Objective: To describe dose optimization, efficacy, and safety of foslevodopa/foscarbidopa (LDp/CDp) in patients with advanced Parkinson’s disease (PwaPD) who completed a 52-week open-label study.

Background: Foslevodopa/foscarbidopa (LDp/CDp) administered as a 24-h/day continuous subcutaneous infusion significantly improves motor fluctuations in PwaPD with a favorable safety profile. Little information is available regarding dose titration from initial dose calculation to optimization of LDp/CDp and outcomes in patients who adhere to LDp/CDp long-term.

Method: Post hoc analysis of study completers (completed baseline and final visits) from a 52-week, open-label study (NCT03781167) of LDp/CDp. The study included a 4-week optimization and a 48-week maintenance period. Optimization time was the number of visits needed from visit 1 to when no changes were made to the base infusion rate for ≥15 days. LDp/CDp could be adjusted at any time during the maintenance period, while concomitant medications had to remain stable unless changes were medically necessary.

Results: There were 137 study completers, with a baseline mean (SD) age of 63.1(9.2) years, PD duration of 12.0(5.2) years, and time from motor fluctuation onset of 6.2(4.3) years. Optimization was achieved in 1 visit for 34% of completers. From baseline to end of optimization, 86(63%) patients had increased infusion rates (mean[SD] change 15.1[11.1] mg/hr), 22(16%) had decreased (-11.2[8.5] mg/hr), and 29(21%) had no change. During the maintenance period, the daily levodopa equivalent dose (LED) from LDp/CDp gradually increased and at week 52, was approximately 270 mg (17.4%) higher than baseline and 129 mg (7%) higher than the end of the optimization period[Figure1]. Study completers showed meaningful improvements from baseline in “Off” and “On” time without troublesome dyskinesia as early as week 1 (-2.7[3.4] and 2.6[3.5] h/day), which were maintained through week 52 [Figure2]. Adverse events (AEs) were reported in 131(95.6%) completers, and serious AEs reported in 34(24.8%); these rates were similar to the full study population[1].

Conclusion: For most study completers, LDp/CDp optimization required increased doses after the initial conversion calculation. Rapid and sustained improvements in motor fluctuations were observed with an acceptable AE profile. These results in study completers complement previous analyses and show benefit of maintained LDp/CDp treatment in PwaPD.

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References: [1] Aldred J, Freire-Alvarez E, Amelin AV, Antonini A, Bergmans B, Bergquist F, et al. Continuous Subcutaneous Foslevodopa/Foscarbidopa in Parkinson’s Disease: Safety and Efficacy Results From a 12-Month, Single-Arm, Open-Label, Phase 3 Study. Neurol Ther. 2023;12(6):1937-1958.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dose-optimization-of-foslevodopa-foscarbidopa-post-hoc-analysis-of-study-completers/