Endo Pharmaceuticals Inc., a wholly owned subsidiary of Endo Pharmaceuticals Holdings Inc. (Nasdaq: ENDP), today announced that the U.S. Food and Drug Administration (FDA) has granted final approval of the company's New Drug Applications (NDAs) for its extended- release and immediate-release formulations of oxymorphone hydrochloride. These products are now known under the trade names Opana(R) ER tablets and Opana(R) tablets.

A new oral extended-release opioid analgesic option for patients, Opana(R) ER is indicated for the relief of moderate-to-severe pain in patients requiring continuous, around-the-clock opioid treatment for an extended period of time and is not intended to be used on an as-needed basis. This is the first time oxymorphone will be available in an oral, extended-release formulation. Opana(R) ER will be available in 5mg, 10mg, 20mg and 40mg tablets. Opana(R) (the immediate release version) is indicated for the relief of moderate-to-severe acute pain where the use of an opioid is appropriate and will be available in 5mg and 10mg tablets. Both products are expected to be commercially available in the U.S. in the coming weeks. Endo also plans to re- launch its oxymorphone hydrochloride injection under the new trade name in the hospital setting.

Peter A. Lankau, President and Chief Executive Officer, said, "We are pleased with the approval of Opana(R) ER and Opana(R), which represent Endo's first internally developed NDAs to be granted FDA approval. The clinical program for Opana(R) ER and Opana(R) represents one of the most comprehensive ever conducted for an opioid analgesic, with more than 15 clinical trials enrolling over 3,000 patients. Further, Endo is very excited to be able to provide physicians and patients with these important new options for pain management."

Lankau added, "As a market leader in pain management, Endo is committed to the appropriate use of opioids, and we have worked closely with the FDA and external consultants to develop a program that gives health care providers and patients essential information and guidance on responsible opioid use."

Opana(R) ER will compete in the market for long-acting, strong opioid analgesics, a $3.2 billion market in 2005. Its clinical profile demonstrates it can be dosed consistently on a twice-daily basis and is well-tolerated when titrated effectively. Opana(R) ER has also demonstrated maintenance of effective pain control at a stable dose over the three-month period of the pivotal clinical trials, which the company believes highlights the durability of its analgesic effect. Experts agree that patients suffering from moderate- to-severe chronic pain which is present much or all of the day need around- the-clock coverage with an analgesic agent to sustain pain relief. Opana(R) ER utilizes a patented delivery system that was specifically developed to provide continuous delivery of medication over a 12-hour period, helping patients maintain a steady level of pain relief. Opana(R) ER and Opana(R) were both formulated using oxymorphone hydrochloride, which had been available only as an injectable formulation. Both products have been proven to achieve effective relief in multiple moderate-to-severe pain models, in both opioid- na?ve and opioid-experienced patients.

"The availability of Opana(R) ER is great news for physicians as it adds to the arsenal of chronic pain management tools," said Richard Rauck, M.D., Clinical Associate Professor in the Department of Anesthesiology at Wake Forest University School of Medicine and Medical Director of the Center for Clinical Research in Winston-Salem, N.C. "Not only is the active ingredient in Opana(R) ER one of the most extensively studied oral opioids in a clinical development program, its proven dosing every 12 hours can provide durable, lasting relief. Additionally, physicians may need to rotate opioids to effectively manage a patient's chronic pain, maintaining an acceptable balance between pain relief and side-effects."

Revised Financial Guidance

Endo is revising its guidance for 2006 and currently expects net sales in 2006 to be approximately $880 to $910 million. Combined net sales of Opana(R) ER and Opana(R) are expected to be approximately $20 to $30 million, substantially comprised of Opana(R) ER. Net sales of Lidoderm(R) in 2006 continue to be estimated to be approximately $530 to $540 million. Over the next few weeks, Endo plans to expand its current 370-person sales force by approximately 220 sales representatives to promote all formulations of Opana(R) as well as its existing portfolio of branded products, including Lidoderm(R) and Frova(R). Additionally, Endo will substantially increase its investment in the Opana(R) franchise and, accordingly, expects to incur a loss for this product franchise in 2006 in connection with this launch. However, the company believes this launch provides another significant growth opportunity to complement its existing portfolio.

At this time, Penwest Pharmaceuticals Co., Endo's development partner, continues to elect not to fund Opana(R) ER; therefore, Endo will recognize 100% of the losses attributable to Opana(R) ER during its launch phase. Endo expects to recover Penwest's share of these losses from the future profits of Opana(R) ER, which will be recognized as an increased share of the profits at that time. As such, the impact of the launch of Opana(R) ER and Opana is expected to reduce Endo's 2006 adjusted diluted earnings per share by approximately $0.20. The company now estimates adjusted diluted earnings per share for 2006 to be approximately $1.55 to $1.60. This excludes estimated upfront and milestone payments to partners, stock compensation charges related to the adoption of SFAS 123(R) -- estimated to be approximately $0.05 per diluted share -- and compensation expense and related employer payroll taxes funded by Endo Pharma LLC. Of course, there can be no assurance of Endo achieving these results. These 2006 estimates continue to include net sales of the company's generic OxyContin of approximately $50 to $60 million and earnings attributable to its generic OxyContin sales of approximately $0.20 to $0.24 per diluted share.

Conference Call Information

Endo will conduct a conference call with financial analysts to discuss this news release today at 11:00 a.m. ET. Investors and other interested parties may access the conference call by dialing (866) 482-1020 (domestic) or (706) 758-1722 (international). Please dial in 10 minutes prior to the scheduled start time. A replay of the call will be available from June 23, 2006 at 2:00 p.m. ET by dialing (800) 642-1687 (domestic) or (706) 645-9291 (international), and will run until 12:00 a.m. ET on June 30, 2006.

A simultaneous webcast of the call for interested investors and others may be accessed by visiting http://www.endo.com. In addition, a replay of the webcast will be available until 12:00 a.m. ET on June 30, 2006. The replay can be accessed by clicking on "Events" in the Investor Relations section of the website.

Opana(R) ER and Opana(R) Clinical Trials

The clinical development program for Opana(R) ER and Opana(R) (immediate- release) included 15 Phase II and Phase III trials involving more than 3,000 patients. Among these trials were the first Phase III, placebo-controlled, double-blind studies ever conducted with an oral opioid for 12 weeks in chronic moderate-to-severe low back pain. These two studies -- one trial in opioid-na?ve patients and the other in opioid-experienced patients -- showed that patients titrated to an effective and well-tolerated dose of Opana(R) ER, and then randomized to receive either placebo or Opana(R) ER, could have their pain level maintained effectively at that same dose level of Opana(R) ER for a period of 12 weeks. These patients achieved a statistically significant reduction in average pain intensity compared to placebo (p<0.0001). The data confirm that in patients titrated effectively to an appropriate dose, Opana(R) ER offered a durable analgesic effect in a broad base of patient types.

A multiple-dose study of immediate-release Opana(R) assessed time to discontinuation for any reason and pain intensity in patients with moderate- to-severe pain following abdominal surgery. Results showed a statistically significant decrease in the primary endpoint (time to discontinuation for any reason) when comparing Opana(R) to placebo (p<0.0001).

Endo's Commitment to Responsible Pain Management

Endo is committed to helping physicians and other healthcare providers manage the care of their moderate-to-severe chronic pain patients while minimizing the risks that may be associated with the use of opioids, such as potential misuse, abuse and diversion. Endo has worked closely with the FDA and outside experts to develop a comprehensive program focused on the proper prescribing and clinical use of opioid analgesics. As the launch of the Opana(R) product line approaches, Endo also will launch its PROMISE(TM) initiative (Partnership for Responsible Opioid Management through Information, Support, and Education). For more information on the PROMISE(TM) initiative, visit http://www.endopromise.com.

About Opana(R) ER and Opana(R) Tablets

Oxymorphone hydrochloride, the active ingredient in Opana(R) ER and Opana(R), is a semisynthetic, pure .-opioid agonist that has been formulated as a 12-hour extended-release (ER) tablet and as an immediate-release tablet. Opana(R) ER has been studied in a wide range of chronic pain conditions, including low back pain, osteoarthritis pain, and cancer pain. Opana(R) has been studied as a treatment for acute pain conditions, such as post-surgical pain. Endo developed Opana(R) ER using Penwest Pharmaceuticals' proprietary time-release technology, TIMERx(R). The two companies provided funding for the Opana(R) ER studies. Immediate-release Opana(R) is a proprietary product developed by Endo.

Important Safety Information

Opana(R) ER and Opana(R) are opioid agonists and Schedule II controlled substances with an abuse liability similar to morphine. Opana(R) ER and Opana(R) can be abused in a manner similar to other opioid agonists, legal or illicit.

WARNING:

OPANA ER contains oxymorphone, which is a morphine-like opioid agonist and a Schedule II controlled substance, with an abuse liability similar to other opioid analgesics.

Oxymorphone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when prescribing or dispensing OPANA ER in situations where the physician or pharmacist is concerned about an increased risk of misuse, abuse, or diversion.

OPANA ER is an extended-release oral formulation of oxymorphone indicated for the management of moderate to severe pain when a continuous, around-the- clock opioid analgesic is needed for an extended period of time.

OPANA ER is NOT intended for use as a prn analgesic

OPANA ER TABLETS are to be swallowed whole and are not to be broken, chewed, dissolved, or crushed. Taking broken, chewed, dissolved, or crushed OPANA ER TABLETS leads to rapid release and absorption of a potentially fatal dose of oxymorphone.

Patients must not consume alcoholic beverages, or prescription or non- prescription medications containing alcohol, while on OPANA ER therapy. The co-ingestion of alcohol with OPANA ER may result in increased plasma levels and a potentially fatal overdose of oxymorphone.

Opana(R) ER is not indicated for pain in the immediate post-operative period (12-24 hours following surgery), or if pain is mild or not expected to persist for an extended period of time.

Opana(R) ER and Opana(R) are contraindicated in patients with a known hypersensitivity to oxymorphone hydrochloride, morphine analogs such as codeine, or any of the other ingredients of Opana(R) ER and Opana(R); in patients with moderate or severe hepatic impairment or in any situation where opioids are contraindicated.

Respiratory depression is the chief hazard of Opana(R) ER and Opana(R), particularly in elderly or debilitated patients.

The most common adverse drug reactions (.10%) in clinical trials for Opana(R) ER were nausea, constipation, dizziness, vomiting, pruritus, somnolence, headache, increased sweating, and sedation. The most common adverse drug reactions (.10%) reported in clinical trials for Opana(R) were nausea and pyrexia.

For full prescribing information, visit http://www.opana.com.

About Endo

A wholly owned subsidiary of Endo Pharmaceuticals Holdings Inc., Endo Pharmaceuticals Inc. 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 http://www.endo.com.

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 March 21, 2006. Readers should evaluate any statement in light of these important factors.

Endo Pharmaceuticals Inc.
http://www.endo.com