News Release

Landmark, pivotal Phase IIb/III trial of biotoxin for cancer pain begins

Phase IIa final results released at North American Pain conference

Peer-Reviewed Publication

WEX Pharmaceuticals Inc.

Investigators involved in the pivotal clinical trial of TectinTM enrolled and dosed the first of up to 150 patients that will participate in the study. It is one of the largest Canadian clinical trials to evaluate the efficacy and safety of a drug for treatment of medically refractory cancer pain, and will take place in up to 25 treatment centres across Canada.

Tectin, a drug derived from the puffer fish, also known as blow fish or fugu, has been developed by Vancouver-based International Wex Technologies Inc. to block slow sodium channel nocicipetive pain fibers in a highly selective manner. Results from a recently completed open-label Phase IIa dose were presented in a podium presentation by the lead investigator, Dr. Neil Hagen, during the 2nd Joint Scientific Meeting of the American Pain Society and the Canadian Pain Society that was held in Vancouver, B.C, on May 6-9, 2004.

The Phase IIa results demonstrate that TectinTM, administered intramuscularly for four days at the studied doses, is well tolerated and can relieve refractory cancer pain for up to two weeks in some patients. Consistent with the interim analysis, the final results show that almost three-quarters (72%) of cancer pain patients experienced a clinically meaningful analgesic response.

Based on these promising results, the Company was encouraged to pursue a larger trial to further confirm the effectiveness of the compound. The current trial is a multicentre, randomized, double-blind and placebo-controlled study designed to compare the efficacy and safety of TectinTM versus placebo in moderate to severe inadequately controlled cancer-related pain.

The study is being led by two nationally respected leaders in cancer pain assessment and management, Dr. Neil Hagen, Head of the Division of Palliative Medicine, Department of Oncology at the University of Calgary and Dr. Bernard Lapointe, Chief of the Palliative Care Division of the Jewish General Hospital in Montreal, and Associate Professor in the Department of Oncology and the Department of Family Medicine at McGill University.

"We are definitely encouraged by the Phase IIa results," said Dr. Neil Hagen, Lead Investigator of the study. "In light of the safety profile of tetrodotoxin within this study, and the unsatisfactory pain management options available for patients with refractory cancer pain, further study of tetrodotoxin in a large multicenter controlled trial is warranted. We believe that the current Phase IIb/III study will be one of the largest and most important Canadian clinical trials conducted to date to evaluate the efficacy and safety of a drug for medically refractory cancer pain."

Wex originally used the drug compound for the treatment of drug withdrawal but it was noted that the main factor in its ability to relief or eliminate withdrawal symptoms was its ability to reduce pain. Thus, Wex pursued testing of TectinTM for refractory cancer relief in cancer patients. With these encouraging results, TectinTM will also be investigated for clinical use in patients suffering from non-cancer chronic pain.

The Pivotal trial of TectinTM in cancer pain is expected to continue for the next 12 months, with interim results expected in 2005.

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For additional information on our products, visit us at http://www.wextech.ca or call Don Evans, Corporate Communications at 604-683-8880/ 800-722-7549 OR Mark Butler, Media Communications at 416-518-6804. (Interviews and B-roll)


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