hdmASIT+TM product is based on highly purified allergen fragments from house dust mites. The purpose of this study is to assess the safety and clinical tolerability of subcutaneous immunotherapy with hdmASIT+TM in patients with house dust mite-induced allergic rhinoconjunctivitis compared to placebo.

Inclusion Criteria:

• A medical history of moderate to severe allergic rhinoconjunctivitis for house dust mite for at least 12 months (definition of allergy severity according to ARIA (Bousquet et al., 2001))
• A positive skin prick test to house dust mite Dermatophagoides pteronyssinus
• Specific IgE against house dust mite Dermatophagoides pteronyssinus ≥ 0.7 kU/L
• Positive response to Conjunctival Provocation Test (CPT)
• Being treated with anti-allergic medication for at least 12 months prior to enrollment
• For asthmatic patients: confirmed diagnosis of controlled asthma according to Global Initiative for Asthma (GINA) guidelines (steps 1-3, GINA 2014), FEV1 ≥ 80% of the patient's reference value

Exclusion Criteria:

• Previous immunotherapy with house dust mite allergens within the last 5 years
• Ongoing immunotherapy with house dust mite allergens or any other allergens
• History of severe systemic reactions and/or anaphylaxis, including to food (e.g. peanut, marine animals) or to Hymenoptera venom (e.g. bee, wasp stings) or to medication (e.g. penicillin), etc.
• Partly controlled or uncontrolled asthma according to GINA guidelines (GINA 2014)
• Chronic asthma or emphysema, particularly with a forced expiratory volume in 1 second (FEV1) < 80% of the patient's reference value (ECSC)
• History of a respiratory tract infection and/or exacerbation of asthma within 4 weeks before the screening