Pain Therapeutics Inc., a biopharmaceutical company, results of a phase III study with PTI-901, an investigational drug candidate for the treatment of irritable bowel syndrome (IBS), did not demonstrate a meaningful benefit in the third month of treatment, which was defined as the primary endpoint.

According to current regulatory standards, an experimental drug for chronic IBS needs to show efficacy at the end of a three-month treatment period. Based on the adequacy of the study itself, coupled with clinical results, the company is discontinuing all further clinical development activities with PTI-901.

According to a company release, this study was well designed to detect any durable benefits of PTI-901 versus placebo in a large patient population with IBS.

This randomised, double-blinded, multi-centre US study compared a daily dose of PTI-901 against placebo in 600 women with documented IBS over a three-month treatment. PTI-901 showed a favourable safety profile and patients reported statistically meaningful relief of IBS symptoms in the second month of treatment but failed to show promising results in the third month.

"This is an opportunity to sharpen our focus on our late-stage pipeline. We're ready to start 2006 with a strong balance sheet, a modest cash burn rate and two lead drug candidates in phase III clinical development. In addition, in 2006 we plan to add depth to the pipeline by announcing, with our commercial partner, investigational new drug applications for one or more new abuse-resistant opioid painkillers," said Remi Barbier, president and chief executive officer of Pain Therapeutics.