Restless Legs Syndrome

If you have restless legs syndrome, your experience might be something like this:

You sit at the dinner table eating an evening meal and feel an uncomfortable, sometimes painful sensation deep within your legs. It worsens as the evening wears on. When you walk or move, the pain subsides. At night, these sensations frequently disturb sleep, and result in chronic fatigue or insomnia. You begin to experience a deterioration of your quality of life.

These are classic symptoms of restless legs syndrome, or RLS, a condition that affects up to 10% of the population. In 1995, the International RLS Study Group developed standardized criteria for the diagnosis of RLS, which has served to help doctors to more accurately diagnose RLS. Four Criteria were set forth by the study group and are summarized as follows:

• An urge to move or unpleasant sensations that:
  • Occur primarily in the legs
  • Begins or worsens during periods of rest
  • Are partially or totally relieved by movement
  • Worsen in the evening or night

The cause of RLS is unknown, but some associated risk factors include uremia (accumulation of urinary waste products in the blood), iron deficiency (ferritin < 20 µg/mL), diabetes and spinal cord or peripheral nerve injury.

XenoPort's Approach to the Treatment of RLS

XenoPort has created and is developing a new drug candidate, XP13512, which is being studied as a treatment for RLS and other diseases. A key component of XP13512 is gabapentin, which is an FDA-approved drug for the treatment of epilepsy and the management of post-herpetic neuralgia. Investigator-led clinical studies have shown that gabapentin treats the symptoms of RLS, but XenoPort believes that gabapentin's inherent problems with absorption and current dosing requirements limit its more widespread use to treat RLS.

XenoPort is conducting Phase 3 clinical trials to determine whether XP13512, given once a day at the evening meal, will effectively treat RLS, the symptoms of which can be especially prominent at night. Because XP13512 is a Transported Prodrug of gabapentin, which has been used to treat over 12 million people with various neurological disorders, the design of our clinical trials of XP13512 benefits from a comprehensive understanding of the safety and efficacy of gabapentin.

This icon indicates a link to an external site.