A Study of CS1001 in Subjects With Esophageal Squamous Cell Carcinoma

Inclusion Criteria

• •1. ≥ 18 years and ≤ 75 years on the day of signing informed consent form (ICF).
• •2. Fully informed of the study, with good compliance and willing to provide written ICF. The ICF must be signed before performing any protocol-related procedure (that is not a part of subject's routine medical care).
• •3. Subjects with pathohistologically or cytologically confirmed unresectable locally advanced, relapsed or metastatic ESCC (based on American Joint Committee on Cancer \[AJCC\] Guideline version 8, see Appendix 14.2)
• •4. Subjects must not be eligible for radical therapy such as radical chemoradiotherapy or surgery.
• •5. Subjects who have not received any systemic anti-neoplastic therapy as the main regimen for locally advanced or metastatic ESCC. (Subjects who received prior neoadjuvant, adjuvant or radical chemoradiotherapy for ESCC but had relapse or progression of disease 6 months after the completion of these treatments are allowed.)
• •6. ECOG PS 0 or 1.
• •7. Life expectancy ≥ 3 months.
• •8. Subjects have at least one measurable lesion as evaluated by the investigator according to RECIST v1.1, and the baseline imaging assessment must be performed within 28 days prior to the first dose of investigational product. Target lesions in the past radiation fields, if confirmed as radiological progression, are considered as measurable lesions.
• •9. Palliative treatment (e.g. radiotherapy) for local lesion must be completed ≥ 14 days prior to the first dose of investigational product.
• •10. Subjects must provide tumor tissue samples (formalin fixed-paraffin embedded \[FFPE\] tissue block or unstained tumor tissue sections) for biomarker analysis, in order to determine the expression of PD-L1.
• •11. Subjects must have adequate organ function as assessed in the following laboratory tests (subjects must not receive any blood transfusion or any hematopoietic growth factor within 7 days prior to the test)
• •12. Female subjects with childbearing potential (unless with documentation of sterilization surgery or being post-menopausal) must have negative serum pregnancy test result at screening. Female subject with childbearing potential (unless with documentation of sterilization surgery or being post-menopausal) or male subjects and their partners must agree to use an effective contraceptive measure from the day of signing ICF till at least 6 months after the last dose of investigational product.