Tofacitinib for Glucocorticoid-Resistant Moderate-to-Severe Thyroid Eye Disease

Inclusion Criteria: 1. Age and Gender: Male or female participants aged 18 to 75 years (inclusive). 2. Diagnosis: Clinical diagnosis of Graves' orbitopathy (GO) consistent with EUGOGO criteria. 3. Severity: Moderate-to-severe GO as defined by EUGOGO guidelines (impact on daily life, but not sight-threatening). 4. Activity: Active disease, defined as a Clinical Activity Score (CAS) \>=3 points (on the 7-point scale). 5. Refractory Status (Must meet ONE of the following):Glucocorticoid-Resistant: Failure to respond (no significant improvement in proptosis or CAS) after receiving a cumulative dose of at least 3g of intravenous methylprednisolone (or equivalent).Glucocorticoid-Intolerant: Documented contraindications to high-dose systemic glucocorticoids (e.g., uncontrolled diabetes mellitus, severe osteoporosis, glaucoma, severe psychiatric disorders) or history of severe adverse events leading to discontinuation. 6. Thyroid Function: Euthyroid or mild hypothyroidism/hyperthyroidism maintained on stable antithyroid drugs or thyroxine replacement therapy for at least 4 weeks prior to baseline. 7. Contraception: Women of childbearing potential must agree to use effective contraception during the study period and for at least 4 weeks after the last dose of the study drug. 8. Consent: Willing and able to provide written informed consent and comply with study procedures. Exclusion Criteria: * 1.Sight-Threatening Disease: Presence of Dysthyroid Optic Neuropathy (DON) or severe corneal breakdown requiring immediate surgical intervention. 2.Chronic/Inactive Disease: Fibrotic or burnout stage of GO with a Clinical Activity Score (CAS) \< 3. 3.Prior Orbital Treatment:Orbital radiotherapy at any time.Orbital surgical decompression at any time.Strabismus surgery or eyelid surgery within 3 months prior to baseline. 4.Concomitant Immunomodulation: Use of other biologic agents (e.g., Teprotumumab, Rituximab, Tocilizumab) within 3 months prior to baseline. 5.Active Infection Risk (Critical for JAK Inhibitors):Active tuberculosis (TB) or untreated latent TB.Active or chronic Hepatitis B or Hepatitis C infection.Human Immunodeficiency Virus (HIV) infection.History of disseminated herpes zoster or herpes simplex.Any severe active infection requiring hospitalization or IV antibiotics within 4 weeks of baseline. 6.Thrombosis Risk: History of venous thromboembolism (VTE), including deep vein thrombosis (DVT) or pulmonary embolism (PE), or known coagulation disorders. 8.Malignancy: History of any malignancy within the past 5 years (except adequately treated basal cell or squamous cell carcinoma of the skin, or carcinoma in situ of the cervix). 9.Laboratory Abnormalities:Absolute Neutrophil Count (ANC) \< 1.0 \*10\^9/L and/or Absolute Lymphocyte Count (ALC) \< 0.5 \*10\^9/L and /or Hemoglobin \< 90 g/L and/or AST or ALT \> 2\* Upper Limit of Normal (ULN) and/or Estimated Glomerular Filtration Rate (eGFR) \< 60 mL/min/1.73 m²