The US FDA has told Endo Pharmaceuticals that the marketing application for the new formulation of Opana ER is not approvable in its current form
The US Food and Drug Administration (FDA) has issued a complete response letter to Endo Pharmaceuticals stating that the marketing application for the company's new abuse-resistant formulation of its pain drug Opana ER (oxymorphone) is not approvable in its current form.
The company did not release details about the concerns listed in the FDA's letter, but did note that the agency had not indicated that additional clinical studies would be necessary in order for the drug eventually to be approved. Endo said it remains confident that the drug will be cleared for marketing and expects to be able to submit a response to the FDA's concerns by the middle of 2011.
Endo is seeking approval of the new drug for the relief of moderate to severe pain in patients requiring continuous, around-the-clock opioid treatment for an extended period of time. The product is formulated to be resistant to crushing, breaking, powdering or pulverising in order to make it harder for people to abuse.
The drug was granted a priority review last year. Under the programme, which is reserved for drugs that offer major advances in treatment or provide a treatment where no adequate therapy exists, the FDA aims to act on a new drug application (NDA) within six months rather than the standard 10 to 12 months. Endo said it expects that the FDA will take another six months to make a decision once the planned update to the NDA is filed to address the agency's outstanding concerns.
Endo has marketed oxymorphone in the US since 1959. Approval of a new abuse-resistant formulation of Opana ER could help protect the company from the financial implications of generic competition to the existing version of Opana ER. Last year, Endo entered into a settlement agreement with Watson Pharmaceuticals that will allow Watson to begin marketing generic Opana ER on September 15, 2012, before Endo's patent protection on the drug is set to expire.
Watson filed an abbreviated NDA in March 2010 that included a paragraph IV certification claiming that the Opana patents are invalid or unenforceable. Under similar settlement agreements that were previously announced, the generics firm Sandoz may also enter the US market with its version of the drug on September 15, 2012, and Impax may begin selling generic Opana ER on January 1, 2013.