AMERICAN BIOGENETIC SCIENCES ISSUES 2000 ANNUAL REPORT

Copiague, New York, May 24, 2001 - American Biogenetic Sciences, Inc. (ABS) (NASDAQ:MABA) announced today its annual report for 2000 highlights commercial and scientific achievements during the past year and sets forth the framework for enhancing the company’s partnering and licensing programs in the current year.

The full text of the report is available on the company’s website at www.mabxa.com.

Key developments described in the report include status updates on programs involving the company’s two neurological drug candidates and partnering of its patented Antigen-Free technology for producing monoclonal antibodies.

ABS-103 / Abbott Laboratories

In January 2000, ABS signed a license agreement with Abbott Laboratories for ABS’ neurological compound, called ABS-103, a small molecule being developed for the treatment of epilepsy, mania associated with bipolar depression and the prevention of migraine headache. Under the terms of the agreement, ABS is entitled to milestone payments of $17 million, as the compound progresses through development and regulatory approval as well as royalties on ultimate sales of the drug when approved.

Abbott has indicated that ABS-103 is one of the candidates being evaluated to become the next generation version of Depakote, Abbott’s best selling U.S. drug and the one which underpins its $700+million franchise in anticonvulsant, bipolar, and migraine therapies

Abbott has issued progress reports on the studies using ABS-103, particularly ABS-103R. The Abbott preclinical reports indicate the program is steadily proceeding with efforts to focus on evaluating formulations for a clinical product, determining optimum dosing ranges and dosing schedules, and further toxicology and metabolism studies.

In preclinical studies conducted by ABS, ABS-103, has shown anticonvulsant activity without sedation, is not associated with increased incidence of birth defects, has lower side effects and a better safety profile than valproic acid.

According to biopharmaceutical consultants Paisley and Habermas, sales of an enhanced Depakote by Abbott could reach $450 million in the second year of introduction, growing to peak sales of $3 billion. This could provide an exceptionally strong royalty stream for ABS. The full report from Paisley & Habermas is available on our website at www.mabxa.com/research.html.

ABS-205 / Unlicensed

Another neurological product being developed by the company is ABS-205, which is the leading compound under investigation as a potential treatment for neurodegenerative disorders such as Alzheimer's disease, stroke and head trauma.

Studies have uncovered impressive results and meritorious properties in ABS-205, a small molecule compound which crosses the blood brain barrier. Evidence suggests that the drug promotes rapid improvements in learning and memory tests by enhancing the efficiency of information processing for long-term memory. Chronic administration has been shown to markedly improve cognitive function. A study conducted by Dr. Ciaran Regan at University College Dublin, Ireland, and funded by the Institute for the Study of Aging demonstrated improved cognitive abilities (memory) in aged animals.

In 2000, the ABS scientist who co-invented ABS-205, Dr. Heinz Nau of the University of Hanover, Germany, fast-tracked the development of an efficient production and purification system to produce optically pure ABS-205R and ABS-205S. The compounds have been synthesized and purified in sufficient quantities to perform three additional important studies, human liver toxicity, and comparative cognition and efficacy studies. The results of the liver toxicity study indicated that ABS-205 was similar to valproic acid (VPA) which is currently being used in humans. Drug activity studies performed by Dr. Nau indicate that the effective dose of ABS-205 may be one fifth that of VPA. Therefore, the toxicity at the effective dose is expected to be better than VPA. ABS now intends to seek pharmaceutical partners to develop this compound through clinical trials.

Antibody Partnering Programs

The centerpiece of ABS’ research and development remains its patented antigen-free mouse technology. This enabling technology is designed for the production of monoclonal antibodies of high affinity and specificity that are used in diagnostics and therapeutics for a variety of diseases. The antigen-free (AF) technology is superior to conventional techniques in generating highly specific antibodies exhibiting high-affinity for difficult immunogens.

The company’s Thrombus Precursor Protein test (TpPTM) and Functional Intact Fibrinogen Assay (FiF®) tests which have been cleared by the U.S. Food & Drug Administration (FDA), both utilize antibodies that were produced by the AF mouse colony. The two tests utilize ABS’ most notable and commercially successful monoclonal antibodies: MH1, the antibody that targets soluble fibrin is used in the TpP test; and 45J, an antibody that binds to fibrinogen is used in the FiF and TpP tests.

Subsequent to year-end, we completed a non-exclusive agreement with Biosite Diagnostics, Incorporated under which Biosite will validate our TpP diagnostic marker and antibodies for potential use with its rapid, quantitative Triage Meter testing platform. Should Biosite decide to include TpP as a marker on its highly successful panel, it will purchase antibodies from ABS and pay milestone fees and royalties. Part of Biosite’s validation work will be done in collaboration with a study group at Brigham and Woman’s Hospital in Boston, MA, an investigative team that has been at the forefront of clinical research of acute coronary syndromes for the past two decades.