News Release

First head-to-head study to compare lidoderm patch and Celebrex in treating pain

Study results suggest that lidoderm can alleviate the pain associated with osteoarthritis of the knee

Peer-Reviewed Publication

Cohn & Wolfe

CHADDS FORD, Pa., March 31, 2005 – Today at the 24th Annual Scientific Meeting of the American Pain Society, Endo Pharmaceuticals Inc. released new clinical trial data which found patients receiving either Lidoderm® (lidocaine patch 5%) or Celebrex® (celecoxib) 200 mg for pain associated with osteoarthritis (OA) of the knee experienced improvement in average daily pain intensity. Lidoderm is a topical analgesic patch approved by the U.S. Food and Drug Administration (FDA) in 1999 to treat the pain associated with post-herpetic neuralgia (PHN), a chronic condition resulting from nerve damage caused by shingles.

"The results of this exploratory study examining Lidoderm and Celebrex suggest that Lidoderm can alleviate the pain associated with osteoarthritis of the knee," said Alan Kivitz, M.D., of Altoona (Pa.) Center for Clinical Research. "I am encouraged by these findings since there is a critical need for new approaches to managing this type of pain."

OA affects more than 20 million Americans annually and generates more than seven million physician visits per year. If left untreated, chronic pain conditions such as OA can have significant physical, psychological and financial consequences by affecting daily functioning and quality of life.

Due to safety concerns regarding the entire COX-II inhibitor class in the fall of 2004, the sponsor of the study, Endo Pharmaceuticals Inc., voluntarily elected to prematurely halt the study prior to reaching the original enrollment target. However an analysis of data after six weeks of treatment showed that of the patients treated in the Lidoderm group (N=56), 54% experienced a 30% or greater improvement in average daily pain intensity; (studies have reported that 30% or greater reductions in pain intensity are clinically meaningful to pain patients). In the Celebrex group (N=63), 62% experienced a 30% or greater improvement in average daily pain intensity. In addition, clinically meaningful reductions in pain were noted in both treatment groups at week 12.

"Although these results need to be confirmed with further randomized controlled trials, the potential of Lidoderm to treat osteoarthritis knee pain is promising," added Dr. Kivitz. "Lidoderm has been used since 1999 to treat the pain of post-herpetic neuralgia and, because it is a non-systemic patch, has demonstrated a minimal risk of side effects or drug-to-drug interaction. Our hope is to see similar results in further Lidoderm osteoarthritis knee pain studies."

About the Study
The randomized, open-label, active-control, parallel-group study, which was intended to enroll 200 patients, contained data for 143 patients experiencing OA pain of either one or both knees and evaluated efficacy and safety of treatment. After a 7- to 14-day wash-out period during which all analgesic medications, chondroitin, and glucosamine were discontinued, patients with an average daily pain intensity score of =5 on a scale of 0 to 10 for three of five consecutive days and an OA severity score of =7 on a scale of 0 to 24 prior to the baseline visit were randomized to 12 weeks of treatment with either one full Lidoderm patch on the front of the knee and one-third of a patch on the back of each affected knee (69 patients) once daily for 24 hours or Celebrex 200 mg once daily (74 patients). Efficacy measures included the Western Ontario and McMaster Universities OA Index, Brief Pain Index (BPI), Pain Quality Assessment Scale and global assessments of change in OA pain and treatment satisfaction.

In the study, both treatments were well tolerated, with adverse events reported in eight patients in each group. The most common adverse events were itchiness or redness at the patch site. Additionally, three patients in the Lidoderm group discontinued the study due to adverse events. There were no discontinuations due to treatment-related adverse events in the Celebrex group.

About Lidoderm
Lidoderm (lidocaine patch 5%) is FDA-approved for the relief of pain associated with post herpetic neuralgia (PHN). Lidoderm produces an analgesic effect by the penetration of lidocaine from the patch into the epidermal and dermal layers of the skin, without loss of sensation or numbness. The Lidoderm patch should only be applied to intact skin. The most frequently reported adverse events with the Lidoderm patch are application site reactions, including erythema, edema, discoloration, burning sensation, pruritus or abnormal sensation. These reactions are generally mild and transient, resolving spontaneously within a few minutes to hours.

The FDA-approved dosing for Lidoderm is up to three patches applied for up to 12 hours within a 24-hour period. Lidoderm has not been approved by the FDA for any indications other than for the relief of pain associated with PHN, and its safety and efficacy in other indications have not been established.

About Endo
A wholly owned subsidiary of Endo Pharmaceuticals Holdings Inc. (Nasdaq: ENDP), Endo Pharmaceuticals is a fully integrated specialty pharmaceutical company with market leadership in pain management products. The company researches, develops, produces and markets a broad product offering of branded and generic pharmaceuticals, meeting the needs of healthcare professionals and consumers alike. More information, including this and past press releases of Endo Pharmaceuticals Holdings Inc., is available online at www.endo.com.

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Celebrex® is a registered trademark of Pfizer Inc.

Forward-Looking Statements
This press release contains forward-looking statements, within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, as amended, that are based on management's beliefs and assumptions, current expectations, estimates and projections. Statements that are not historical facts, including statements which are preceded by, followed by, or that include, the words "believes," "anticipates," "plans," "expects" or similar expressions and statements are forward-looking statements. Endo's estimated or anticipated future results, product performance or other non-historical facts are forward-looking and reflect Endo's current perspective on existing trends and information. Many of the factors that will determine the Company's future results are beyond the ability of the Company to control or predict. These statements are subject to risks and uncertainties and, therefore, actual results may differ materially from those expressed or implied by these forward-looking statements. The reader should not rely on any forward-looking statement. The Company undertakes no obligation to update any forward-looking statements whether as a result of new information, future events or otherwise. Several important factors, in addition to the specific factors discussed in connection with these forward-looking statements individually, could affect the future results of Endo and could cause those results to differ materially from those expressed in the forward-looking statements contained in this press release. Important factors that may affect future results include, but are not limited to: market acceptance of the Company's products and the impact of competitive products and pricing; dependence on sole source suppliers; the success of the Company's product development activities and the timeliness with which regulatory authorizations and product launches may be achieved; successful compliance with extensive, costly, complex and evolving governmental regulations and restrictions; the availability on commercially reasonable terms of raw materials and other third party manufactured products; exposure to product liability and other lawsuits and contingencies; dependence on third party suppliers, distributors and collaboration partners; the ability to timely and cost effectively integrate acquisitions; uncertainty associated with pre-clinical studies and clinical trials and regulatory approval; uncertainty of market acceptance of new products; the difficulty of predicting FDA approvals; risks with respect to technology and product development; the effect of competing products and prices; uncertainties regarding intellectual property protection; uncertainties as to the outcome of litigation; changes in operating results; impact of competitive products and pricing; product development; changes in laws and regulations; customer demand; possible future litigation; availability of future financing and reimbursement policies of government and private health insurers and others; and other risks and uncertainties detailed in Endo's filings with the Securities and Exchange Commission, including its Registration Statement on Form S-3 filed with the SEC on April 30, 2004, as amended. Readers should evaluate any statement in light of these important factors.


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