COMT and Parkinson disease: In Brazil, the prevalence of PD is rising, largely attributed to the aging population.5As the disease advances, patients often experience fluctuations in motor response and the emergence of motor and non-motor complications that are less responsive to conventional pharmacological therapies, including monoamine oxidase B (MAO-B) inhibitors, dopamine agonists, and catechol-O-methyltransferase (COMT) inhibitors.6, 7, 8, 9This clinical stage is commonly referred to as advanced PD (aPD).