The randomized, double-blind, placebo-controlled study achieved its primary endpoints, demonstrating that sodium oxybate significantly decreased pain and fatigue, and improved daily function, in patients with fibromyalgia.
The 14-week study included 548 adult patients with fibromyalgia randomized to one of three treatment arms: sodium oxybate 4.5g/night, sodium oxybate 6g/night or placebo. The primary outcome measure, viewed by both US and EU regulatory authorities as a clinically meaningful endpoint, was the proportion of patients who achieved at least 30% reduction in pain from baseline to endpoint based on the pain visual analog scale.
In the top-line results, a significant number of patients treated with sodium oxybate achieved 30% or greater improvement in their pain compared to patients treated with placebo. Of those patients receiving sodium oxybate treatment, 46.2% of patients on 4.5g/night and 39.3% of patients on 6g/night reported this level of pain relief, compared with 27.3% of patients on placebo. These results were highly statistically significant.
Patients’ physical functioning and ability to perform daily tasks, as measured by the FIQ, were significantly different from placebo for the 4.5g/night dose and approached significance for the 6g/night dose. Patients receiving sodium oxybate also reported significant improvement in fatigue, another common symptom of fibromyalgia, at both active dosage levels.
Only primary efficacy and safety data have been reviewed at this time. Further analyses will be undertaken to examine the full results, including secondary endpoints, in greater detail. The sodium oxybate Phase III clinical trial program also includes a second randomized, double blind, placebo-controlled study, which is continuing at sites in the US and Europe. More than 90% of the subjects have been enrolled in this second Phase III trial.
Jazz Pharmaceuticals anticipates submitting a new drug application for sodium oxybate to the FDA by the end of 2009. UCB anticipates filing in the EU shortly after. UCB has the exclusive marketing and distribution rights to sodium oxybate for fibromyalgia in Europe and some other countries outside North America and will manage registrations accordingly.