Additional data from ChemoCentryx' study of Traficet-EN in Crohn's disease patients

In addition to data released in late November, ChemoCentryx, Inc., announced today more data from the Company's PROTECT-1 (the Prospective Randomized Oral Therapy Evaluation in Crohn's disease Trial) of Traficet-EN(TM) (CCX282-B) in patients with moderate-to-severe Crohn's disease. While the earlier announcement concerned the Induction period of the study, new data from the Maintenance period of the study showed that a statistically significant number of patients receiving continuous therapy of Traficet-EN versus placebo for 36 weeks were in clinical remission of Crohn's disease, defined as a score of 150 points or less in the Crohn's Disease Activity Index (CDAI). At week 36, a statistically significant percentage of patients receiving Traficet-EN versus placebo were in corticosteroid-free remission. Traficet-EN continued to be safe and well-tolerated after extended use. Additionally, conclusive evidence was provided that the involvement of the CCR9 and its chemokine ligand (TECK) in inflammatory bowel disease (IBD) is not just restricted to the small bowel, but is relevant to inflammation of the large bowel as well.

The new Crohn's disease clinical remission findings, as well as the expanded understanding of the role of CCR9 and its ligand TECK in the gastrointestinal system (GI) tract, were highlighted in poster and oral presentations titled "PROTECT-1 Maintenance Phase Study Results Demonstrate Efficacy of the Intestine-Specific Chemokine Receptor Antagonist CCX282-B (Traficet-EN) in Crohn's Disease" and "CCR9 Inhibition in the Treatment of Colonic Inflammation" at the 2009 Advances in Inflammatory Bowel Diseases, Crohn's & Colitis Foundation's Clinical & Research Conference in Hollywood, Florida.

Traficet-EN is an orally-active antagonist of the chemokine receptor known as 'CCR9', which is selectively expressed by inflammatory T cells that migrate to the digestive tract in a process that ultimately results in the persistent inflammation underlying IBD. Targeting the CCR9 chemokine receptor represents a novel approach for the treatment of Crohn's disease and other inflammatory disorders of the GI system.

"Current approaches to the treatment of Crohn's disease often result in serious side effects, especially following long-term use of these drugs," said Pirow Bekker, M.D., Ph.D., Senior Vice President, Medical and Clinical Affairs of ChemoCentryx. "These results suggest that Traficet-EN has the potential to keep Crohn's patients in remission without complications such as broad immunosuppression associated with current therapies."

"Data generated from these two studies are groundbreaking in nature and have the potential to revolutionize the way Crohn's disease and ulcerative colitis are treated," said Thomas J. Schall, Ph.D., President and Chief Executive Officer of ChemoCentryx. "We are particularly pleased that we have for the first time definitively identified the CCR9 chemokine ligand in the large bowel which will broaden the scope of digestive tract disorders that Traficet-EN could potentially treat successfully."