

Patients could be treated with KEYTRUDA for up to 24 months in the absence of disease progression. Treatment with KEYTRUDA or chemotherapy continued until unacceptable toxicity or disease progression.

Randomization was stratified by tumor histology (squamous cell carcinoma vs.

Patients with active autoimmune disease, a medical condition that required immunosuppression, or who received prior systemic therapy in the locally advanced or metastatic setting were ineligible. PD-L1 status was centrally determined in tumor specimens in all patients using the PD-L1 IHC 22C3 pharmDx kit. The efficacy of KEYTRUDA was investigated in KEYNOTE-590, a multicenter, randomized, placebo-controlled trial that enrolled 749 patients with metastatic or locally advanced esophageal or gastroesophageal junction (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma who were not candidates for surgical resection or definitive chemoradiation.
