The purpose of this study is to evaluate the efficacy and safety of recombinant anti-EGFR monoclonal antibody（SCT200）in patients with advanced esophageal squamous cell carcinoma progressed following treatment with taxane/platinum/fluorouracil.

This is a open label, single-arm multicenter phase Ib study,and is designed to evaluate Objective Response Rate (ORR) in advanced esophageal squamous cell carcinoma progressed following treatment with taxane/platinum/fluorouracil treated with anti-EGFR monoclonal antibody SCT200.

Inclusion Criteria:

• Males or females. Aged 18 to 75 years old;
• Histologically or cytologically proven squamous cell carcinoma of the esophagus, which is locally unresectable or distant metastatic disease;
• Disease progressed following standard therapies. Patients has treated with taxane/platinum/fluorouracil and/or radiotherapy. Failure of standard therapy ：Disease progressed or developed non-tolerable toxicity during or within 3 months after last systemic chemotherapy or radical concurrent chemoradiotherapy. For adjuvant therapy/neoadjuvant therapy, disease relapse or progression during treatment or within 6 months after treatment is considered as failure of standard therapy;
• According to RECIST 1.1 , patients must have at least one measurable lesion which was not treated with local treatment such as radiotherapy. Tumour lesions situated in a previously irradiated area which have been demonstrated progression in the lesion, are considered measurable;
• With an Eastern Cooperative Oncology Group (ECOG) performance status 0-1;
• Life expectancy of longer than 3 months ( clinical assessment);
• Adequate organ and marrow function as defined below:

Absolute neutrophil count (ANC) greater than/equal to 1.5×l09/L; Platelets greater than/equal to 75×109/L; Hemoglobin greater than/equal to 80g/L; Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) less than/equal to 3 times ULN, or less than/equal to 5 times ULN if known liver metastases; Total bilirubin less than/equal to 1.5 within institutional limit of normal (ULN); Serum creatinine less than/equal to 1.5 times ULN; Electrolyte: magnesium greater than/equal to normal.

• Women of childbearing potential must not be pregnant as assessed by a negative urine or serum beta HCG test upon admission to the hospital, and must agree to use adequate contraception during the study until to 6 months after the last dose of SCT200.For male,if his sexual partners is child-bearing potential, he should use effective contraception from the time of signing the informed consent form until at least 6 months after the last dose of study drug.
• Able to provide written informed consent and can understand and comply with the requirements of the study;

Exclusion Criteria:

• Patients with active central nervous system metastasis or a history of central nervous system metastasis;(If the subject has been suspected with central nervous system metastasis,imaging examination confirmation must be performed within 28 days to exclude central nervous system metastasis;
• Patients with other primary malignancies except cured of non-melanoma skin cancer, carcinoma in situ of cervix or prostatic intraepithelial neoplasia;
• Patients who are allergic to analogue of SCT200 and/or its inactive ingredients;
• Patients administrated EGFR target treatment including EGFR TKI agent or anti- EGFR monoclonal antibody;
• Within 4 weeks, patients received anti-tumor drugs (such as chemotherapy, hormone therapy, immune therapy, the antibody therapy, radiotherapy) or research drugs, or patients with grade 2 or more adverse reaction caused by previous anti-tumor therapy(except alopecia or neurotoxicity grade 2 or less);
• Patients are currently enrolled in other research devices or in research drugs, or less than 4 weeks from other research drugs or devices;
• Patients received major surgery(such as need general anesthesia ) within 4 weeks , should recover from the injury associated with the surgery;
• Patients treated with EPO, G-CSF or GM-CSF;
• Patients who have clinically significant cardiovascular disease (defined as unstable angina pectoris, symptomatic congestive heart failure (NYHA, greater than II), uncontrollable severe arrhythmia);
• Patients occurred myocardial infarction within 6 months;
• Patients who have interstitial lung disease, such as interstitial pneumonia, pulmonary fibrosis, or CT or MRI reminder ILD ;
• Patients with clinical symptoms, required clinical intervention or stable time less than 4 weeks of serous cavity effusion (such as pleural effusion and ascites);
• Patients with active hepatitis B or active hepatitis C, etc. (for patients with a history of hepatitis B, whether treated or not, HBV DNA ≥104 or ≥ 2000IU/ml, HCV RNA≥15IU/ml); HIV antibody positive (if there is no clinical evidence suggesting that there may be HIV infection, there is no need to detect);
• Patients with uncontrolled active infections before enrollment 2 weeks (except simple urinary tract infection or upper respiratory tract infection);
• Patients have alcohol or drug addiction;
• Patients with serious abnormal medical, psychological or laboratory results history which may affect explanation of study results;
• Subjects are considered not suitable for the study by investigator,who have other conditions that may affect their adherence and the evaluation of study indicators.,