Study to Evaluate Safety and Tolerability of sc Immunotherapy With DM-101 in Adults With Birch Pollen Allergy

Key Inclusion Criteria: * Males or females, aged 18 to 65 years * Good general health * A documented clinical history of birch pollen-induced allergic rhinitis or rhinoconjunctivitis with symptoms that interfere with daily activities or sleep and remain bothersome despite the use of relevant symptomatic medication, and have been present over, at least, 2 allergy seasons. * Bet v 1 specific serum IgE ≥ 0.7 kU/L * Positive SPT to birch pollen allergen, with a wheal diameter ≥ 5 mm * Body weight ≥50 kg and body mass index (BMI) within the range 18-35 kg/m2. Key Exclusion Criteria: * History or findings on physical examination of any significant disease or disorder which, in the opinion of the Investigator, may put the subject at risk because of participation in the study, influence the results of the study or the subject's ability to participate in the study. * Current diagnosis of asthma (other than seasonal during the birch pollen allergy season), requiring Global Initiative for Asthma (GINA) Step 2 or higher treatment, or asthma partially controlled or uncontrolled according to GINA classification in the 6 months before Screening. * History of asthma deterioration that resulted in emergency treatment or hospitalisation in the 12 months before screening, or a life-threatening asthma attack at any time in the past. * Forced Expiratory Volume in one second (FEV1) \< 70% of predicted, regardless of asthma status at screening or baseline assessment at the first dosing visit. * History of severe drug allergy, severe angioedema or systemic allergic reaction of Grade 3 or greater, according to the World Allergy Organization (WAO) scale, due to any cause.