Abgenix and U3 Pharma Form Collaboration to Develop Therapeutic Antibodies for Cancer.

Business Editors/Health & Medical Writers

FREMONT, Calif. & MARTINSRIED, Germany--(BW HealthWire)--June 11, 2002

Abgenix, Inc. (Nasdaq:ABGX), an antibody-based biopharmaceutical company, and U3 Pharma AG, a privately-held company developing products for hyperproliferative diseases such as cancer, announced today the formation of a collaboration to discover, develop and potentially commercialize fully human monoclonal antibody therapies directed against validated proprietary drug targets selected from U3 Pharma's portfolio. These targets are derived from key components of cellular signal transduction pathways.

Under the terms of the collaboration, Abgenix will use its XenoMouse(R) and/or XenoMax(TM) human antibody technologies to generate and select fully human antibodies against U3 Pharma targets. Both parties will conduct in vitro and in vivo studies of the antibody candidates. Subsequently, Abgenix and U3 Pharma will have the right to co-develop and commercialize antibody products discovered during the collaboration. The parties will share equally in the development costs and any potential profits from sales of any co-developed products.

Raymond Withy, Ph.D., president and chief executive officer of Abgenix said, "Abgenix is excited to join forces with U3 Pharma to create novel antibody therapies against cancer. U3 Pharma's portfolio of drug targets derived from signal transduction systems, such as cell surface receptors and ligands, fits well into one of the functional approaches to targeting cancer within our overall oncology strategy. Prof. Axel Ullrich, U3 Pharma's scientific founder, and his team have already demonstrated the utility of these signal transduction targets as clearly defined starting points for product development."

Signal transduction is one of the most important mechanisms through which cells communicate processes such as proliferation, metabolic regulation and survival. The signals presented to a cell are received largely via membrane-bound receptors whose function is to determine which of the signals are aimed at the cell and subsequently to relay these messages to its interior. Once inside the cell, a cascade of intermediary proteins conducts the signal to the nucleus, where it elicits a modification in transcriptional activity that in turn directs the activity of the cell.

"This alliance with Abgenix will spearhead U3 Pharma's development of therapeutic antibodies in several major clinical indications, including cancer," noted Dr. Ed Stuart, chief business officer at U3 Pharma. "We believe that Abgenix's antibody generating technology, clinical expertise and production capabilities offers significant benefits to our business development objectives."

Abgenix's proprietary XenoMouse(R) technology involves transgenic mouse strains possessing an immune system in which the mouse antibody-producing genes have been inactivated and functionally replaced by most of the human antibody-producing genes. Upon immunization, XenoMouse mice generate fully human, high-affinity monoclonal antibodies that bind with high specificity to antigens (targets) of diverse structures. XenoMax(TM) technology allows researchers to rapidly scan the immune repertoire of an immunized XenoMouse animal using microplate-based assays to measure and rank antibodies according to design goals (e.g., potency, affinity, specificity). Within three to five weeks after immunizing XenoMouse animals, XenoMax technology produces a ranked set of multiple antibodies from which to choose an optimal candidate for development.

Abgenix is a biopharmaceutical company focused on the development and commercialization of human therapeutic antibodies. The company's technology platform, which includes XenoMouse(R) and XenoMax(TM) technologies, enables the rapid generation and selection of high affinity, fully human antibody product candidates to a variety of disease targets. Abgenix leverages its leadership position in human antibody technology by building a diversified product portfolio through the development of its own internal proprietary products and through the establishment of licensing arrangements with multiple pharmaceutical, biotechnology and genomics companies. For more information on Abgenix, visit the company's website at www.abgenix.com.

U3 Pharma AG is an emerging biotech company focused on the creation of novel therapeutic products that specifically target key components of cellular signal transduction systems that are involved in major hyperproliferative diseases such as cancer. The company has licensed a portfolio of drug targets from the Max Planck Society that are being used to develop small molecules and therapeutic antibodies. In addition, U3 Pharma has created a second generation functional genomics platform, TASC, which mimics the progression of a tumor cell as it progresses towards its fully malignant cancerous state. U3 Pharma is privately-held and based in Martinsried, Munich, Germany. For additional information, please visit our website at www.u3pharma.com.

Statements made in this press release about Abgenix's technologies, product development activities and collaborative arrangements 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 development programs, the regulatory approval process, competitive products, 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.