Inclusion Criteria:

• Patients must have a positive skin prick test for birch and hazel and alder allergen.
• Positive skin prick test to positive histamine control
• Negative skin prick test to negative control
• Specific IgE for birch as documented by radioallergosorbent or equivalent test with class ≥ 2
• History of at least 1 season of moderate to severe seasonal rhinoconjunctivitis due to an IgE – mediated allergy to pollen from birch, hazel, and alder
• Patients must score on the disease severity questionnaire as moderate or severe.
• Males or non-pregnant, non-lactating females
• Patients who are normally active and otherwise judged to be in good health
• Patients must be willing and able to attend required study visits.
• Patients must be able to follow instructions.
• Patients must be willing and able to give written informed consent and must provide this consent.

Exclusion Criteria:

• Acute or subacute atopic dermatitis and/or urticaria factitia and/or urticaria due to physical or chemical influence and/or chronic dermatitis
• Moderate to severe asthma
• Visual inspection of the forearms indicates potential problems with the conduct or interpretation of the skin prick test; both forearms must be available for testing.
• History or presence of diabetes, cancer or any clinically significant cardiac, metabolic, renal, or hematologic diseases or disorders
• Recent clinically significant history of hepatic, gastrointestinal, dermatologic, venereal, neurologic or psychiatric diseases or disorders
• Any clinically significant abnormal laboratory value at Visit 1
• Perennial allergens: clinically relevant sensitivity to house dust mites, molds, and epithelia
• Patient has clinically relevant sensitivity to the following summer/autumn season flowering plants:

plantain, orache, nettle, mugwort, Parietaria judaica, Bermuda grass, or ragweed.

• Secondary alteration at the affected organ
• History of autoimmune diseases and/or rheumatoid diseases
• Patient is taking ß-blockers for any indication including eye drops
• Patient who is not allowed to receive adrenalin
• Patients in whom tyrosine metabolism is disturbed
• Presence of a disease with a pathogenesis interfering with the immune response and patient has received medication which could influence the results of this study
• Acute or significant chronic infection
• History of anaphylaxis
• Documented history of angioedema
• Hypersensitivity to excipients in the study medications
• Previous or current immunotherapy with comparable tree allergen extracts
• Currently using anti-allergy medication and other drugs with antihistaminic activity
• Patients currently participating in a clinical trial or who have been exposed to study medication within the last 30 days
• Patients who cannot communicate reliably with the Investigator or who are not likely to cooperate with the requirements of the study
• Patient is pregnant or planning pregnancy and/or lactating
• Patient has received treatment with preparation containing MPL during the past 12 months
• Concurrent use of any prohibited medication(s), as listed in the study protocol, or inadequate washout of any medication
• Any systemic disorder that could interfere with the evaluation of the study medication(s)
• Clinical history of drug or alcohol abuse, at the Investigator’s discretion, that would interfere with the patient’s participation in the study
• Study site staff or immediate relatives of study site staff or other individuals who would have access to the clinical study protocol