The objective of this study was to assess the efficacy, safety, and pharmacokinetics of XP21279-carbidopa in patients with Parkinson’s disease who experience motor fluctuations compared with immediate-release carbidopa-levodopa tablets. XP21279 is a levodopa prodrug that is actively absorbed by high-capacity nutrient transporters expressed throughout the gastrointestinal tract and then rapidly converted to levodopa by carboxylesterases. XP21279-carbidopa sustained-release bilayer tablets were developed to overcome pharmacokinetic limitations of levodopa by providing more continuous exposure…