The objective of the present study is to characterize the dose-response relationship of PURETHAL® Mites with a nasal provocation test in order to support the optimal dose in terms of clinical efficacy and safety.

For this purpose 5 groups of 50 patients, suffering from rhinitis or rhinoconjunctivitis due to House Dust Mite Allergy will be treated during 1 year. Before start, after 6 months of treatment and at the end of the study patients will be subjected to a nasal provocation test.

Inclusion Criteria:

• Signed informed consent
• Patients (male or female) must be ≥ 18 and ≤ 60 years at screening
• Patients with allergic rhinitis or rhinoconjunctivitis for at least 1 year; allergic symptoms related to HDM, with or without concomitant clinically stable controlled mild to moderate asthma (according to GINA classification)
• Patients with a history of concomitant asthma should have a FEV1 > 70% at inclusion. Patients without a history of asthma should have a FEV1 > 70% or a PEF > 80%.
• Positive SPT to HDM D. pter and/or D. far
• Serum specific IgE-test (ssIgE) level for HDM D. pter or D. far at screening
• Positive nasal provocation test for HDM extract at screening

Exclusion Criteria:

• Current clinically relevant symptoms of seasonal rhinitis/rhinoconjunctivitis caused by other allergen(s) than HDM (with a demonstrated positive SPT for this allergen) at the time of inclusion
• Patients sensitized to animals should not be included if they are symptomatic upon exposure and regularly exposed to animals
• Completed allergen-specific immunotherapy (SCIT or SLIT) with HDM within the last 5 years
• Completed unsuccessful allergen-specific immunotherapy (SCIT or SLIT) within the past 5 years
• Allergen-specific immunotherapy (SCIT or SLIT) with other allergens than HDM during the study period
• Any vaccination one week before start of therapy and during the up-dosing phase
• Any anti-IgE therapy within the last 6 months prior to inclusion and during study
• Severe immune disorders (including auto-immune diseases) and/or diseases requiring immunosuppressive drugs
• Active malignancies or any malignant disease in the past 5 years
• A chronic or acute disease that in the opinion of the investigator might place the patient at an additional risk, including but not limited to the following: cardiovascular insufficiency, any severe or unstable lung diseases, endocrine disorders, clinically significant renal or hepatic diseases, or haematological disorders
• Moderate to severe nasal obstructive diseases such as polyps, septal deviations etc.
• Clinically significant chronic sinusitis or ocular infection
• Diseases with a contra-indication for the use of adrenaline (e.g. hyperthyroidism, glaucoma)
• Use of systemic corticosteroids within 4 weeks of screening
• Treatment with systemic or local b-blockers
• Participation in a clinical study with a new investigational drug within the last 3 months or a biological within the last 6 months prior to the study or during the study
• Pregnancy, lactation or inadequate contraceptive measures (contraceptive measures considered as adequate include appropriate use of oral contraception, i.m. contraception or a contraceptive device)
• Alcohol, drug, or medication abuse within the past year and during study
• Any abnormal laboratory parameter at screening that in the opinion of the investigator is considered clinically relevant
• Lack of co-operation or compliance
• Severe psychiatric, psychological, or neurological disorders
• Patients who are employees of the department, 1st grade relatives, or partners of the investigator
• Expected changes in HDM exposure during the study (avoidance measures, move, etc.)