At the screening visit (Visit 1), patients will be instructed how to complete the eDiary. Eligible patients will return for visit 2 as soon as they experience significant allergic symptoms. Significant allergic symptoms are defined by a symptom score ≥ 2. If the patients' eligibility has been confirmed according to inclusion/exclusion criteria checklist, randomization to one of the 2 treatment arms will be conducted. Patients will receive two consecutive subcutaneous injections of study medication (0,2 and 0,3 ml) with a time lag of ≥ 30 minutes. Patients return to the study site in weekly intervals for visit 3, visit 4, visit 5, visit 6, and visit 7 to receive study medication injections (0,5 ml each). If treatment is completed before the end of the tree pollen season, patients will be followed-up by telephone calls every 4 weeks until the end of the tree pollen season. The study completion visit will take place 4 weeks after the end of the tree pollen season.

At the screening visit (Visit 1), patients will be instructed how to complete the eDiary. Eligible patients will return for visit 2 as soon as they experience significant allergic symptoms. Significant allergic symptoms are defined by a symptom score ≥ 2. If the patients' eligibility has been confirmed according to inclusion/exclusion criteria checklist, randomization to one of the 2 treatment arms will be conducted. Patients will receive two consecutive subcutaneous injections of study medication (0,2 and 0,3 ml) with a time lag of ≥ 30 minutes. Patients return to the study site in weekly intervals for visit 3, visit 4, visit 5, visit 6, and visit 7 to receive study medication injections (0,5 ml each). If treatment is completed before the end of the tree pollen season, patients will be followed-up by telephone calls every 4 weeks until the end of the tree pollen season. The study completion visit will take place 4 weeks after the end of the tree pollen season.

The SMS represents the sum of the mean daily symptom severity score plus the mean daily rescue medication score. The symptom severity score is defined as the mean of the daily symptom severity scores during the pollen season. The rescue medication score is defined as the mean of the daily rescue medication scores during the pollen season. A lower score indicates an improvement in the allergic condition. Minimum score of the SMS is "0", maximum score is dependent on intake of rescue medication.

The SMS represents the sum of the mean daily symptom severity score plus the mean daily rescue medication score. The symptom severity score is defined as the mean of the daily symptom severity scores during the pollen season. The overall severity rhinitis/rhinoconjunctivitis (including nasal itching, sneezing, rhinorrhea, nasal obstruction, ocular itching/grittiness/redness, and ocular tearing) and asthma (including chest tightness, shortness of breath, cough, wheezing) will be evaluated by the patient daily