Abgenix Appoints Kristen M. Anderson as Senior Vice President of Human Resources.

FREMONT, Calif. -- Abgenix, Inc. (Nasdaq:ABGX) announced today the appointment of Kristen M. Anderson as Senior Vice President of Human Resources effective January 24.

"Kristen brings over a decade of experience leading human resources departments and implementing a variety of personnel programs," said Bill Ringo, president and chief executive officer of Abgenix. "She joins Abgenix at an important juncture as the company moves closer to commercializing its lead product candidate, panitumumab. We are confident that Abgenix will greatly benefit from her extensive experience."

Prior to joining Abgenix, Ms. Anderson served as Vice President of Human Resources at Applied Biosystems, a developer of innovative products and services for life science research, pharmaceutical research and development, diagnostics and agriculture. From 1997 until 2001, Ms. Anderson was Vice President, Human Resources and Communications for the Digital Linear Tape Group at Quantum Corporation, a diversified mass storage company with leadership positions in both fixed and removable storage markets.

Prior to her work at Quantum, Ms. Anderson worked in Human Resources leadership positions at Motorola and Allied Signal.

Ms. Anderson received her B.A. and completed her graduate coursework in Industrial Relations and Organizational Psychology from the University of Minnesota.

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.

This press release contains forward-looking statements about Abgenix's technologies, product development activities, collaborative arrangements, projected financial and operating results, and achievement of milestone or similar payments or other revenues. Such statements are subject to a number of uncertainties that could cause actual results to differmaterially 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 and meeting requirements for regulatory approval, competitive products and services, capital requirements and the extent and breadth of Abgenix's patent portfolio, and other factors set forth in Abgenix's public filings with the Securities and Exchange Commission, including the risks described in Abgenix's quarterly report on Form 10-Q for the quarter ended September 30, 2004 and annual report on Form 10-K for the year ended December 31, 2003. Abgenix is providing this information as of the date of this press release and does not undertake any obligation to update any forward-looking statements.