Introduction of Rasagiline
Rasagiline is a second-generation monoamine oxidase inhibitor that blocks the breakdown of dopamine, a neurotransmitter, and is 5-10 times more potent than Slegiline (a first-generation monoamine oxidase inhibitor, including Stigmine, Midolpir, and Goldspine). In addition, the metabolite of resagiline is an inactive non-amphetamine substance with low side effects, and more importantly, the drug has certain symptom relief effects and more evidence of neuroprotective effects. Lian Xinfu, Department of Encephalology, Guangdong Provincial Hospital of Traditional Chinese Medicine
Clinical efficacy study of Rexagiline
In 2005, an international joint study published in The Lancet reported that the anti-tremor paralysis drug rasagiline was effective in relieving symptoms of motor disability in patients with Parkinson’s disease. In the 18-week clinical study, 687 patients from Israel, Argentina and Europe (all previously treated with levodopa) were randomized to be given either rasagiline, an ineffective placebo or entacapone + levodopa, another anti-tremor paralysis drug. The results showed that both resagiline and entacapone significantly reduced the period of loss of motor function (1.18 and 1.2 hours per day, respectively) and prolonged the period of function, and that they had similar types and incidence of side effects, including decreased blood pressure on changing position, syncope, constipation, nausea, and leg and ankle swelling. Considering that resagiline is given orally only once a day, experts generally believe that it would be more appropriate as an adjunct to conventional Parkinson’s disease treatment.
Three randomized controlled clinical trials of 18 to 26 weeks have confirmed the safety and efficacy of resagiline. One study included 404 patients with early-stage Parkinson’s disease, and the scale showed that patients treated with resagiline were significantly less likely to experience worsening of their disease compared to the placebo group. Two other studies comparing the efficacy of resagiline in combination with placebo or levodopa in more than 1,100 patients with more advanced Parkinson’s disease showed that patients treated with resagiline in combination with levodopa had a significantly shorter duration of daily functional and mobility limitations.
The Canadian Medical Post also reported that new long-term study data showed that treatment with Rasagiline resulted in symptomatic remission of Parkinson’s disease for up to six years. In addition, long-term outcomes were better for patients given Rasagiline early than later.
A recently completed Phase III clinical trial called ADAGIO by Teva Pharmaceuticals, Israel, Inc. was the largest trial of a drug for Parkinson’s disease conducted to date to test the efficacy of resagiline. 1,176 early-stage patients, all in the early stages of Parkinson’s disease, were treated in 129 medical centers in 14 countries worldwide. The study showed that resagiline slowed the progression of the disease in patients, achieving significant levels of improvement in several assay trials.
Market Prospects for Resagiline
In 2006, the FDA approved the marketing of resagiline in the United States under the trade name Azilect for the initial monotherapy of early-stage Parkinson’s disease and as a supplement to levodopa for more advanced patients. Available in 0.5 mg and 1 mg sizes, both priced between $7 and $8, resagiline is the drug of choice in early Parkinson’s disease treatment strategies for patients with no functional impairment and mild functional impairment.
Currently, resagiline is available in Canada and several European countries, and annual sales are expected to reach more than $1 billion. Rexagiline has not yet been marketed in China, and no clinical trials have been heard in China. The pharmacists at Baekje Sinte Pharmacy believe that, based on the trend of other heavyweight drugs in neurology being marketed in China, it is likely that Rexagiline will not set foot in the Chinese market until around 2015, and by then, it is difficult to say whether a domestic Rexagiline will be available in China. However, the neurology pharmacists and editors of Baiji Xinte Pharmacy will always pay attention to the trend of new special drugs like Resagiline, and report the research progress and market situation of neuropsychiatric drugs in a timely manner.