Purdue Pharma, at the center of some major opioid abuse litigation, aired post-marketing studies of its abuse-fighting OxyContin formulation at an FDA advisory panel confab last week, and the group wasn't convinced the tweaked formulation combats misuse.
Members of the FDA’s Drug Safety and Risk Management (DSaRM) and Anesthetic and Analgesic Drug Products (AADP) advisory committees, in a joint meeting, voted 20-7 that Purdue’s abuse-deterrent formulation (ADF) of OxyContin “meaningfully reduced” abuse via snorting or injection, Medscape reported.
Still, the panel found the reformulation did not curb overall risk because it can still be taken orally—one of the most common routes of opioid misuse.
Purdue’s ADF OxyContin formulation, which snared a green light in 2010 and won abuse-deterrent labeling in 2013, includes an inactive polymer called polyethylene oxide (PEO), which makes the tablet more difficult to crush and turns it into a gel-like substance when wet. The formulation aims to deter abuse by keeping patients from snorting the drug or dissolving it for injection.
The panel members reviewed presentations from the FDA and the public, alongside several Purdue post-marketing studies on the ADF formulation carried out at the regulator’s request.
In a 66,897-subject study in patients undergoing evaluation for substance abuse or entering an opioid addiction program—the first of four post-marketing trials laid out in an FDA AdCom briefing (PDF)—Purdue’s ADF tablet cut self-reported OxyContin abuse via injection and snorting by up to 52% over a 30-day period. That study compared the anti-abuse formulation with other pain meds, including extended release morphine and fast-acting hydrocodone.
A claims-based analysis of patients given OxyContin or a comparator opioid yielded no evidence that the abuse-deterrent product curbed overdoses.
Meanwhile, agency staffers who reviewed the data were mixed or negative on the results of Purdue’s two other studies. An analysis of 308,465 calls to U.S. poison centers showed a reduction of up to 28% in calls related to intentional OxyContin misuse immediately following the drug’s reformulation, but the agency reviewers couldn’t say for sure whether that trend was linked to Purdue’s tweaked OxyContin tablet or to broader opioid crackdowns in healthcare.
The ADF tablet did lead to a 27% reduction in OxyContin abuse among 63,528 people entering methadone clinics or treatment programs, but because the Purdue study failed to detail the drug's administration route in those patients, the FDA concluded the results were mixed and didn’t provide compelling evidence on the reformulation.
All told, the joint committee was underwhelmed by Purdue’s evidence. Meeting chair Sonia Hernandez-Diaz, M.D., suggested that the positive trends in abuse reduction could be linked to broader reduction in opioid use overall, rather than Purdue’s ADF tablet.
The panel cited public health initiatives targeting drug addiction, the opening of more treatment centers and concerted efforts to crack down on over-prescribers—all of which kicked off around the time of the drug’s launch in 2010.
While Purdue’s reformulation makes abuse more difficult, it can still be crushed or dissolved with the right set of tools, or simply taken by mouth, the panel said. A scant two members of the committee voted that Purdue's ADF OxyContin reduced opioid abuse overall, and only one member voted that the reformulation curbed overdoses.