METABASIS THERAPEUTICS, INC. FILES REGISTRATION STATEMENT FOR INITIAL PUBLIC OFFERING OF COMMON STOCK

SAN DIEGO, CA - February 3, 2004 - Metabasis Therapeutics, Inc. announced today that it has filed a registration statement with the Securities and Exchange Commission relating to an initial public offering of its common stock. All the shares of common stock to be offered by the Company will be newly issued shares.

SG Cowen Securities Corporation is acting as the sole book-runner for the offering. Deutsche Bank Securities is acting as co-lead manager, with Thomas Weisel Partners LLC and Legg Mason Wood Walker, Incorporated acting as co-managers. The offering will be made only by means of a prospectus, a copy of which may be obtained, when available, from SG Cowen Securities Corporation, Prospectus Department, 1221 Avenue of the Americas, 6th Floor, New York, NY 10020, or through ADP by fax at (631) 254-7268.

A registration statement relating to these securities has been filed with the Securities and Exchange Commission but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Metabasis

Metabasis Therapeutics, Inc. (www.mbasis.com) is a biopharmaceutical company focused on the discovery, development and commercialization of novel small molecule drugs principally to treat liver diseases and metabolic diseases linked to pathways in the liver. The company has established a broad product pipeline targeting large markets with significant unmet medical needs. Metabasis currently has three internally discovered product candidates in clinical trials indicated for the treatment of type 2 diabetes, hepatitis B and primary liver cancer.