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.