Pain Therapeutics Inc. achieved its primary endpoint once again in its second Phase III trial with Remoxy, an abuse-deterrent version of long-acting oxycodone.

The data "confirm that abuse-deterrence and effective analgesia can coexist," said Remi Barbier, chairman, president and CEO of San Mateo, Calif.-based Pain Therapeutics.

Pain Therapeutics is not the only company to prove that point. Just last week, Bridgewater, N.J.-based Alpharma Inc. said its abuse-deterrent opioid ALO-01 met its endpoint of significantly reducing pain (p<0.05) in a randomized, double-blind, placebo-controlled, 500-patient, pivotal Phase III trial. ALO-01 combines an extended-release opioid with a sequestered core of naltrexone, an opioid antagonist used to treat addiction.

Remoxy uses a different approach, delivering the opioid oxycodone in a gel capsule that is difficult to crush, snort or inject. Patients treated with the drug demonstrated a statistically significant (p<0.01) mean decrease in pain intensity compared to the placebo group in the randomized, double-blind, placebo-controlled, 412-patient, pivotal Phase III trial. The trial, which was conducted under a special protocol assessment, also met its secondary endpoints of improving quality of analgesia and global assessment scores (p<0.01 for both).

All patients enrolled in the Remoxy trial had moderate-to-severe pain associated with osteoarthritis of the knee or hip and were randomized to receive drug or placebo twice daily for 12 weeks. No drug-related safety issues were noted, and Barbier said during a conference call that the dropout rate of 36 percent was "well within the statistical plan."

In a previous Phase III trial, Remoxy also significantly (p<0.05) decreased pain scores. Pain Therapeutics expects to file a new drug application in the second quarter of 2008. (See BioWorld Today, Sep. 12, 2005.)

Abuse-deterrent opioids such as Remoxy and ALO-01 are needed to combat the illicit use of prescription pain killers. In 2006, an estimated 12 million Americans took those products for non-medical uses, including about one in 10 children, ages 12 to 17. During the Pain Therapeutics conference call, Lynn Webster, an anesthesiologist and principal investigator in the Remoxy trial, said prescription analgesics have replaced marijuana as the most common choice for first-time drug users. He added that up to 20 percent of those experimental users are taking sustained-release oxycodone.

In response to questions from analysts, Webster said he ideally would prescribe Remoxy to all new patients who are candidates for sustained-release oxycodone, if the price and insurance coverage of the two drugs were comparable. Although some patients can be categorized as "high-risk" due to addiction problems, he noted that there is no way to predict who accidentally may leak the drug into the community.

Sustained-release oxycodone is marketed as OxyContin by privately held Purdue Pharma LP. Annual sales topped $1.5 billion before the introduction of generics, which Purdue has since battled for patent infringement. Earlier this year, Purdue settled with IMPAX Laboratories Inc., which admitted to patent infringement and agreed to take a license from Purdue. Settlements were reached last year with Teva Pharmaceuticals Inc. and Endo Pharmaceuticals Inc.

Yet Barbier said he does not believe that Remoxy infringes on Purdue's patents because the drug has a unique "pharmacologic signature," including a different time period to maximum concentration (Tmax) than OxyContin. He declined to provide specifics but told analysts, "At the right time, I promise you, you will not be disappointed."

Pain Therapeutics is developing Remoxy in partnership with King Pharmaceuticals Inc., of Bristol, Tenn. In 2005, King agreed to pay $150 million up front and another $150 million in milestones, as well as 15 percent to 20 percent royalties, in exchange for worldwide commercialization rights to the drug and other abuse-deterrent opioids in Pain Therapeutics' pipeline. The gel capsule delivery technology used in Remoxy was licensed from Cupertino, Calif.-based Durect Corp. (See BioWorld Today, Jan. 15, 2003, and Nov. 11, 2005.)

Shares of Pain Therapeutics (NASDAQ:PTIE) gained 62 cents on Thursday to close at $10.81, while shares of King (NYSE:KG) gained 15 cents to close at $10.35 and shares of Durect (NASDAQ:DRRX) gained 61 cents to close at $6.72.