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 treatm…