A Study of Tolerability and Safety of Two New Doses of Grass MATA MPL

There is increasing evidence that the effectiveness of allergy immunotherapy to control symptoms of rhinoconjunctivitis is related to the cumulative dose of allergen or allergoid administered during a single regimen of subcutaneous (SC) injections or of sublingual administration. Two new cumulative doses of the Grass MATA MPL 10200 and 18200 SU (Standardized Units) are being developed to compare with the current dose of 5100 SU. The purpose of this study is to evaluate the tolerability and safety of these two new cumulative dose regimens of Grass MATA MPL compared with placebo in patients with seasonal allergic rhinoconjunctivitis (SAR) due to grass pollen, to enable selection of the best dose to go into a larger scale study to assess the efficacy and safety of the higher cumulative doses.