This is a multicenter, randomized, double-blind, placebo-controlled, Phase 3 study designed to compare the efficacy and safety of tislelizumab + either cisplatin or carboplatin + gemcitabine versus placebo+ either cisplatin or carboplatin + gemcitabine in approximately 420 participants with locally advanced or metastatic urothelial carcinoma who have not received prior systemic therapy.

Key Inclusion Criteria:

1. Male or female aged 18 to 75 years on the day of signing the Informed Consent Form (ICF)
2. Histologically confirmed, inoperable, locally advanced, or metastatic urothelial cancer (UC)
3. Must be eligible to receive cisplatin or carboplatin in the investigator's judgment
4. Have had no prior systemic chemotherapy for locally advanced or metastatic UC
5. Must be able to provide fresh or archival tumor tissues with an associated pathological report.
6. Must have evaluable disease (either measurable or non-measurable) as defined per RECIST v1.1.
7. Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1.
8. Adequate organ function before randomization:

Key Exclusion Criteria:

1. Received prior therapies targeting PD-1, PD-L1, PD-L2, CTLA4, or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways.
2. Any approved anticancer therapy within 28 days before randomization.
3. Active leptomeningeal disease or uncontrolled, untreated brain metastasis
4. Participants with uncontrolled hypercalcemia
5. Participants with active autoimmune diseases or history of autoimmune diseases that may relapse
6. History of interstitial lung disease, noninfectious pneumonitis, or uncontrolled diseases
7. A known history of HIV infection.
8. Prior allogeneic stem cell transplantation or organ transplantation.
9. History of severe hypersensitivity reactions to other monoclonal antibodies. 10．History of allergic reactions to cisplatin, carboplatin, or other platinum-containing compounds.

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

BeiGene shares data on completed studies responsibly and provides qualified scientific and medical researchers access to data and supporting documentation for clinical trials in dossiers for medicines and indications after submission and approval in the United States, China, and Europe. Clinical trials supporting subsequent local approvals, new indications, or combination products are eligible for sharing once corresponding regulatory approvals are achieved.

BeiGene shares data only when permitted by applicable data privacy and security laws and regulations, when it is feasible to do so without compromising the privacy of study participants, and other considerations.

Qualified researchers with appropriate competencies who are engaged in novel scientific research may submit a request for participant-level data with a research proposal for BeiGene review. Research teams must include a biostatistician and sign a Data Sharing Agreement prior to receiving access to clinical trial data.

See plan description

See plan description