Current status of chemokine receptor inhibitors in development.

The chemokine network plays pivotal role in a large number of inflammatory, allergic and autoimmune diseases, as well as in the promotion of tumor growth and metastasis. Considerable effort has been put in the pharmaceutical industry to identify therapeutic agents that specifically target chemokine receptors. Despite the fact that several promising programs have proven unsuccessful in Phase II trials the research activity both in academia and industry is still highly intense, whereas for some of the chemokine receptors the progress is still at the preclinical stage. In this review the authors discuss possible reasons beyond successes and failures of early clinical development programs and discuss the most relevant and recent pharmacological approaches with the aim to point out new theories, open issues and expectations in this research field.