The aim of this study is to test the pharmacodynamic equivalence with respect to IgE-blocking factor and to compare the tolerability of two different updosing schedules with ALK-Flex SQ

Inclusion Criteria:

• A clinical history of grass pollen induced allergic rhinoconjunctivitis of two years or more requiring treatment during the grass pollen season
• Lack of adequate relief with symptomatic medication during the previous grass pollen season
• Positive Skin Prick Test (SPT) response to Phleum pratense (wheal diameter >= 3mm) currently performed or not older than 60 days before screening

Exclusion Criteria:

• FEV1 < 70% of predicted value at screening
• Bronchial asthma corresponding to GINA step 3 or more, even if controlled
• History of asthma exacerbation or emergency visit or admission for asthma in the previous 12 months
• Previous treatment by immunotherapy with grass pollen allergen or any other allergen within the previous 5 years
• Exclusion criteria in accordance with contraindications in the SPC of ALK-Flex SQ