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Slower progression of Parkinson's disease with ropinirole versus levodopa: The REAL-PET study


  • REAL-PET study investigators are listed in the Appendix on page 00.


Preclinical studies suggest ropinirole (a D2/D3 dopamine agonist) may be neuroprotective in Parkinson's disease (PD), and a pilot clinical study using 18F-dopa positron emission tomography (PET) suggested a slower loss of striatal dopamine storage with ropinirole compared with levodopa. This prospective, 2-year, randomized, double-blind, multinational study compared the rates of loss of dopamine-terminal function in de novo patients with clinical and 18F-dopa PET evidence of early PD, randomized 1 to 1 to receive either ropinirole or levodopa. The primary outcome measure was reduction in putamen 18F-dopa uptake (Ki) between baseline and 2-year PET. Of 186, 162 randomized patients were eligible for analysis. A blinded, central, region-of-interest analysis showed a significantly lower reduction (p = 0.022) in putamen Ki over 2 years with ropinirole (−13.4%; n = 68) compared with levodopa (−20.3%; n = 59; 95% confidence interval [CI], 0.65–13.06). Statistical parametric mapping localized lesser reductions in 18F-dopa uptake in the putamen and substantia nigra with ropinirole. The greatest Ki decrease in each group was in the putamen (ropinirole, −14.1%; levodopa, −22.9%; 95% CI, 4.24–13.3), but the decrease was significantly lower with ropinirole compared with levodopa (p < 0.001). Ropinirole is associated with slower progression of PD than levodopa as assessed by 18F-dopa PET. Ann Neurol 2003