Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has accepted and granted priority review for a new supplemental Biologics License Application (sBLA) for KEYTRUDA, Merck's anti-PD-1 therapy, in combination with platinum and fluoropyrimidine based chemotherapy for the first-line treatment of patients with locally advanced unresectable or metastatic carcinoma of the esophagus and gastroesophageal junction (GEJ). This sBLA is based on data from the pivotal Phase 3 KEYNOTE-590 trial, in which KEYTRUDA plus chemotherapy demonstrated significant improvements in the primary endpoints – overall survival (OS) and progression-free survival (PFS) – versus chemotherapy in these patients regardless of PD-L1 expression status and tumor histology. These data were presented at the European Society for Medical Oncology (ESMO) Virtual Congress 2020. The FDA has set a Prescription Drug User Fee Act (PDUFA), or target action, date of April 13, 2021.

KEYNOTE-590 is a Phase 3, randomized, double-blind trial evaluating KEYTRUDA in combination with platinum and fluoropyrimidine based chemotherapy versus placebo plus chemotherapy (cisplatin plus 5-fluorouracil [5-FU]) for the first-line treatment of patients with locally advanced unresectable or metastatic carcinoma of the esophagus and GEJ. The major efficacy outcome measures were OS and PFS. Additional efficacy outcome measures were objective response rate and duration of response. The study enrolled 749 patients.