Adherex Initiates Clinical Proof-Of-Mechanism Trial of Eniluracil

Adherex Technologies Inc. (TSX:AHX)(AMEX: ADH), a biopharmaceutical company with a broad portfolio of oncology products under development, today announced that it has initiated a clinical proof-of-mechanism trial of eniluracil. This study, which will be conducted at the University of Alabama at Birmingham, is expected to involve up to 20 patients and provide Adherex with human data on the effects of low doses of eniluracil in tumor tissue. Adherex is developing eniluracil to improve the therapeutic value and effectiveness of 5-fluorouracil (5-FU), one of the world's most commonly used anti-cancer drugs.

This clinical study will primarily involve patients with colorectal cancer scheduled to undergo surgery to remove their tumors. These patients will receive a single, oral dose of eniluracil prior to their surgery. Samples of tumor, surrounding normal tissue and liver will be evaluated directly for the degree and duration of eniluracil's effect on the various enzymatic pathways for 5-FU. This trial, which the Company expects to complete in mid-2006, is designed to confirm the dose effect of eniluracil directly in tumor cells. Adherex has already demonstrated eniluracil's effect on 5-FU metabolism in animal and human cell line studies.

"I believe 5-FU remains a very important tool in the fight against cancer. If we can make 5-FU more effective with fewer side effects, countless patients worldwide could benefit," said Robert Diasio, MD, Chairman, Department of Pharmacology and Toxicology at the UAB School of Medicine and Associate Director for Basic Sciences, UAB Comprehensive Cancer Center, and an investigator for the Adherex study.

This trial is the second in a series of three preliminary studies planned for 2006 to optimize Adherex's proprietary method of administration for the combination of eniluracil and 5-FU with the goal of returning eniluracil to Phase III as early as 2007.

About Adherex Technologies

Adherex Technologies Inc. is a biopharmaceutical company dedicated to the discovery and development of novel cancer therapeutics. We aim to be a leader in developing innovative treatments that address important unmet medical needs in cancer. We currently have multiple products in the clinical stage of development, including ADH-1 (Exherin(TM)), eniluracil and sodium thiosulfate (STS). ADH-1, our lead biotechnology compound, selectively targets N-cadherin, a protein present on certain tumor cells and established blood vessels that feed solid tumors. Eniluracil, an oral dihydropyrimidine dehydrogenase (DPD) inhibitor, was previously under development by GlaxoSmithKline for oncology indications. STS, a drug from our specialty pharmaceuticals pipeline, protects against the disabling hearing loss that can often result from treatment with platinum-based chemotherapy drugs. With a diversified portfolio of unique preclinical and clinical-stage cancer compounds and a management team with expertise in identifying, developing and commercializing novel cancer therapeutics, Adherex is emerging as a pioneering oncology company.

This press release contains forward-looking statements that involve significant risks and uncertainties. The actual results, performance or achievements of the Company might differ materially from the results, performance or achievements of the Company expressed or implied by such forward-looking statements. Such forward-looking statements include, without limitation, those regarding the development plans of the Company and the expected timing and results of such development. We can provide no assurance that such development will proceed as currently anticipated or that the expected timing or results of such development will be realized. We are subject to various risks, including the uncertainties of clinical trials, drug development and regulatory review, other risks inherent in the biopharmaceutical industry, the early stage of our product candidates, our reliance on collaborative partners, our need for additional capital to fund our operations, and our history of losses. For a more detailed discussion of related risk factors, please refer to our public filings available at www.sedar.com and www.sec.gov.

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