Pain Therapeutics Inc has reached mid-point patient enrollment in a 21-day multi-dose safety study with its novel painkiller Oxytrex. This clinical study is designed to assess multi-dose safety of Oxytrex in patients with severe osteoarthritic pain.

"We are pleased with the progress of this study," said Remi Barbier, Pain Therapeutics' president and chief executive officer."Patient enrollment is on-track and expenses are on-budget.We expect to complete patient enrollment in the second quarter of this year, followed by the initiation of a Phase III efficacy study."

This randomized, double-blind, placebo and active controlled study will enroll a total of 350 patients with severe osteoarthritic pain in 30 clinical sites across the United States.Patients are randomly assigned to treatment groups consisting of either immediate release oxycodone, a similar dose of Oxytrex or placebo.Safety and efficacy parameters are assessed over the 21-day treatment period and during a subsequent follow-up period.