Eisai Co., Ltd. (President & CEO: Haruo Naito) and TorreyPines Therapeutics, Inc. (President & CEO: Neil Kurtz, M.D.) today jointly announced the signing of a new research agreement that focuses on the discovery of genes responsible for late onset Alzheimer's disease. This latest agreement marks the continuation of Eisai's support for this program that began in 2001. A second collaboration agreement between TorreyPines and Eisai was signed in February of this year to support the discovery of small molecules that lower A-beta42, a peptide involved in the creation of amyloid plaques, a hallmark of Alzheimer's disease.

In this latest agreement, the research program will focus on "unbiased genome-wide screening" of genes associated with Alzheimer's disease and will not depend on known biology, including the beta-amyloid hypothesis, enabling it to reveal the whole picture of the pathogenesis of the disease, as well as to identify genes associated with Alzheimer's disease from candidate genes discovered through the previous research collaboration.

Under the terms of this multi-year agreement, TorreyPines will receive a signing fee and full research support of its late onset Alzheimer's disease genetics program. Eisai will have exclusive rights of first negotiation and refusal for gene targets discovered and validated through the research. Eisai and TorreyPines may enter into drug discovery agreements involving the gene targets.

The genetics program is part of TorreyPines' growing Alzheimer's disease franchise. The company's active research and development programs are directed at novel therapies that not only may relieve the symptoms of Alzheimer's disease but also target the pathogenesis. In addressing both the cause and symptoms, these therapies may have the potential to halt or reverse disease progression.

"We are proud to enter into this new research agreement with Eisai, demonstrating the validity of our approach and the strength of our collaboration with a recognized leader in the field of Alzheimer's disease research," said Dr. Kurtz.

The genetics research will be performed at TorreyPines in collaboration with Rudolph Tanzi, Ph.D., scientific co-founder of TorreyPines and Director of the Genetics and Aging Research Unit at the MassGeneral Institute for Neurodegenerative Disorders (MIND). To date, researchers have identified a number of gene variants that may contribute to the development of Alzheimer's disease. One gene variant was announced in March in the New England Journal of Medicine (N Engl J Med 2005;352:884-94.)

"TorreyPines and MIND are exploring innovative solutions to develop therapies that ameliorate or prevent Alzheimer's disease," said Dr. Tanzi. "This new agreement reflects the continued confidence Eisai places in our research programs."

About Eisai Co., Ltd.

Eisai Co., Ltd. Is a research-based human health care company, which discovers, develops and markets products in more than 30 countries. Eisai is a global leader in Alzheimer's disease research and treatment. Aricept(R), a symptomatic Alzheimer's disease treatment launched by Eisai in the United States in 1997, is currently sold in more than 70 countries worldwide. Eisai has been committed to discovering next generation treatments for Alzheimer's disease with multi-faced approaches targeted at production inhibition and antibody of beta-amyloid, which is believed to be responsible for the onset of Alzheimer's disease. Eisai further stepped into the novel remedy of the disease based on genetic information. This new agreement will allow for significant advance in the search for a remedy. For additional information, visit Eisai's web site at http://www.eisai.co.jp/ [1].

About TorreyPines Therapeutics

TorreyPines Therapeutics, formerly Neurogenetics Inc., is a biopharmaceutical company that discovers and develops breakthrough small molecule drugs to treat diseases and disorders of the central nervous system. Led by an accomplished management team, the company is leveraging novel drug targets and technologies to deliver new therapies for Alzheimer's disease, migraine and neuropathic pain. Its breakthrough therapies are intended to offer significant advantages over current therapies. Further information is available at www.torreypinestherapeutics.com [2].