SAN DIEGO, CA September 19, 2000 -- Metabasis Therapeutics, Inc. today announced that Arnold Oronsky, Ph.D. and Luke Evnin, Ph.D. have joined the company's Board of Directors. The Company also announced that David Herzig, Ph.D. has resigned from the corporate Board and joined the company's Scientific Advisory Board.

Dr. Oronsky is a General Partner at Interwest Partners, one of the Silicon Valley's most experienced and successful venture capital partnerships, with $1.6B capital under management. His focus at Interwest is on Biopharmaceuticals & Medical Devices. Before joining Interwest he served as Vice President in charge of the Discovery Research Center at Lederle Laboratories and prior to that he was Head of Inflammation, Allergy, and Immunology Research at Ciba-Geigy Pharmaceutical. He was also an Assistant Professor at Harvard Medical School and a Lecturer at Johns Hopkins Medical School. He received his PhD at Columbia University, College of Physicians and Surgeons and his BS degree from University College, New York University.

Dr. Evnin is Vice-Chairman of the MPM Group and a General Partner of the BioVentures funds, believed to be the world's largest venture capital pool dedicated to healthcare investments on a global scale. Before joining MPM in 1998, Dr. Evnin was at Accel Partners for seven years including four years as a General Partner. He was involved in biopharmaceutical, pharmaceutical, medical device and healthcare service companies for Accel funds III, IV and V. He was also responsible for overall investment strategy, deal origination, analyses, investment and gain realization. Dr. Evnin began his career in the field of science. He earned his Ph.D. in the Department of Biochemistry at the University of California-San Francisco. He received his A.B. in Molecular Biology from Princeton University.

Dr. Paul Laikind, Chairman, President and CEO of Metabasis stated, "We are very pleased to have two such accomplished and distinguished individuals join our Corporate Board. Both possess the scientific and business acumen necessary to help guide Metabasis through an expected period of rapid growth. We are planning for as many as four of our drugs to reach the clinic over the next two years beginning with our exciting diabetes drug in the first half of 2001. Dr. Oronsky's extensive experience running a research organization and Dr. Evnin's long association with the biotechnology industry will undoubtedly serve us well during this exciting time."

The company also announced that Dr. David Herzig, former Vice President, Drug Development and Scientific Development at Parke-Davis Pharmaceutical Research, has resigned his position on the Board and joined Metabasis' scientific Advisory Board.

Dr. Mark Erion, Executive Vice President of Research at Metabasis said, "Dr. Herzig played an important role on our corporate Board as we set a new course for the company over the last year. We look forward to his continued help and advice as a member of our Scientific Advisory Board. At Parke Davis, Dr. Herzig was responsible for the acquisition, development and registration of the diabetes drug Rezulin (Troglitazone) which was launched in 1997. That experience will be invaluable to us as we move our diabetes product through clinical testing."

Metabasis Therapeutics, Inc. is a privately held, biopharmaceutical company that develops proprietary products for the treatment of human disease with a focus on diseases that involve the liver. The Company is a leader in the field of nucleoside/nucleotide metabolism and chemistry and has expertise and proprietary technology in the fields of liver biology and organ-specific drug delivery. Metabasis, in collaboration with Sankyo Co., Ltd., is developing novel drugs to treat Type II diabetes that act by lowering liver glucose production. Metabasis has also developed a platform technology, the HepDirect™ Technology, which is useful for liver targeting of new and existing drugs. The company is using the HepDirect™ Technology to develop new treatments for diseases such as hepatitis type B, hepatitis type C and primary liver cancer. Metabasis' patent portfolio includes over 23 issued United States patents in its fields of study. The Company occupies state-of-the-art research facilities in San Diego, California.