Covalent warheads as a versatile platform for molecular glue development.

Targeted protein degradation (TPD) has become a novel therapeutic modality for diseases in drug discovery. Most progress on TPD has focused on the ubiquitin proteasome system; however, only a handful of >600 human genome-encoded E3 ligases have been successfully applied. Expansion of the E3 ligase toolbox with novel E3 ligases and their ligands will broaden the potential applications of TPD. Besides that, covalent molecular glue degraders (MGDs) provide a promising direction for TPD. Covalent MGDs may offer several advantages, including increased selectivity, broad applicability to traditionally undruggable proteins, and efficient protein degradation. This review systematically summarizes the latest progress in the field of covalent MGDs, focusing on validated E3 ligases and their corresponding covalent warheads. Structural features, modes of action, and design strategies of covalent MGDs are discussed aiming to provide guidance for the development of novel covalent MGDs.