Esophageal Cancer Clinical Trials

• The patient or their legal representative is able to sign the written informed consent form and understands and agrees to comply with the study requirements;

• Age ≥ 18 years and \< 75 years at the time of signing the informed consent form, regardless of gender;

• Histologically confirmed esophageal squamous cell carcinoma, confirmed by imaging examinations such as CT, MRI, or PET-CT as locally advanced unresectable ESCC (medically unsuitable for surgery or refusal of surgical intervention), and suitable for cCRT, including: stages II-IVa and certain cases of stage IVb (involving only supraclavicular lymph node metastasis) (AJCC version 8 ) meeting the criteria;

• Estimated life expectancy of at least 6 months;

• ECOG performance status score of 0-2;

• Presence of measurable and/or non-measurable lesions as defined by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1);

• No prior systemic anti-tumor therapy (including but not limited to systemic chemotherapy, radiotherapy, molecular targeted therapy, immunotherapy, biological therapy, local therapy, or other investigational treatments);

• Adequate organ function, as indicated by laboratory test results obtained within 14 days prior to enrollment:

• a. Achieved without the need for blood transfusion, growth factor therapy, or other supportive medications that significantly affect neutrophil count, platelet count, or hemoglobin within ≤ 14 days before sample collection during screening: absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L; platelet count ≥ 100 × 10⁹/L; hemoglobin ≥ 90 g/L;

⁃ b. Estimated glomerular filtration rate ≥ 60 mL/min/1.73 m² using the Chronic Kidney Disease Epidemiology Collaboration equation (Appendix 9);

⁃ c. Serum total bilirubin ≤ 1.5 × ULN (for patients with Gilbert's syndrome, total bilirubin must be ≤ 3 × ULN);

⁃ d. Aspartate aminotransferase and ALT \< 3 × ULN;

⁃ For patients with inactive/asymptomatic carriers, chronic or active HBV infection, the following criteria must be met:

⁃ HBV DNA \< 500 IU/mL (or 2500 copies/mL) during screening;

⁃ Note: Patients with positive hepatitis B surface antigen or detectable HBV DNA should be managed according to treatment guidelines. Patients receiving antiviral therapy during screening must have undergone treatment for \> 2 weeks prior to enrollment;

⁃ Female patients of childbearing potential must voluntarily agree to use highly effective contraception during the study period, for ≥ 120 days after the last dose of camrelizumab or placebo, and for ≥ 180 days after the last dose of chemoradiotherapy, and must have a negative urine or serum pregnancy test result within ≤ 7 days prior to enrollment;

⁃ Male patients who are not sterilized must voluntarily agree to use highly effective contraception during the study period, for ≥ 120 days after the last dose of camrelizumab or placebo, and for ≥ 180 days after the last dose of chemoradiotherapy.