Study of IBI308 With Advanced/Metastatic Esophageal Squamous Cell Carcinoma After Failure of First-line Treatment

Inclusion Criteria

• Histologically or cytologically confirmed locally advanced unresectable or metastatic esophageal squamous cell carcinoma (excluding mixed adenosquamous carcinoma and other pathological types).
• Imaging evidence (e.g. CT scan) or clinical evidence (e.g. cytological report of new ascites or pleural effusion) of disease progression during or after first-line chemotherapy; Subjects have to receive at least one dose of first-line treatment, permitting discontinuation or dose reduction of one drug or exchange of fluorouracil drugs used during first-line treatment, and patients discontinuing first-line treatment due to intolerable toxicity are allowed to be enrolled; Neoadjuvant or adjuvant therapy (chemotherapy or chemo-radiotherapy) should be regarded as first-line treatment if there is disease progression during treatment or within 6 months after treatment discontinuation.
• At least one measurable lesion according to RECIST v1.1.
• ECOG PS score of 0 or 1.
• Subjects who have signed the written informed consent form and are able to follow the visit schedule and relevant procedures as specified in the study protocol.
• Age ≥ 18 and ≤ 75 years.
• Life expectancy ≥ 12 weeks.
• Female subjects of childbearing potential or male subjects with sexual partners of childbearing potential should use effective contraception throughout and within 6 months after treatment.
• Adequate organ and bone marrow functions, defined as follows:
• Hematology: absolute neutrophil count (ANC) ≥ 1.5×10^9/L; Platelet (PLT) count ≥ 100×10^9/L; Hemoglobin (HGB) ≥ 9.0 g/dL.
• Liver function: serum total bilirubin (TBIL) ≤ 1.5×upper limit of normal (ULN); Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5×ULN; Serum albumin ≥ 28 g/L.
• Renal function: Serum creatinine (Cr) ≤ 1.5 × ULN, or creatinine clearance (Ccr) ≥ 40 mL/min (calculated using the standard Cockcroft -Gault formula):
• Females: CrCl = (140-age) x body weight (kg) x 0.85/(72 x serum creatinine (mg/dL))
• Males: CrCl = (140-age) x body weight (kg) x 1.00/(72 x serum creatinine (mg/dL))

Exclusion Criteria

• Prior exposure to any anti-PD-1 or anti-PD-L1 antibody.
• Concurrent participation in another interventional clinical study, except for observational (non-interventional) clinical studies or in the follow-up phase of an interventional study.
• Receipt of any investigational products within 4 weeks prior to the first dose of study treatment.
• Receipt of the last dose of anti-tumor therapy (chemotherapy, targeted therapy, tumor immunotherapy, tumor embolization) within 3 weeks prior to the first dose of study treatment.
• Radiotherapy within 4 weeks prior to the first dose of study treatment.
• Receipt of immunosuppressive agents within 4 weeks prior to the first dose of study treatment, excluding topical glucocorticoids for intranasal, inhalation or other routes of administration, or physiological doses of systemic glucocorticoids (i.e., no more than 10 mg/day prednisone or equivalent doses of other glucocorticoids).
• Receipt of a live attenuated vaccine within 4 weeks prior to the first dose of study treatment or planned receipt of a live attenuated vaccine during the study.
• Subjects who have undergone major surgical procedures (craniotomy, thoracotomy or laparotomy) within 4 weeks prior to the first dose of study treatment or have unhealed wound, ulcers or bone fracture.
• Presence of toxicities induced by previous anti-tumor therapy that have not recovered to Grade 0 or 1 as assessed per NCI CTCAE 4.03 (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03) prior to the first dose of study treatment, excluding alopecia, and non-clinically significant and asymptomatic laboratory abnormalities.
• Known symptomatic metastases to central nervous system (CNS) and/or carcinomatous meningitis. Subjects previously treated for brain metastasis are eligible for the study provided the brain metasta