Pain Therapeutics Inc has initiated another clinical study for PTI-188, an investigational drug intended to treat a lethal form of skin cancer called metastatic melanoma (MM). This study follows the release of promising data in an earlier phase I study for PTI-188, published at the Meeting of the Society for Nuclear Medicine.

"No drug therapy exists today to eliminate this cancer," said Remi Barbier, president & chief executive officer of Pain Therapeutics. "I am encouraged by our progress with PTI-188 and believe earlier results indicate PTI-188 may play a significant role in improving survival for patients with MM."

This is an open-label, phase I, dose-escalation study for PTI-188. The primary objective of this study is to assess the safety, pharmacokinetics and anti-tumour activity of PTI-188 in MM patients. Twelve or more cancer patients with confirmed MM will receive a single intravenous dose of PTI-188. Metastatic tumours will be evaluated at baseline, post-treatment and monthly thereafter until disease progression. Patient enrolment is currently underway in Israel. This study is expected to be completed later this year.

PTI-188 is a monoclonal antibody (PTI-6D2) labelled with a radio-isotope (188-rhenium). This antibody binds to extracellular (but not intracellular) melanin released during tumour cell turnover; the radio-isotope is intended to deliver a cytotoxic dose of radiation to local tumour sites, thus promoting anti-tumour activity.

Metastatic melanoma is a lethal form of skin cancer. According to the American Cancer Society, nearly 8,000 people die annually from MM in the United States. If diagnosed early and surgically removed, early-stage melanoma is potentially curable. However, the advanced form of this cancer, or MM, has a poor prognosis and limited treatment options. MM patients have a median survival time of 9 months and a 5-year survival rate of about 3%. There has been little change in these results in the past 25 years.

Pain Therapeutics, Inc. is a biopharmaceutical company that develops novel drugs. In addition to Remoxy, a unique abuse-resistant controlled-release oxycodone, the company has three drug candidates in clinical programmes, including PTI-188, PTI-202 and PTI-721.