ILEX to Sublicense CAMPATH Diagnostic Rights for Hematologic Diseases to U.K.-Based BioAnaLab for European Markets.

Business Editors & Health/Medical Writers

SAN ANTONIO--(BUSINESS WIRE)--Dec. 18, 2002

Second Key Agreement Aimed at Establishing Commercial

CD52 Testing Worldwide

ILEX(tm) Oncology Inc. (Nasdaq:ILXO) has agreed in principle to exclusively sublicense CAMPATH(R)-related diagnostic testing rights for Europe, the Middle East and Israel to U.K.-based BioAnaLab Ltd., whose core competencies are flow cytometry and enzyme-linked assays for measurement of antigen and antibody levels in blood or body fluids.

"This transaction means we will have an experienced and enthusiastic partner for CD52 and CAMPATH-related testing with state-of-the-art diagnostic technology for hematologic diseases," said Jeffrey Buchalter, ILEX president and CEO, adding that last week ILEX concluded an agreement with a diagnostic partner that is developing a CD52 test for lymphomas and solid tumors. "With agreements now being put in place with the leaders in the two major diagnostic technologies in use today, we are well on the way to making CD52 testing commercially available worldwide."

"We are delighted to be taking on the commercial development of CAMPATH(R) testing," said Geoff Hale, founder of BioAnaLab. "This is a continuation of 22 years' work with the CAMPATH(R) antibodies in our laboratory. There is a rapidly growing demand for these tests and I believe that they will facilitate the safe and effective use of CAMPATH(R)."

BioAnaLab, a new company, is a spin-out from the Therapeutic Antibody Centre (TAC) at the University of Oxford. The TAC, headed by Geoff Hale, developed the validated assays for assessing antibody levels and antiglobulin responses to CAMPATH used by ILEX in support of pivotal clinical trials in CLL. Both the U.S. Food and Drug Administration and the EMEA accepted these assay results in their initial approval of CAMPATH for treating refractory CLL. This detailed know-how, licensed from the University of Oxford to BioAnaLab, will enable the company to quickly develop CD52 assays for broad-scale commercial use.

As a part of the strategic development plan for CAMPATH, ILEX recently acquired exclusive commercial rights to CD52 antigen testing worldwide from BTG International Limited, the global technology commercialization company. The acquisition followed ILEX studies that employed the technology to explore the expression of CD52 in leukemias and lymphomas.

To broaden the scope of testing for CD52, ILEX expects to conclude additional agreements with diagnostic companies in other territories.

CAMPATH (alemtuzumab) works by targeting the CD52 antigen, resulting in the removal of malignant lymphocytes from the blood, lymph nodes, bone marrow and other affected organs. The drug is approved in the United States for the treatment of patients with B-cell chronic lymphocytic leukemia (B-CLL) who have been treated with alyklating agents and have failed fludarabine treatment.

About ILEX

Founded in 1994 as an oncology drug development company, ILEX is strategically positioned to become a product-driven, oncology-focused biopharmaceutical company. 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 Form 10-K for the year ended Dec. 31, 2001, and in other filings made by ILEX with the SEC. ILEX disclaims any obligation to update these forward-looking statements.