Through a proprietary research platform based on cloned, human opioid receptors, we have identified a series of novel, orally active delta agonists that selectively stimulate the delta opioid receptor.

The delta opioid receptor has potential utility in a variety of indications, including the modulation of pain. At the forefront of research in this area, Adolor has identified a series of novel agonists with a broad range of potential analgesic activity and possibly a more favorable side-effect profile than traditional mu opioid agonists, including a lower incidence of respiratory depression and constipation, and a lower potential for dependence/abuse. These delta agents would be first in class -- there are no selective delta agonists currently approved by the FDA.

Delta Opioid Receptor Agonist Program - Clinical Status

Pfizer Inc and Adolor currently are evaluating ADL5747 in a Phase 2a study of patients with post-herpetic neuralgia (PHN) to evaluate the safety and efficacy of this compound in addressing neuropathic pain. This study began in the first quarter of 2010 and is expected to conclude early in 2011, with an interim analysis to be conducted later this year.

Pfizer Collaboration

In December 2007, we announced an exclusive, world-wide collaboration with Pfizer, Inc. to develop and commercialize our delta compounds. The agreement focuses on ADL5859 and ADL5747 for pain indications. Adolor will be responsible for IND filings and clinical evaluation through Phase 2a, at which point Pfizer will undertake the completion of development, regulatory approval and commercialization for each compound. Adolor will share profits with Pfizer in the United States and receive royalties on net sales outside the country.