To evaluate the efficacy and safety of different doses of Sublingual Film for Dermatophagoides Pteronyssinus in adult patients with Dust Mite Allergic Rhinitis via a randomized, double-blind, placebo-controlled Phase II clinical trial, and to explore the optimal dose for the Phase III clinical trial.

This study consisted of 5 groups, including 4 treatment groups with different doses and 1 placebo group.

Subjects used Sublingual Film for Dermatophagoides pteronyssinus or a placebo (a look-alike substance that contains no drug) for approximately 52 weeks, and recorded in E-diary the usage of the investigational product, adverse events, concomitant medications, and the use of rescue medication.

Four efficacy data collection periods (each lasting 4 weeks) were scheduled during the trial: Week 13-16, Week 25-28, Week 37-40, and Week 49-52.

During these efficacy data collection periods, subjects were required to complete E-diary to record rhinitis symptoms (conjunctivitis symptoms were recorded simultaneously for subjects with concurrent conjunctivitis).

Inclusion Criteria:

• Aged between 18 and 60 (including 18 and 60), male or female;
• Diagnosed with allergic rhinitis (documented by medical records/prescriptions/specific IgE test reports for allergens, etc.) for ≥ 6 months prior to screening;
• Skin Prick Test (SPT) during screening shows a maximum wheal diameter of ≥ 5 mm for Dermatophagoides pteronyssinus;
• Dermatophagoides pteronyssinus (or mite mix containing Dermatophagoides pteronyssinus) specific immunoglobulin E (IgE) levels of class 3 or higher during screening;
• Pulmonary function test (routine spirometry) during screening shows FEV₁ % predicted ≥ 70%;
• Total daily nasal symptom score ≥ 6 for at least 5 days out of the last consecutive 10 days within the 14 days prior to randomization;
• Use of symptomatic medication for allergic rhinitis on at least 5 days out of the last consecutive 10 days within the 14 days prior to randomization;
• Subjects have fully understood the purpose, nature, methods and potential adverse reactions of the trial, voluntarily participate in this clinical trial, and are able to provide written informed consent prior to initiation of any study procedures;
• Subjects are able to communicate well with the investigators and understand and comply with all requirements of this clinical trial.

Exclusion Criteria:

• Subjects have a history of seasonal allergic rhinitis, and the onset season may overlap with the baseline or primary efficacy data collection period;
• Subjects have a serum specific IgE test result of Grade ≥ 2 for common allergens such as pollen, animal dander, and mold; and in the investigator's judgment, the subject has a history of allergen exposure/contact and will be exposed to/come into contact with the relevant allergens during the trial;
• Currently suffering from nasal diseases such as chronic sinusitis or nasal polyps that, in the investigator's judgment, may affect the evaluation of efficacy;
• Received beta-blockers or angiotensin-converting enzyme (ACE) inhibitors prior to dosing, with a washout period of less than 5 elimination half-lives of the respective drug;
• Received mite-allergen and specific immunotherapy (including Subcutaneous Immunotherapy and Sublingual Immunotherapy) within 3 years prior to dosing, or is currently receiving any allergen-specific immunotherapy;
• Received Anti-IgE antibody therapy (e.g., omalizumab) or other biological agents affecting IgE production (e.g., dupilumab, spicabiosen) prior to dosing, with a washout period of less than 5 elimination half-lives of the respective drug;
• Received systemic immunosuppressive therapy within 14 days prior to dosing;
• Currently suffering from oral diseases such as oral ulcers, or upper gastrointestinal diseases including esophagitis and dysphagia that, in the investigator's judgment, may affect medication compliance;
• Has a history of severe allergic reaction/anaphylaxis;
• Experienced an asthma exacerbation requiring emergency treatment or hospitalization within 1 year prior to screening; or had > 2 episodes of nocturnal awakening due to asthma within 1 month prior to screening; or used inhaled short-acting beta2 agonists > 2 times per week;
• Has a history of irreversible obstructive respiratory disease, severe cardiovascular disease, severe autoimmune disease, immunodeficiency disorder, or malignant tumor;
• Lactating female, positive pregnancy test, or female of childbearing potential unwilling to use effective contraception during the trial;
• Participated in another clinical trial and received investigational medicinal product within 1 month prior to screening;
• Any other condition that, in the investigator's opinion, renders the subject unsuitable for participation in this study.