This study is researching 2 experimental drugs, REGN5713 and REGN5715. The study drugs will be either of these drugs given alone (either REGN5713 or REGN5715) or given together (REGN5713 and REGN5715) to reduce eye allergy signs and symptoms due to birch tree pollen allergy.

The aim of the study is to see how safe and effective the study drugs are at lowering eye allergy signs and symptoms compared with placebo.

The study will also evaluate whether the combination (REGN5713-5715) has different effectiveness than REGN5713 or REGN5715 alone.

The study is looking at several other research questions, including:

• What side effects may happen from taking the study drugs
• How much of the study drugs is in the blood at different times
• Whether the body makes antibodies against the study drugs (which could make the drug less effective or could lead to side effects)

Key Inclusion Criteria:

1. Positive SPT to birch allergen extract
2. Positive allergen specific Immunoglobulin E (sIgE) tests for birch and Bet v 1
3. Positive CAC criteria

Key Exclusion Criteria:

1. Significant and/or severe environmental allergies causing symptoms (outside of the challenge setting) that are expected to interfere with study assessments
2. Presence of any ophthalmic disease/abnormality/condition that may interfere with study assessments, affect the study outcomes or negatively impact participant safety
3. A clinical history of asthma with treatment of asthma requiring systemic (oral or parenteral) corticosteroid treatment more than twice within prior 12 months or once within 3 months prior to screening visit 1 or has been hospitalized or has attended the Emergency Room/Urgent Care facility for asthma in the 12 months prior to screening

Note: Other protocol defined Inclusion/Exclusion criteria apply.

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf