Inclusion Criteria:
* Subjects must meet all of the following criteria to be eligible for participation in this clinical trial.
1. The subject must understand the investigational nature of this study and must provide written informed consent, approved by an Institutional Review Board (IRB)/Independent Ethics Committee (IEC), prior to undergoing any study-related procedures.
2. Aged ≥18 and ≤65 years, regardless of gender.
3. Diagnosed with Non-Allergic Rhinitis with Eosinophilia Syndrome (NARES) according to the following criteria: chronic course lasting ≥2 years, with intermittent nasal symptoms including alternating nasal congestion, watery rhinorrhea, paroxysmal sneezing, nasal itching, postnasal drip, and hyposmia; with evidence against allergic rhinitis.
4. Laboratory evidence: negative serum Specific Immunoglobulin E (sIgE) and negative Skin Prick Test (SPT); nasal secretion eosinophil proportion \>20% (after excluding epithelial cells).
5. The subject's history prior to the screening period indicates inadequate control of NARES symptoms (with an iTNSS ≥4 and at least one of the symptoms - nasal congestion, rhinorrhea, nasal itching, or sneezing - scoring ≥2) despite the use of intranasal corticosteroids or other medications (e.g., antihistamines, leukotriene receptor antagonists) following symptom onset.
6. At the baseline visit (after run-in treatment), the subject must meet the following criteria: an iTNSS ≥4, the average of the most recent 6 daily Reflective Total Nasal Symptom Scores (rTNSS) ≥4, and at least one of the symptoms - nasal congestion, rhinorrhea, nasal itching, or sneezing - scoring ≥2 in these assessments (i.e., the 3 morning and 3 evening evaluations over the last three 24-hour periods, including the iTNSS assessment at the baseline visit).
7. Willing and able to comply with all visits, study-related procedures, and questionnaires, including adherence to required background medications and completion of a daily electronic diary (eDiary). During the screening/run-in period, subjects must complete at least 80% of the diary assessments.
8. Subjects agree to use highly effective contraception (including vasectomy, abstinence, etc.) throughout the study period (from signing the ICF until 3 months after the last dose of study drug).
Exclusion Criteria:
* Subjects who meet any of the following criteria are not eligible to participate in this clinical trial.
1. History of allergy to study drugs: hypersensitivity or intolerance to mometasone furoate, loratadine, CM310 injection, or any component of the placebo.
2. Laboratory abnormalities: severe hepatic or renal dysfunction, abnormal liver function \[Alanine Aminotransferase (ALT)/Aspartate Transaminase (AST) \>1.5 × Upper Limit of Normal (ULN), or Total Bilirubin (TBIL) \>1.5 × ULN with abnormal AST\] or abnormal renal function (serum creatinine \>1.2 × ULN); clinically significant abnormalities in laboratory blood chemistry or hematology results at screening (Visit 1) or baseline (Visit 2) as judged by the investigator.
3. History of harmful behavior: history of drug abuse, alcohol dependence (average daily alcohol intake \>40 g) within 2 years prior to screening, or current drug user.
4. Currently receiving allergen immunotherapy (subcutaneous or sublingual immunotherapy \[SCIT/SLIT\]). Subjects who discontinued SCIT/SLIT ≥3 years prior to randomization and are not on a maintenance regimen are eligible.
5. Use of any rescue medication during the screening and run-in periods.
6. Nasal procedure history at screening (Visit 1): nasal sinus surgery within 1 year prior to screening or presence of unhealed nasal trauma.
7. Drug exposure at screening (Visit 1): participation in another drug clinical trial and use of an investigational drug within 3 months prior to screening, or planned use of another investigational drug during the study.
8. Vaccination at screening (Visit 1): receipt of a live attenuated vaccine within 12 weeks prior to screening or planned vaccination with a live attenuated vaccine during the trial.
9. Ocular disease at screening (Visit 1): presence of glaucoma, cataract, ocular herpes simplex, infectious conjunctivitis, or other ocular infections.
10. Infection history at screening (Visit 1): active or inactive pulmonary tuberculosis infection; untreated localized or systemic fungal, bacterial, viral, or parasitic infection requiring ongoing treatment which, in the investigator's judgment, may place the subject at undue risk or affect result interpretation (e.g., severe infection requiring hospitalization and/or IV or equivalent oral antibiotics); symptomatic herpes zoster infection not resolved at screening; recurrent infections (including but not limited to recurrent cellulitis, chronic osteomyelitis). Subjects with only recurrent, mild, uncomplicated herpes labialis and/or genital herpes may be enrolled. Subjects with a history of active or latent tuberculosis with written evidence of adequate treatment, no history of re-exposure since completion of treatment, and no evidence of active tuberculosis on chest X-ray at screening may be enrolled.
11. Subjects with comorbid asthma (including suspected asthma) are excluded if they meet any of the following: FEV1 ≤60% of predicted; or an asthma exacerbation within 3 months prior to screening requiring systemic corticosteroids or hospitalization (\>24 hours); or required inhaled corticosteroid dosage \>1000 μg fluticasone propionate or equivalent.
12. Known history of recurrent acute or chronic rhinosinusitis, defined as requiring systemic antibiotic treatment within 3 months prior to screening, or \>4 recurrences within 2 years prior to screening.
13. Conditions affecting drug deposition: nasal disease or symptoms/signs identified during screening or prior to randomization that, in the investigator's judgment, may affect intranasal drug deposition, such as acute or chronic sinusitis, symptoms/signs of chronic purulent postnasal drip, rhinitis medicamentosa, nasal polyps, vasomotor rhinitis, other clinically significant respiratory tract deformities/nasal structural abnormalities, significant nasal trauma (e.g., penetrating injury), or significant nasal septum deviation; any nasal mucosal erosion, nasal septum ulcer, or perforation at screening or prior to randomization; recent nasal piercing not fully healed that may cause nasal symptoms, or planned new nasal piercing during the study.
14. Restricted medication use prior to run-in period: use of the following medications and/or treatments within a specified time prior to the run-in period or within 5 half-lives of the drug: IL-4Rα antagonists (within 10 weeks or 5 half-lives), vasoconstrictors (3 days), strong sedatives (3 days), antihistamines (10 days), decongestants (3 days), leukotriene receptor antagonists (7 days), anticholinergics (7 days), cromolyn-like drugs (14 days), systemic antibiotics (14 days), ocular mast cell stabilizers (14 days), monoamine oxidase inhibitors (14 days), tricyclic antidepressants (14 days), strong CYP3A4 inducers/inhibitors (14 days), anti-allergy Chinese herbal medicines (14 days), short- or medium-acting systemic corticosteroids (4 weeks), long-acting systemic corticosteroids (6 weeks), immunotherapy such as desensitization therapy and other biologic monoclonal antibody therapies (3 months), etc.
15. Immunosuppression: treatment with biologics/systemic immunosuppressants (including but not limited to methotrexate, cyclosporine, mycophenolate mofetil, tacrolimus, penicillamine, sulfasalazine, hydroxychloroquine, azathioprine, cyclophosphamide) for inflammatory or autoimmune diseases (e.g., rheumatoid arthritis, inflammatory bowel disease, primary biliary cholangitis, systemic lupus erythematosus, multiple sclerosis) within 8 weeks prior to randomization or within 5 half-lives (whichever is longer); known or suspected history of immunosuppression, including history of invasive opportunistic infections (e.g., histoplasmosis, listeriosis, coccidioidomycosis, pneumocystosis, aspergillosis) even if resolved; or abnormally frequent, recurrent, or prolonged infections as judged by the investigator.
16. Restricted medication use during the trial: planned use during the trial of the following drugs and/or treatments: a. strong CYP3A4 inducers/inhibitors; b. chronic or intermittent use of corticosteroids (except investigational product); c. antihistamines; d. leukotriene receptor antagonists; e. mast cell membrane stabilizers; f. systemic or intranasal decongestants; g. anticholinergics; h. immunosuppressants; i. anti-allergy Chinese herbal medicines/proprietary Chinese medicines/health products; j. anti-IgE antibodies (e.g., omalizumab for injection); k. nasal irrigations (including saline).
17. Female subjects who are pregnant, breastfeeding, or planning to become pregnant or breastfeed during the study.
18. Presence of any other medical or psychological condition that, in the investigator's opinion, may indicate a new and/or insufficiently understood disease, participation in this clinical study may pose an unreasonable risk to the subject, may make the subject unable to participate stably in the study, or may interfere with study evaluations.
19. Geographical restrictions: planned long-term travel away from the place of residence for ≥4 consecutive weeks during the trial, or planned residence in an area with a significantly different climate from the long-term place of residence.
20. Previous participation in a CM310 clinical trial.
21. Previous use of any anti-IL-4Rα monoclonal antibody (e.g., dupilumab) with inadequate treatment response (e.g., treatment failure or intolerance).
22. Presence of other uncontrolled severe diseases or recurrent chronic comorbidities, including but not limited to active infection, cardiovascular and cerebrovascular diseases, tuberculosis or other pathogen infections, diabetes, autoimmune diseases, human immunodeficiency virus (HIV) infection, Treponema pallidum infection, active hepatitis B or C, or parasitic diseases.
23. History of malignancy within 5 years prior to screening.
24. Any other medical or non-medical condition that, in the investigator's opinion, makes the subject unsuitable for participation in this study
