Rasagiline and Parkinson's disease

Does rasagiline slow the progression of Parkinson's disease? A recent study suggests lower doses of the drug may be beneficial. In this multinational study, 1176 subjects with untreated Parkinson's disease were randomized to rasagiline 1 mg or 2 mg per day for 72 weeks or placebo for 36 weeks followed by rasagiline for 36 weeks. Disease progression was rated on a standard rating scale. Patients who were started at baseline on rasagiline 1 mg met all endpoints in the primary analysis: a slower rate of worsening between weeks 12 and 36 (P = 0.01), less worsening of the score between baseline and week 72 (P = 0.02), and non-inferiority between weeks 48 and 72 (P ≤ 0.001). Interestingly, all 3 endpoints were not met with the higher dose of 2 mg per day. The authors conclude that early treatment with rasagiline at a dose of 1 mg per day provided a possible disease-modifying effect, but suggested the results must be interpreted with caution (N Engl J Med 2009;361:1268-1278). Although the findings of this paper are somewhat confusing, it offers some hope since there is currently no effective therapy to slow or stop disease progression in Parkinson's disease.