Study of BLU-808 in Allergic Rhinoconjunctivitis

Key Inclusion Criteria 1. Adults, 18 years of age or older, willing to provide written informed consent, and willing to comply with all study requirements. 2. History (\>2 years) of ragweed-induced ARC. 3. A positive ragweed skin prick test (mean diameter of ≥ 5 mm) in the last 6 months. 4. Must meet clinically relevant nasal and ocular symptoms as defined by the protocol. Key Exclusion Criteria Participants are excluded from the study if any of the following criteria are met: 1. Receiving medications (oral, nasal, topical, ocular, or injectable) to treat their ragweed or other allergy symptoms and/or receiving any medications that impact participants' safety or interfere with study assessments or interpretation of study results. 2. Have active rhinitis, sinusitis, and/or other severe allergies not associated with the ragweed pollen that may interfere with study symptom assessments. 3. Any prior or ongoing clinically significant illness, medical or psychiatric condition, surgical history, or physical finding that may interfere with the assessment or interpretation of study results. 4. Clinically significant moderate to severe, uncontrolled cardiovascular, renal or hepatic disease. 5. Significant bleeding risk or coagulation disorders. 6. Any form of smoking, vaping or history of alcohol and drug abuse. 7. Any malignancy within the past 5 years prior to Screening/AEC 1, except for basal cell or squamous cell carcinomas of the skin or carcinoma in situ. 8. Inadequately controlled asthma that could affect the safety of the participant or interfere with the assessment or interpretation of study results. 9. Known active/latent infection (viral, bacterial, fungal, helminth, or mycobacterial) such as tuberculosis, hepatitis B, hepatitis C, AIDS-related illness, or COVID-19 infection. 10. History of sinonasal conditions that may confound the assessment or interpretation of study results.