A Phase II Single-arm Clinical Study in the Treatment of Locally Advanced Esophageal Cancer After Failed Neoadjuvant Chemoimmunotherapy

Inclusion Criteria: * Age 18 to 75 years, male or female; * Histologically confirmed locally advanced squamous cell carcinoma or adenocarcinoma of the esophagus or esophagogastric junction; * ECOG performance status 0-1; ④ Failure of or local progression after 2-4 cycles of first-line chemotherapy combined with immunotherapy, or deemed unresectable by surgical evaluation; ⑤ At least one measurable lesion according to RECIST v1.1 criteria; ⑥ Adequate major organ and bone marrow function: Hematology: Hemoglobin (Hb) ≥90 g/L (without transfusion within 14 days); Absolute neutrophil count (NEUT) ≥1.5×10⁹/L; Platelets (PLT) ≥100×10⁹/L; Biochemistry: Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5×ULN (≤5×ULN in cases of liver metastases); Total bilirubin (TBIL) ≤2×ULN; Serum albumin (ALB) ≥28 g/L; Serum creatinine (Cr) ≤1.5×ULN and creatinine clearance \>50 μmol/L; Coagulation: International normalized ratio (INR) and activated partial thromboplastin time (APTT) ≤1.5×ULN (unless the subject is receiving anticoagulant therapy and INR and APTT are within the expected therapeutic range); ⑦ Effective contraception during the study period; * Voluntary participation in this study with signed informed consent and good compliance. Exclusion Criteria: * Active bleeding or high risk of bleeding (as assessed by the investigator); * Patients requiring systemic anti-infective therapy; * Concurrent primary malignant tumors o…