Emerging peptide therapeutics for inflammatory diseases

Steroids are the best known anti-inflammatory drugs and have been in use for more than 50 years. Their chronic use however was limited by safety concerns. Non-steroidal anti-inflammatory drugs (NSAIDs) including COX-2 inhibitors although devoid of steroid side effects often possess gastrointestinal side effects. In addition recent data suggest that chronic use of some Cox inhibitors is associated with cardiovascular risk. Currently biologics represent the best option for many inflammatory diseases where TNFalpha is the main culprit. These include rheumatoid arthritis, ulcerative colitis, inflammatory bowel disease and psoriasis. A wealth of information is now available on the role of different cytokines and adhesion molecules in the origin and progression of inflammatory diseases. With the success of protein therapeutics such as Etanercept (Enbrel), which binds TNFalpha and inhibits its activity, research has been focused on developing small peptides that can interfere with cytokines or specific cell surface molecules and inhibit the inflammatory reactions. Here we review these peptides that are in discovery and development phases and their potential in the treatment of inflammatory diseases.