Pain Therapeutics, Inc. (Nasdaq: PTIE) today announced the initiation of a Phase III study with Oxytrex, an investigational drug. Oxytrex is a unique oral painkiller for patients who suffer from persistent severe chronic pain. The Company believes Oxytrex offers less physical dependence/withdrawal than oxycodone, an 80-year-old prescription painkiller still widely used today to treat persistent severe chronic pain.

"We remain encouraged by the strong science around Oxytrex published in several top journals, including a recent article in Journal of Neurobiology that further elucidates the unique attributes of ultra-low-dose opioid antagonists," said Remi Barbier, president and chief executive officer.

This study is being referred to as the "Extreme Study" in deference to patients who depend on extremely high daily doses of oxycodone (greater than or equal to 120 mg per day) to treat severe chronic pain. The Company believes this sub-population of patients is prone to physical dependence/withdrawal.

In the second half of 2007, Pain Therapeutics plans to initiate a large study with Oxytrex in a broad patient population.

"Extreme Study" Design

This clinical study is randomized, double-blinded, multi-center and placebo-controlled. The study will enroll approximately 120 patients who have each been taking greater than or equal to 120 mg of oxycodone per patient per day for over a year. Patients who meet this and all other eligibility requirements are randomized to receive twice-daily doses of 100 nanograms (i.e., 0.0001 mg) ultra-low-dose naltrexone or matching placebo for two weeks. At the conclusion of the treatment period, patients check into a clinic and receive an injection of a high-dose opioid antagonist to precipitate withdrawal. During the withdrawal phase of the study, patients are closely monitored and measured for signs and symptoms of physical dependence/withdrawal using the Subjective Opiate Withdrawal Scale. The study's primary endpoint is prospectively defined as physical dependence/withdrawal scores in the treated arm compared to placebo. For ethical and other reasons, the study protocol allows an interim analysis.

About Oxytrex

Pain Therapeutics owns commercial rights to Oxytrex, a unique oral painkiller that preferentially inhibits an excitatory effect of opioid receptors. This excitatory effect is believed to counteract analgesia (pain relief) and cause tolerance. Its inhibition enhances pain relief and minimizes opioid tolerance. The FDA has not yet evaluated the merits, safety or efficacy of Oxytrex.

About Pain Therapeutics, Inc.

Pain Therapeutics is a biopharmaceutical company that develops novel drugs for pain management and oncology. We have three investigational drug candidates in clinical programs. Remoxy(TM) and PTI-202 are proprietary, abuse-resistant forms of opioid drugs. Oxytrex is a novel, next-generation painkiller that potentially offers less physical dependence than currently marketed opioid painkillers. We are also developing a novel radio-labeled monoclonal antibody to treat metastatic melanoma, a rare but deadly form of skin cancer. The FDA has not yet evaluated the merits, safety or efficacy of our drug candidates. For more information, please consult our website: paintrials/.

Note Regarding Forward-Looking Statements:

This press release contains forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995 (the "Act"). PTI disclaims any intent or obligation to update these forward-looking statements, and claims the protection of the Safe Harbor for forward-looking statements contained in the Act. Examples of such statements include, but are not limited to, any statements relating to the timing, scope or expected outcome of the Company's clinical development of its drug candidates, the potential benefits of the Company's drug candidates and the size of the potential market for the Company's products. Such statements are based on management's current expectations, but actual results may differ materially due to various factors. Such statements involve risks and uncertainties, including, but not limited to, those risks and uncertainties relating to difficulties or delays in development, testing, regulatory approval, production and marketing of the Company's drug candidates, unexpected adverse side effects or inadequate therapeutic efficacy of the Company's drug candidates that could slow or prevent product approval or market acceptance (including the risk that current and past results of clinical trials are not necessarily indicative of future results of clinical trials), the uncertainty of patent protection for the Company's intellectual property or trade secrets, the Company's ability to obtain additional financing if necessary and unanticipated research and development and other costs. For further information regarding these and other risks related to the Company's business, investors should consult the Company's filings with the Securities and Exchange Commission.

Pain Therapeutics, Inc.
paintrials/

View drug information on Naltrexone Hydrochloride Tablets; Oxycodone and Aspirin.