Interventions against (mostly protein) drug targets must have compatible molecular characteristics; Many targets are amenable to small molecule activation or inhibition, but a large number are undruggable. This chapter begins with small molecule development focusing on the exploration of chemical space using virtual methods to identify diverse drug-like molecules. Efforts to influence undruggable targets are covered, notably in connection with covalent drugs or targeted protein degradation. Selected small molecule approaches are reviewed including those relating to macrocycles, GPCRs, prodrugs, RNA splicing and deuterated compounds. The section on protein therapeutics involves engineered forms of monoclonal antibodies and modified cytokines as well as virtual protein design. Nucleic acids are covered in the form of gene and RNA therapy either by direct administration, or through stem cell engineering. Finally, developments in cell therapies are reviewed, particularly in light of the intense interest in engineered cells of the immune system and in tissue regeneration.