SAN DIEGO, CA - May 22, 2002 -- Metabasis Therapeutics, Inc. today announced that Ed Baracchini, Ph.D., M.B.A. has joined the company to lead its business development and strategic planning efforts. In addition to assuming the position of Vice President, Business Development he will also be a Corporate Officer of the Company.

Dr. Baracchini came to Metabasis from Elitra Pharmaceuticals where he was Vice President of Business Development. He began his industry career as part of the business development team at Isis Pharmaceuticals, Inc. He then went on to lead the Business Development and Strategic Planning group at Alanex Corporation. When Agouron Pharmaceuticals, Inc., acquired Alanex in 1997, Dr. Baracchini continued as Director, Business Development and then joined Elitra in 1999. During his career, Dr. Baracchini has been directly responsible for establishing lucrative collaborations with corporations such as Merck & Co., Zeneca, Boehringer Ingelheim, Novo Nordisk, LG Chem and many others. Dr. Baracchini received his Ph.D. in Molecular and Cell Biology from the University of Texas at Dallas and conducted post-doctoral work at the University of California, San Diego and at The Scripps Research Institute. He received his MBA from the University of California, Irvine.

Dr. Paul Laikind, Chairman, President and CEO of Metabasis stated, "Dr. Baracchini is a welcome addition to our executive management team. His record of achievement in the industry speaks for itself. He has been responsible for structuring many important agreements with leading pharmaceutical and biotechnology companies. Each agreement, in addition to often providing important capital resources, also furthered the strategic goals of his company. Ed's experience, combined with his strong scientific background and business acumen, will help us build on the success we have already achieved at Metabasis. With three important products in or soon to be in the clinic and more coming from our liver-related disease focus, there is much to be done. Strong partnerships, like the ones we already have with Sankyo Co., Ltd. and Ribapharm, Inc. for our diabetes and hepatitis B products respectively, are an essential part of our strategic plan. Ed will be responsible for establishing new such strategic partnerships and will also be working to seek further applications for our liver targeting platform, the HepDirect Technology."

Metabasis Therapeutics, Inc. (http://www.mbasis.com) is a privately-held, biopharmaceutical company that develops proprietary products for the treatment of human disease with a current focus on liver or liver-related diseases. The Company employs various resources for discovering and perfecting new products, is a leader in the field of nucleoside/nucleotide chemistry and metabolism, and has proprietary expertise in liver biology and organ-specific drug delivery. Metabasis has discovered and developed a new class of drugs for treating diabetes that act to lower liver glucose production in diabetic patients. The first drug from this program is being developed in collaboration with Sankyo Co., Ltd. and is currently undergoing clinical testing. The Company has also developed the HepDirect™ Prodrug Technology that allows liver-specific delivery of new and existing drugs. Two drugs derived from the HepDirect Technology are in development, a drug for hepatitis B and a drug for primary liver cancer. The hepatitis B drug is the subject of a partnership with Ribapharm Pharmaceuticals, Inc. and is expected to begin clinical trials during the third quarter of 2002. The drug for primary liver cancer is expected to enter the clinic during the first quarter of 2003. The Company has approximately 75 employees and occupies state-of-the-art research facilities in San Diego, California.