pollen allergen extract (at least at the third concentration step). This is a test where the allergen is introduced to the nose to see if it causes symptoms.
    • Patients must be able to understand and use an electronic diary to record their symptoms and any rescue medication they take.
    • Patients must have safety laboratory results within the normal range or results that are not considered clinically significant.

Who cannot join the trial?

3 criteria

  • Patients who do not have moderate-to-severe allergic rhinitis or rhinoconjunctivitis caused by birch pollen for at least two years cannot participate. Rhinitis is a condition where the inside of the nose becomes inflamed, and rhinoconjunctivitis includes inflammation of both the nose and eyes.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who are part of a vulnerable population, such as those who cannot give consent or are at higher risk, cannot participate.
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Investigated drugs

SULGEN® Spray Betula verrucosa is a type of treatment known as sublingual immunotherapy. This therapy is designed to help people who are allergic to birch pollen. The treatment involves using a spray that is applied under the tongue. The goal is to gradually help the body become less sensitive to birch pollen, which can reduce allergy symptoms over time. This therapy aims to find the best balance between effectiveness and safety, helping patients manage their symptoms with fewer side effects.

What is already known about the treatment

SULGEN® Spray Betula verrucosa – This medication is administered as a spray under the tongue, known as sublingual immunotherapy. It is currently being studied in clinical trials to determine its effectiveness and safety for treating moderate-to-severe allergic rhinitis or rhinoconjunctivitis caused by birch pollen. The main therapeutic use of this medication is to alleviate symptoms associated with birch pollen allergies. At the molecular level, it works by gradually desensitizing the immune system to birch pollen, reducing allergic reactions over time. It is classified pharmacologically as an immunotherapy agent.

Investigated diseases

Allergic Rhinitis – Allergic rhinitis is an inflammatory condition of the nasal passages caused by an allergic reaction to airborne substances, such as pollen. It is characterized by symptoms like sneezing, nasal congestion, runny nose, and itchy eyes. The condition progresses with exposure to allergens, leading to increased inflammation and symptom severity. Over time, repeated exposure can cause persistent symptoms and may affect daily activities and quality of life. The severity of symptoms can vary depending on the level of allergen exposure and individual sensitivity. In some cases, allergic rhinitis can also be associated with other allergic conditions, such as asthma or eczema.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2023-505567-37-00Estimated enrolment512 patientsSponsorROXALL Medizin GmbH

sourced from the EU Clinical Trials Register and site verification

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