A Clinical Study of Firsekibart for Injection in Adult-Onset Still's Disease

INTERVENTION: Control group:Glucocorticoids and immunosuppressive agents;Experimental group:Firsekibart, 200 mg, subcutaneous injection, once every 8 weeks.; CONDITION: Adult‐Onset Still’s disease (AOSD) PRIMARY OUTCOME: To evaluate the effects of Firsekibart on maintaining remission, preventing relapse, safety, and improving quality of life.; SECONDARY OUTCOME: Proportion of patients achieving AOSD 50%/70%/90% improvement criteria;Changes in SF‐36 score and fatigue VAS;Immunological mechanism outcomes: changes in peripheral blood immune cell subsets; inflammasome activity;Inflammatory storm‐related biomarkers;Time to disease relapse;Adverse Events; INCLUSION CRITERIA: 1.Aged 18–75 years, diagnosed with AOSD according to the Yamaguchi criteria; 2.Patients are in "clinical remission," defined as: absence of fever (body temperature <= 37.5°C); absence of typical rash; swollen joint count (SJC) <= 1; normalization of C‐reactive protein (CRP); 3.Received a stable dose of prednisone (or equivalent) of less than 10 mg/day for at least 8 weeks prior to screening to maintain remission.