Randomized, controlled trial of rasagiline as an add-on to dopamine agonists in Parkinson's disease.

Dopamine agonists (DA) are often used as first-line monotherapy for the symptomatic control of Parkinson's disease (PD). However, DA monotherapy typically becomes inadequate within a few years, at which time the DA dosage must be increased or other antiparkinsonian medications added. Adding a monoamine oxidase-B (MAO-B) inhibitor to DA monotherapy might improve symptomatic control while maintaining good safety and tolerability. We conducted an 18-week, randomized, double-blind, placebo-controlled trial of rasagiline 1 mg/d as an add-on to DA therapy (ropinirole ≥ 6 mg/d or pramipexole ≥ 1.0 mg/d) in early PD patients whose conditions were not adequately controlled on their current treatment regimen. The primary efficacy variable was the change in total Unified Parkinson Disease Rating Scale (UPDRS) score (sum of parts I, II, and III) from baseline to week 18, comparing rasagiline and placebo groups. The modified intent-to-treat (ITT) population included 321 subjects whose mean ± SD age was 62.6 ± 9.7, and duration of PD was 2.1 ± 2.1 years. Results demonstrated a significantly greater improvement in total UPDRS scores from baseline to week 18 in the rasagiline group compared with the placebo group (least squares [LS] mean difference ± SE, -2.4 ± 0.95; 95% confidence interval [CI], -4.3, -0.5; P = 0.012). Mean improvement (LS mean ± SE) was -3.6 ± 0.68 in the rasagiline group and -1.2 ± 0.68 in the placebo group. Rasagiline was well tolerated, and the most common adverse events (AEs; rasagiline vs. placebo) were dizziness (7.4% vs. 6.1%), somnolence (6.8% vs. 6.7%), and headache (6.2% vs. 4.3%). Rasagiline 1 mg/d provided statistically significant improvement when added to dopamine agonist therapy and was well tolerated.