Jazz Pharmaceuticals, Inc (PALO ALTO, California), a specialty pharmaceutical company, announced completion of enrollment in the first of two phase III pivotal clinical trials of JZP-6 (sodium oxybate, Xyrem^®) for the treatment of fibromyalgia (FMS).

The JZP-6 phase III clinical trial program includes two randomized, double-blind, placebo-controlled, parallel group studies in subjects diagnosed with FMS in accordance with the American College of Rheumatology.

In the first phase III study, total duration is up to 21 weeks. Subjects will undergo a screening and withdrawal/washout period lasting up to 5 weeks combined, followed by baseline period lasting 1 week. Total treatment duration will be 14 weeks followed by 1 week safety follow-up posttreatment period. The first study has enrolled 550 FMS patients at 65 centers in the US, and the company expect to report top line trial results in the fourth quarter of 2008.

The second phase III study is enrolling patients at sites in the US and Europe. Total trial duration is up to 22 weeks. As in the first phase III study, subjects will undergo a screening and withdrawal/washout period lasting up to 5 weeks combined, followed by baseline period lasting 1 week. Total treatment duration will be 14 weeks followed by a 2-week safety follow-up posttreatment period.

The primary endpoint for both studies is change from baseline in pain based on the pain visual analog scale (VAS), which the US FDA and the European Medicines Agency have indicated is the appropriate primary endpoint. The JZP-6 clinical program also includes an open-label continuation trial to provide long-term safety data. Enrollment is underway and the trial is open to patients who complete one of the two pivotal phase III trials. The company anticipates submitting the new drug application to the FDA by end of 2009.

In a phase II clinical trial completed in 2005, FMS patients taking sodium oxybate achieved a statistically significant improvement in pain compared with placebo based on VAS.

Sodium oxybate is approved by the FDA for the treatment of excessive daytime sleepiness and cataplexy in patients with narcolepsy. Sodium oxybate has not been approved for the treatment of FMS.