CAMBRIDGE, Mass.--(BUSINESS WIRE)--Xanthus Pharmaceuticals, Inc. today presented preclinical data further supporting the potential for Symadex™ to reverse the clinical and pathological signs of multiple sclerosis (MS), including new data demonstrating increased spinal cord remyelination. The study was presented by Dr. Stephen J. Karlik, Ph.D., Professor of Diagnostic Radiology at the University of Western Ontario, London, Ontario and researchers from Xanthus at a meeting of the Multiple Sclerosis Society of Canada in Banff, Canada.

Using an animal model of experimental autoimmune encephalomyelistis (EAE) designed to replicate MS, Dr. Karlik studied the efficacy of Symadex in both acute and chronic phases of the disease. While treatment with Symadex in this study attenuated acute EAE, it prevented chronic disease. Importantly, in chronic disease Symadex also demonstrated a statistically significant ability to reverse clinical signs of EAE, including perivascular inflammation, myelitis (inflammation of the spinal cord resulting in a loss of its ability to transmit nerve impulses) and demyelination (the loss of myelin, a protective coating of the nerve fibers, that can lead to impaired bodily functions).

Of significant note, Symadex also increased spinal cord remyelination (the repair of damaged myelin) in the study. Myelin repair occurs spontaneously in MS, but happens very slowly. Identifying ways to speed the healing process is an important component in finding an effective treatment for MS. In the study, remyelination was determined after four weeks of treatment by a blinded observer who measured the size of all lesions and the amount remyelinated in all sections of the animal.

The study also builds on prior data demonstrating Symadex’s novel mechanism of action, which is believed to directly target macrophages and monocytes, key cells responsible for driving the autoimmune response.

“This study adds to the growing body of work supporting the ability of Symadex to prevent and reverse chronic disease in the animal model of multiple sclerosis,” said Dr. Karlick. “The newly observed evidence of remyelination is noteworthy and warrants additional study.”

“Repeated studies of Symadex continue to support the promise of the candidate,” said Richard T. Dean, Ph.D, Xanthus’s Chief Executive Officer. “We remain on track to initiate a human proof-of-concept study in autoimmune disease in 2008 and believe the data on remyelination enhances the partnering opportunities for Symadex™.”

About Symadex™

Symadex (formerly C-1311) is the lead compound in clinical development from a new series of agents, the imidazoacridinones, which have shown in vitro to be potent and selective FLT3 receptor tyrosine kinase inhibitors. Symadex is currently in a Phase 2 study for women with metastatic breast cancer, and has the potential to be active in hematological malignancies. Xanthus is also exploring the use of Symadex and follow-on compounds for the treatment of a number of autoimmune diseases, such as multiple sclerosis and inflammatory bowel disease. Early preclinical data has shown encouraging signs of activity in models of autoimmune disease. Given the compound's safety profile and oral availability, Xanthus believes Symadex represents an exciting drug opportunity. Further preclinical studies are currently being conducted, after which the Company expects to enter clinical development.

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