Diagnostic Products and XOMA Announce International Launch of LBP-based Diagnostic Test for Systemic Bacterial Infections.

Business Editors & Health/Medical Writers

BERKELEY, Calif.--(BW HealthWire)--April 27, 2000

XOMA Ltd. (Nasdaq: XOMA) and Diagnostic Products Corporation (DPC)(NYSE: DP) today announced that DPC has introduced in Europe an automated laboratory diagnostic test for early diagnosis and prognosis of systemic gram-negative infections. The test was developed with XOMA's patented technology that uses LBP (lipopolysaccharide binding protein) as a biochemical marker of systemic exposure to gram-negative bacteria and endotoxin, a potent bacterial poison that can trigger deadly infectious complications. XOMA will receive royalties on LBP-related products sold worldwide by DPC.

Endotoxin (lipopolysaccharide) is a structural component of gram-negative bacteria that can induce an overwhelming inflammatory response in infected patients. This systemic reaction may cause severe complications including respiratory distress, circulatory shock, organ failure and death. LBP, secreted by the body in response to bacteria and their endotoxins, is an early marker of this inflammatory response.

Researchers at XOMA discovered that elevated LBP levels correlate with exposure to bacteria and their endotoxins. They have measured LBP levels in plasma samples from healthy adults and from nearly 1,000 patients suffering from 20 different diseases. The highest LBP levels were seen in patients with infectious diseases, such as gram-negative sepsis, complicated abdominal infections, pyelonephritis and meningococcemia.

DPC's successful IMMULITE product line includes the IMMULITE and IMMULITE 2000 immunoassay systems. The IMMULITE benchtop analyzer, a continuous random-access chemiluminescent analyzer, is designed for ease of use, reliability and high-performance assays. Since its introduction in 1993, approximately 4,500 units have been placed worldwide. IMMULITE 2000, introduced in 1998, has over 600 placements. With a processing throughput of 200 tests per hour, it achieves optimum efficiency and consolidation in medium- and high-volume laboratories. The IMMULITE system will provide real-time LBP test results, an important factor in diagnosing and following a life-threatening disease such as bacterial sepsis. LBP is currently available only on the IMMULITE benchtop analyzer. The DPC LBP assay is being released internationally while licensing is pursued in the U.S.

Diagnostic Products Corporation is dedicated exclusively to immunodiagnostic testing. The company's products include over 300 assays to measure microorganisms, hormones, drugs and other medically important analytes present at infinitesimal concentrations in body fluids and tissues. DPC also designs and manufactures automated laboratory instruments which provide rapid and accurate results while reducing labor and reagent costs. DPC sells its products to hospitals, clinics, and laboratories in the United States and worldwide.

XOMA has three U.S. patents and a European patent that protect diagnostic and prognostic methods for measuring LBP levels in humans. In addition, the Company has acquired from Johnson & Johnson an exclusive sublicense to fundamental LBP-related patents based on the discovery of LBP by Drs. Richard Ulevitch and Peter Tobias at The Scripps Research Institute in San Diego.

XOMA develops and manufactures biopharmaceuticals in Berkeley and Santa Monica, Calif. Medical targets include infectious diseases, immunologic and inflammatory disorders, and cancer. The Company's infectious disease product development platform is BPI (bactericidal/permeability-increasing protein), a human protein with multiple anti-infective properties that is part of the body's defenses against microbial infection. Peter Elsbach, M.D., and Jerrold Weiss Ph.D. discovered BPI at New York University School of Medicine (NYU). XOMA has an exclusive license to NYU's BPI-related patents. XOMA has agreements with the Hyland Immuno Division of Baxter Healthcare Corporation and with Allergan, Inc. to develop BPI-related products. For more information, visit XOMA's website at www.xoma.com.

Statements in this press release related to collaborative relationships, other aspects of product development, or that otherwise relate to future periods, are forward-looking statements within the meaning of Sections 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements are based on assumptions that may not prove accurate. Actual results could differ materially from those anticipated due to risks inherent in the regulated market. These risks, including those related to the time or results of pending or uncertainties regarding the legal standards applicable to biotechnology patents, and actions by the U.S. Food and Drug Administration or the U.S. Patent and Trademark office, are discussed in the company's most recent annual report on Form 10-K and in other SEC filings. Consider such risks carefully in evaluation XOMA's prospects.