Positive Phase III data for Sodium Oxybate as a treatment for Fibromyalgia Syndrome

Jazz Pharmaceuticals' medication sodium oxybate (JZP-6) demonstrated statistically significant and clinically meaningful improvement in pain and the core symptoms associated with Fibromyalgia Syndrome, according to Phase III data presented last week at the 2009 Associated Professional Sleep Societies meeting in Seattle, USA.

These data have not been evaluated by the FDA or other regulatory authorities for use of sodium oxybate in the treatment of Fibromyalgia Syndrome.

However, Dr. Todd Swick, one of the study's investigators and Medical Director of the Houston Sleep Center and Assistant Clinical Professor of Neurology at the University of Texas-Houston School of Medicine, said:

"The data showed that sodium oxybate improves the key symptoms of fibromyalgia: pain, fatigue, and sleep disturbances...

Millions of people are diagnosed with fibromyalgia and there is a continuing unmet need for therapies that address the constellation of symptoms that can have a significant impact on patients' quality of life."

Unlike some other medications for Fibromyalgia Syndrome that primarily target pain, Sodim Oxybate works by improving sleep quality.

The 14-week randomized, double-blind, placebo-controlled study included 548 adult patients with Fibromyalgia Syndrome randomized to one of three treatment arms: sodium oxybate 4.5 g/night, sodium oxybate 6 g/night or placebo. The primary outcome measure was the proportion of patients who achieved at least 30% reduction in pain from baseline to endpoint based on the Pain Visual Analog Scale (VAS).

At three months, 54.2% (p<0.001) of patients treated with sodium oxybate 4.5 g/night and 58.5% (p<0.001) of patients treated with sodium oxybate 6 g/night showed significantly greater reduction in pain as measured by at least a 30% improvement in baseline pain VAS score, compared with 35.2% of patients taking placebo using Last Observation Carried Forward analysis.

These results may suggest that sodium oxybate could be an effective treatment for more people with Fibromyalgia Syndrome than most of the drugs used at the moment.

Please note however, that sodium oxybate is NOT yet available as a treatment specifically for Fibromyalgia Syndrome in either the US or the EU.

Sodium oxybate is approved by the American Food & Drug Administration (FDA), under the brand name Xyrem, for the treatment of excessive daytime sleepiness and cataplexy (the sudden loss of muscle tone) in adult patients with narcolepsy. It is also approved by the European Medical Evaluation Agency (EMEA) for the treatment of narcolepsy with cataplexy in adult patients.

Additional data highlights from the Phase III trials included:

~ Patients treated with sodium oxybate 4.5 g/night and 6g/night showed significant reductions in fatigue as early as Week 1 after dosing compared with placebo as measured by the Fatigue VAS (p<0.001). These differences were maintained throughout the 14 weeks of the study (p less than or equal to 0.009).

~ Patients taking sodium oxybate 4.5 g/night and 6g/night showed significant improvement in sleep patterns compared to placebo as measured by the Jenkins Sleep Scale (p<0.001).

~ Statistically significant improvements in mean scores on the Fibromyalgia Impact Questionnaire, a measure of daily function, and on Patient Global Impression of Change were seen in patients receiving sodium oxybate compared to placebo.

~ Sodium oxybate was generally well tolerated, with the majority of adverse events reported being mild to moderate in nature. Adverse events were similar to those seen in previous sodium oxybate experience.

~ In this study, the most common adverse events, with incidence greater than or equal to 5% and at least twice the rate of placebo, were headache, nausea, dizziness, vomiting, diarrhea, anxiety, and sinusitis.

Jazz Pharmaceuticals also announced that it has completed its second Phase III clinical trial of JZP-6 (Sodium Oxybate) and expects to announce top-line results from this study around mid-2009. Assuming positive results for the second study, the company anticipates submitting a New Drug Application for sodium oxybate for the treatment of Fibromyalgia Syndrome to the US Food and Drug Administration 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.