In short
It is being studied in a Phase 3 clinical trial involving 492 adolescents and adults with moderate to severe allergic rhinitis or rhinoconjunctivitis caused by house dust mites, with or without controlled allergic asthma. The trial, authorised in the EU, compares a subcutaneous allergoid preparation against placebo over approximately 12 months of treatment.
Key points
- A Phase 3 trial is evaluating a subcutaneous allergoid preparation in 492 participants with house dust mite allergy.
- The trial includes people with moderate to severe allergic rhinitis or rhinoconjunctivitis, with or without controlled allergic asthma.
- The main outcome is the Adapted Rhinitis Combined Symptom and Medication Score (arCSMS) measured over four weeks after about 12 months of treatment.
- The trial is currently authorised in the EU Clinical Trials Information System.
- House dust mite extracts are also available as sublingual tablets for adults aged 18 to 65 in Europe.
What is Dermatophagoides farinae (504)?
House dust mites are microscopic creatures that live in household dust, and their droppings contain proteins that can trigger allergic reactions in sensitised people. The extract is prepared from the mites and used in allergy immunotherapy, also called allergen immunotherapy (AIT), which aims to reduce the immune system's overreaction to these allergens over time.
In the European Union, standardised allergen extracts from house dust mites are authorised as medicines for house dust mite allergy immunotherapy. One such product, a sublingual tablet marketed as Acarizax, Amitend, or Aitaro, contains a 1:1 mixture of allergen extracts from Dermatophagoides pteronyssinus and Dermatophagoides farinae. The substance also appears in standardised injectable allergenic extracts used for subcutaneous immunotherapy, as described in product information from Nelco Laboratories.
How does Dermatophagoides farinae (504) work?
Allergy immunotherapy with house dust mite extracts works by repeatedly exposing the immune system to small, controlled amounts of the allergen. Over time, this is intended to change how the immune system responds, reducing the allergic symptoms that occur when a person naturally encounters house dust mites. The exact mechanisms are complex and involve shifting the immune response away from the allergic pathway.
In the ongoing Phase 3 trial, the study treatment is described as a subcutaneous allergoid preparation of house dust mite allergens. An allergoid is a chemically modified form of an allergen designed to reduce its ability to trigger allergic reactions while still stimulating the immune system in a beneficial way.
Which conditions is Dermatophagoides farinae (504) used or studied for?
- Allergic rhinitis and rhinoconjunctivitis caused by house dust mites — inflammation of the nose and eyes triggered by house dust mite allergens, causing sneezing, a runny or blocked nose, and itchy or watery eyes. The Phase 3 trial focuses on moderate to severe forms of this condition.
- Allergic asthma — a form of asthma triggered by allergens, in this case house dust mites, leading to airway inflammation and breathing difficulties. The trial includes participants who have controlled allergic asthma alongside their rhinitis.
How is Dermatophagoides farinae (504) given?
House dust mite allergen extracts are given in different forms depending on the product. The standardised injectable extract is a sterile solution for subcutaneous injection, meaning it is injected under the skin. The product information states that deep subcutaneous routes have proven to be safe and that the product should not be injected intravenously.
A sublingual tablet form is also authorised in Europe. This oral lyophilisate dissolves under the tongue and is indicated for adults aged 18 to 65 years with allergic rhinitis and/or allergic asthma caused by house dust mites. The ongoing Phase 3 trial uses a subcutaneous preparation.
What do the clinical trials show?
The EU Clinical Trials Information System lists one authorised Phase 3 trial for this substance. The trial is designed to evaluate the efficacy and safety of a subcutaneous allergoid preparation of house dust mite allergens, including Dermatophagoides farinae, in 492 participants with moderate to severe allergic rhinitis or rhinoconjunctivitis, with or without controlled allergic asthma.
The main measure of efficacy is the Adapted Rhinitis Combined Symptom and Medication Score (arCSMS). This score combines daily rhinitis symptom scores and daily rhinitis medication scores into a single value, averaged over a four-week evaluation phase that follows the final administration of study treatment at approximately 12 months. The trial compares the active treatment against a placebo solution.
The placebo solution contains all constituents of the active formulation except aluminium hydroxide and the modified house dust mite allergens. It contains a small amount of histamine to help preserve blinding, because local reactions are common with allergy immunotherapy injections.
The trial also includes several other medications as part of the study setting: desloratadine tablets, a levocabastine eye drop solution, and a mometasone furoate nasal spray. These are used as rescue or background medications within the trial.
Older research on house dust mite subcutaneous immunotherapy in elderly patients with allergic rhinitis has been published, but the current Phase 3 trial is the registry record that describes the status of research for this specific allergoid preparation.
What side effects are known?
Injectable house dust mite allergen extracts can cause side effects. The product information for standardised mite extract warns that sensitive patients may experience severe anaphylactic reactions, which can include respiratory obstruction, shock, coma, and in rare cases death. Patients are observed for at least 30 minutes after treatment, and emergency measures must be immediately available.
Local reactions at the injection site are common with allergy immunotherapy injections. In the ongoing Phase 3 trial, a small amount of histamine is added to the placebo solution to mimic these mild local reactions and keep participants from knowing which treatment they are receiving.
The product information also advises caution when using allergenic extracts in people with unstable or steroid-dependent asthma or underlying cardiovascular disease, and notes that patients taking beta-blocker medications may not respond to epinephrine if a serious reaction occurs.