A Study of Tislelizumab (BGB-A317) Versus Chemotherapy as Second Line Treatment in Participants With Advanced Esophageal Squamous Cell Carcinoma

Key Inclusion Criteria:

Histologically confirmed diagnosis of esophageal squamous cell carcinoma (ESCC)
Tumor progression during or after first-line treatment for advanced unresectable / metastatic ESCC
At least one measurable/evaluable lesion by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 prior to randomization

Key Exclusion Criteria:

Receipt of 2 or more prior systemic treatments for advanced/metastatic unresectable ESCC
History of gastrointestinal perforation and /or fistula or aorto-esophageal fistula within 6 months prior to randomization
Tumor invasion into organs located adjacent to the esophageal disease site (eg, aorta or respiratory tract) at an increased risk of fistula in the study treatment assessed by investigator
Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage
Received prior therapies targeting programmed death 1 (PD-1) or programmed death ligand 1 (immunotherapy-drugs-are-boosting-survival/" >PD-L1)
Prior malignancy active within the previous 2 years (exceptions include the tumor under investigation in this trial, and locally recurring cancers that have undergone curative treatment, such as resected basal or squamous cell skin cancer, superficial bladder cancer or carcinoma in situ of the prostate, cervix or breast)
Active brain or leptomeningeal metastasis.
Has active autoimmune disease or history of autoimmune diseases at high risk for relapse
Known history of, or any evidence of interstitial lung disease, non-infectious pneumonitis, pulmonary fibrosis diagnosed based on imaging or clinical findings, or uncontrolled systemic diseases, including diabetes, hypertension, acute lung diseases, etc
Known history of Human Immunodeficiency Virus (HIV)
Has cardiovascular risk factors
Pregnant or breastfeeding woman.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.