Bintrafusp alfa is a first-in-class bifunctional fusion protein that was designed for colocalized, simultaneous inhibition of two nonredundant immunosuppressive pathways, transforming growth factor-β (TGFβ) and programmed death-ligand 1 (PD-L1), within the tumor microenvironment.

In this expansion cohort of a phase 1 study, bintrafusp alfa had a manageable safety profile and demonstrated clinical activity in Asian patients with pretreated, PD-L1–unselected esophageal squamous cell carcinoma.

Along with the results of an expansion cohort of patients with advanced, post-platinum esophageal adenocarcinoma from a separate phase 1 study described in the accompanying article, further investigation of bintrafusp alfa in esophageal cancer is warranted.