Pfizer to withdraw from partnership to develop tamper-proof oxycodone formulation

Oradur sustained-release capsule--Courtesy of Durect

The prospects for Remoxy, the twice-rejected, investigational, extended-release oral formulation of oxycodone, look bleak. Pfizer ($PFE) is pulling out of a partnership with Durect ($DRRX) to commercialize the candidate, after reviewing the results of 5 clinical trials conducted in response to the FDA's second complete response letter, issued in 2011.

"We are surprised by Pfizer's decision given the late stage of this program, and continue to believe that Remoxy could play an important role in serving the needs of chronic pain patients while potentially reducing the misuse and abuse of oxycodone," said Durect CEO James Brown in a statement.

Remoxy uses Durect's Oradur sustained-release oral capsule. The company says the delivery technology uses a high-viscosity base component such as sucrose acetate isobutyrate to deliver the drug over a period of 12 to 24 hours. Crucially for Remoxy, the capsules may be less prone to abuse than other controlled release dosage forms that are currently available, Durect says.

The failed partnership is all the more striking because prescription drug abuse has reached epidemic proportions. The U.S. National Institutes of Health estimates that more than 3% of 12th graders have used OxyContin--brand name oxycodone--in the past year. And the FDA has come under fire for approving Zohydro, the first extended-release uncut form of hydrocodone.

According to Durect's website, the 2011 complete response letter was primarily about manufacturing. In 2013 Pfizer stated, that "having achieved technical milestones related to manufacturing," it would continue the development program. But that part of the Durect website has turned out to be incorrect. The trials of the modified formulation included a bioequivalance study and an abuse potential study.

Remoxy has a long and convoluted history. It was first handed a complete response letter in 2008. Pfizer obtained commercial rights to the candidate with the 2011 acquisition of King Pharmaceuticals. King had entered into an agreement to jointly develop and commercialize Remoxy with Pain Therapeutics in 2005. And finally, Pain Therapeutics obtained a license to the global development and commercialization rights of Remoxy from Durect in 2002, according to the release.

It just goes to show the extent of partnerships in the drug delivery world and is a reminder that many of them don't work.

- read the release
- here's the Oradur website explaining the delivery platform