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

This study is comparing KC1036 (an experimental treatment) against standard chemotherapy chosen by the doctor for people with advanced esophageal cancer that has already been treated with immunotherapy and at least one other line of chemotherapy. **You may be eligible if...** - You are between 18 and 75 years old - You have advanced esophageal or esophagogastric junction squamous cell carcinoma, confirmed by biopsy - Your cancer previously received a PD-1 or PD-L1 inhibitor and at least one other line of chemotherapy - You have at least one measurable tumor - Your general health (ECOG 0–1), weight (≥40 kg), and organ function meet study requirements **You may NOT be eligible if...** - You have untreated brain metastases - You have another cancer diagnosis in the last 5 years - You previously received irinotecan, docetaxel, or tegafur gimeracil oteracil (S-1) - You have significant cardiovascular disease - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.