NEW ORLEANS, March 8 /PRNewswire/ -- The dopamine agonist pramipexole demonstrated rapid effectiveness and was well-tolerated in the treatment of Restless Legs Syndrome (RLS), according to study results revealed today from a large clinical study in RLS patients. Full details were presented during the 9th International Congress of The Movement Disorder Society in New Orleans, LA. 
The study -- part of Boehringer Ingelheim's ongoing clinical development program to assess the therapeutic potential of pramipexole for the treatment of Restless Legs Syndrome -- demonstrated that a once-daily dose regimen improved RLS symptoms for a 24-hour period. The study also showed that pramipexole had a rapid onset of action and produced significant improvements in patients' sleep.
Restless Legs Syndrome -- a common chronic neurological disorder characterised by an uncontrollable urge to move the legs -- is usually accompanied by unpleasant and sometimes painful sensations in the legs. Although RLS affects up to ten percent of the adult population, it is often unrecognized by sufferers or misdiagnosed by doctors.  Approximately one-third of sufferers experience symptoms more than twice weekly causing moderate to severe distress. The motor restlessness worsens during the evening and night causing difficulty initiating and maintaining sleep. Movement temporarily relieves symptoms, but the resulting sleep disruption can lead to excessive daytime sleepiness and compromise work performance. The syndrome also has considerable impact on social activities that require prolonged sitting, such as working at a desk, going to the movies, making long car journeys, or dining out.
The study was designed to evaluate the efficacy and safety of pramipexole in a large population in a clinical setting over a six-week treatment period. The study also included a 46-week extension period to assess the long-term safety and efficacy of treatment.
Patients of at least 18 years of age with idiopathic Restless Legs Syndrome were randomized to treatment with pramipexole or placebo. Patients underwent a flexible dose titration phase during weeks one to four (dose range: 0.125 mg to 0.75 mg daily). A total of 345 patients in five European countries received treatment. The mean age at RLS onset was 55.5 years and the mean duration of RLS was 5.2 years.
The results showed that the mean change from baseline to week six in the International RLS Rating Scale (IRLS Scale) of severity was significantly greater for the pramipexole group compared to the placebo group (adjusted mean change from baseline -12.3 versus -5.7, p<0.0001). Moreover, nearly two-thirds (62.9%) of the patients treated with pramipexole were classified as responders (much or very much improved) using the Clinical Global Impressions-Improvement (CGI-I) scale at week 6 compared to 32.5% of the placebo patients (p<0.0001).
Just under one-third of patients (30.6%) treated with pramipexole showed a Patient Global Impression response (much or very much improved) after one week on the starting dose of just 0.125 mg per day compared to only 7.0% receiving placebo.
Sleep disturbance is one of the main features of RLS and often the presenting symptom. Patients were therefore asked to rate the severity of RLS symptoms at the time of getting to sleep as well as their satisfaction with sleep the following morning at baseline and at week 6 using a visual analogue scale. Pramipexole-treated patients reported a significantly reduced severity of RLS symptoms while getting to sleep compared to placebo (-30.6 versus -13.8, p<0.0001). Overall, satisfaction with sleep was also significantly higher (-29.9 versus -13.8, p<0.0001).
Finally, patients were asked to rate the severity of RLS symptoms during the night and the day on a visual analogue scale. The severity of RLS over both periods during pramipexole treatment was decreased significantly compared to placebo after the six-week treatment period. This indicates that a once daily dose regimen with pramipexole has the potential to improve RLS symptoms over a 24-hour time span.
In general, pramipexole was well tolerated. The most frequent adverse events reported at week 6 in patients receiving pramipexole were headache (13% versus 9.6 % placebo), nausea (12.2% versus 6.1% placebo) and fatigue (9.1% versus 6.1% placebo). Most adverse events were of mild or moderate intensity.
No medication is currently approved by the U.S. Food & Drug Administration for Restless Legs Syndrome.
Pramipexole, a compound from Boehringer Ingelheim research, was jointly developed by Boehringer Ingelheim and Pharmacia Corp. (today Pfizer). Currently, pramipexole is approved in the U.S. for the treatment of the signs and symptoms of idiopathic Parkinson's disease, as monotherapy or in combination with levodopa. The most commonly reported adverse events in early and late Parkinson's disease in clinical trials were dizziness, dyskinesia, extrapyramidal syndrome, hallucinations, headache, insomnia, somnolence, and nausea. In the U.S., Boehringer Ingelheim and Pfizer co-promote Mirapex(R) (pramipexole) for Parkinson's disease.
Boehringer Ingelheim Pharmaceuticals, Inc.
Boehringer Ingelheim Pharmaceuticals, Inc., based in Ridgefield, CT, is the largest U.S. subsidiary of Boehringer Ingelheim Corporation (Ridgefield, CT) and a member of the Boehringer Ingelheim group of companies.
The Boehringer Ingelheim group is one of the world's 20 leading pharmaceutical companies. Headquartered in Ingelheim, Germany, it operates globally with 152 affiliates in 45 countries and more than 34,000 employees. Since it was founded in 1885, the family-owned company has been committed to researching, developing, manufacturing and marketing novel products of high therapeutic value for human and veterinary medicine.
In 2003, Boehringer Ingelheim posted net sales of US $8.37 billion (7.4 billion euro) while spending more than one fifth of net sales in its largest business segment, Prescription Medicines, on research and development.
For more information please visit http://www.boehringer-ingelheim.com/
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Boehringer Ingelheim Pharmaceuticals, Inc.