Pain Therapeutics, Inc (SAN MATEO, California) and King Pharmaceuticals, Inc (BRISTOL, Tennessee) announced that a pivotal phase III study of Remoxyâ„¢, an abuse-deterrent version of long-acting oxycodone, in osteoarthritis (OA) patients with chronic pain met the primary endpoint (P <.01) that was prospectively defined by the US FDA during the Special Protocol Assessment (SPA) process.

The SPA documents the agreement among the FDA and the companies regarding the study's design, endpoints, and statistical analyses needed to support approval. The FDA has agreed that a single phase III pivotal study is needed to support the regulatory approval of Remoxy. As a result, Pain Therapeutics expects to file a New Drug Application (NDA) for Remoxy in mid-2008. If approved, Remoxy will be the first oxycodone on the market that is specifically designed to deter common methods of abuse.

The pivotal phase III randomized, double-blinded, placebo-controlled, multicenter study was designed to evaluate the analgesic efficacy of twice-daily Remoxy versus placebo over a 12-week treatment period. The study randomized 412 male and female patients. All patients were diagnosed with OA of the knee or hip, as evidenced by X-ray and clinical criteria of the American College of Rheumatology. Additionally, all patients had pain intensity scores corresponding to moderate-to-severe pain.

Following informed consent and wash-out and dose titration, patients were randomized (1:1) into a double-blinded treatment period. The total daily drug dose per patient ranged from 10 mg to 80 mg. Pain intensity scores were assessed on a Likert pain scale. Concomitant pain medications or rescue medications were not allowed at any point during the 12-week treatment period.

Pursuant to the SPA, the primary endpoint was defined as mean decrease in pain intensity scores between Remoxy and placebo. Top-line data indicates that the study achieved a statistically significant result in its primary endpoint (P <.01). In addition, the study achieved statistically significant results in secondary endpoints such as Quality of Analgesia (P <.01) and Global Assessment (P <.01). No drug-related safety issues were noted.

Pain Therapeutics is Durect Corp's licensee of the rights to Remoxy, and it in turn has sublicensed the commercialization rights to King Pharmaceuticals. In 2005, King and Pain Therapeutics entered into a strategic alliance to develop and commercialize Remoxy and other opioid painkillers designed to deter common methods of abuse. Under this alliance, Pain Therapeutics is substantially responsible for drug formulation, clinical development, and regulatory filings for Remoxy and other codeveloped opioid painkillers; upon regulatory approval, King will assume sole control and worldwide responsibility to exclusively commercialize Remoxy and the other codeveloped opioid drugs that are part of the alliance.