Endo Files Amended Citizen Petition Seeking Public FDA Resolution of Several Safety and Efficacy Issues Prior to Approval of a Generic Formulation of LIDODERM®

CHADDS FORD, Pa., March 13, 2012 /PRNewswire-FirstCall/ -- Endo Pharmaceuticals (Nasdaq: ENDP) announced today that it has filed an amendment to its Citizen Petition (CP) with the U.S. Food and Drug Administration (FDA) calling on FDA to publicly address numerous concerns raised by Endo and other experts about approval requirements for generic versions of LIDODERM (lidocaine patch 5%).  The amended CP highlights the growing scientific and regulatory support for requiring generic manufacturers to conduct comparative clinical endpoint studies to demonstrate bioequivalence to locally acting topical products like LIDODERM.  The amended CP also raises several new issues that need to be resolved before FDA approves a generic formulation of LIDODERM.    

"Since we filed the original Citizen Petition in 2006, new studies and opinions from research scientists, as well as public statements from FDA officials, have further validated the need for comparative clinical endpoint studies to ensure a locally acting topical medication is bioequivalent to the branded product," said Dr. Ivan Gergel, Executive Vice President of R&D and Chief Scientific Officer at Endo.  "FDA must publicly address the many unanswered questions from the original petition, as well as the additional concerns raised in this amendment, before taking any formal steps toward the approval of a generic version of LIDODERM."

The amended CP asks FDA to address the repeated public statements by scientific experts and FDA officials that pharmacokinetic (PK) studies, which measure the level of a drug in the bloodstream, have not yet been validated as a bioequivalence method for locally acting topical drugs like LIDODERM.  As stated in its FDA-approved labeling, LIDODERM produces an analgesic effect without complete sensory block in patients with post-herpetic neuralgia (PHN), which cannot be demonstrated and measured with PK studies.  The amendment also points out that FDA has not produced any evidence indicating that PK studies are sufficiently sensitive to determine whether a proposed generic product will replicate LIDODERM's clinical effect.

Additionally, the amended CP raises a number of new issues that FDA needs to address prior to approving a generic version of LIDODERM, including:

• The importance of requiring clinical endpoint studies demonstrating, consistent with LIDODERM's FDA-approved labeling, the ability of generic patches to be repeatedly applied to the same area of skin while having the same safety and efficacy as LIDODERM in patients with PHN;
• Scientific experts have not identified any method other than clinical endpoint studies to demonstrate bioequivalence for locally acting topical products like LIDODERM, despite an ongoing search for other options by FDA, as seen in the discussions at FDA Advisory Committee meetings, at medical conferences and in peer-reviewed scientific journals;
• The need for generic applicants to comply with FDA regulations promulgated in 2009 requiring the submission of all bioavailability and bioequivalence studies, including those that failed, with any Abbreviated New Drug Application to the FDA; and
• The public assertions by another drug manufacturer that, even though FDA has not formally addressed the issues raised in Endo's CP, the 2006 CP has been answered by FDA in private correspondence, which, if true, would violate the law and FDA regulations prohibiting selective disclosure.

"After more than five years of ongoing scientific discussion, there are no validated data to support using the level of lidocaine in the bloodstream as an appropriate method to demonstrate bioequivalence to LIDODERM," said Gergel.  "All parties, including Endo, generic applicants, physicians, patients, and FDA will benefit from an open and transparent process for resolving the many scientific and legal questions presented in this CP, and we are calling on FDA to engage on this issue immediately."

Additional background information about LIDODERM and Endo's amended CP can be found at http://www.endo.com/investors/overview.

About Endo

Endo Pharmaceuticals Holdings Inc. (Endo) is a US-based diversified healthcare company that is redefining healthcare value by finding solutions for the unmet needs of patients along care pathways for pain management, pelvic health, urology, endocrinology and oncology. Through our operating companies: AMS, Endo Pharmaceuticals, HealthTronics and Qualitest, Endo is dedicated to improving care through a combination of branded products, generics, devices, technology and services that creates maximum value for patients, providers and payers alike. Learn more at www.endo.com.

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SOURCE Endo Pharmaceuticals