Factors Predicting Efficacy of Allergen Injection Immunotherapy for Grass Pollen Hayfever

Inclusion Criteria: * Male and female 18-65 years of age * Written informed consent obtained before entering the trial * A clinical history of grass pollen induced allergic rhinoconjunctivitis of two years or more requiring treatment during the grass pollen season * A clinical history of severe rhinoconjunctivitis symptoms (interfering with usual daily activities or sleep), which remain troublesome despite treatment with anti-allergic drugs during the grass pollen season * Positive Skin Prick Test (SPT) response (wheal diameter ≥ 3 mm) to Phleum pratense * Positive specific IgE against Phleum pratense (≥ IgE Class 2) * Physical examination with no clinically relevant findings * If pre-menopausal female of childbearing potential, the subject must test negative on standard urine pregnancy test and must be willing to practice appropriate contraceptive methods for the duration of the trial * Willingness to comply with this protocol Exclusion Criteria: * FEV1 \< 70% of predicted value * A clinical history of symptomatic seasonal allergic rhinitis and/or asthma due to tree pollen or weed pollen adjacent to the start of - and potentially overlapping - the grass pollen season * A clinical history of significant symptomatic perennial allergic rhinitis and/or asthma caused by an allergen to which the subject is regularly exposed * A clinical history of significant recurrent acute sinusitis (defined as 2 episodes per year for the last two years all of which required antibiotic treatment) or chronic sinusitis * At randomisation, current symptoms of, or treatment for, upper respiratory tract infection, acute sinusitis, acute otitis media or other relevant infectious process (serous otitis media is not an exclusion criterion) * History of emergency visit or admission for asthma in the previous 12 months * Use of an investigational drug within 30 days prior to screening * Previous treatment by immunotherapy with grass pollen allergen or any other allergen within the previous 5 years * History of anaphylaxis, including anaphylactic food allergy, bee venom anaphylaxis, exercise anaphylaxis or drug induced anaphylaxis * History of angioedema * Any of the following underlying conditions known or suspected to be present: * Cystic fibrosis * Malignancy * Insulin-dependent diabetes * Malabsorption or malnutrition * Renal or hepatic insufficiency * Chronic infection * Drug dependency or alcoholism * Ischemic heart disease or angina requiring current daily medication or with any evidence of disease making implementation of the protocol or interpretation of the protocol results difficult or jeopardising the safety of the subject (e.g. clinically significant cardiovascular, serious immunopathologic, immunodeficiency whether acquired or not, hepatic, neurologic, psychiatric, endocrine, or other major systemic disease) * Immunosuppressive treatment * History of hypersensitivity to the excipients of the trial medications * History of allergy, hypersensitivity or intolerance to trial medications or rescue medications * A mental condition rendering the subject unable to understand the nature, scope and possible consequences of the trial, and/or evidence of an uncooperative attitude * Unlikely to be able to complete the trial, for any reason, or likely to travel for extended periods of time during the grass pollen season