A Study of KC1036 Versus Investigator's Choice of Chemotherapy in Patients With Advanced Esophageal Cancer

Inclusion Criteria: * Males or females aged 18 to 75 years; * Histologically or cytologically confirmed esophageal or esophageal-gastric junction squamous cell carcinoma; * Patient with advanced recurrent or metastatic esophageal squamous cell carcinoma previously treated with a PD-1 or PD-L1 inhibitor and at least second-line systemic therapy; * At least one measurable tumor lesion according to RECIST 1.1; * Eastern Cooperative Oncology Group performance status score of 0 or 1; * Life expectancy \> 12 weeks; * BMI≥16.0 and weight≥40 kg ; * Adequate bone marrow, renal, and hepatic function; * Female patients of childbearing potential with a negative blood pregnancy test completed within 7 days before randomization； * Patients should participate in the study voluntarily and sign informed consent. Exclusion Criteria: * Any patient who is known to have untreated central nervous system (CNS) metastasis; * Other kinds of malignancies within 5 years; * Gastrointestinal abnormalities; * Cardiovascular and cerebrovascular diseases; * Prior therapies with vascular targeting inhibitor； * Previously treated with Irinotecan, Docetaxel and Tegafur Gimeracil Oteracil Potassium； * Involved in other clinical trials within 4 weeks before enrollment；Prior anti-tumor therapies with radiotherapy, immunotherapy, operation within 4 weeks before enrollment;Prior anti-tumor therapies with small molecule targeting drugs within 2weeks or 5 half-lives (whichever is longer) before enrollment; Prior anti-tumor therapies with chemotherapy within 3 weeks or 5 half-lives (whichever is longer) before enrollment; * Presence of unresolved toxicities from prior anti-tumor therapy, defined as having not resolved to NCI CTCAE 5.0 Grade 0 or 1; * Uncontrolled massive ascites, pleural or pericardial effusion; * Severe infection within 4 weeks prior to randomization (CTCAE \> Grade 2); * Known history of human immunodeficiency virus (HIV) infection or current active hepatitis B or C infection; * Pregnant or lactating women; * Female subjects of child-bearing potential and male subjects of reproductive capacity who do not agree to use contraceptive measures during the study and for 6 months after the end of the study. * Other patients are not eligible for enrollment assessed by investigators.