Efficacy and Safety Study of a Sublingual Immunotherapy Solution to Treat Patients Suffering From Birch Pollen Allergic Rhinoconjunctivitis

Inclusion Criteria:

• Symptomatic birch pollen-related allergic rhinoconjunctivitis for at least theprevious 2 pollen seasons requiring intake of symptomatic treatment.

• Sensitization to birch pollen demonstrated by a positive Skin Prick Test to birchpollen with wheal diameter > 3 mm and birch pollen allergens specific IgE levels ≥ 0.70 kU/L.

• RRTSS based on the previous or on the penultimate birch pollen season ≥ 12 out of amaximum possible score of 18.

• Patients with an FEV1 (Forced Expiratory Volume at one second) ≥ 80% of the predictedvalue.

• Patients who are willing to comply with the protocol.

• Patients having given a signed informed consent before completing any study relatedprocedure.

Exclusion Criteria:

• Patients with symptoms of rhinitis/rhinoconjunctivitis during the birch pollen seasondue to any other allergens (except alder and hazel). This includes patients withsymptomatic allergic rhinitis/rhinoconjunctivitis due to cat or dog allergens, andliving with these animals at home or at risk of frequent contacts with these animals (family, friends etc.) during the course of the study.

• Patient who previously received desensitization treatment to birch pollen and/oranother Betulaceae sp. (for example hazel or alder) within the previous 5 years.

• Patients with ongoing treatment by immunotherapy with another allergen.

• Pregnancy (positive pregnancy test), breast-feeding.

• Female patients of childbearing potential planning a pregnancy during this study ornot using a medically accepted contraceptive method (hormonal birth control [orally,injectable or by implant, for at least 2 months before enrolment], intrauterinedevice, spermicide used with a male condom, bilateral tubal ligation, diaphragm withspermicide, female condom, monogamous relationship with a vasectomised partner).

• Patients planning to move during the study or planning to leave the area during thebirch pollen season for more than 1 week (7 consecutive days).

• Patients with moderate or severe persistent asthma (GINA 3 or 4).

• Patients with seasonal mild persistent asthma (GINA 2) necessitating treatment withinhaled glucocorticosteroids at a dose level greater than 400 mcg budesonidedose-equivalents.

• Patients with any nasal or oral condition that could interfere with the efficacy orsafety assessments (such as nasal polyposis or oral inflammation).

• Patients with severe immune deficiency.

• Patients with a past or current disease, which as judged by the Investigator, mayaffect the patient's participation in or outcome of this study.

• Any other disease or condition which would place a patient at undue risk by beingincluded in the study (according to the Investigator's opinion).

• Usual contra-indications of immunotherapy such as concomitant beta-blocker therapywhatever the route and/or immunosuppressive drugs.

• Patients treated with inhaled/systemic steroids (whatever the indication) within 4weeks prior to Visit 1 (Screening), or with long acting systemic corticosteroids 12weeks before Visit 1 (Screening).

• Patients under continuous corticotherapy (inhaled or systemic drugs).

• Patients following a strict low sodium diet as the study treatment contains 590 mg ofsodium chloride per vial in a 10 mL solution.

• Investigators, co-Investigators, as well as their children or spouses and all studycollaborators.