Efficacy and Safety of Grass Sublingual Tablet in Children and Adolescents (P05239 AM3)(COMPLETED)

Inclusion Criteria

• Participant must be 5 to =5 mm larger than the saline control after 15 to 20 minutes) to Phleum pratense at the Screening Visit.
• Participant must have positive specific IgE against Phleum pratense (>= IgE Class 2) at the Screening Visit.
• Participant must have an FEV1 >=70% of predicted value at the Screening Visit.
• A participant's safety laboratory tests and vital signs conducted at the Screening Visit must be within normal limits or clinically acceptable to the investigator/sponsor.
• A participant (and/or parent/guardian for subjects under the age of legal consent or who otherwise are unable to provide independent consent) must be willing to give written informed consent/assent and be able to adhere to dose and visit schedules.
• Female participants of childbearing potential must be using a medically acceptable and adequate form of birth control. These include:
• hormonal contraceptives as prescribed by a physician (oral, hormonal vaginal ring, hormonal implant or depot injectable);
• medically prescribed intra-uterine device;
• medically prescribed topically-applied transdermal contraceptive patch;
• double-barrier method (eg, condom in combination with a spermicide); vasectomy and tubal ligation should each be considered as single barrier.
• Female participants of childbearing potential should be counseled in the appropriate use of birth control while in the study. Female participants who are not currently sexually active must agree and consent to use one of the above-mentioned methods if they become sexually active while participating in the study.
• Female participants of childbearing potential must have a negative urine pregnancy test at the Screening Visit in order to be considered eligible for enrollment.

Exclusion Criteria

• Participant with a clinical history of symptomatic seasonal allergic rhinitis and/or asthma, having received regular medications due to another allergen during or potentially overlapping the GPS.
• Participant with a clinical history of significant symptomatic perennial allergic rhinitis and/or asthma having received regular medication due to an allergen to which the participant is regularly exposed.
• Participant with sufficient pre-seasonal data in the observational phase will not be eligible to continue in the treatment phase if the participant: 1) does not experience an increase in rhinoconjunctivitis symptom score of equal to or greater than 4 above the pre-seasonal average symptom score for at least 2 days, 2) does not use allergy rescue medication for at least 2 days, during the observational phase Year 1 2008 GPS.
• Participant has received an immunosuppressive treatment within 3 months prior to the Screening Visit (except steroids for allergic and asthma symptoms).
• Participant with a clinical history of severe asthma.
• Participant with history of anaphylaxis with cardiorespiratory symptoms.
• Participant with history of self-injectable epinephrine use.
• Participant with a history of chronic urticaria and angioedema.
• Participant with clinical history of chronic sinusitis during the 2 years prior to the Screening Visit.
• Participant with current severe atopic dermatitis.
• Female participants who are breast-feeding, pregnant, or intending to become pregnant.
• Participant who has had previous treatment by immunotherapy with grass pollen allergen or any other allergen within the 5 years prior to the Screening Visit.
• Participant with a known history of allergy, hypersensitivity or intolerance to the ingredients of the IMP (except for Phleum pratense), rescue medications, or self-injectable epinephrine.
• Participant with any clinically significant condition or situation, other than the condition being studied that, in the opinion of the investigator, would interfere with the study evaluations or optimal participation in the study. Specific examples include but are not limited to hypertension being treated with beta blockers, coronary artery disease,