XOMA Corp. Chooses Lead Antifungal Compound, Mycoprex-tm-, for Development.

BERKELEY, Calif.--(BUSINESS WIRE)--Jan. 11, 1996--XOMA Corp. (NASDAQ:XOMA) today announced an important step forward in its antifungal drug development program. The company has selected a lead compound and several alternates to move from the research phase into an intensive process of product development. XOMA's goal is to submit an IND for its lead compound, Mycoprex(TM), for one or more indications by the end of 1996.

These fungicidal compounds are peptides and peptidomimetics derived from XOMA's BPI drug platform. BPI (bactericidal/permeability-increasing protein), is a human host-defense protein that kills bacteria and neutralizes bacterial endotoxin.

XOMA scientists initially discovered that certain peptide sequences derived from BPI displayed potent antifungal activity. Further research demonstrated that many BPI-derived compounds not only killed strains of Candida, the most common fungi to cause systemic illness, but also showed broad-spectrum activity against fungi resistant to the currently available drugs.

Based on these findings, the company initiated a program to screen for compounds with a broad spectrum of fungicidal activity and in vivo potency at least comparable to amphotericin B (the most potent fungicidal currently available), but with a better safety profile. XOMA is also screening for compounds that may facilitate oral administration.

"There is an urgent medical need for safer and more powerful fungicidals," said Lowell Young, MD, Director of the Kuzell Institute, San Francisco. "The incidence of systemic fungal infections is rising in hospitalized patients as the population with impaired immune systems -- due to AIDS, chemotherapy or treatment with immunosuppresive drugs -- continues to grow. There are few approved antifungals, and none of the available treatments is completely satisfactory. What's worse, certain common fungi are developing resistance to the approved drugs. The BPI-derived peptides show powerful fungicidal activity and so far appear to have a favorable safety profile. These are essential features one looks for in new antifungal agents."

"We are pleased with our progress in the Mycoprex (TM) program for a number of reasons," stated John Castello, chairman, president and CEO of XOMA. "First, it further diversifies our product portfolio, in a potentially significant market. Second, it provides a further demonstration of BPI as a prolific product development platform. Finally, it underscores our ability to move rapidly from discovery into product development."

XOMA Corporation is a biopharmaceutical company developing products for the treatment of primary infections and major complications due to infectious diseases, traumatic injury and surgery. The company is focused on the accelerated development of products derived from BPI (bactericidal/permeability-increasing protein), a human white blood cell protein that kills bacteria, neutralizes endotoxins and inhibits neovascularization.

Neuprex(TM), XOMA's first BPI-derived product, is in three distinct clinical trials for serious endotoxin-related complications: hemorrhagic trauma, meningococcemia, and partial hepatectomy. A fourth trial is scheduled to begin early in 1996, testing the product's ability to enhance the potency of conventional antibiotics and reverse bacterial resistance in severe intra-abdominal infections. The company also recently announced I-PREX(TM), a BPI-derived topical formulation for treatment of ophthalmic disorders.

CONTACT: XOMA Corp., Berkeley

Ellen M. Martin, 510/644-1170 or 800-BIO-XOMA