Burnham and ILEX Join Forces to Translate New Pharmacology for Cancer Therapy Into Patient Reality; Blood Vessel Plus Tumor Targeting May Reduce Side Effects, Increase Efficacy.

NEW ORLEANS--(BW HealthWire)--March 30, 1998--The Burnham Institute has licensed to ILEX(tm) Oncology, Inc. (NASDAQ:ILXO), a new weapon in the battle against cancer that attacks with a wholly novel approach, the organizations announced here today at the 89th Annual American Association for Cancer Research meeting. In the first application of a unique therapeutic modality, reported earlier this year in the journal Science, ILEX and Burnham will develop and test a compound that not only cuts off a tumor's supply line but also delivers a poisonous last meal directly to the tumor.

Historically, cancer therapies have attacked the tumor. However, like an army without intelligence data, chemotherapy attacks both healthy and cancerous tissue, causing severe side effects with limited efficacy. More recently, therapies such as monoclonal antibodies and angiogenesis inhibitors have been found to act like "smart bombs," targeting either a specific tumor or the tumor's supply line -- its blood vessels.

The new compound, discovered and developed by Drs. Erkki Ruoslahti, President and CEO, and Renata Pasqualini, Assistant Professor, of The Burnham Institute, with grant support from the National Cancer Institute, links a "Tumor Homing Peptide" (THP) to one of the most widely used chemotherapy drugs, doxorubicin. THP-dox seeks out and binds only to blood vessels that nourish solid tumors, simultaneously destroying these critical blood vessels and passively releasing doxorubicin into the tumor tissue -- delivering a powerful "one-two punch."

In the study published in the January 16, 1998 issue of Science, Ruoslahti and Pasqualini reported that mice implanted with human breast tumors and treated with THP-dox survived, while those treated with doxorubicin alone died either of tumors or of drug poisoning at high doses.

In an accompanying editorial, tumor-cell biologist Bruce Zetter of Harvard Medical School, said, "The technique probably targets both the vessels and the tumor cells. That is its big advantage. It gives you a double-pronged therapeutic effect that should be quite powerful."

Unlike angiogenesis inhibitors, THP-dox destroys rather than inhibits formation of tumor-nourishing blood vessels. Thus, as a targeted therapy, THP offers therapeutic opportunities in a broad spectrum of cancers.

"The Burnham Institute and ILEX share a true passion for this novel technique and a clear vision to translate the discovery into a clinical reality," said Dr. Ruoslahti. "We are confident that the ILEX team has the development expertise we have been searching for to take this important compound into the clinic," he added.

"We are extremely enthusiastic to join forces with The Burnham Institute and begin development of THP-dox," said Daniel D. Von Hoff, M.D., Co-Chair of ILEX's Scientific Advisory Board. "While drug safety studies as well as process development, scale-up and manufacturing must now be conducted, we do hope to begin clinical trials within two years," he explained.

The license agreement provides that Burnham shall receive milestone and royalty payments, as well as a warrant to acquire $5 million of ILEX stock at a per share exercise price of 120% of the average price for 30 days prior to closing.

ILEX Oncology, Inc. is a drug development company focused exclusively on the development and marketing approval of drugs for the treatment and prevention of cancer. ILEX provides pharmaceutical and biotechnology companies with compounds for their pipeline through its Products subsidiary, as well as drug development and manufacturing services on a contract basis via its Services subsidiary. ILEX's close association with cancer research and treatment institutions allows access to both the opinion leaders and patients necessary for the development of oncology drugs.

The Burnham Institute is an independent, non-profit, public benefit organization dedicated to basic biomedical research. The Institute was originally known as La Jolla Cancer Research Foundation. Since 1981 it has earned National Cancer Institute designation as a Cancer Center.

Certain statements contained herein are "forward-looking" statements, (as such term is defined in the Private Securities Litigation Reform Act of 1995). Because such statements include risks and uncertainties, actual results may differ materially from those expressed or implied by such forward looking statements. 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 in technology and product development, failure to successfully complete clinical trials, failure to receive market clearance from regulatory agencies, competitive risks, and those risks and uncertainties discussed in filings made by ILEX Oncology, Inc. with the Securities and Exchange Commission.

This release and other information about ILEX(tm) Oncology can be found on the World Wide Web at http://www.ilexoncology.com and http://www.businesswire.com/cnn/ilxo.htm

Information about The Burnham Institute can be found at http://www.burnham-institute.org

CONTACT: ILEX Oncology (PR)

Beth Shapiro, 210/949-8223

On Monday, 3/30/98: 512/426-8323

or

ILEX Oncology (IR)

Ann Stevens, 210/949-8230

or

The Burnham Institute

Nancy Beddingfield, 619/646-3125

or

Makovsky & Company

Craig Heit, 212/508-9600