New data support the efficacy and safety of dopamine agonist Pramipexole ( Mirapex ) in treating patients with restless legs syndrome ( RLS ).

Restless legs syndrome is one of the most common, but treatable, neurological conditions in the world. It is estimated that RLS affects up to one in ten of the population aged between 30 to 79 years.
Symptoms of RLS include an uncontrollable urge to move the legs, and unpleasant and/or painful sensations in the legs. People often describe their symptoms as feeling like they have insects or "creepy-crawlies" running through their legs or a sensation of pins and needles.
Symptoms can begin or worsen during periods of rest or inactivity and often are worse at nighttime.

The latest results from the large, double-blind, placebo-controlled European study in 345 patients suggest that Pramipexole is effective in reducing the severity of RLS symptoms, over a six-week period, and is well-tolerated.

Efficacy was demonstrated in this study using two measurement criteria: the International RLS Rating Scale of severity ( IRLS ) and the Clinical Global Impressions – Improvement ( CGI – I ) scale.

Results after six weeks of trial therapy showed that:

- Improvement in the IRLS was significantly greater for the Pramipexole group, compared to the placebo group ( adjusted mean change from baseline -12.3 vs -5.7, p= 0.0001 ).

- On the CGI-I scale almost two-thirds ( 62.9% ) of patients taking Pramipexole were classified as "improved" or "much improved," compared to only one-third ( 32.5% ) of patients treated with placebo ( p<0.0001 ).

A new subanalysis of the European study has shown that Pramipexole treatment significantly improves patients' quality of life, as measured by the SF-36 ( Medical Outcomes Study 36 –Item Short Form health survey ).

This assessment test has eight sub-scales upon which patients are scored.
Low scores on this scale indicate poor or worsening quality of life; high scores indicate better quality of life.

After six weeks of study treatment, compared to placebo, patients treated with Pramipexole had statistically significant higher scores for 'Vitality' ( i.e. fatigue ), 'Social Functioning' ( i.e. interference with normal social activities with family, friends and others ) and 'Bodily Pain' ( i.e. bodily pain during the past four weeks on a six-point verbal rating scale ).
For the other five subscales ( physical functioning, role limitations due to physical problems, role limitations due to emotional problems, general mental health, and general health perceptions ), Pramipexole showed an improvement on scores over placebo, but these data did not reach statistical significance. These data are important as recent studies have shown that the Quality of Life impact of RLS is comparable to that of other chronic diseases such as hypertension, diabetes, and other cardiovascular conditions.

Previous studies in RLS have suggested that Pramipexole may provide rapid relief from symptoms. The efficacy and safety of Pramipexole has been studied from a starting dose of 0.125mg single dose per day and up to 0.75mg single dose per day.

Two pivotal studies of Pramipexole in RLS have showed significant short- and long-term efficacy versus placebo.

. 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, headache, insomnia, somnolence, and nausea. Hallucinations and orthostatic hypotension may occur. Patients have reported falling asleep without perceived warning signs during activities of daily living, including operation of a motor vehicle, which sometimes resulted in accidents.

Source: European Federation of Neurological Societies ( EFNS ) Annual Meeting, 2005


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