Flexion’s Osteoarthritis Painkiller Passes Phase III Clinical Trial

Flexion Therapeutics’ has announced the success of its osteoarthritis drug in a Phase III clinical trial. Despite earlier setbacks with the painkiller, the company is optimistic that the recent win will pave the way for US Food and Drug Administration (FDA) approval.

The experimental injectable drug – designated as FX006 – was able to meet its primary endpoint of being more effective than the placebo at reducing pain in patients, over a 12 week period. The study involved 486 patients with osteoarthritis-related knee pain.

One third of the study participants were given the FX006 treatment, another third were administered corticosteroid triamcinolone acetonide, and the final third were given a placebo. According to Flexion, FX006 beat the placebo by providing a statistically significant improvement in pain level. In a secondary assessment, the drug performed better than the corticosteroid treatment on measures of stiffness, pain and function, after 12 weeks of treatment.

Though the drug performed well on the Phase III clinical trial’s primary endpoint, it failed to meet a secondary goal of improving self-reported scores on a daily pain rating scale, compared to treatment with triamcinolone acetonide. Flexion’s shares soared by 35 percent during after-hours trading on Tuesday, as a result of the positive trial results.

The positive results were much needed for Flexion, who reported that FX006 failed to be more effective at pain relief compared to the placebo, in a Phase IIb clinical trial which concluded last year. According to a statement released by the company, they believe the data could be sufficient to file an FDA application later this year.

Pending approval, Flexion plans to market the drug – which is a potentially a more stable and effective form of triamcinolone acetonide – as Zilretta. “We believe that Zilretta has the potential to become an important new non-opioid treatment in a therapeutic area that hasn’t seen meaningful innovation in many years,” said Dr. Michael Clayman, CEO of Flexion.

“There have been no major advances in the treatment of ostearthritis for decades and given the limited efficacy and the safety liabilities of available therapies, patients are in need of a new treatment option,” said Dr. Stan Cohen, Medical Director, Metroplex Clinical Research Center and Clinical Professor of Internal Medicine, UT Southwestern Medical School, Dallas. “These data suggest that Zilretta has the potential to be a significant advance in pain management for patients with osteoarthritis of the knee.”