Adolor Corporation has initiated a phase 1 clinical trial of ADL5859, a novel, orally bio available Delta opioid receptor agonist. The phase 1 study is designed to investigate the safety, tolerability and pharmacokinetics of a single dose of ADL5859 in healthy volunteers. As a next step in the development, the company plans to conduct a multi dose safety study.

Adolor submitted an investigational new drug application (IND) with the US Food and Drug Administration (FDA) in December of 2005. After reviewing the application, the FDA placed the IND on clinical hold pending additional acute toxicity information. The FDA reviewed the company's complete response and lifted the clinical hold, allowing for the initiation of the phase 1 clinical trial.

"We are pleased to have been able to address the FDA's questions, refine the clinical protocol and commence our clinical program," said James Barrett, PhD, senior vice president, chief scientific officer and president, research of Adolor Corporation. "Discovered in house, ADL5859 is Adolor's third product currently in clinical development and represents a new class of potential analgesics."

The Delta receptor is one of three opioid receptors that modulate pain and may have application in other medical conditions. Adolor has discovered a series of selective, novel Delta agonists, with the lead candidate, ADL5859, showing analgesic activity in pre-clinical evaluation. There are no selective Delta agonists approved by the FDA.