Safety Study of Sublingual Immunotherapy Tablets of House Dust Mite Allergen Extracts

Inclusion Criteria: * Written informed consent. * Male or female patient from 18 to 50 years. * Diagnosed asthma with medical history consistent with HDM-induced allergic asthma. * Positive SPT to House Dust Mites(HDM)and HDM-specific IgE serum value ≥ 0.7 kU/L. * Stable asthma treatments. * Spirometry with best FEV1 \> 70% of the predicted value. * Spirometry with reversibility of FEV1 of ≥ 12% and ≥ 200 mL. * Asthma Control Test™ (ACT) score ≥ 20. Exclusion Criteria: * Current smoker or former smoker with \> 10 pack/year history. * Co-sensitisation to any allergen possibly leading to clinically relevant respiratory allergy likely to significantly change the symptoms of the patient throughout the treatment period. * Patient with a past or current disease, which as judged by the Investigator, may affect the patient's participation in or the outcome of this study. * Patient with any oral condition that could confound the safety assessments or planning to have a dental extraction during the study. * Female patient pregnant or breast-feeding/lactating. * Female patient of childbearing potential not using a medically accepted contraceptive method. * Patient treated with beta-blockers, tricyclic antidepressants or monoamine oxidase inhibitors (MAOIs). * Patient who received allergen immunotherapy for HDM in the last 10 years. * Ongoing treatment by immunotherapy with another allergen.