GlaxoSmithKline and Adolor Announce the Completion of Enrollment of Pivotal Clinical Studies of Entereg(R) (Alvimopan).

LONDON & EXTON, Pa. -- Entereg(R) is Being Evaluated to Treat the GI Side Effects of Opioids Used for Persistent Pain in Cancer and Non-Cancer Patients

GlaxoSmithKline (NYSE:GSK) and Adolor Corporation (Nasdaq:ADLR) announced today that GSK has completed enrollment of the Phase 3 clinical program to evaluate the efficacy and safety of the oral investigational drug Entereg(R) (alvimopan) for the treatment of gastrointestinal adverse events caused by opioids used for persistent non-cancer pain. Enrollment of a Phase 2b study in cancer patients with persistent pain has also been completed.

The Phase 3 international, multi-center program includes two efficacy-safety studies (SB-767905/012 and SB-767905/013) and one long-term safety study (SB-767905/014). GSK completed the enrollment earlier than anticipated and the companies are targeting the submission of New Drug Application (NDA) and Marketing Authorization Application (MAA) filings in mid-2007. The initiation of the Phase 3 clinical program was announced in September 2005.

The Phase 2b study (SB-767905/008) is evaluating Entereg(R) in cancer pain patients taking chronic opioid therapy.

"We are pleased to have surpassed the ambitious recruitment milestones we set for Entereg(R) in studies to evaluate the treatment of GI side effects associated with opioid use," said Dr. Yvonne Greenstreet, Senior Vice President, Medicine Development Centre at GlaxoSmithKline. "Our ability to enroll these studies faster than expected, we believe, may indicate large unmet need in this patient population. This will help us advance the development of Entereg(R) for the millions of patients using opioids for persistent pain."

"Millions of people worldwide take opioid analgesics to treat moderate-to-severe pain," said David Madden, interim president and chief executive officer of Adolor Corporation. "The successful completion of the enrollment of this large-scale program faster than expected may indicate a willingness on the part of these patients to try alternatives to the poor therapeutic options available today."

About Studies SB-767905/012 and SB-767905/013

    --  SB-767905/012 and SB-767905/013 are international randomized,
        double-blind, placebo-controlled studies, each designed to
        enroll approximately 480 adults who were taking opioid therapy
        for persistent non-cancer pain and had resulting
        opioid-induced bowel dysfunction.

    --  The primary objective of these confirmatory studies was to
        compare Entereg(R) with placebo for efficacy in the treatment
        of gastrointestinal adverse events commonly associated with
        opioid-induced bowel dysfunction.

    --  The primary endpoint for both studies was based on frequency
        of spontaneous bowel movements, i.e., bowel movement with no
        laxative use in the previous 24 hours.

    --  Under the protocols, the patients were randomized to receive
        placebo or one of two Entereg(R) arms for twelve weeks of
        treatment:

        --  0.5 mg. once daily

        --  0.5 mg twice daily

    About Study SB-767905/014

    --  SB-767905/014 is an international randomized, double-blind,
        placebo-controlled study designed to enroll approximately 750
        adults who were taking opioid therapy for persistent
        non-cancer pain and have resulting opioid-induced bowel
        dysfunction.

    --  The primary objective of this Phase 3 study was to compare the
        long-term safety and tolerability of Entereg(R) with placebo.

    --  The primary endpoint was based on the frequency of reported
        adverse events.

    --  Under the protocol, the patients were randomized to receive
        placebo or Entereg(R) 0.5 mg. twice daily for twelve months of
        treatment.

    About Study SB-767905/008 - in cancer pain

    --  SB-767905/008 is an international, multi-centre, randomized,
        double-blind, placebo controlled study in cancer pain patients
        taking chronic opioid therapy and suffering from
        gastrointestinal adverse events.

    --  The primary endpoint is based on frequency of spontaneous
        complete bowel movements, i.e., bowel movement with no
        laxative use in the previous 24 hours and that provides the
        patient with a feeling of complete evacuation of the rectum.

    --  Patients are randomized to either placebo, 0.5 mg alvimopan
        twice daily, or 1mg alvimopan twice daily for three weeks of
        treatment.

About the GI Adverse Events of Opioids Used for Persistent Pain

Opioids are highly effective in the treatment of pain and are widely used to treat persistent pain such as pain associated with, or as a result of, back pain, arthritis and other pain conditions. However, the use of opioids is associated with medium to longer term GI side effects such as constipation, characterised by infrequent, difficult or incomplete bowel movements, abdominal pain and discomfort, bloating, gastro-oesophageal reflux and loss of appetite. These GI effects, which do not resolve over time, occur when opioids bind to mu-opioid receptors in the gut, reducing gastrointestinal motility and secretions. The consequences are not only distressing, but they may, in some patients, be dose-limiting for the pain therapy, which can then interfere with adequate pain control. There is currently no approved drug specifically for the treatment of gastrointestinal adverse events associated with opioid use for persistent pain. Taking stool softeners, bowel stimulants, increasing daily fluid and fiber intake and increasing exercise are methods often used to manage this condition. Laxatives may provide limited relief for some patients, but can be also be associated with side effects such as abdominal cramping, bloating and unpredictability of effect, and are not recommended for long-term use.

About Entereg(R) (Alvimopan)

Entereg(R) (alvimopan) is an investigational peripherally-acting mu-opioid receptor antagonist, designed to inhibit the negative effects of opioids, like morphine or codeine, on the gastrointestinal system without interfering with the analgesic effects on the central nervous system. Alvimopan is the first of this new class of compounds with a New Drug Application (NDA) that has been accepted for review by the U.S. Food and Drug Administration (FDA) for postoperative ileus (POI).

Adolor Corporation and GlaxoSmithKline are collaborating on the worldwide development and commercialization of Entereg(R) for POI and the treatment of gastrointestinal side effects from opioids used for persistent pain.

About Adolor

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(R) in multiple indications. Adolor is developing a sterile lidocaine patch which is in Phase 2 clinical development for post-surgical incisional pain. 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.

About GSK

GlaxoSmithKline is one of the world's leading research-based pharmaceutical and healthcare companies and is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For more information, visit GlaxoSmithKline on the World Wide Web at www.gsk.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 the results of the alvimopan (Entereg(R)) pivotal clinical studies SB-767905/012, SB-767905/013, SB-767905/014 and SB-767905/008 are not positive; the risk that regulatory approvals for use of alvimopan in patients taking opioids for persistent pain are not achieved; the risk that Adolor may not obtain FDA approval for the new drug application for Entereg(R) in postoperative ileus (POI); the risk that further studies of Entereg(R) are not positive or have adverse safety findings; 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; 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.