The objective of this study is to evaluate the efficacy and safety of specific subcutaneous immunotherapy with modified allergen extracts.

Inclusion Criteria:

• Positive history of perennial allergic rhinitis due to house dust mites
• Positive screening skin prick test (wheal diameter > 3 mm)
• Compliance and ability of the patient to complete a Diary Card for self-evaluating of the symptoms and antisymptomatic medication
• Signed and dated patient´s Informed Consent,

Exclusion Criteria:

• Previous immunotherapy with mite extracts within the last 3 years,
• Simultaneous participation in other clinical trials,
• Other reasons contra-indicating an inclusion into the trial according to the investigator´s estimation (e.g. poor compliance),
• Auto-immune disorders,
• Severe chronic inflammatory diseases,
• Malignancy,
• Alcohol abuse,
• Existing or intended pregnancy, lactation and/or lack of adequate contraceptive protection,
• Treatment with beta-blockers (incl. local application) and/or other contra-indicated drugs.