Clinical Trial of TQC2731 Injection in Patients With Chronic Sinusitis and Nasal Polyps

Inclusion Criteria: * Signed informed consent form prior to trial participation, demonstrating full understanding of trial objectives, procedures, and potential adverse reactions. * Age between 18 and 75 years (inclusive) at the time of informed consent signing, regardless of gender. * Diagnosis of bilateral chronic rhinosinusitis with nasal polyps (CRSwNP) meeting the diagnostic criteria of the "Chinese Guidelines for the Diagnosis and Treatment of Chronic Rhinosinusitis (2018)" * At least one prior course of systemic corticosteroids (prednisone 0.5-1 mg/kg/day or 15-30 mg/day or equivalent for minimum 5 days) within 2 years before screening, with persistent bilateral CRSwNP; AND/OR contraindication/intolerance to systemic corticosteroids; AND/OR prior nasal polyp surgery performed more than 6 months before screening. * Bilateral Nasal Polyp Score (NPS) ≥5 (maximum score 8) with ≥2 points per nostril, as assessed by nasal endoscopy during screening and randomization. * Nasal Congestion Score (NCS) ≥2 at screening (daily average) and randomization (weekly average). * Persistent symptoms of rhinorrhea and/or hyposmia/anosmia for over 8 weeks prior to screening. * 22-item Sino-Nasal Outcome Test (SNOT-22) score ≥30 at screening and randomization. * Stable dose of intranasal corticosteroids (INCS) for \>4 weeks prior to screening (subjects using non-mometasone furoate nasal spray \[MFNS\] products must agree to switch to Mometasone Furoate Nasal Spray (MFNS) during the study). * Subjects with comorbid asthma must have had stable asthma symptoms for ≥4 weeks prior to screening (if using medications, such as inhaled corticosteroids, the same dose must have been stably maintained for ≥4 weeks before screening, and the dose is assessed to remain stable during the first phase). * The evaluation during the lead-in period showed that the medication adherence to intranasal mometasone furoate nasal spray (MFNS) was greater than 70%, and the adherence to daily symptom assessment records in the subjects' electronic logs was also greater than 70%. Note: Days with missing electronic log data were considered non-adherent to this criterion. * Agreement to practice effective non-pharmacologic contraception from informed consent until 6 months post-final dose, for subjects/partners of childbearing potential. Exclusion Criteria: * Conditions/Diseases Affecting Efficacy Evaluation * Nasal septum deviation causing ≥1 nostril obstruction； * Perforation of the nasal septum * Acute sinusitis, nasal infection, or upper respiratory infection within 2 weeks pre-screening or during screening/run-in periods； * Rhinitis medicamentosa； * Eosinophilic granulomatosis with polyangiitis (EGPA), granulomatosis with polyangiitis (GPA), Young's syndrome, Kartagener's syndrome, other ciliary dyskinesia syndromes, or cystic fibrosis； * Suspected or confirmed fungal sinusitis by imaging； * Prior nasal surgery altering lateral wall structure precluding NPS assessment； * Nasal malignancies or benign tumors (e.g., papilloma, hemangioma)； * Any intranasal and/or sinus surgery (including polypectomy) within 6 months prior to screening. * Uncontrolled epistaxis within 2 months prior to screening. * Regular use of decongestants (topical or systemic) prior to screening, except for short-term use during endoscopic examinations. * Patients who have received any of the following treatments prior to randomization: * Treatment with immunosuppressants (including but not limited to: cyclophosphamide, cyclosporine, interferon gamma, azathioprine, methotrexate, mycophenolate, tacrolimus, Secukinumab) within 8 weeks or 5 half-lives prior to screening (whichever is longer)； * Treatment with any monoclonal antibodies (including but not limited to: benralizumab, mepolizumab, omalizumab, dupilumab, or other similar drugs \[e.g., TSLP blockers\]) within 8 weeks or 5 half-lives prior to screening (whichever is longer). * Patients who used medium- or short-acting systemic corticosteroids (SCS, including oral, intravenous, or intramuscular administration), systemic traditional Chinese medicine preparations for treating CRS within 4 weeks prior to screening, or received long-acting SCS (e.g., triamcinolone acetonide injection) within 6 weeks prior to screening, or who plan to receive the aforementioned medications during the study period. * Use of corticosteroid-eluting nasal stents within 6 months prior to screening; * Treatment with immunoglobulins or blood products within 28 days prior to screening; * Administration of live attenuated vaccines within 28 days prior to screening or planned during the study period; * Allergen-specific immunotherapy within 6 months prior to screening (allowed only if: initiated \>3 months before screening, maintained at a stable dose for ≥1 month before Visit 1, and no planned dose changes during the study)； * Participation in other drug/medical device clinical trials within 3 months prior to screening (based on last administration/use). * Use nasal antihistamines (such as olopatadine nasal spray, azelastine nasal spray, levocabastine nasal spray, etc.) for the first 3 days. * Screening for a history of active pulmonary tuberculosis within the past 12 months； * Exclusion of infections within the last 14 days requiring systemic antibiotic, antiviral, antifungal, antiparasitic, or antiprotozoal therapy; * Exclusion of subjects diagnosed with helminthic parasitic infection in the past 6 months who either did not receive standard treatment or had treatment failure； * Known or suspected history of immunosuppression, immune dysfunction, or immune dysregulation, including but not limited to invasive opportunistic infections (histoplasmosis, listeriosis, coccidioidomycosis, pneumocystosis, aspergillosis), even if the infection has resolved; Or there is an unusual frequency, recurrence, or prolonged infection (as judged by the investigator). * The forced expiratory volume in the first second (F