Contacts:

Sharon Tetlow diaDexus 408-330-5003 stetlow@diadexus.com

DIADEXUS NAMES PATRICK PLEWMAN AS CHIEF EXECUTIVE OFFICER

Santa Clara, CA - June 20, 2000 - diaDexus today announced that Patrick Plewman, currently president and chief operating officer, will also assume the responsibility of chief executive officer.

"As one of the founders and a driving force in the success of diaDexus to date, Patrick has amply demonstrated his leadership qualities," said Dr. George Poste, diaDexus' chairman and former chief science and technology officer of SmithKline Beecham. "He was instrumental in securing our most recent financing, and we will look to his leadership as chief executive officer to capitalize fully on the Company¹s impressive pipeline of novel biomarkers."

Plewman assumed the responsibility of president of diaDexus, as well as chief operating officer in January of this year. Prior to joining diaDexus, he was with SmithKline Beecham for eight years, where he was most recently director, business development-molecular diagnostics. During his tenure at SmithKline Beecham, Plewman held various positions of increasing responsibility in sales, marketing, business development and strategic planning.

"I am delighted to assume the additional position of chief executive officer," said Plewman. "We have made material progress since we formed the company in September 1997 and I look forward to leading diaDexus through our next growth phase following the successful $102.5 million private placement this past April."

Plewman holds a Masters of Business Administration degree from the Harvard Business School. He also holds a bachelor's degree in both chemistry and political science from the University of North Carolina at Chapel Hill, where he was a Morehead Scholar.

diaDexus, formed in September 1997 by SmithKline Beecham and Incyte Pharmaceuticals and based in Santa Clara, Calif., is dedicated to the discovery and commercialization of novel genomic biomarkers for the detection of disease, as potential antigens for the development of therapeutic monoclonal antibodies and as immunizing antigens for therapeutic vaccines.

For more information, visit the diaDexus Web site.