Interim Phase 2 Data Demonstrate Single-Agent Antitumor Activity With ABX-EGF In Advanced Colorectal Cancer| Amgen

Interim Phase 2 Data Demonstrate Single-Agent Antitumor Activity With ABX-EGF In Advanced Colorectal Cancer


CHICAGO, IL, May 31, 2003 -- Abgenix, Inc. (Nasdaq: ABGX) and Amgen, Inc. (Nasdaq:AMGN) today announced interim results from a phase 2 study of ABX-EGF, a fully human monoclonal antibody, demonstrating that ABX-EGF has antitumor activity when administered as a single-agent treatment to patients with advanced colorectal cancer. Results from an interim analysis of a multicenter study, presented at the 39th Annual Meeting of the American Society of Clinical Oncology (ASCO), showed that a majority of patients with measurable metastatic colorectal cancer who over-expressed epidermal growth factor receptor (EGFr) experienced either partial antitumor responses or had stable disease. Results were presented (Abstract #1026) by Neal J. Meropol, MD, Director, Gastrointestinal Cancer Program,

Fox Chase Cancer Center, Philadelphia, PA.

"ABX-EGF was well tolerated and clearly showed single-agent antitumor activity in patients with metastatic colorectal cancer," said Dr. Meropol. "The fully human nature of ABX-EGF confers potential benefits with virtually no risk of allergic reactions. These results are certainly encouraging."

In the planned analysis of this ongoing trial, 44 patients were evaluated by intent to treat and 40 patients were efficacy-evaluable following eight weeks of ABX-EGF treatment. Patients had measurable disease and were previously treated with 5FU (with or without leucovorin) and either irinotecan or oxaliplatin, or both. Patients received 2.5 mg/kg of ABX-EGF by intravenous infusion weekly for an eight-week treatment cycle for up to six cycles. At the end of the first eight-week cycle, four of the 40 efficacy-evaluable patients had partial responses and 22 patients had stable disease. All other patients had progressive disease. Study enrollment of 100 patients is underway and an additional cohort of 50 patients is being added. All 150 patients are expected to be accrued shortly.

"As our knowledge of cancer continues to grow, we are able to develop targeted treatments for different tumor types. These ABX-EGF interim phase 2 data are encouraging," said Beth Seidenberg, MD, Chief Medical Officer and Senior Vice President for Amgen.

"These data further extend our knowledge and understanding of the exciting potential of ABX-EGF," said Raymond M. Withy, PhD, President and Chief Executive Officer, Abgenix. "ABX-EGF remains our lead product and we will be working with Amgen to move it forward and continue to resource it accordingly."

In this study ABX-EGF was well tolerated, with mild to moderate skin rash and asthenia as the most common side effects. In those patients tested, no allergies, anaphylaxis or human antihuman antibodies (HAHAs) have been observed.


ABX-EGF targets the epidermal growth factor receptor (EGFr), which is over-expressed in a variety of cancers including lung, breast, pancreatic, bladder, prostate, colorectal, kidney and head and neck cancers. Research has demonstrated that cancer cells can become dependent on growth signals mediated through EGFr for their survival. In preclinical research, ABX-EGF monotherapy has been shown to inhibit the growth of human tumors in mice. Co-developed by Abgenix and Amgen, ABX-EGF is being evaluated in a comprehensive clinical program in several indications. Results of several clinical studies have demonstrated single-agent activity and a favorable pharmacokinetic and tolerability profile.

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

About Amgen

Amgen is a global biotechnology company that discovers, develops, manufactures and markets important human therapeutics based on advances in cellular and molecular biology.

Statements made in this press release about Abgenix's technologies, product development activities, collaborative arrangements and manufacturing activities, other than statements of historical fact, and about its projected financial results, 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, 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.

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Note: Copies of the study abstracts are available upon request.

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