News Releases

July 2, 2001

Sumitomo Pharmaceuticals and Novirio Pharmaceuticals Announce Agreement to Develop Chronic Hepatitis B Drug

Sumitomo Pharmaceuticals Co., Ltd. today announced it has entered into an agreement with Novirio Pharmaceuticals Limited on June 29, 2001, for the development of LdT (generic name), a drug for the treatment of chronic hepatitis B infections. The accord grants Sumitomo exclusive rights to develop the compound for Japan, China, S. Korea and Taiwan.

Founded in 1998, Novirio is a biopharmaceutical company focusing on the discovery, development and commercialization of antiviral agents. LdT is a proprietary small molecule therapeutic compound (nucleic acid derivative) for the treatment of chronic hepatitis B infections. The antiviral agent, currently in overseas clinical trials, inhibits the activity of DNA polymerase in the hepatitis B virus.

Liver diseases are one of the therapeutic areas Sumitomo is targeting. The Company has marketed the natural alpha interferon Sumiferon for the treatment of chronic hepatitis B and C, and is conducting clinical trials of a proprietary compound, SM-11355, for the treatment of liver cancer. The agreement with Novirio for the exclusive rights to develop LdT for the Japan, China, S. Korea and Taiwan markets in exchange for initial and milestone paymentsbroadens Sumitomo's line of products in this therapeutic area.

Although an orally-administered antiviral drug was approved for chronic hepatitis B last year and is now being used while injectable interferon has been the principal therapy, neither therapy provides satisfactory results, giving rise to hopes among doctors for more efficacious drugs.

An orally-administered medication LdT has demonstrated a powerful antiviral activity that is based on a different mode of action than that of conventional orally-administered drugs. Since this compound acts uniquely against hepatitis B virus, the Company expects it to form the core of a new therapy for chronic hepatitis B.

Sumitomo will begin clinical trials of the compound as soon as possible in order to obtain approval to market the drug at an early date.

About Novirio Pharmaceuticals:

Trade name : Novirio Pharmaceuticals Limited
Chairman and C.E.O. : Jean-Pierre Sommadossi, Ph.D.
Business Location of US Affiliate : 125 Cambridge Park Drive, 3rd Floor, Cambridge, MA 02140, U.S.A
Establishment : May 1998
Capitalization : US$180 million
Line of business : Discovery, development and commercialization of antiviral therapeutic agents
Employees : 57