Multicentre Phase II trial, comparing two different administration routes of SLITonePLUS Birch in regard to pharmacodynamic efficacy and tolerability.

Inclusion Criteria:

• A history of Birch pollen allergy
• Positive skin prick test to birch
• Positive specific IgE to birch

Exclusion criteria:

• Uncontrolled or severe asthma (FEV1<70% of predicted value in spite of adequate pharmacologic treatment)
• Previous treatment by immunotherapy with birch or a cross-reactingtree pollen allergen within the previous 5 years
• Concomitant SLIT with any allergen