Endo Pharmaceuticals Inc., a subsidiary of Endo Health Solutions Inc. has filed suit against the US Food and Drug Administration (FDA) seeking a formal determination whether the original formulation of OPANA ER (oxymorphone HCl).

OPANA ER was voluntarily removed from the market in 2012 for reasons of safety involving the misuse of the drug; and FDA's immediate suspension of any abbreviated new drug applications (ANDAs) for generic versions of non-tamper resistant formulations of extended-release oxymorphone HCl until FDA has made a determination as to whether the original formulation of OPANA ER was withdrawn from sale for safety reasons.

There is currently a non-tamper resistant generic of extended-release oxymorphone available in 7.5mg and 15mg dosage strengths, and if the FDA does not promptly suspend the approval of all non-tamper resistant formulations, all doses of the product will be available in non-tamper resistant versions in January 2013.

Endo reformulated OPANA ER to a version designed to be crush-resistant and launched this reformulated version in March 2012. Current data monitoring abuse rates show a substantial decrease in abuse since the launch of the reformulated product, while simultaneously showing a more than 122 percent increase in abuse rates of the 7.5mg and 15mg non-tamper resistant extended release oxymorphone HCl.

The lawsuit, filed in theUS District Court for the District of Columbia, is based on the failure of the FDA to meet its legal obligation to determine in a timely manner whether the old formulation of OPANA ER was withdrawn from the market for reasons of safety. Since its launch, Endo has collected surveillance data on the rates of abuse of oxymorphone HCl from two national programs – the first includes surveillance of substance abusers and the second collects data from US Poison Control Centres. The data show a 59 per cent drop in abuse rates of the reformulated OPANA ER which is designed to be crush-resistant. The same data demonstrate a 122 per cent increase in abuse rates of non-tamper resistant extended-release oxymorphone HCl.

"Sufficient evidence exists to support the determination that the old formulation of OPANA ER was discontinued for reasons of safety," said Dave Holveck, president and chief executive officer of Endo Health Solutions. "Unless FDA acts before Jan 1, 2013, the launch of a generic non-crush-resistant OPANA ER will irreparably undermine recent progress in the reduction of abuse and misuse of oxymorphone."

Prior to filing the lawsuit, Endo submitted to FDA two Citizen Petitions in Aug 2012 requesting that any generic formulations of OPANA ER meet the same tamper-resistant properties as the reference drug, as well as determining that the original formulation of the product was discontinued for reasons of safety.

OPANA 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.

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.