A Study of Tolerability and Safety of a New Cumulative Dose of Grass MATA MPL

Inclusion Criteria: * Patients must have a positive skin prick test for grass pollen allergen. * Positive skin prick test to positive histamine control * Negative skin prick test to negative control * Specific IgE for grass pollen as documented by ImmunoCAP test with class ≥ 2 * A history of moderate to severe symptoms of seasonal allergic rhinitis and/or conjunctivitis due to grass (Pooideae) pollen exposure that required repeated use of antihistamines, nasal steroids, and/or leukotriene modifiers for relief of symptoms during the last two consecutive seasons prior to the study * Males or non-pregnant, non-lactating females who are not of child-bearing potential or using effective contraception * Patients who are normally active and otherwise judged to be in good health * For patients with a history of asthma, forced expiratory volume in 1 second (FEV1) ≥ 80% of National Health and Nutrition Examination Surveys (NHANES) predicted, with a FEV1/forced vital capacity (FVC) ratio ≥ 70%. * Able to observe the drug washout times listed in the Prohibited Medications Table below prior to screening * Patients willing and able to attend required study visits and able to follow the protocol requirements. * Patients willing and able to give written informed consent. Exclusion Criteria: * Symptoms outside the grass pollen season due to a perennial and/or non-grass seasonal allergen, if the patient is unable to avoid the offending allergen. * Immunological disorders or other diseases that in the opinion of the investigator may pose a safety risk. * Presence of moderate to severe asthma, characterized by the current use of inhaled steroids at a daily dose above 400 micrograms of budesonide (or equivalent) * Emergency room visit or admission for asthma in the 12 months prior to Visit 1 or history of a life-threatening asthma attack ever. * Presence of non-atopic rhinitis and/or rhino-sinusitis (with or without polyps). * Presence of any skin conditions (skin abnormalities, tattoos etc.) which might interfere with the interpretation of the SPT results. * Current diagnosis of type I diabetes. Patients with type II diabetes will only be allowed to participate at the discretion of the investigator. * Treatment with a preparation containing MPL (e.g. Cervarix) within 6 months prior to screening * Moderate to severe upper or lower respiratory tract infections requiring medication within 14 days of or a diagnosis of sinusitis within 30 days of randomisation * Clinical history of severe or life-threatening anaphylactic reactions to foods, insect venom, exercise, drugs or idiopathic anaphylaxis. * Clinical history of allergy, hypersensitivity or intolerance to the excipients of the study medication. * Tyrosine metabolism disorders, especially tyrosinemia and alkaptonuria. * Unable to receive epinephrine therapy (i.e., use of epinephrine is contraindicated). * Clinical history of immunodeficiency, including those who are on immunosuppressant therapy. * Clinical history of recurrent idiopathic angioedema. * Beta-blocker medication, including eye drops, for any indication. * Treatment with monoamine oxidase inhibitors, tricyclic antidepressants or ACE inhibitors. * Clinical history of drug or alcohol abuse which, in the investigator's opinion, could interfere with the patient's ability to participate in the study. * Participation in a clinical research trial with any investigational medicinal product within 4 weeks of screening or concomitantly with this study.