ILEX Initiates ILX-651 Phase II Melanoma Study; Preliminary Results Show Agent Active in Range of Solid Tumors.

Business Editors/Health/Medical Writers

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SAN ANTONIO--(BUSINESS WIRE)--Oct. 7, 2003

ILEX(tm) Oncology Inc. (Nasdaq:ILXO) today announced that it has opened a multi-center Phase II study of the anticancer compound ILX-651. The study will examine the efficacy and tolerability of the novel tubulin-interactive agent in patients with recurrent or metastatic melanoma at 19 sites throughout the U.S. In addition, ILEX expects to broaden the Phase II program by opening a non-small cell lung cancer study later this year.

"We were encouraged to see significant activity in earlier Phase I studies," said William Hyman, M.D., Tyler Cancer Center, part of the US Oncology network of cancer research centers. "One confirmed complete response (CR) was observed in a patient with metastatic melanoma, along with complete healing of bone lesions and liver metastases. In addition, a number of patients that received ILX-651 achieved stable disease."

Interim results of a Phase I study recently presented by clinical investigators at the American Society of Clinical Oncology meeting in Chicago showed that ILX-651 appeared to be biologically active and well-tolerated in patients with advanced refractory solid tumors.

"Metastatic melanoma currently has few effective chemotherapeutic options therefore we are excited at the opportunity to investigate this new agent that has shown activity in this disease in previous studies," stated Casey Cunningham, M.D., associate medical director of the Mary Crowley Medical Research Center, part of US Oncology Network.

About ILX-651

ILX-651 is a third-generation synthetic pentapeptide analog of the natural substance dolastatin and has a unique mechanism of action that targets tubulin. The drug has been chemically modified to provide improved pharmacological properties and is orally bioavailable with a potentially enhanced therapeutic window over first-generation dolastatins. ILX-651 has shown significant anti-tumor activity in preclinical models in a wide range of solid tumors, including cancer cells that are resistant to other tubulin-interactive drugs, such as the commonly prescribed taxanes.

About ILEX

Founded in 1994 as an oncology drug development company, ILEX is strategically positioned to become a product-driven biopharmaceutical company, focused primarily in oncology. ILEX has a marketed product, CAMPATH(R) in the United States and MABCAMPATH(R) in the European Union, and is advancing an innovative and diversified pipeline of compounds focused on the treatment of cancer. The ILEX pipeline comprises product candidates at various stages of clinical development, including cytotoxic and cytostatic agents with novel mechanisms of action, monoclonal antibodies, angiogenesis inhibitors and signal transduction inhibitors. ILEX maintains a core competency in oncology drug development, with locations in San Antonio, Texas, and Guildford, England. ILEX also conducts research in angiogenesis inhibition, cell signaling, medicinal chemistry and nuclear receptor biology at its laboratories in Boston, Mass., and Geneva, Switzerland. Further information about ILEX can be found on the company's web site at www.ilexonc.com.

Certain statements contained herein are "forward-looking" statements (as such term is defined in the Private Securities Litigation Reform Act of 1995). Because these statements include risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Specifically, factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements include, but are not limited to: risks associated with preclinical and clinical developments in the biopharmaceutical industry in general and in ILEX's compounds under development in particular; market acceptance of CAMPATH(R); the ability to expand the number and scope of the indications for which CAMPATH(R) is approved; the potential failure of ILEX's compounds under development to prove safe and effective for treatment of disease; uncertainties inherent in the early stage of ILEX's compounds under development; failure to successfully implement or complete clinical trials; failure to receive marketing clearance from regulatory agencies for our compounds under development; acquisitions, divestitures, mergers, licenses or strategic initiatives that change ILEX's business, structure or projections; the ability of ILEX to predict its future expenses and capital needs; the development of competing products; uncertainties related to ILEX's dependence on third parties and partners; and those risks described in ILEX's report on Form 8-K filed on August 14, 2003, and in other filings made by ILEX with the SEC. ILEX disclaims any obligation to update these forward-looking statements.