Clinical trial to assess the efficacy and safety of a vaccine for dust mite and Blomia tropicalis allergy.

Prior treatment

• Participants who have received allergen immunotherapy with the study aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis) within the last 5 years, or who are currently receiving immunotherapy with any allergen.
• Unstable participants who have experienced a respiratory tract infection and/or asthma exacerbation within the 4 weeks prior to the screening/baseline visit.
• Participants with a history of chronic urticaria, severe anaphylaxis, or personal history of hereditary angioedema within the 2 years prior to the screening/baseline visit.
• Use of medications that may interfere with skin prick test reactions (e.g. antihistamines) within the timeframes specified in the protocol.
• Participants who have undergone any desensitization procedure (e.g. oral immunotherapy (OIT), milk or egg), except those who have been in the maintenance phase for at least 12 months.
• Participants requiring regular treatment with antihistamines and/or corticosteroids (systemic [oral or injectable], topical, cutaneous, or inhaled) for indications other than the relief of allergic rhinitis symptoms, except for temporary use (≤ 15 days) for conditions such as common colds.
• Simultaneous participation in another clinical trial, or prior participation within 30 days before the screening/baseline visit.
• Participants with a forced expiratory volume in 1 second (FEV₁) < 80%, with respect to the reference value despite pharmacological treatment. Results will be considered valid if obtained within 12 months prior to signing the informed consent form.
• Participants with severe asthma, according to GINA 2025(2), receiving Step 5 treatment, or Step 4 treatment with uncontrolled asthma requiring escalation to Step 5.
• Participants receiving treatment with β-blockers, except for those administered topically, or angiotensin-converting enzyme (ACE) inhibitors.
• Participants receiving immunosuppressive drugs (excluding corticosteroids), except for topical formulations, or biological therapies.
• Participants requiring regular treatment with systemic corticosteroids (oral or injectable) for the treatment of rhinitis/rhinoconjunctivitis and asthma. Regular use of topical, cutaneous, or inhaled corticosteroids for the treatment of the aforementioned conditions and atopic dermatitis is permitted.

Other illness

• Participants with any condition in which the administration of adrenaline is contraindicated (e.g. hyperthyroidism, heart disease, or hypertension), according to the investigator’s judgment.
• Participants with any other serious disease unrelated to rhinoconjunctivitis or asthma that may interfere with study treatment or follow-up (e.g. epilepsy or renal disease), according to the investigator’s judgment.
• Participants with uncontrolled autoimmune diseases (e.g. thyroiditis or lupus), tumoral diseases, or immunodeficiencies.
• Participants that could not comply with the study protocol, according to investigator’s criteria, or have a serious mental illness.
• Participants with a known allergy to any component of the investigational medicinal product, other than the study allergens.
• Participants with lower respiratory tract diseases other than asthma, such as emphysema, bronchiectasis, or chronic obstructive pulmonary disease (COPD).
• Participants with any nasal condition (e.g. nasal polyps or non-allergic rhinitis) that could affect an adequate evaluation of efficacy and/or safety, according to the investigator’s judgment.
• Participants with a history of severe systemic allergic reactions, including reactions to foods, hymenoptera venom, medications, etc.
• Participants with controlled or uncontrolled cancer.
• Participants for whom allergen-specific immunotherapy is absolutely contraindicated, according to the criteria of the European Academy of Allergy and Clinical Immunology (EAACI) Immunotherapy Subcommittee.

Other

• Pregnant or breastfeeding women.
• Participants who are immediate family members of the investigator.
• Participants with uncontrolled or partially controlled asthma. Asthma control will be assessed using the asthma control assessment questionnaire (GINA 2025)

• Participants who have signed the informed consent form.
• Participants capable of complying with the dosing regimen.
• Participants capable of recording symptoms and medication use in an electronic diary via a smartphone (preferably) or in a paper diary.
• Participants with a Rhinoconjunctivitis Combined Symptom and Medication Score (RCSMS) ≥ 2 out of 6, recorded for at least 10 days, corresponding to moderate-to-severe allergic rhinitis/rhinoconjunctivitis.
• Male or female participants aged 12 to 65 years, inclusive.
• Participants with a confirmed clinical history of inhalant allergy with moderate-to-severe persistent rhinitis/rhinoconjunctivitis according to ARIA classification(1) of at least 1 year duration (treated with antiallergic medication) with or without controlled intermittent or persistent mild-to-moderate asthma according to the definition of GINA 2025 (2), caused by Dermatophagoides pteronyssinus and/or Dermatophagoides farinae and Blomia tropicalis. The asthma diagnosis will be valid up to 12 months prior to signing the informed consent.
• Participants with positive skin prick test to standardized extracts of Dermatophagoides pteronyssinus and/or Dermatophagoides farinae and Blomia tropicalis. The major diameter of the wheal must be ≥ 5 mm and greater than or equal to the major diameter of the wheal of the positive control (histamine). The results will be valid up to 12 months prior to the signature of the informed consent.
• Specific IgE ≥3.5 kU/L against a complete extract of D. pteronyssinus and/or D. farinae and Blomia tropicalis or any of the molecular components of allergenic sources with a value ≥ 3.5 kU/L. The results will be valid up to 12 months prior to the signature of the informed consent.
• Of participants sensitized to other aeroallergens, only those meeting the following criteria may be included in the study (results valid up to 12 months prior to the signing of the informed consent form): a) Participants with a positive skin prick test to Lepidoglyphus destructor and/or other mites may be included, provided that the specific IgE value for this allergen is ≤ 3.5 kU/L. b) Participants with a positive skin prick test to animal dander may be included only if exposure and related symptoms are occasional. Participants with regular exposure to animal dander or who live with animals must have a negative skin prick test to these danders. c) Participants sensitized (positive skin prick test) to one or more pollens must complete the first symptom and medication recording period (after the Baseline Visit (BV) under the following conditions: 1. The first symptom and medication recording period must be carried out outside the pollen season. 2. The first symptom and medication recording period must begin at least one month before or one month after the pollen season. 3. Participants who do not meet both condition 1 and condition 2 at the time of the Baseline Visit (BV) will be considered a screening failure. These participants may be re-screened and re-included at a later time (see Section 7.3.3). In addition, the final symptom and medication recording period (after Visit 12 (V12)) must also be conducted in accordance with conditions 1 and 2 described above. An individual assessment of each participant will be performed in conjunction with the pollen calendar established for each geographical region to verify that symptom and medication recording can be carried out under the conditions described above. If this is not possible, the participant may not be included in the study.
• Participants with a negative skin prick test to molds.
• Women of childbearing potential (i.e., from menarche until postmenopause, defined as the absence of menstruation for 12 months without an alternative medical cause, and who have not undergone permanent sterilization procedures such as hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) must have experienced menarche and present a negative urine pregnancy test at the time of study inclusion.
• Women of childbearing potential must agree to use a highly effective contraceptive method throughout the study and for 1 month after completion of treatment with the investigational medicinal product. Acceptable methods include: combined hormonal contraception (containing estrogen and progestogen), hormonal contraception associated with inhibition of ovulation (oral, intravaginal, or transdermal), progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, or implantable), intrauterine device (IUD), hormone-releasing intrauterine system (IUS), male condom, bilateral tubal occlusion, partner vasectomy, or sexual abstinence.