Therapeutic potential of adenosine receptor antagonists and agonists.

The adenosine receptors (A(1), A(2A), A(2B) and A(3)) are important and ubiquitous mediators of cellular signalling, which play vital roles in protecting tissues and organs from damage. Launched drugs include the adenosine receptor antagonists theophylline and doxofylline (both used as bronchodilators in respiratory disorders such as asthma), while several compounds are presently in clinical trials for a range of indications, including heart failure, Parkinson's disease, rheumatoid arthritis, cancer, pain and chronic obstructive pulmonary disease. A host of companies and institutions are addressing the huge potential for the development of selective adenosine receptor agonists and antagonists, so that it appears we are on the verge of a new wave of compounds approaching the market for many unmet medical needs. This review presents an analysis of the patenting activity in the area for 2006 and an interpretation and reflection on the developments that we can expect in the future.