KEYNOTE-590

KEYNOTE-590, trial NCT03189719 sponsored by Merck and reported in 2020, added pembrolizumab to first-line cisplatin and fluorouracil chemotherapy for all types of advanced oesophageal cancer and Siewert type I junction tumours, with a survival benefit that held at five years. It randomised 749 patients and met its primary overall survival endpoint in all patients, with a larger effect in PD-L1 CPS 10 or higher, and the five-year follow-up published in ESMO Open in 2025 confirmed the benefit; the FDA approved it for all patients in March 2021 while the EMA restricted it to CPS 10 or higher. OnCo links it to oesophageal cancer, PD-1 as a target, pembrolizumab, the CPS term and Ken Kato. Benefit in PD-L1-negative disease is uncertain, which is the open question behind the regional label split.