Adherex Announces ASCO Abstract of ADH-1 in Melanoma

Research Triangle Park, NC, May 19, 2008 - Adherex Technologies Inc. (AMEX:ADH, TSX:AHX), a biopharmaceutical company devoted to solving problems for patients with cancer, announced today the publication of an abstract on the phase I/II study of ADH-1 in combination with isolated limb infusion melphalan as a treatment for melanoma.  The abstract was prepared for the 2008 American Society of Clinical Oncology (ASCO) Annual Meeting, which takes place May 30 - June 3, 2008 in Chicago, IL.   The abstract, which is reproduced below, highlights initial human data indicating that the synergy previously noted in our preclinical studies is also being seen in the clinic.  Regional infusion of melphalan alone for melanoma has historically led to complete responses in about thirty percent of cases.  Using ADH-1 in combination with regionally-infused melphalan, the melanoma tumors appear to be more vulnerable to the chemotherapy with complete responses being noted in approximately half of the patients in the study thus far.   As of May 16, 2008, 33 patients had been enrolled in the study.  As reported in a WRAL interview with Dr. Georgia Beasley, independent lead investigator on the study at the Duke Comprehensive Cancer Center (available at http://www.wral.com/business/local_tech_wire/biotech/story/2897670/), eight of the initial 16 patients had in field complete responses at three months following treatment.  Data on an aggregate of approximately 20 patients with three month follow-up will be presented June 1st in a poster discussion session at the 2008 ASCO annual meeting in Chicago.   The incidence of malignant melanoma is increasing at a rate faster than any other cancer, with 60,000 new cases expected to be diagnosed this year in the United States. Melanoma that has spread beyond the primary site is rarely curable, and treatment options are limited. Even when it is treated, the response rates are typically poor, and most people die within six to nine months after diagnosis.   Adherex is evaluating ADH-1 in combination with melphalan via isolated limb infusion for the treatment of melanoma in an ongoing multi-institutional Phase I/IIB trial.  Current participating centers include Duke University Medical Center, MD Anderson Cancer Center, Lehigh Valley Hospital and H. Lee Moffitt Cancer Center, with four additional centers in the process of being added.  We currently expect the trial to enroll a total of 56 patients.   Earlier this year, Adherex was granted orphan drug designation for the use of ADH-1 in conjunction with melphalan for the treatment of Stage IIB/C, III and IV malignant melanoma.   The full abstract reads as follows :   “Title: A phase I/II study of systemic ADH-1 in combination with isolated limb infusion with melphalan (ILI-M) in patients (pts) with locally advanced in-transit melanoma.   Abstract No: 9013   Citation: J Clin Oncol 26: 2008 (May 20 suppl; abstr 9013)   Author(s): G. Beasley, N. McMahon, G. Sanders, P. Zipfel, C. Augustine, W. Petros, J. Padussis, M. I. Ross, A. Selim, W. Peters, D. S. Tyler Background: ILI-M is a well tolerated treatment for pts with in-transit melanoma of the extremity with a 30% CR rate in our own cohort of 50 previously treated pts. ADH-1 is a cyclic pentapeptide that targets N-cadherin adhesion complexes. In a preclinical model of melanoma treatment with ILI-M, the combination of systemic ADH-1 and regional melphalan resulted in a synergistic increase in durable CRs. Methods: A phase I/II study was performed to evaluate the safety, tolerability, pharmacokinetics, and anti-tumor activity of systemic ADH-1 in combination with ILI-M in pts with measurable in-transit melanoma of the extremity. The initial phase I study consisted of ADH-1 dose escalation cohorts of 3 pts each at 1.0, 2.0, and 4.0 gm administered systemically on Days 1 (6-8 hr pre ILI-M) and 8 in combination with standard dose ILI-M corrected for ideal body weight. The phase II study expanded the 4.0 gm ADH-1 cohort to 25 pts. N-cadherin IHC staining was performed on pretreatment tumor tissue. Response was defined at 3 months using RECIST criteria.   Results: Eleven pts, including 6 previous ILI-M alone failures, have been treated with no observed dose limiting toxicities. Common treatment related grade 1/2 toxicities included pain (n=8), skin/dermatologic (n=11), musculoskeletal (n=4), and nausea (n=4). Grade 3 toxicities included neutropenia (n=1), anemia (n=1), and serologic CPK elevation (n=1). There was 1 Grade 4 CPK elevation. To date, in field responses of the 7 pts followed 3 months post treatment include 4 CRs (57%), 1 SD, and 2 PDs. Interestingly, the 2 pts with PD had tumors that were negative for N-cadherin by IHC. PK analysis demonstrated minimal variability in melphalan plasma levels across pts while ADH-1 plasma concentrations immediately pre-ILI-M increased with each dose cohort (mean=901 ng/mL at 1.0 gm, 1,985 ng/mL at 2.0 gm, and 11,491 ng/mL at 4.0gm.). Conclusions: Systemic ADH-1 administered pre and post ILI-M is a well tolerated, novel targeted therapeutic approach to regionally advanced melanoma. Tumor responses, especially CRs, exceeded expectations in this group of heavily pretreated pts and appear to require N-cadherin expression. Complete accrual to the study is expected by May 2008.â€� About Adherex Technologies Adherex Technologies Inc. is a biopharmaceutical company dedicated to the discovery and development of novel cancer therapeutics. We are in the business of solving problems for patients with cancer.  We have multiple products in the clinical stage of development, including eniluracil, ADH-1 and sodium thiosulfate (STS).  Eniluracil, an oral dihydropyrimidine dehydrogenase (DPD) inhibitor, is being developed to improve the tolerability and effectiveness of 5-fluorouracil (5-FU), one of the most widely used oncology drugs in the world. ADH-1 is a biotechnology compound which selectively targets N-cadherin, a protein present on certain tumor cells and the blood vessels of solid tumors. STS is a chemoprotectant being developed to reduce or prevent hearing loss that may 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 aims to become a leader in developing innovative treatments that address important unmet medical needs in cancer. For more information, please visit our website at www.adherex.com.   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 or results of our development.  We can provide no assurance that such development will proceed as currently anticipated, that previous results will be predictive of future outcomes 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, the early stage of our product candidates, our reliance on collaborative partners, our need for additional capital to fund our operations, our history of losses, and other risks inherent to the biopharmaceutical industry.  For a more detailed discussion of related risk factors, please refer to our public filings available at www.sedar.com and www.sec.gov.   -- END -- For further information, please contact: D. Scott Murray Senior Vice President, Corporate Development Adherex Technologies Inc. T: (919) 484-8484 info@adherex.com