The patch, containing the non-steroidal anti-inflammatory drug ketoprofen, was to be submitted as a New Drug Application in the first half of next year, but the company has withdrawn this plan following a lack of significant outcomes in two Phase III trials looking at the treatment of soft-tissue injuries.
One study evaluated the patch as a treatment for ankle sprains and strains, and the second was targeted at treating the pain associated with tendonitis or bursitis of the shoulder, elbow or knee.
Findings showed no significant difference was observed in either trial in the primary endpoint - average pain intensity during daily activities - between patients treated with the ketoprofen patch and patients using a placebo patch.
"Our initial view is that the results if the first two Phase III trials illustrate the difficulty of demonstrating a statistically significant separation between the treated and control groups in clinical studies involving topical patches," Endo Pharmaceuticals chief scientific officer David Lee said in a statement.
"Before determining our next course of action, we intend to review the results of these two trials in relation to the positive placebo-controlled trials conducted in Europe.
We expect to provide further clarification during our second quarter earnings call, tentatively scheduled for August 1," he said.
Two other Phase III trials would be ongoing - one evaluating the ketoprofen patch in the treatment of pain associated with tendonitis of the shoulder, elbow or knee; the other evaluating the patch in patients with osteoarthritis flare in the knee.
Ketoprofen is currently marketed in capsule form as Orudis and Oruvail by Wyeth.
While Orudis is an immediate release formulation, Oruvail is a slow release formulation.
Endo Pharmaceuticals currently markets pain relief patch Lidoderm (lidocaine).
Endo Pharmaceuticals was unavailable for comment at time of publishing.