Efficacy and Safety of Envafolimab Plus Doxorubicin and Ifosfamide for Advanced Soft Tissue Sarcoma

Inclusion Criteria: 1. Pathologically confirmed advanced soft tissue sarcoma with at least one measurable lesion. 2. No previous systemic treatment. 3. ≥18 years old; expected survival time more than 3 months; 4. Major organ function within 7 days before treatment, meeting the following criteria: (1) Routine blood test criteria (without blood transfusion within 14 days): * Hemoglobin (HB) ≥90g/L; ② Absolute neutrophil count (ANC) ≥1.5×109/L; ③ Platelet count (PLT) ≥80×109/L. (2) Biochemical examinations must meet the following criteria: ① Total bilirubin (TBIL) ≤ 1.5 times the upper limit of normal (ULN); ② Alanine aminotransferase (ALT) and aspartate aminotransferase AST ≤ 2.5 ULN. If liver metastasis is present, ALT and AST ≤ 5 ULN; ③ Serum creatinine (Cr) ≤ 1.5 ULN or creatinine clearance (CCr) ≥ 60ml/min; (3) Doppler ultrasound assessment: left ventricular ejection fraction (LVEF) ≥ lower limit of normal (50%). 5. Women of childbearing age must agree to use contraceptive measures (such as intrauterine devices, birth control pills or condoms) during the study and within 6 months after the study; serum or urine pregnancy tests must be negative within 7 days before study enrollment, and the patients must not be breastfeeding; men must agree to use contraceptive measures during the study and within 6 months after the study. Exclusion Criteria: 1. Chondrosarcoma (CS), osteosarcoma (OS), Ewing's sarcoma, dermatofibrosarcoma protuberans (DFSP), and gastrointestinal stromal sarcoma (GIST) are excluded; 2. Pregnant or lactating women, or women of childbearing potential who are not using contraceptive measures; 3. Current severe, uncontrolled acute infection; or purulent or chronic infection with a persistent wound; 4. Presence of a second primary tumor (excluding basal cell carcinoma of the skin); 5. Participation in other drug clinical trials within 4 weeks; 6. Presence of severe heart disease, including congestive heart failure, uncontrolled high-risk arrhythmias, unstable angina, myocardial infarction, severe valvular heart disease, and refractory hypertension; 7. Suffering from uncontrolled neurological, psychiatric, or mental disorders, poor compliance, and inability to match the medication. Patients with uncontrolled primary brain tumors or central nervous system metastases and significant intracranial hypertension or neuropsychiatric symptoms are excluded. 8. Evidence of a hereditary bleeding diathesis or coagulopathy. 9. A history of severe allergic/anaphylactic reactions to humanized antibodies. 10. Diagnosed with immunodeficiency or receiving systemic glucocorticoids or any other form of immunosuppressive therapy within 14 days prior to the first dose of the study drug. Physiological doses of glucocorticoids (≤10 mg/day of prednisone or equivalent) are permitted. 11. Subjects with active, known, or suspected autoimmune diseases (e.g., interstitial pneumonitis, colitis, hepatitis, hypophysitis, vasculitis, nephritis, including but not limited to these diseases or syndromes) are excluded.