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Anesiva Announces Clinical Plan for Pivotal Testing of 4975, Long-Acting Pain Candidate

Phase 2/3 Clinical Trials to Start This Year to Treat Severe Pain For Weeks to Months Following a Single Application of 4975 in Surgical Settings and Osteoarthritis Conference Call Today 9:00 a.m. Eastern Time to Discuss Plan

SOUTH SAN FRANCISCO, Calif., Jan 08, 2007 /PRNewswire-FirstCall via COMTEX News Network/ -- Anesiva, Inc. (Nasdaq: ANSV) today outlined the planned Phase 2/3 clinical trial program for the development of 4975, the company's long-acting, non-opioid drug candidate for the acute treatment of severe pain. After a successful meeting with the FDA, the company will be focusing its near-term development efforts of 4975 in two areas-post-surgical pain and osteoarthritis.

In initial Phase 2 studies, 4975 was shown to provide a statistically significant reduction in the pain associated with total knee replacement surgeries and osteoarthritis of the knee for weeks to months following a single application. Anesiva anticipates commencing a series of clinical trials during the first half of this year to confirm the safety and efficacy of 4975. Following is a list of trials that are planned for the company's post-surgical and osteoarthritis indications:

    Post-surgical
    -- A 50-patient Phase 2 trial evaluating a higher dose of 4975 to reduce
       the pain associated with knee replacement surgeries (Begin in 1H07)
    -- A 50-patient Phase 2 trial evaluating the safety and efficacy of 4975
       to reduce the pain associated with hip replacement surgeries (Begin in
       1H07)
    -- A 50-patient Phase 2 trial evaluating the safety and efficacy of 4975
       to reduce the pain associated with arthroscopic shoulder surgeries
       (Begin in 1H07)
    -- A 450-patient Phase 3 trial evaluating the safety and efficacy of 4975
       to reduce the pain associated with knee replacement surgeries (Begin in
       2H07)
    Osteoarthritis
    -- A 200-patient Phase 2 trial evaluating the safety and efficacy of 4975
       to reduce the pain associated with osteoarthritis of the knee (Begin in
       1H07)

"We are eager to begin the next phase of our development to confirm our earlier findings of 4975, which has shown significant potential to treat debilitating pain in a number of indications without the substantial side effects associated with current opioid pain medications," stated John P. McLaughlin, chief executive officer of Anesiva. "We believe our Phase 2/3 program will provide an overview of the efficacy and safety profile of 4975 to treat pain associated with surgery and osteoarthritis."

How 4975 May Address Need for Long-Duration, Well-Tolerated Pain Relief

4975 is long-acting, with the potential to provide pain relief for weeks or months after just a single localized treatment. It is a non-opioid TRPV1 agonist with a unique mechanism of action that provides a long-lasting, localized effect on C-fibers and blocks the transmission of aching, throbbing pain caused by major surgical procedures and end-stage osteoarthritis. Because it selectively acts on pain-sensing nerve endings, 4975 does not affect other nerve fibers necessary for sensory or motor sensations, such as those needed to sense temperature or pressure.

In clinical studies to date, 4975 has not had the side effects often associated with other conventional pain medications and has been shown to be well tolerated. Opioid drugs, such as morphine, which are commonly used agents to relieve pain in post-surgical and musculoskeletal pain conditions, have significant side effects including sedation, respiratory depression, euphoria, and nausea and vomiting during acute use, and constipation and physical dependence during chronic use.

About Total Knee Replacement Surgery and Osteoarthritis of the Knee

Total knee replacement (also known as total knee arthroplasty) is performed in patients with end-stage osteoarthritis of the knee. These patients have disabling pain which imposes severe limitations on their mobility, and knee replacement is performed with the goal of restoring or improving patients' quality of life.

Osteoarthritis of the knee is a common, progressive disease in which the joint cartilage breaks down. This breakdown causes the bones to rub against each other resulting in stiffness, pain, and loss of movement in the joint. In advanced stages, the pain becomes intractable and disabling, limiting patients' mobility and activities. Approximately 1.1 million patients are candidates for knee replacement or aggressive non-surgical interventions to address the debilitating effects of end-stage osteoarthritis of the knee.

There were an estimated 470,000 total knee replacement procedures performed in the United States in 2005, and the number of replacements will continue to grow as the average age of the U.S. population increases and as these individuals conduct more active lives. The American Academy of Orthopedic Surgery projects that approximately 3.5 million of these procedures will be done each year by 2030.

Conference Call Details

Anesiva will conduct a webcast conference call with the investment community at 9:00 a.m. EST, today, January 8, 2007 to discuss the company's clinical trial plans for 4975. Interested parties can listen to the live audio webcast by dialing 877-266-9200 (international dial: 706-634-1538) or by logging on to www.anesiva.com and going to the Investor Information page. For those unable to participate via the Internet, a 24-hour replay will be available for seven days after the call by dialing 800-642-1687 (international dial: 706-645-9291) and giving the following pass code: 5711122.

About Anesiva

Anesiva, Inc. is a late-stage biopharmaceutical company that seeks to be the leader in the development and commercialization of novel therapeutic treatments for pain. Anesiva is based in South San Francisco, CA. For more information about Anesiva's leadership in the development of products for pain management, and an overview of the clinical challenges being addressed by its product candidates, go to www.anesiva.com.

Forward Looking Statements

This press release includes "forward-looking statements" within the meaning of the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. Words such as "expect," "estimate," "project," "budget," "forecast," "anticipate," "intend," "plan," "may," "will," "could," "should," "believes," "predicts," "potential," "continue," and similar expressions are intended to identify such forward-looking statements. Forward-looking statements in this press release include, without limitation, projected timing of FDA filings and clinical data announcements and other matters that involve known and unknown risks, uncertainties and other factors that may cause actual results, levels of activity, performance or achievements to differ materially from results expressed or implied by this press release. Such risk factors include, among others: whether Anesiva can successfully develop new products and the degree to which these gain market acceptance. Actual results may differ materially from those contained in the forward-looking statements in this press release. Additional information concerning these and other risk factors is contained in Anesiva's most recent quarterly report on Form 10-Q.

Anesiva undertakes no obligation and does not intend to update these forward-looking statements to reflect events or circumstances occurring after this press release. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. All forward-looking statements are qualified in their entirety by this cautionary statement.

SOURCE Anesiva, Inc.

Jennifer Cook Williams, Vice President, Investor Relations of Anesiva, Inc.,
+1-650-624-9600, or [email protected]

http://www.anesiva.com

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