BIOSITE® DIAGNOSTICS AND AMERICAN BIOGENETIC SCIENCES SIGN A RESEARCH AND LICENSE AGREEMENT FOR TpP

TpP Test Is Cleared For Marketing To Detect Levels Of A Blood Protein Whose Levels Rise Before A Clot Forms

COPIAGUE, NY – April 3, 2001 – American Biogenetic Sciences, Inc. (ABS) (Nasdaq: MABA) announced today that it has entered into a research and non-exclusive license agreement with Biosite Diagnostics, Incorporated (Nasdaq: BSTE) to validate the use of ABS’ Thrombus Precursor Protein (TpP™) diagnostic marker and antibodies for potential use with Biosite’s rapid, quantitative Triage“ Meter testing platform.

Biosite will conduct an evaluation of the TpP assay as part of its on-going discovery program aimed at the identification of diagnostic markers for cardiovascular and cerebrovascular diseases. Should Biosite commercialize a product containing ABS’ patented monoclonal antibodies, Biosite will purchase the antibodies from ABS and pay milestone fees and royalties. In assessing diagnostic utilities of potential markers, Biosite will use blood samples from clinical collaborators such as the Thrombolysis In Myocardial Infarction (TIMI) study group of Brigham and Woman’s Hospital, an investigative team that has been at the forefront of clinical research of acute coronary syndromes for the past two decades.

“Biosite’s evaluation of TpP could further establish the utility of this sensitive antibody-based assay and lead to its use on Biosite’s point-of-care testing platform,” said Josef C. Schoell, ABS’ president.

“A recent publication1 using the TpP ELISA supports the utility of this protein as a marker for the diagnosis and management of chest pain patients experiencing an MI,” said David Carville, Ph.D., Cardiovascular Consultant to ABS. “After the research is completed, TpP may emerge as a useful adjunct to future generations of Biosite products.”

The TpP assay is based on ABS’ highly specific patented MH-1 monoclonal antibody, a product of its patented Antigen-Free antibody generation technology. The TpP diagnostic is approved for use in aiding in the risk assessment of thrombosis and the monitoring of anticoagulant (heparin) therapy.

Biosite’s rapid, quantitative Triage® Meter was first commercialized as the testing platform for the Triage Cardiac System, which provides measurements of cardiac markers. The Triage Cardiac System aids in the diagnosis of AMI, or heart attack, by detecting and measuring three blood proteins (creatinine kinase [CK-MB isoenzyme], myoglobin, and troponin I) that are released as a result of heart muscle damage following a heart attack. Results from the system are available within 20 minutes.

The American Heart Association estimates that of the 2.5 million people admitted to critical care with heart attack-like symptoms, only 900,000, or roughly 35 percent, have actually experienced an acute myocardial infarction. The Triage panel of rapid test for key cardiac markers is designed to help “rule in” or “rule out” heart attack as the cause of the symptoms.

American Biogenetic Sciences, Inc., based in Copiague, N.Y., researches and develops diagnostic tests for cardio-pulmonary conditions and infectious diseases, as well as for new treatments for neurological disorders including epilepsy, migraine, mania, Parkinson’s disease and Alzheimer’s disease.

1Song KS, et al Clinical Usefulness of Thrombosis Precursor Protein (TpP) in the Diagnosis of Ischemic Heart Disease and Changes of TpP after LMWH Therapy. Proceedings of the 03rd International Congress on Coronary Artery Disease 2000; 443-447. Moduzzi Editore SpA, publisher.

Statements in this press release that are not strictly historical are "forward looking" statements within the meaning of the Private Securities Litigation Reform Act of 1995, and should be considered as subject to various risks and uncertainties that could cause actual results to differ materially from those anticipated, including the risk that Biosite may determine not to commercialize the TpP assay. For further details and a discussion of these risks and uncertainties, see the Company’s Securities and Exchange Commission filings including its annual report on Form 10-K.