Thursday, September 28, 2006

Xanthus' Symadex Can Reverse Disease in Preclinical Multiple Sclerosis Animal Model

Thursday September 28, 9:30 am ET

- Results Presented at the 22nd Congress of the European Committee for Treatment and Research in Multiple Sclerosis -

CAMBRIDGE, Mass., Sept. 28 /PRNewswire/ -- Xanthus Pharmaceuticals, Inc., a privately-held drug development company, today presented data that Symadex(TM) reverses the clinical and pathological signs of chronic disease in an animal model for multiple sclerosis (MS). The presentation was made by Stephen J. Karlik, PhD, Professor of Diagnostic Radiology at the University of Western Ontario, London, Ontario, together with researchers from Xanthus in a poster session at the 22nd Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) meeting in Madrid, Spain.

Dr. Karlik used a model of experimental allergic encephalomyelitis (EAE) for the study. This same model was used by Dr. Karlik and his colleagues for published studies with natalizumab and related molecules. The study demonstrated that Symadex can reverse the clinical and pathological signs of chronic disease and that it can permit nerve remyelination. In addition, longer dosing resulted in continued benefit and the pathological changes including inflammation and vascular abnormalities were reversed. Importantly, Symadex did not affect circulating immune cell numbers, suggesting that it is not a general immunosuppressive agent.

"We believe that Symadex has a distinct activity profile in the field of MS therapies. Interestingly, we found that Symadex has no effect on the acute, T-cell mediated portion of the disease process which is the target of most proposed new therapies for MS," stated Alfred Ajami, PhD, Chief Scientific Officer at Xanthus.

About Symadex(TM)

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 Phase 2 clinical trials in oncology indications. Xanthus is also exploring the use of Symadex for the treatment of a number of autoimmune diseases, such as multiple sclerosis and rheumatoid arthritis, where early preclinical data has shown encouraging signs of activity.

About Xanthus Pharmaceuticals, Inc.

Xanthus Pharmaceuticals, Inc. is developing a portfolio of novel, clinical-stage, small-molecule oncology candidates through a management team whose accomplished track record encompasses all aspects of drug development, from discovery through regulatory approval and commercialization. The Company is applying its expertise both to advance its current pipeline and expand it into indications of unmet medical need beyond oncology.

Xanthus is headquartered in Cambridge, Massachusetts with an additional facility in Montreal, Quebec. More information is available at

This press release contains forward-looking statements concerning Xanthus that involve a number of risks and uncertainties. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, the words, "believes," "anticipates," "plans," "expects," "estimates," "intends," "should," "could," "will," "may," and similar expressions are intended to identify forward-looking statements. There are a number of important factors that could cause Xanthus' actual results to differ materially from those indicated by such forward-looking statements, including risks as to whether results obtained in early clinical studies or in preclinical studies such as the studies referred to above will be indicative of results obtained in future clinical trials or warrant additional trials; whether products based on Xanthus' technology will advance through the clinical trial process and receive approval from the United States Food and Drug Administration or equivalent foreign regulatory agencies; whether the company will have the cash resources to develop and commercialize its products; and whether the patent and patent applications owned or licensed by Xanthus will protect the Company's technology and prevent others from infringing it. Xanthus disclaims any intention or obligation to update any forward-looking statements.


Kari Watson, MacDougall Biomedical Communications, Inc. -- or (508) 647-0209

Lisa Terry, Xanthus Pharmaceuticals, Inc. -- or (617) 225-0522, x 105

Source: Xanthus Pharmaceuticals, Inc.

Xanthus' Symadex shows Remyelination in Multiple Sclerosis Animal Model

02/14/2006 - Xanthus Life Sciences, Inc., announced that data from a study conducted with a Multiple Sclerosis (MS) animal model demonstrated that Symadex(TM) permitted remyelination by prevention of inflammatory cell infiltration. Stephen J. Karlik, Ph.D., Professor of Diagnostic Radiology at the University of Western Ontario, London, Ontario presented the research findings in Vancouver.

Symadex was found to produce remyelination in the study even after 40 days of inflammatory insult by preventing the infiltration of autoreactive cells into the central nervous system. Treatment proved to be effective in both the acute and chronic presentations of disease.

"The early results from this study showed that the animals in the study, which were paralyzed due to neurological impairment, were able to recover and regain their mobility after treatment with Symadex," commented Dr. Karlik.

"Symadex is now in Phase 2 trials in oncology and the positive results of this animal model study show the candidate's potential for treating MS and provide the support needed to advance Symadex towards human trials for MS," said Michael A. Boss, PhD. Chief Business Officer at Xanthus. Symadex (formerly C-1311) is a next-generation investigational drug that has shown a potentially novel, targeted mechanism of action in studies of cancer and autoimmune disease. Symadex was developed to deliver efficacy comparable to the anthracenediones (e.g., Novantrone(R) (mitoxantrone)), but with a molecular scaffold intended to reduce the cardio- and hemato-toxicities known to be associated with these active drugs. Additionally, in previous preclinical studies, Symadex has shown early evidence of both oral activity and efficacy in various models of acquired drug resistance and autoimmune disease. The Company is conducting Phase 2 clinical trials with Symadex in several tumor indications and is also exploring the use of Symadex for the treatment of a number of autoimmune diseases, such as Multiple Sclerosis.