A Study to Evaluate the Efficacy and Safety of AK139 in Participants With Seasonal Allergic Rhinitis

Inclusion Criteria: 1. Male or female aged 18-65. 2. Able to understand the study and voluntarily sign the ICF; 3. Diagnosed SAR according to the Criteria stated in the Chinese Guidelines for the Diagnosis and Treatment of Allergic Rhinitis (2022, Revised Edition), with or without allergic conjunctivitis, and have SAR history at least two years; 4. Have immunoglobulin E (Ig E)-mediated hypersensitivity to at least one pollen allergen in the current environment; 5. The SAR symptoms of participants remained inadequately control ledafter nasal spray corticosteroids and/or other SAR medications treatment throughout the previous same pollen season; 6. Adequate pollen exposure during the pollen season. 7. The SAR symptoms scores of the participants meet the requirements of the protocol at screening and baseline. 8. During the screening/run-in period, participants must complete at least 80% of the assessments in the diary card; 9. The participants agree to use highly effective contraception methods from the moment of signing of the ICF to 3 months after the last dose of the investigational product. Exclusion Criteria: 1. Type of rhinitis other than allergic rhinitis within 2 weeks before screening; 2. Allergic to any component of the investigational drug or intolerant to basis treatment.. 3. Concomitant or associated nasal diseases/conditions that, as determined by investigators, may affect the severity of the disease and the evaluation of therapeutic effects. 4. Ongoing use of prohibited treatments. Washout periods detailed in the protocol have to be adhered to. 5. Other reasons the investigators believes that the participants is not suitable to enrolled in this study.