BACKGROUND:Rasagiline was safe and effective when used as adjunct therapy with levodopa in patients with moderate-to-advanced Parkinson's disease (PD) in the phase III PRESTO and LARGO studies. OBJECTIVE:To assess clinical effects of rasagiline 1 mg/day on cardinal PD symptoms and motor fluctuations in defined patient subgroups using pooled data from PRESTO and LARGO. METHODS:Both double-blind, randomized, and placebo-controlled studies included PD patients with motor fluctuations despite optimized therapy with levodopa, with or without concomitant dopamine agonists (DA) or catechol-O-methyltransferase inhibitor (COMT-I) treatment. These post hoc analyses measured effects of rasagiline 1 mg vs placebo on individual cardinal PD symptoms during ON time and mean change from baseline in daily OFF time in subgroups of patients who at baseline were receiving only levodopa, were considered "mild fluctuators" (daily OFF time ≤ 4 h), and who were or were not receiving concomitant DA or COMT-I therapy. RESULTS:Compared with placebo, rasagiline significantly improved all cardinal PD symptoms and significantly reduced adjusted mean daily OFF time when used as first adjunct therapy in levodopa-treated patients and in patients with mild motor fluctuations. Significant improvement in motor fluctuations was reported with rasagiline regardless of concomitant DA or COMT-I use. Overall incidence of dopaminergic adverse events did not increase with concomitant DA or COMT-I use. CONCLUSION:Rasagiline was an effective first adjunct therapy in levodopa-treated patients; benefited patients with signs of early "wearing off"; improved all cardinal PD symptoms; and further improved symptoms in patients already receiving other adjunctive dopaminergic treatment.