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Rasagiline Slightly Boosts Motor Benefits of Dopamine Agonists in Early PD
- Jul 07 2014
Debate still exists about which treatment is most beneficial as an initial therapy for Parkinson’s disease (PD). A study published online June 11 in Movement Disorders, suggests that when dopamine agonists such as (Requip®) or pramipexole (Mirapex®) are chosen as an initial therapy, the addition of rasagiline (Azilect®) as a complement may slightly improve motor symptoms of early PD.
In the early stages of Parkinson’s disease, some people with PD and their doctors opt to begin treatment with levodopa, the gold-standard therapy that provides the best relief for movement symptoms. Others opt instead to first take alternatives to levodopa — drugs known as dopamine agonists and MAO-B inhibitors. But dopamine agonists typically become inadequate after a few years, at which time the dose must be increased or other medications added. And MAO-B inhibitors, such as rasagiline (Azilect®), by themselves have only a modest impact on motor symptoms.
A team led by Robert A. Hauser, M.D., at the University of South Florida, which included scientists from Teva Pharmaceuticals in Israel (the manufacturers of rasagiline), wondered whether using the treatments together – adding rasagiline to dopamine agonist therapy – would improve symptoms in people with early PD more effectively than using dopamine agonists alone. They recruited 328 people with early PD whose symptoms were not adequately controlled with dopamine agonists alone. The people were treated at 69 centers across the United States. The researchers randomly assigned the study participants to two groups: one that received rasagiline alongside the dopamine agonist and another that received a placebo alongside the dopamine agonist. The study was double-blind, meaning that neither the study participants nor their doctors knew to which group the participants had been assigned.
At the beginning of the study (baseline) and at the end of the study 18 weeks later, participants were evaluated with several measures, including the Unified Parkinson’s Disease Rating Scale (UPDRS), a standard test used to monitor cognition, activities of daily living and motor skills in people with PD. Participants and their doctors were also asked to rate their improvement at week 18, on a scale from “very much improved” to “very much worse.”
Of the 328 people initially enrolled, 289 (88.1 percent) completed the study: 144 in the rasagiline group and 146 in the placebo group. Of these, 67.5 were male. The average age of the participants was around 63 years and on average each participant had lived with PD for about two years.
- After 18 weeks, for the rasagiline group, the total UPDRS score improved an average of 3.6 points from baseline compared with 1.2 points from baseline for the placebo group.
- No significant differences were seen between groups for the UPDRS activities of daily living score.
- The participants’ and their doctors’ ratings of improvement were not significantly different between the rasagiline and placebo groups.
- Side effects such as dizziness, sleepiness and headache were similar in both groups.
What Does It Mean?
An unresolved question in PD has been which therapy is best to initially treat the disease. Recent research has indicated that levodopa shows a slight edge over dopamine agonists and MAO-Bs for the initial treatment of PD. However, for most PD therapies, one drug alone will often not be sufficient.
The study showed that when dopamine agonists are no longer useful, adding rasagiline can offer slightly better results than simply taking dopamine agonists alone. The medication was also safe and well tolerated, with similar side effects to the dopamine agonists alone. However, those people with PD who added rasagiline to their regimen did not report better ability to perform activities of daily living. And the participants themselves did not rate their improvement significantly better than that of the placebo group.
Therefore, although total UPDRS scores were statistically improved for the rasagiline group compared to placebo, the study authors were cautious in interpreting the results. They recognized the very small improvements offered by adding rasagiline to dopamine agonists are modest at best and may not make a meaningful difference in the lives of people with PD.
A major strength of this study was that it was double-blind, meaning that neither the participants nor their doctors knew to which group the participants had been assigned (rasagiline or placebo). This study design helps avoid any bias participants and doctors may have with regard to the anticipated treatment benefits or side effects. A weakness of the study is that it excluded people on dopamine agonists who had a history of impulse control disorders (ICDs), a relatively common side effect of dopamine agonist therapy. Therefore, the researchers were unable to determine whether rasagiline could help avoid recurrence of ICDs. In addition, the study lasted only 18 months, so it could not assess long-term benefits of rasagiline or whether the medication could delay the need for levodopa.
PDF recommends that when deciding whether to add rasagiline to dopamine agonist therapy, people with PD consult with their doctors.
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Reference: Hauser RA, Silver D, Choudhry A, Eyal E, Isaacson S, for the ANDANTE study investigators (2014) Randomized, controlled trial of rasagiline as an add-on to dopamine agonists in Parkinson's disease. Mov Disord: Ahead of Print. DOI: 10.1002/mds.25877 http://dx.doi.org/10.1002/mds.25877
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Source Date: Jul 07 2014