Jazz Pharmaceuticals and UCB have announced positive preliminary top-line results from the first of two phase III clinical trials of sodium oxybate (JZP-6) for the treatment of fibromyalgia.
The randomized, double-blind, placebo-controlled study achieved its key endpoints, demonstrating that sodium oxybate significantly decreased pain and fatigue, and improved daily function in patients with fibromyalgia.
I. Jon Russell, one of the study’s lead investigators said: “There is a significant unmet need in diagnosing and treating millions of patients with fibromyalgia. Potential new treatments that address the various symptoms can have a significant impact on patients’ quality of life.”
The 14-week placebo-controlled study included 548 adult patients with fibromyalgia randomised to one of three treatment arms: sodium oxybate 4.5 g/night, sodium oxybate 6 g/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 percent reduction in pain from baseline to endpoint based on the pain Visual Analog Scale (VAS). In the EU, it is also considered that the Fibromyalgia Impact Questionnaire (FIQ) data is equally relevant.
In the top-line results, significantly more patients treated with sodium oxybate achieved 30 percent or greater improvement in their pain compared with placebo. Of those patients receiving sodium oxybate treatment, 46.2 percent of patients on 4.5 g/night and 39.3 percent of patients on 6 g/night reported this level of pain relief (VAS), compared with 27.3 percent of patients on placebo. These results were highly statistically significant.
Adverse events were similar to those seen in other clinical studies of sodium oxybate. The most common adverse events were headache, nausea, dizziness, vomiting, diarrhea, anxiety, and sinusitis. Sodium oxybate was generally well tolerated, with the majority of adverse events reported being mild to moderate in nature.