Subcutaneous Immunotherapy in Patients Sensitized to Phleum Pratense

Inclusion Criteria: 1. Patients must sign the informed consent form. 2. Patients must be between 18 and 60 years of age. 3. Patients who obtained a prick test result greater or equal to 3 mm diameter and a specific IgE greater or equal to class 2 (CAP/PHADIA) to Phleum pratense. 4. Patients with seasonal allergic rhinoconjunctivitis against Phleum pratense during a minimum of 2 years prior to study participation. Although allergic rhinoconjunctivitis is the pathology under study, the inclusion of patients with mild or moderate concomitant asthma is allowed. 5. Patients will preferably be monosensitized to Phleum pratense. Polysensitized patients to other seasonal allergens will be accepted if sensitizations are caused by Pollens whose seasons do not overlap with Phleum pratense. Polysensitized patients to perennial allergens will also be accepted if not clinically relevant during the study period. 6. Women of childbearing potential must have a negative urine pregnancy test at Screening visit/Visit 0 7. Women of childbearing potential must agree to use an appropriate contraception method during the study if they are sexually active. Exclusion Criteria: 1. Stable and continued use of medication for allergic pathology during 2 weeks prior to inclusion. 2. Patients sensitised to other overlapping seasonal allergens and with specific IgE levels greater or equal to class 2 CAP/PHADIA. 3. Patients who received immunotherapy in the previous 5 years for Phleum pratense or for any allergen with cross reactivity or patients that are currently receiving immunotherapy for any allergen. 4. Patients with severe asthma or FEV1 lower than 60% or asthma requiring inhaled or systemic corticoid treatment at the time of study entry or within 8 weeks prior to treatment commencement. 5. Patients with: immunological, cardiac, renal or hepatic illnesses or any other medical condition that the investigator deems relevant so as to interfere with the study. 6. Patients with a previous history of anaphylaxis 7. Patients with unstable angina 8. Patients with uncontrolled hypertension 9. Patients with clinically significant arrythmias 10. Patients with neoplasia 11. Patients with clinically relevant malformations of the upper respiratory tract. 12. Other chronic or immunological disease that could interfere with the assessment of the investigation product or that could generate any additional risk for the patient 13. Patients who have participated in another clinical trial within 3 month prior to enrolment. 14. Patients under treatment with tricyclic antidepressives, psychotropics or beta-blockers 15. Female patients who are pregnant or breast-feeding or women of childbearing potential that do not agree to use an appropriate contraception method during the study if they are sexually active, if they have not been surgical sterilised or present any other incapacity to bear 16. Patient who does not attend the visits 17. Patient's lack of collaboration or refusal to participate.