Adolor Corporation Initiates Second Phase 2 Study of Novel Delta Agonist.

ADL5859 Being Studied in a Variety of Pain Indications

EXTON, Pa. -- Adolor Corporation (Nasdaq:ADLR) announced today the initiation of a second Phase 2 study of ADL5859, a novel delta opioid agonist in development for the treatment of pain. Study 33CL232 will explore the analgesic efficacy of ADL5859 in treating inflammatory pain associated with rheumatoid arthritis.

"This study represents an important component of our ongoing program to assess our delta agonists across a number of pain conditions," said Michael R. Dougherty, president and chief executive officer of Adolor Corporation. "We believe there is a significant need for novel medicines to treat a variety of pain states, and are pleased to now begin our second Phase 2 study with ADL5859."

Study 33CL232 is expected to enroll approximately 60 subjects, who will be scheduled to complete both a single dose phase and a subsequent multiple dose phase.

Along with Study 33CL232, ADL5859 is being evaluated in an acute pain study, in a dental pain model (Study 33CL230) which commenced in the second quarter of this year. A third study in neuropathic pain is planned to start later this year.

Additionally, Adolor expects to file an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA) for ADL5747, a second Delta agonist compound, in the fourth quarter of this year.

About the Delta Receptor Program

One of three opioid receptors, the Delta receptor has potential utility in a variety of indications, including the modulation of pain. Through a proprietary research platform based on cloned, human opioid receptors, Adolor has identified a series of novel, orally active Delta agonists - compounds that selectively stimulate the Delta opioid receptor. Delta compounds may have a number of potential advantages, including an improved side effect profile, as compared to mu opioid receptor agonists. On the basis of preclinical evaluation in animal models of human conditions, one might expect a Delta agonist to show effect in inflammatory pain, among other pain conditions. In addition, Delta agonists are thought to modulate other biological processes that may manifest themselves in disease states or conditions such as cardioprotection, overactive bladder, and depression.

There are currently no selective Delta agonists approved by the FDA.

About Adolor Corporation

Adolor Corporation (Nasdaq:ADLR) is a biopharmaceutical company specializing in the discovery, development and commercialization of novel prescription pain management products. Entereg[R] (alvimopan) is Adolor's lead product candidate under development for the management of the gastrointestinal side effects associated with opioid use. Adolor and GlaxoSmithKline (GSK) are collaborating in the worldwide development and commercialization of Entereg in multiple indications. Adolor also has a number of discovery research programs focused on the identification of novel compounds for the treatment of pain. By applying its knowledge and expertise in pain management, along with ingenuity, Adolor is seeking to make a positive difference for patients, caregivers and the medical community. For more information, visit www.adolor.com.

This release, and oral statements made with respect to information contained in this release, constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include those which express plan, anticipation, intent, contingency, goals, targets or future development and/or otherwise are not statements of historical fact. These statements are based upon management's current expectations and are subject to risks and uncertainties, known and unknown, which could cause actual results and developments to differ materially from those expressed or implied in such statements. Such known risks and uncertainties relate to, among other factors: the risk that our Delta product candidates ADL5859 and ADL5747 will show adverse safety findings that make them unsuitable for further development; the risk that our Delta product candidates do not show utility in treating pain or any other clinical indications; the risk that we do not initiate further clinical studies for our product candidate ADL5859; the risk that we do not file an IND by the end of this year or at all for our product candidate ADL5747; the risk that filing targets for regulatory filings are not met; the costs, delays and uncertainties inherent in scientific research, drug development, clinical trials and the regulatory approval process; Adolor's history of operating losses since inception and its need for additional funds to operate its business; Adolor's reliance on its collaborators, including GlaxoSmithKline in connection with the development and commercialization of Entereg[R]; market acceptance of Adolor's products, if regulatory approval is achieved; reliance on third party manufacturers; product liability claims; competition; and securities litigation.

Further information about these and other relevant risks and uncertainties may be found in Adolor's Reports on Form 8-K, 10-Q and 10-K filed with the U.S. Securities and Exchange Commission. Adolor urges you to carefully review and consider the disclosures found in its filings which are available in the SEC EDGAR database at http://www.sec.gov and from Adolor at http://www.adolor.com. Given the uncertainties affecting pharmaceutical companies in the development stage, you are cautioned not to place undue reliance on any such forward-looking statements, any of which may turn out to be wrong due to inaccurate assumptions, unknown risks, uncertainties or other factors. Adolor undertakes no obligation to (and expressly disclaims any such obligation to) publicly update or revise the statements made herein or the risk factors that may relate thereto whether as a result of new information, future events, or otherwise.