Lidocaine patch shown in large trial to relieve post-herpetic neuralgia

Most patients with pain after shingles had pain relief within a week

CHADDS FORD, PA – May 14, 2001 – Endo Pharmaceuticals Inc. announced today that new data shows that two-thirds of patients experience significant relief from the agonizing pain caused by post-herpetic neuralgia (PHN) when they use the company’s product, Lidoderm® (lidocaine patch 5%), a topical treatment patch containing 5% lidocaine. Further, the majority of patients report improvement in their quality of life within the first week of treatment. This new research was presented at the 20th Annual Scientific Meeting of the American Pain Society (APS). Endo Pharmaceuticals Inc. is a wholly owned subsidiary of Endo Pharmaceuticals Holdings Inc. (NASDAQ: ENDP; ENDPW).

"PHN pain has been historically difficult to treat," said Nathaniel Katz, MD, an investigator in the clinical trial and assistant professor of anesthesia at Harvard Medical School. "This study is significant for PHN sufferers as it demonstrated that Lidoderm® effectively relieved PHN pain in a large patient population and that the majority of patients experienced reduced pain relief and improved quality of life within the first week of treatment. Achieving pain relief with the Lidoderm® patch offers hope to the significant number of people who suffer from PHN."

PHN is pain that results from nerve damage from shingles, a painful viral infection that is a reactivation of the herpes zoster (chicken pox) virus. In most of the estimated one million Americans who develop shingles each year, the shingles rash and pain subside after about a month. But about 20% of shingles patients develop PHN, or pain that continues after the shingles rash heals.

Study Involved Over 300 Patients With PHN

This open-label, nonrandomized, multicenter Phase IV trial is one of the largest PHN studies ever conducted. Thirty-seven academic medical centers and large institutional primary care settings participated in the trial, which included 332 patients who suffer from PHN. Most had experienced pain for a year or more. One patient suffered from PHN for 23 years after developing shingles. Each day during the 28-day trial, study patients applied up to three Lidoderm® patches on the most painful area of their body and left them there for 12 consecutive hours.

In the first week of treatment, 66% of patients rated their pain as feeling "better." Patients continued to report highly significant pain relief throughout the study, which was conducted over a 28-day treatment period. Almost 8% said they experienced "complete" pain relief, and half of the study population reported "moderate" or "a lot" of improvement. Seventy-eight percent experienced improvements in their quality of life within the first week of treatment with Lidoderm®, when compared to prior use of other pain relievers.

Lidoderm® was well tolerated and was not associated with any serious adverse events. Rash in the area where the patch was applied was the most common adverse event, occurring in 13.5% of patients. The abstract from this trial was published in the April 2001 supplement of The Journal of Pain (Vol. 2, No. 2).

Shingles and PHN Cause Excruciating Pain

Anyone who has had chicken pox could develop shingles. Once reactivated from its dormant state, the herpes zoster virus travels along nerve paths to the skin, causing a severe, painful rash usually on one side of the body. After about a month, the shingles rash and pain usually end.

About 1 in every 5 persons diagnosed with shingles go on to suffer the long-lasting pain from PHN, which can be more painful than shingles. PHN pain and skin sensitivity can continue for months or even years.

The elderly are particularly prone to developing PHN. One out of 4 persons under age 55 years old who have been diagnosed with shingles will experience PHN. However for persons over 70 years of age, 3 out 4 persons will develop PHN. The median age of patients in the study was 74 years old.

The pain of PHN is the result of damage to nerve fibers. Pain from nerve damage is one of the most excruciating types of pain. Patients with PHN have described the pain as deep and aching, "fire under the skin," piercing, stabbing, or "like constant electric shocks." Sensitivity to touch is frequently intense.

"The pain can be so debilitating that it greatly diminishes quality of life," said Robert H. Dworkin, PhD, another investigator in the clinical trial and a professor of anesthesiology, oncology and psychiatry at the Strong Pain Clinic, University of Rochester Medical Center. "The pain often causes sleep loss and depression. Many patients withdraw from social activity because of the pain, and these consequences of PHN can affect the spouse or caregiver as well as the patient."

The study was sponsored by Endo Pharmaceuticals, makers of Lidoderm®, the only drug approved by the Food and Drug Administration specifically for PHN pain. Lidoderm® is a hand-sized patch, which should be applied directly to intact skin over the most painful area. The potential exists for a small child or pet to suffer serious adverse effects from chewing or ingesting a new or used Lidoderm® patch. Patients should store and dispose of Lidoderm® out of the reach of children and pets. Please see full prescribing information for Lidoderm® at http://www.lidoderm.com.

Endo Pharmaceuticals is a fully integrated independent pharmaceutical company with market leadership in pain management products. The company researches, develops, produces and markets a broad product offering of both branded and generic pharmaceuticals, meeting the needs of healthcare professionals and consumers alike. This and past press releases of Endo are available on Endo’s website at http://www.endo.com