Keytruda meets OS endpoint for second-line esophageal cancer

Merck & Co. Inc. (NYSE:MRK) said Keytruda pembrolizumab as monotherapy met the primary endpoint of improving overall survival (OS) vs. investigator's choice of chemotherapy in the Phase III KEYNOTE-181 trial as second-line treatment of advanced or metastatic esophageal or esophagogastric junction carcinoma.

Per the open-label trial's statistical analysis plan, Merck said the primary endpoint was evaluated in three patient groups -- patients whose tumors expressed PD-L1 with a Combined Positive Score (CPS) of at least 10; patients with squamous histology; and in the intent-to-treat (ITT) population of over 600 patients -- and that the trial would be considered successful if a significant improvement in OS was achieved in any of the three groups. Keytruda significantly improved OS vs. chemotherapy in patients whose tumors expressed PD-L1 with a CPS of at least 10, but did not significantly improve the endpoint in patients with squamous histology or in the ITT population. The company said the data will be presented at a medical meeting and submitted to worldwide regulatory authorities...