A Study of Tolerability and Safety of Two New Doses 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 radioallergosorbent or equivalent test with class ≥ 2 * History of at least 2 seasons of moderate to severe seasonal rhinoconjunctivitis due to an IgE - mediated allergy to pollen from grass * Males or non-pregnant, non-lactating females who are: * Post-menopausal (defined as at least 12 months natural spontaneous amenorrhea or at least 6 weeks following surgical menopause, i.e. bilateral oophorectomy) * Naturally or surgically sterile (hysterectomy; bilateral oophorectomy; bilateral tubal ligation with surgery at least 6 weeks prior to study initiation) * Of childbearing potential - with negative urinary and serological pregnancy test and use at least one of the following contraception methods: * Stable hormonal contraceptive for ≥ 90 days prior to Visit 1 and at least 7 days after the final injection. If \< 90 days prior to the study, additional use of a double barrier method until 90 days reached is required. * Placement of an intrauterine device (IUD) or intrauterine system * Use of barrier methods of contraception (e.g., condom or occlusive cap) with spermicidal foam/gel/film/cream /suppository * Use of double barrier methods of contraception (e.g., male condom with diaphragm, male condom with cervical cap) * Patients who are normally active and otherwise judged to be in good health * Patients must be willing and able to attend required study visits. * Patients must be able to follow instructions. * Patients must be willing and able to give written informed consent and must provide this 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. * Concurrent disease that might complicate or interfere with investigation or evaluation of the study medications or the skin prick test result, such as: * Any ocular disorder (other than allergic conjunctivitis) including presumed infectious ocular disease (bacterial, fungal, viral, etc.), which could interfere with the evaluation of the study medication Rhinitis medicamentosa * Documented evidence of acute or significant chronic sinusitis, upper or lower respiratory tract infection within 30 days before Visit 2 as determined by the Investigator * Asthma, with the exception of mild intermittent asthma * 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 acute or subacute atopic dermatitis, chronic dermatitis, urticaria factitia, or urticaria due to physical/chemical influence * Presence of emphysema or bronchiectasis * Auto-immune disease, cancer, or concomitant illness that in the opinion of the Investigator would pose a safety risk or compromise the interpretation of study results * Use of oral, intramuscular, intravenous corticosteroids, or potent or super-potent topical corticosteroids, from 30 days prior to screening up to Visit 8 * Presence of tattoos or other skin abnormalities in the upper arms which would prevent an accurate assessment of local skin reaction * Allergy, hypersensitivity or intolerance to the excipients of the study medication * Anaphylactic reactions to foods, insect venom, exercise, drugs or idiopathic anaphylaxis * Immunodeficiency, including those who are on immunosuppressant therapy * Recurrent idiopathic angioedema * Tyrosine metabolism disorders, especially tyrosinemia and alkaptonuria * β-blocker (including eye drops), monoamine oxidase medication * Unable to receive epinephrine therapy (i.e., use of epinephrine is contraindicated) * Clinical history of drug or alcohol abuse, at the Investigator's discretion, that would interfere with the patient's participation in the study * Any clinically significant abnormal laboratory value (as determined by the Investigator) at Visit 1 * Study site staff or immediate relatives of study site staff or other individuals who would have access to the clinical study protocol or people considered as vulnerable or institutionalized * Have undergone specific immunotherapy with comparable allergen extracts. An exception will be allowed if prior immunotherapy with comparable allergen was successful, symptoms reappeared some-time after stopping the immunotherapy, and the immunotherapy was completed ≥ 3 years before Visit 1 * Treatment with a preparation containing MPL® within 6 months prior to Visit 1. * Participation in a clinical research study with an investigational medicinal product within 4 weeks of Visit 1 or concomitantly with this study, including the safety follow-up period up to 12 months following the last injection.