Anesiva, Inc. announced that it has begun a phase 2 clinical trial of Adlea, the company's long-acting, site specific, non-opioid drug candidate for the management of acute pain in patients undergoing arthroscopic shoulder surgery involving rotator cuff repair.

Adlea is currently in two pivotal phase 3 trials in the US: one in total knee replacement surgeries and one in bunionectomy surgeries. An additional phase 2 Adlea trial is in progress in total hip replacement surgeries. These trials are among those intended to support an Adlea label indication for the management of acute pain following orthopaedic surgery.

The phase 2 arthroscopic shoulder surgery trial is being conducted in South Korea. Unlike the United States, where the procedure is often conducted on an outpatient basis, arthroscopic shoulder surgery patients in South Korea are routinely hospitalized for up to two days, thus allowing more extensive near-term follow-up.

"We believe Adlea holds promise for treating pain associated with a number of orthopaedic surgical indications, and may reduce the need for other pain treatments such as opioids," said Michael L. Kranda, Anesiva's president and chief executive officer. "As we pursue a broad indication of management of post-surgical pain following orthopaedic procedures, each specific procedure that we can evaluate will add to the breadth of available data for Adlea."

Arthroscopic surgery is performed through small incisions using an arthroscope, or camera, to visualize the inside of a joint. Through the incisions, a surgeon inserts a camera and small instruments to perform the procedure. According to the American Academy of Orthopedic Surgeons, about six million Americans go to the doctor each year for shoulder pain, dislocation, or other shoulder problems and up to 500,000 arthroscopic shoulder surgeries are performed in the United States each year.

This multi-centre, randomized, double-blind, dose-escalating, placebo-controlled study is evaluating the safety, tolerability, efficacy, and pharmacokinetics of a single dose of Adlea administered via injection following surgical closure of the wound. The trial is designed to enrol 74 patients.

Anesiva announced approval of its investigational new drug application for Adlea in South Korea in June 2008.

Adlea is a long-acting, non-opioid drug with the potential to provide pain relief for weeks to months after a single localized treatment. Its novel mechanism of action results in site-specific analgesia, which has the potential to reduce the use of and minimize the side effects associated with systemically administered analgesic drugs, such as opioids and NSAIDs.

Adlea is a highly purified form of capsaicin (derived from chili peppers) that acts primarily on C-fiber neurons, which transmit long-term pain, by binding to and desensitizing the TRPV1 pain receptors. This leads to a prolonged, reversible and localized desensitization of the pain fibers. The drug generally has a short half-life of 1 to 2 hours, and is undetectable in the blood after 24 hours.

Adlea's short duration of systemic exposure relative to the longer duration of analgesia may offer a safe, additive treatment option in the management of post-surgical orthopaedic pain, as well as pain due to moderate to severe osteoarthritis. In clinical trials to date, adverse events have been similar in patients receiving Adlea or placebo.