This is a multicenter, randomized, double-blind, placebo-controlled phase III clinical study to evaluate the efficacy and safety of LP-003 injection in patients with moderate to severe seasonal allergic rhinitis inadequately controlled by standard-of-care.

Inclusion Criteria:

• Male or female, aged 18 to 65 years
• Subjects with SAR for at least 2 years
• At least one serum-specific IgE test for an allergen associated with the onset of allergic rhinitis during the current season or the same period
• Subjects who did not achieve satisfactory efficacy from Standard-of-Care prior to screening
• Subjects who experienced nasal symptoms for ≥ 2 days, or nasal and ocular symptoms for ≥ 1 day; with rTNSS ≥ 1 prior to randomization

Exclusion Criteria:

• Combined with non-allergic rhinitis, such as drug-induced rhinitis, vasomotor rhinitis, non-allergic rhinitis with eosinophilia syndrome, a history of acute or chronic sinusitis
• Subjects with perennial allergic rhinitis (PAR)
• Underwent any nasal or sinus surgery within 1 year prior to screening
• Presence of glaucoma, cataract, ocular herpes simplex, infectious conjunctivitis, or other ocular infections
• Clinically significant conditions upon the judgement of investigator
• Subjects with concomitant asthma who, upon the judgement of investigator, require inhaled corticosteroid treatment during the study
• The laboratory results at screening: a) white blood cell (WBC) < 2.5×10^9/L; b) aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 2.0 ×upper limit of normal (ULN) or total bilirubin > 1.5 ×ULN; c) Serum creatinine (Cr) > 1.5 × ULN
• Received treatment with similar drugs (e.g., Omalizumab) or used LP-003 Injection within 6 months prior to screening
• Received systemic glucocorticoids within 4 weeks prior to screening
• Received intranasal glucocorticoids, mast cell membrane stabilizers, tricyclic antidepressants, leukotriene receptor antagonists, or antihistamine medications within 1 week prior to randomization
• Received traditional Chinese medicine treatment for allergic rhinitis within the 7 days prior to randomization
• Received allergen immunotherapy within 6 months prior to screening (for those who have not completed the therapy), or within 3 years prior to screening (for those who have completed the therapy)
• Subjects for whom exposure to allergens in the home or work environment are expected to undergo significant changes during the trial, as assessed by the investigator, which may interfere with the evaluation of efficacy
• Subjects planning to travel outside their area of residence during the trial to an area without pathogenic pollen, for either 2 consecutive days or a total duration exceeding three days