In recent years, technologies have been developed to degrade target proteins in cells, and drug discovery research has been actively conducted. Molecular glues such as lenalidomide, and chimeric compounds such as PROTACs (Proteolysis Targeting Chimeras) and SNIPERs (Specific and Nongenetic IAP-dependent Protein Erasers) are well known. These compounds degrade the target proteins in the cells, and thus exhibit different pharmacological properties from small molecule inhibitors. PROTACs/SNIPERs are chimeric compounds, in which a ligand that binds to a target protein is linked to a ligand that binds to the E3 ubiquitin ligase, forcing the target protein to be ubiquitylated and degraded by proteasome in the cells. The modular structure of PROTACs/SNIPERs allows us to rationally design the compounds to degrade protein of your interest by substituting target ligands, and therefore, it is expected to be a novel platform technology for drug discovery. In this talk, I will introduce our SNIPER compounds and the current status of proteolytic drug development.