Peptides are short sequences of amino acids and among the most potent bioactive substances known to man. Nature makes ample use of peptides to control, trigger and maintain its physiological processes. However, the use of peptides as therapeutic agents has always been handicapped by their intrinsic instability and inability to cross cellular membranes. Peptides also require specialized technology to tackle the lengthy and challenging syntheses or harness the potential of biological processes to produce targeted peptides. Roche continues to explore the possibility of designing and engineering peptides that overcome their natural limitations and allow these powerful chemical entities to be deployed as therapeutic agents.