RATIONALE-306

RATIONALE-306, trial NCT03783442 sponsored by BeOne, formerly BeiGene, and reported in 2022, is the trial behind tislelizumab's US approval for first-line advanced oesophageal squamous cell carcinoma, with the biggest gains in PD-L1-positive tumours. It randomised 649 patients to tislelizumab or placebo with platinum chemotherapy and met its primary overall survival endpoint in all patients, published in Lancet Oncology in 2023, with a larger effect in PD-L1-positive disease; the FDA approved it on 4 March 2025 restricted to PD-L1 tumour area positivity of one percent or more, and the EU approved it in 2024. OnCo links it to oesophageal cancer, PD-1 as a target and tislelizumab, and the result is consistent with KEYNOTE-590, CheckMate 648 and ESCORT-1st. Whether a fifth PD-1 antibody in this setting competes on price rather than data is the practical question.