The original formulation of extended-release oxymorphone (Opana ER) that lacked abuse-resistant mechanisms was not pulled from the market for safety reasons, and therefore generics based on that recipe are permissible, the FDA said.
In a response to a citizen's petition from Opana drugmaker Endo Pharmaceuticals, the FDA denied the company's requests to block generic formulations of its drug from reaching the market.
Endo pulled its original version of Opana from the market in March 2012, after reformulating it with abuse-deterrent technology -- much the way long-acting oxycodone (OxyContin) was reformulated in 2010.
Unlike the case with Opana, the FDA declared last month that original OxyContin was pulled from the market for safety reasons, and therefore generic formulations based on that original recipe would not be allowed.
The FDA made the decision on the date that the patent on original OxyContin was set to expire. The agency also updated the current labeling on the reformulated OxyContin to convey that it does indeed have abuse-deterrent properties at that time.
"The potentially abuse-deterrent properties of reformulated Opana ER and reformulated OxyContin and the regulatory implications that result have been the subject of independent, extensive consideration by FDA experts over the course of many months," Morgan Liscinsky, a spokesperson for the FDA, told 鶹ý. "Our decisions must take into account the totality of the evidence for the particular drug at issue, and must be made on a case-by-case basis."
"Accordingly, any attempt to draw parallels between reformulated OxyContin and reformulated Opana ER and thereby make assumptions regarding the regulatory implications for original Opana ER is misplaced," Liscinsky said. "There are differences in the products and the available data such that it is reasonable to draw different conclusions."
OxyContin drugmaker Purdue Pharma voluntarily withdrew the original OxyContin formulation from the market after the abuse-deterrent version became available in 2010.
Endo Pharmaceuticals had taken several steps to block generics based on its original formulation from hitting the market, including the unusual step of claiming that the first incarnation of the product was unsafe.
In 2012 the company sued the FDA to block such generics, filed citizen's petitions with the agency, and filed lawsuits against several generics companies.
One of those companies, Impax Labs, has been shipping generic Opana based on the original formulation since the patent expired at the beginning of this year.
The FDA said it conducted an extensive, science-based review to conclude that the original formulation of Opana was not withdrawn for concerns about safety or efficacy.
"We disagree with Endo's conclusions about Opana's alleged safety advantages," the agency wrote in its response letter to the company, highlighting several problems with the abuse-deterrent formulations, including the fact that it can still be tampered with via cutting, grinding, or chewing.
The agency also said the abuse-deterrent version can still be easily snorted or injected.
Andrew Kolodny, MD, chair of psychiatry at Maimonides Medical Center in Brooklyn, said all opioids should have some form of abuse-deterrent mechanism. However, he called the abuse-deterrence issue a red herring.
"Extended-release opioids are being marketed for conditions where the evidence suggests more harm than help, even when taken exactly as prescribed," Kolodny, who is a frequent critic of physicians who prescribe opioid medications for chronic pain, told 鶹ý. "Adding abuse-deterrent properties may prevent misuse, but the fact is that even if swallowed whole, [these drugs] are still just as addictive."