Envafolimab: First Approval.

Envafolimab (®) is a subcutaneously (SC) administered single domain anti-programmed death ligand 1 (PD-L1) antibody being developed for the treatment of various solid tumours and chronic hepatitis B in China, and for soft tissue sarcomas and biliary tract cancer in the USA. Single-domain antibodies are more soluble and more rapidly penetrate tissues than full monoclonal antibodies, enabling SC administration. Based on the results of a pivotal phase II trial, SC envafolimab was recently approved in China for the treatment of adult patients with previously-treated microsatellite instability-high (MSI-H) or deficient MisMatch Repair (dMMR) advanced solid tumours. This article summarizes the milestones in the development of envafolimab leading to this first approval.