The study consists of Part A and Part B. All participants will be asked to complete both Part A and Part B of the study. The study lasts for a total duration of up to approximately 46 weeks (including up to a 10-week screening period). Part A of the study lasts up to approximately 28 weeks (including the screening period). Part B of the study starts after completion of Part A and lasts up to approximately 18 weeks (including an approximately 4-week follow-up period after end of birch pollen season (BPS)), dependent on the start and end times of the natural BPS.
Primary objective: To assess the efficacy of a single dose of the anti- Bet v 1 monoclonal antibodies (mAb(s ) in the reduction of allergic nasal symptoms during an out-of-season birch allergen environmental exposure unit (EEU) challenge in participants receiving REGN5713-5714-5715 versus placebo (Part A)