Testing sublingual immunotherapy with dermatophagoides pteronyssinus extract for adults with moderate to severe house dust mite allergy

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What is this study about?

This study examines a treatment for people who have allergic rhinitis or allergic inflammation of the nose and eyes caused by house dust mites. House dust mites are tiny creatures that live in household dust and can trigger allergic reactions in sensitive individuals. The symptoms can range from moderate to severe and must have been present for at least one year. Some participants may also have mild to moderate asthma that is well controlled. The study will test three different doses of a treatment called SLI-RX-DPT high dose, SLI-RX-DPT mid dose, and SLI-RX-DPT low dose, which are sublingual sprays containing Dermatophagoides pteronyssinus extract. This extract comes from a specific type of house dust mite and is used in immunotherapy, a treatment method that aims to reduce allergic reactions by gradually exposing the body to small amounts of the allergen. The study will also include a placebo group for comparison.

The purpose of this study is to determine how well each dose of the treatment works and how safe it is by measuring symptoms and the need for rescue medication. The study will also examine which dose provides the best balance between effectiveness and safety. During the study, participants will use an electronic diary to record their symptoms and any medication they take. The treatment is given as a spray under the tongue and will be administered over a period of time. The study will measure various aspects of the participants’ condition, including how severe their symptoms are, how often they need to use rescue medication, and how their quality of life is affected by their allergies.

Before and after the treatment period, participants will undergo a nasal provocation test, which involves exposing the inside of the nose to increasing amounts of house dust mite extract to see how the body reacts. This test helps determine whether the treatment has made the immune system less sensitive to the allergen. The study will track the number of days when participants feel well, when symptoms are severe, and when they are completely free of symptoms. Quality of life will be measured using questionnaires, and participants will rate their overall discomfort using a scale. Safety will be monitored throughout the study by recording any unwanted reactions to the treatment.

1 Initial assessment and baseline testing

Upon joining the study, your baseline condition will be assessed.

If you have asthma, a breathing test called forced expiratory volume will be performed. This test measures how much air you can forcefully exhale in one second. Your result must be greater than 70 percent of the expected normal value.

A skin prick test will be conducted to confirm your sensitivity to house dust mites. Small amounts of allergen will be placed on your skin to observe any reaction.

A blood sample will be taken to measure allergen-specific IgE, which are antibodies your body produces in response to house dust mites. The level must be at least 0.7 kU/L.

A nasal provocation test will be performed. This involves exposing your nose to increasing concentrations of house dust mite extract to confirm your allergic response. You must show a positive reaction at least at the third concentration level.

You will complete a Rhinoconjunctivitis Quality of Life Questionnaire to assess how your allergy affects your daily life.

You will rate your overall discomfort using a Visual Analogue Scale, which is a scale from 0 to 10 points.

Safety laboratory tests will be performed to ensure the results are within normal range or not clinically significant.

2 Randomization and treatment assignment

You will be randomly assigned to one of four treatment groups. This means neither you nor your doctor will choose which treatment you receive.

The possible treatments are: placebo (an inactive preparation without the allergen extract), low dose of house dust mite extract, mid dose of house dust mite extract, or high dose of house dust mite extract.

All treatments are administered as a sublingual spray solution, which means you will spray the medication under your tongue.

The study is double-blind, meaning neither you nor your doctor will know which treatment you are receiving during the study.

3 Treatment phase with daily medication

You will receive your assigned treatment containing dermatophagoides pteronyssinus extract (house dust mite extract) or placebo.

The medication will be administered as a sublingual spray, which you will apply under your tongue.

You will need to follow the prescribed dosage and frequency as instructed for your specific treatment group.

The treatment will continue for an extended period as part of the immunotherapy process.

4 Daily symptom and medication tracking

Throughout the study, you will complete an electronic diary daily to record your symptoms and any rescue medication you use.

You will rate four nasal symptoms individually each day.

The diary will track well days, defined as days when you do not use any rescue medication and your symptom score is less than 0.5 on a scale from 0 to 3.

The diary will also track severe days, defined as days when any single symptom reaches the maximum score of 3.

Symptom-free days are days with no symptoms and no use of rescue medication.

Your compliance with completing the electronic diary is essential for the study.

5 Primary evaluation period

A specific Primary Efficacy Evaluation Period of 56 days will be designated during the study.

During this period, your Combined Symptom and Medication Score will be calculated. This score combines your daily symptom severity with the amount of rescue medication you use.

Your daily Symptom Score and daily Medication Score will be analyzed separately as well.

The percentage of well days, severe days, and symptom-free days during these 56 days will be calculated.

6 Post-treatment assessment

After completing the treatment phase, you will undergo follow-up assessments.

A titrated Nasal Provocation Test will be repeated. This test uses increasing concentrations of house dust mite allergen extract to assess whether your sensitivity has changed compared to the baseline test.

The number of concentration steps needed to provoke a positive response will be compared to your initial test results.

You will complete the Rhinoconjunctivitis Quality of Life Questionnaire again to assess any changes in how your allergy affects your daily life.

You will rate your overall discomfort again using the Visual Analogue Scale from 0 to 10 points.

These post-treatment results will be compared to your baseline measurements.

7 Safety monitoring throughout the study

Throughout the entire study, any adverse reactions or side effects you experience will be monitored and recorded.

Treatment-Emergent Adverse Drug Reactions are any unwanted effects that occur after you start taking the study medication.

The safety and tolerability of your assigned treatment will be assessed by comparing the occurrence of adverse reactions across all treatment groups.

Who Can Join the Study?

You must sign and date a form agreeing to join the study before any tests or exams are done
You must be between 18 and 65 years old when you sign the agreement form
You must have had moderate-to-severe allergic rhinitis or rhinoconjunctivitis caused by house dust mites for at least one year. Allergic rhinitis means inflammation and irritation inside your nose due to allergens, and rhinoconjunctivitis means this also affects your eyes, causing symptoms like sneezing, runny nose, itchy eyes, and watery eyes. House dust mites are tiny bugs that live in house dust and can trigger allergies
You may have well-controlled mild-to-moderate asthma or no asthma at all. Asthma is a condition that affects your breathing and causes wheezing or shortness of breath. Well-controlled means your asthma symptoms are managed with treatment
If you have asthma, your FEV1 must be greater than 70% of the expected normal value. FEV1 stands for forced expiratory volume in one second, which measures how much air you can forcefully breathe out in one second during a lung function test
You must be allergic to a specific type of house dust mite called Dermatophagoides pteronyssinus. This will be confirmed through several tests: a skin prick test showing a reaction of at least 3 millimeters, a blood test showing allergen-specific IgE levels of at least 0.7 units per liter, a symptom score of at least 2 based on your worst days during the previous winter, and a positive response to a nasal provocation test where the allergen is applied inside your nose. IgE is a type of antibody your body makes when you have an allergy. A nasal provocation test checks if your nose reacts when exposed to the allergen
You must be able to understand and follow instructions from the study staff
You must be able to use an electronic diary on a device to record your symptoms and any rescue medications you take
Your safety laboratory test results must be within normal ranges or not considered medically important if they are outside normal ranges

Who Cannot Join the Study?

The source data does not provide specific exclusion criteria for this clinical trial
Exclusion criteria are reasons why someone cannot participate in a study, but these details were not included in the available information
Without this information, it is not possible to list the specific conditions or situations that would prevent participation in this trial

Where you can join this trial?

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Other Sites

Site Name	City	Country
Hospital General Universitario De Castellon	Castello De La Plana	Spain
Pdmxeu fnp Hbs uti Apkkzqopuafk Dxt Yqsj Ypjxr	Dresden	Germany
Psopgenkqwnj Abrngfdnewip Papmjv Dfd Txcyge Gidwp	Bonn	Germany
Hpyhuepx Uwvwcjozpmetw Heaavwzb Tzqxm y Pgrurj Issjxiju Ckgyvf duwugtpwetyeziqed (ygrp	Badalona	Spain
Hfh Pzyuaa Duqkypb Dxk masn Uxc Sjdlrvr	Dresden	Germany

Trial status

Country	Status	Recruitment Start
Germany	Recruiting	01.03.2026
Spain	Recruiting	01.03.2026

Trial locations

Investigated drugs:

Dermatophagoides Pteronyssinus Extract

SLI-RX-DPT is a sublingual immunotherapy treatment being tested for house dust mite allergy. This medication is placed under the tongue and works by gradually exposing your immune system to small amounts of house dust mite allergens. The goal is to help your body become less sensitive to these allergens over time, which may reduce your allergy symptoms and your need for other allergy medications.

A placebo is also being used in this study. This is an inactive treatment that looks like the real medication but contains no active ingredients. It is used to compare against the actual treatment to see how well the medication works.

Allergic Rhinitis – Allergic rhinitis is a condition where the inside of the nose becomes inflamed after breathing in allergens such as house dust mites. When a person with this condition is exposed to these allergens, their immune system overreacts, causing symptoms like sneezing, a runny or blocked nose, and itching. The condition can range from mild to moderate-to-severe, depending on how much it affects daily activities and sleep. Symptoms occur when allergens are present in the environment and may happen throughout the year if triggered by indoor allergens like dust mites. The inflammation in the nose is caused by the body releasing chemicals like histamine in response to the allergen.

Allergic Conjunctivitis – Allergic conjunctivitis is an inflammation of the thin layer covering the white part of the eye and the inside of the eyelids, triggered by allergens such as house dust mites. When allergens come into contact with the eyes, the immune system reacts and causes the eyes to become red, itchy, and watery. This condition often occurs together with allergic rhinitis, and when both are present, it is called rhinoconjunctivitis. The symptoms appear when a person is exposed to the allergen and can vary in intensity from mild discomfort to more severe irritation. The inflammation results from the release of substances by the immune system that affect the blood vessels and tissues in the eye.

Trial ID:

2025-523119-12-00

Protocol code:

SL-3R2A

Trial Phase:

Therapeutic use (Phase IV)

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Testing sublingual immunotherapy with dermatophagoides pteronyssinus extract for adults with moderate to severe house dust mite allergy

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?