Comparability of Foslevodopa/Foscarbidopa Pharmacokinetics in Healthy Asian and White Participants

Abstract

This phase 1 study assessed the safety, tolerability, and pharmacokinetics of a single 24‐hour continuous subcutaneous dose of foslevodopa/foscarbidopa in healthy adult Japanese (N = 24), Han Chinese (N = 8), and White (N = 24) participants. Three doses of foslevodopa/foscarbidopa were evaluated in healthy participants for this study: 480/24, 960/48, and 1440/72 mg/day. Serial blood samples for measurement of levodopa, carbidopa, foslevodopa, foscarbidopa, and 3‐O‐methyldopa concentrations were collected for 48 hours after foslevodopa/foscarbidopa administration. Safety and tolerability were assessed throughout the study. Point estimates for ratios of central values indicated that the exposure difference between Japanese and White participants was <10%. The maximum concentration and area under the plasma concentration–time curve for both LD and CD following foslevodopa/foscarbidopa continuous subcutaneous infusion were comparable between Han Chinese and White participants. Point estimates for ratios of central values indicated that the exposure difference between Han Chinese and White participants was <14%. The regimens tested were generally well tolerated, and no new safety issues were identified in this study. There were no clinically meaningful differences in LD and CD exposures or pharmacokinetics following administration of foslevodopa/foscarbidopa among White, Japanese, and Han Chinese participants.