Depigoid Birch 5000 Longterm Study in Adults and Adolescents

Inclusion Criteria: * Availability of an appropriately signed and dated informed consent before any study specific examination, * Clinical history of at least 2 years of seasonal allergic rhinitis and/or rhinoconjunctivitis with or without intermittent asthma due to birch pollen allergy that has required repeated use of symptomatic treatment, * Patients must have a minimum level of perception of symptoms from previous seasons defined as at least a moderate symptom level (i.e. a score of 2 on the 4-point-Likert scale) in at least 2 symptom categories prior to randomization, * Lung function ≥ 80% of the predicted normal value, * IgE-mediated sensitization has to be verified by: * suggestive medical history, and * specific IgE reactivity to birch pollen (CAP-RAST ≥ 2), and * a positive SPT to birch pollen at screening or within 1 months prior to the screening visit. An SPT is considered positive if it results in a wheal diameter of at least 3.0 mm * Internet access so that patients can complete the eDiary daily via internet during all 5 pollen seasons covered by the study protocol. Exclusion Criteria: * History of significant clinical manifestations of allergy as a result of sensitization against co-allergies, particularly-but not limited to-grass or weed pollen and perennial allergens (e.g. house dust mites, cat or dog). * History of anaphylactic reaction. * Moderate or severe persistent asthma (GINA 3 or 4). * Mild persistent asthma (GINA 2), according to the Global Initiative for Asthma Guidelines, necessitating treatment with inhaled glucocorticoids at a daily dose level of \> 400 µg budesonide dose equivalents. * Lung function \< 80% of the predicted normal value (for PEF: highest result of 3 measurements). * Acute or chronic inflammatory or infectious airway diseases including recurrent acute or chronic sinusitis. * Chronic structural diseases of the affected organs (e.g. eye, nose, lung). * History or presence of confirmed or potential diseases of the immune system including autoimmune diseases and immune deficiencies of actual clinical relevance. * Any disease that prohibits the use of adrenaline (e.g. hyperthyroidism). * Atopic dermatitis with SCORAD \>30 in the past or at screening. * Ongoing or past full courses of SIT against birch pollen within the last 5 years. * Topical and systemic treatment with β-blockers. * Concomitant treatment with substances interfering with the immune system beginning 1 week prior to start of treatment. * Use of systemic corticosteroids within 3 months prior to Visit 1-1. * Immunization with vaccines within 7 days prior to Visit 1-1. * Treatment with antihistamines for any reason other than allergic symptoms due to birch pollen allergy. * Changed residence between geographical regions since the last birch pollen season or not staying in the geographical region during the pre-determined birch pollen season. * Nursing (lactating) women or women with a positive pregnancy test at the screening visit. Women of childbearing potential must be using highly effective contraception during participation in this clinical study. A highly effective method of birth control is defined as one that results in a low failure rate (i.e. less than 1% per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some IUDs, sexual abstinence, or vasectomised partner.