TorreyPines Therapeutics Initiates Clinical Trial to Evaluate Analgesic Effect of Oral Prodrug of Tezampanel

LA JOLLA, Calif., June 4 /PRNewswire-FirstCall/ -- TorreyPines Therapeutics, Inc. (Nasdaq: TPTX) today announced it has initiated a clinical trial to evaluate the analgesic effect of NGX426, the oral prodrug of its lead product candidate, tezampanel.

The randomized, double-blind, placebo-controlled Phase I trial will enroll 18 healthy volunteers at a single center in the United States. The trial is designed to evaluate the compound's safety and tolerability and to assess the time of onset, magnitude and duration of its analgesic effect. Specifically, the study will evaluate the effect of NGX426 on hyperalgesia, an abnormally increased pain state, and allodynia, pain resulting from normally non-painful stimuli to the skin, induced by intradermal injections of capsaicin. The primary endpoint is subject self-report of spontaneous pain following the injection of capsaicin.

"We believe there is a substantial commercial opportunity for NGX426 as a novel, oral analgesic," said Neil Kurtz, M.D., President and Chief Executive Officer of TorreyPines Therapeutics. "Data we have obtained in our ongoing Phase I maximum tolerated dose study demonstrate that the drug is well-tolerated at single doses up to and including 210 mg and that NGX426 is rapidly converted to tezampanel. Moreover, this capsaicin study, if successful, will enable us to further take advantage of the versatility of NGX426 and the overall tezampanel franchise."

Subjects in the trial, which involves the recognized and validated capsaicin-induced pain model, will receive single doses of 90 mg and 150 mg of NGX426 versus placebo in a three-way crossover design.

Tezampanel is the first AMPA/kainate-type glutamate receptor antagonist to be studied in clinical trials for chronic pain. Glutamate receptors mediate the functioning of glutamate, an important excitatory neurotransmitter. While normal glutamate production is essential, excess glutamate production, either through injury or disease, can have a range of pathological effects. By acting at both the AMPA and kainate receptor site to competitively block the binding of glutamate, tezampanel and its oral prodrug, NGX426, have the potential to treat a number of diseases and disorders. These include migraine and other forms of chronic pain such as neuropathic pain, muscle spasticity and rigidity, thrombosis, epilepsy, Parkinson's disease and a condition known as central sensitization, a persistent state of hypersensitivity to pain that is a core component of many pain conditions.

About TorreyPines Therapeutics

TorreyPines Therapeutics, Inc. is a biopharmaceutical company committed to providing patients with better alternatives to existing therapies through the research, development and commercialization of small molecule compounds. The company's goal is to develop versatile product candidates, each capable of treating a number of acute and chronic diseases and disorders such as migraine, chronic pain, muscle spasticity and rigidity, xerostomia and cognitive disorders. The company is currently developing four product candidates: two ionotropic glutamate receptor antagonists and two muscarinic receptor agonists. Further information is available at http://www.torreypinestherapeutics.com.

This press release contains forward-looking statements or predictions. Such forward-looking statements include, but are not limited to, statements regarding the potential for NGX426 as a novel, oral analgesic and the potential for tezampanel and NGX426 as treatments for migraine and other forms of chronic pain such as neuropathic pain, muscle spasticity and rigidity, thrombosis, epilepsy, Parkinson's disease and central sensitization. Such statements are subject to numerous known and unknown risks, uncertainties and other factors, which may cause TorreyPines' actual results to be materially different from historical results or from any results expressed or implied by such forward-looking statements, including whether any preclinical studies or clinical trials conducted in the future, will prove successful, and if successful, whether the results can be replicated. These and other risks which may cause results to differ are described in greater detail in the "Risk Factors" section of TorreyPines' annual report on Form 10-K for the year ended December 31, 2007 and TorreyPines other SEC reports. The forward-looking statements are based on current information that is likely to change and speak only as of the date hereof.

SOURCE TorreyPines Therapeutics, Inc.