Abgenix, Inc. was a US biopharmaceutical company founded in July 1996 as a spin-out of Cell Genesys, headquartered in Fremont, California, with additional operations in Burnaby, British Columbia. It was publicly traded (Nasdaq) until Amgen completed its acquisition on April 1, 2006 for approximately $2.2 billion in cash plus assumed debt; Abgenix then became a wholly owned Amgen subsidiary known as Amgen Fremont Inc. An SEC filing put headcount at 324 full-time employees as of December 31, 2001.
Products / operations. Abgenix discovered, developed and manufactured fully human therapeutic antibodies. Its core platform was XenoMouse, a genetically engineered mouse strain producing fully human monoclonal antibodies, commercialized through subsidiary Xenotech (a joint venture with Japan Tobacco). Lead clinical candidates included ABX-EGF (panitumumab, an anti-EGFR antibody co-developed with Amgen), ABX-CBL, ABX-IL8 and ABX-MA1. The company also operated a large-scale antibody manufacturing facility in Fremont and maintained numerous antibody-generation collaborations with pharmaceutical and biotech partners. It was an operating company, not a patent-assertion entity.
Litigation posture. The tracked case shows Abgenix as a defendant only (0 plaintiff, 1 defendant), consistent with an operating company defending its platform technology. In GenPharm International, Inc. v. Abgenix, Inc. (N.D. Cal., filed 1996), competitor GenPharm — a transgenic-mouse antibody rival, later acquired by Medarex — alleged infringement of patents covering methods of producing human monoclonal antibodies and sought injunctive relief. Abgenix counterclaimed and moved for summary judgment.
Notable context. The dispute, rooted in a 1994 Cell Genesys–GenPharm trade-secret suit over transgenic mice, was resolved in March 1997 by a worldwide, royalty-free patent cross-license and settlement among Cell Genesys, Abgenix, Xenotech and Japan Tobacco; Abgenix and its affiliates reportedly paid GenPharm approximately $38.6 million. Amgen's 2006 acquisition gave it full ownership of panitumumab and the XenoMouse technology.