WEX Pharmaceuticals Inc.

WEX Pharmaceuticals Inc.

August 18, 2005 08:45 ET

WEX Announces the Results of the Phase IIa Opioid Withdrawal Study

VANCOUVER, BRITISH COLUMBIA--(CCNMatthews - Aug. 18, 2005) - WEX Pharmaceuticals Inc. (TSX:WXI) (the "Company") announces the results of the completed Phase IIa double-blind, placebo-controlled study of the efficacy and safety of tetrodotoxin (Tetrodin™) in reducing withdrawal symptoms in methadone-maintained subjects.

Managing withdrawal is a critical step in the initiation of treatment for opioid-dependent individuals. Traditional medical management of opioid withdrawal involves replacing the shorter acting opioids, such as heroin, with a long-acting opioid, such as methadone, and then the methadone dose is gradually reduced. Withdrawal symptoms include bone and muscle aches, nausea, vomiting, restlessness, muscle twitching and shaking.

The Phase IIa study used the opioid antagonist naloxone to induce opioid withdrawal symptoms in methadone-maintained subjects to evaluate the effects of tetrodotoxin on opioid withdrawal and to serve as a model of spontaneous withdrawal which occurs when heroin or methadone use is discontinued.

The results of the current study suggest that the use of a four-day pre-treatment regimen of 30 micrograms of subcutaneous tetrodotoxin, two times a day, prior to the initiating of withdrawal symptoms with naloxone, does not alleviate the withdrawal symptoms, as assessed in 14 methadone-maintained subjects. However, the results are not conclusive since the study included a relatively small number of subjects with a large variation in response, a small carryover effect was observed from one treatment period to the next and in this pre-treatment study design tetrodotoxin was not administered while subjects were experiencing withdrawal symptoms.

A significant finding from this study was that the safety profile of tetrodotoxin was similar to that observed in previous studies and that the administration of naloxone following tetrodotoxin versus placebo treatment did not produce different safety profiles.

Most importantly, the experience with this study has helped the Company to better understand tetrodotoxin's mechanism of action, such that tetrodotoxin treatment may only be effective when administered during the withdrawal period. Hence, it is possible that in a larger study with a different treatment regimen, tetrodotoxin may prove to have clinical efficacy in this indication.

The Company will continue to focus its efforts on the commercialization of Tectin™ for pain management and therefore, will not pursue the development of Tetrodin™ in Canada until further resources are available or a partnership/collaboration is entered into.

About WEX Pharmaceuticals Inc.

WEX Pharmaceuticals Inc. is dedicated to the discovery, development, manufacture and commercialization of innovative drug products to treat moderate to severe acute and chronic pain, symptom pain relief associated with addiction withdrawal from opioid abuse and medicines designed for local anaesthesia. The Company's principal business strategy is to derive drugs from naturally occurring toxins and develop proprietary products for the global market. The Company's Chinese subsidiary sells generic products manufactured at its facility in China.

Forward-Looking Statements

This News Release contains forward-looking statements which may not be based on historical fact. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the actual results, events or developments to be materially different from any future results, events or developments expressed or implied by such forward-looking statements. These factors should be considered carefully and readers are cautioned not to place undue reliance on such forward-looking statements. The company disclaims any obligation to update any such factors or to publicly announce the result of any revisions to any of the forward-looking statements contained herein to reflect future results, events or developments.

Contact Information

  • WEX Pharmaceuticals Inc.
    Don Evans
    (604) 683-8880 or Toll Free: 1-800-722-7549
    WEX Pharmaceuticals Inc.
    Gordon Stanley
    Corporate Communications
    (604) 683-8880 or Toll Free: 1-800-722-7549
    (604) 683-8868 (FAX)