A Study of Single Dose of LP-003 in Adolescent Subjects

Inclusion Criteria: * Adolescent subjects aged ≥12 years and \<18 years, male or female. * History of allergic diseases (self-reported is acceptable), including, but not limited to, food allergies, allergic rhinitis, allergic asthma, urticaria, and atopic dermatitis. * Agreement to use effective contraception during the study and for 6 months after the end of the study. * Subject and parent or legal guardian able to understand and voluntarily sign the informed consent form, and comply with study visits and related procedures. Exclusion Criteria: * Allergic to LP-003 or its excipients. * Any serious or uncontrolled chronic disease (e.g., severe arrhythmia, ischemic heart disease, NYHA Class III/IV heart failure, severe pulmonary disease, inadequately controlled asthma, hypertension, diabetes, hypo- or hyperthyroidism) that may affect subject safety as determined by the Investigator. * History of severe allergic reactions. * Abnormal venous access, venipuncture or subcutaneous injection intolerance, history of needle or blood phobia. * Estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73m² at screening. * ALT or AST \> ULN and considered clinically significant by the Investigator. * Any other abnormal screening test result that, in the Investigator's opinion, could affect subject safety or study assessments. * Systemic corticosteroid therapy (intravenous, intramuscular, or oral) within 4 weeks prior to study drug administration. * Use of medications known to interact with epinephrine (e.g., β-blockers, ACE inhibitors, tricyclic antidepressants) within 4 weeks prior to administration. * Use of biologic products (e.g., omalizumab) within 6 months prior to administration. * Receipt vaccines within 14 days before administration or planning vaccination during the study. * Participation in other clinical trials within 3 months prior to screening or within 5 half-lives of investigational product discontinuation (whichever is longer). * Any other conditions that the Investigator considers subjects unsuitable for participation in the study.