Evaluation of safety and efficacy of sublingual immunotherapy with grass pollen allergens formulated as solution in comparison to a symptomatic standard treatment with add on placebo in grass pollen allergic children suffering from allergic rhinitis/rhinoconjunctivitis with or without bronchial asthma.

Although highly effective, subcutaneous administration of allergens may cause inconvenience in some patients. Alternative routes, e.g. nasal and oral, have therefore been investigated to find an immunotherapy regimen largely accepted by all groups of patients, including children.

Sublingual specific immunotherapy (SLIT) may represent a more acceptable route of immunotherapy. It may be an optimal therapy option especially for children because they often fear injections.

In this study children are to be treated with a preparation of a grass pollen allergen extract in a water/glycerol solution with phosphate buffered saline in comparison to a symptomatic standard treatment with add on placebo, in order to investigate efficacy and safety of the study drug.

Inclusion Criteria:

• 4 - <12 years (at the time of inclusion)
• Positive SPT
• Positive EAST
• Positive CPT

Exclusion Criteria:

• Serious chronic diseases
• Other perennial allergies