WEX Pharmaceuticals Inc.
TSX : WXI

WEX Pharmaceuticals Inc.

April 29, 2008 18:36 ET

WEX Announces Successful Reexamination of Key Patent Covering Uses of Tectin

VANCOUVER, BRITISH COLUMBIA--(Marketwire - April 29, 2008) - WEX Pharmaceuticals Inc. ("WEX" or the "Company") (TSX:WXI) announced today that the U.S. Patent and Trademark Office has issued a Reexamination Certificate for United States Patent No. 6,407,088, titled "Method of Analgesia". This patent relates to the use of tetrodotoxin (TTX) for producing analgesia in humans. The successful reexamination strengthens the intellectual property rights for Tectin, the Company's lead product candidate.

About the Patent

As reexamined, the patent maintains broad protection for the use of TTX at pharmaceutically acceptable doses to relieve pain in humans. Also covered in the patent's 27 claims are derivatives of TTX and various dosing schedules and routes of administration including subcutaneous injection, intramuscular injection, oral formulations and skin patches.

About the Reexamination

In November 2005, WEX requested that the patent, which was originally issued on June 18, 2002, be reexamined in light of prior art discovered during an extensive search. WEX chose to voluntarily undergo reexamination to ensure that this key patent remains strong and enforceable.

"It is critically important for WEX to maximize the protection for the use of TTX and derivatives. It was for this reason that WEX took the unusual step of requesting a reexamination of its own patent. We are very pleased that this strategy has resulted in strengthening the broadest of our many patents protecting Tectin," said Bin Huang, WEX's President and CEO.

About Tectin

The active ingredient in Tectin is tetrodotoxin (TTX), a highly selective sodium channel blocker derived from the puffer fish. Sodium channels are found on nerves and are involved in transmission of nerve impulses. Tetrodotoxin targets a subset of sodium channels found on nerves which conduct pain impulses. There are changes to this subset of sodium channels in chronic pain conditions. Tetrodotoxin is extremely potent, and much lower dosages are needed to produce an analgesic effect than with other drugs.

WEX recently started a Phase III clinical trial of Tectin for the treatment of cancer pain. This clinical trial (TEC-006) is a multicentre, randomized, double-blind and placebo-controlled trial comparing the efficacy and safety of Tectin to placebo in approximately 120 patients with moderate to severe inadequately controlled cancer-related pain.

Market Opportunity

At present, the management of severe cancer pain generally includes the use of morphine and other opiates. This can often result in undesirable side effects, and treatment with this type of medication is not always effective. Because currently available pain-relieving therapy is unsatisfactory for many patients, there is a need for new therapeutic approaches for the management of moderate or severe cancer pain.

In addition to the unmet medical need, the number of patients suffering from cancer continues to grow. In North America alone, based on estimates provided by the American Cancer Society and the Canadian Cancer Society, 1,604,820 were diagnosed with cancer in the United States and Canada in 2007. Between 75% and 90% of patients with metastatic or advanced stage cancer will experience significant cancer-induced pain. In hospitalized patients, 79% experience pain, with 46% experiencing severe pain despite analgesic therapy. Moreover, the actual treatment of cancer can cause pain, with chemotherapy-induced peripheral neuropathy occurring in about half of patients receiving some types of chemotherapy. The global market for pain therapeutics used in cancer patients was approximately US$15.2 billion in 2005 and this is expected to reach at least US$23 billion by 2010.

About WEX Pharmaceuticals Inc.

WEX Pharmaceuticals Inc. is dedicated to the discovery, development, manufacture and commercialization of innovative drug products to treat pain. The Company's principal business strategy is to derive drugs from naturally occurring toxins and develop proprietary products for the global market.

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