Abgenix to Host Conference Call on Second Quarter 2004 Financial Results.

FREMONT, Calif. -- Abgenix, Inc. (Nasdaq:ABGX) will hold a conference call on Tuesday, July 27, 2004, at 1:30 p.m. PT, 4:30 p.m. ET, to discuss second quarter financial results and to provide an update on the company's antibody discovery, development, and manufacturing activities. The call will be hosted by Raymond Withy, Ph.D., president and chief executive officer of Abgenix.

To participate in the teleconference, please dial 800-299-0433 fifteen minutes before the conference begins. International callers should dial 617-801-9712. The pass code is 56308030. The call will also be webcast live at www.abgenix.com. A replay of the call will be available until August 10, 2004, on the company's website or by dialing 888-286-8010. International callers should dial 617-801-6888. The replay participant code is 75470596.

About Abgenix

Abgenix is a biopharmaceutical company focused on the discovery, development and manufacturing of human therapeutic antibodies. The company's antibody development platform includes a leading technology and state-of-the-art manufacturing capabilities that enable the rapid generation, selection and production of high affinity, fully human antibody product candidates to a variety of disease targets. Abgenix leverages its leadership position in human antibody technology to build a diversified product portfolio through the establishment of collaborations with multiple pharmaceutical and biotechnology companies. For more information on Abgenix, visit the company's website at www.abgenix.com.

Statements made in this press release about Abgenix's technologies, product development activities, collaborative arrangements and process science and manufacturing activities and about its projected financial results and the achievement of milestone or similar payments, other than statements of historical fact, are forward-looking statements and are subject to a number of uncertainties that could cause actual results to differ materially from the statements made, including risks associated with the success of clinical trials, the progress of research and product development programs, product manufacturing, regulatory approval processes, competitive products and services, future capital requirements and the extent and breadth of Abgenix's patent portfolio. Please see Abgenix's public filings with the Securities and Exchange Commission for information about risks that may affect Abgenix.