Objective: To investigate the long-term impact of foslevodopa-foscarbidopa continuous subcutaneous infusion (CSCI) on dyskinesia in Parkinson’s disease (PD).

Background: Foslevodopa-foscarbidopa CSCI is an emerging treatment for advanced PD with motor fluctuations.¹ Clinical trials have demonstrated its efficacy in reducing “off” time and “on” time without troublesome dyskinesia up to 12 months.^2,3 However, long-term data, especially on dyskinesia, is lacking. We previously reported a reduction in dyskinesia by 6 months that was sustained for 3 years post-treatment.⁴ Here, we extend our observations with 5-year follow-up data.

Method: Participants in the AbbVie M15-736, M15-741 and M20-098 studies at Westmead Hospital, Sydney who continued 24-hour foslevodopa-foscarbidopa CSCI for at least 5 years were included. Participants were required to have levodopa-responsive PD, be receiving ³ 400 mg LEDD, and have uncontrolled motor fluctuations including ³ 2.5 hours of “off” time at enrolment. Full inclusion criteria are published separately.^2,3 Unified Dyskinesia Rating Scale (UDysRS) total scores at baseline and last follow-up were compared using the Wilcoxon signed-rank test. p < 0.05 was considered statistically significant.

Results: 9 participants (6 males, 3 females) with a median age of 49 years (IQR 35-56) were included. At baseline, median disease duration was 7 years (IQR 6-9) and median LEDD was 1200 mg (IQR 975-1750). Foslevodopa-foscarbidopa CSCI was continued for a median of 5.8 years (IQR 5.2-5.9) at individualised rates. UDysRS scores were significantly reduced from baseline to last follow-up (V = 43, p = 0.02), with a median reduction of 63.6% (IQR 42.1-88.9%).

Conclusion: Foslevodopa-foscarbidopa CSCI can reduce dyskinesia beyond 5 years in advanced PD with motor fluctuations, suggesting it may be a promising long-term treatment option. More longitudinal data from larger cohorts is required to corroborate this result.

References: 1. Fung VSC, Aldred J, Arroyo MP, Bergquist F, Boon AJW, Bouchard M, Bray S, Dhanani S, Facheris MF, Fisseha N, et al. Continuous subcutaneous foslevodopa/foscarbidopa infusion for the treatment of motor fluctuations in Parkinson’s disease: Considerations for initiation and maintenance. Clin Park Relat Disord. 2024;10:100239. doi: 10.1016/j.prdoa.2024.100239
2. Soileau MJ, Aldred J, Budur K, Fisseha N, Fung VSC, Jeong A, Kimber TE, Klos K, Litvan I, O’Neill D, et al. Safety and efficacy of continuous subcutaneous foslevodopa-foscarbidopa in patients with advanced Parkinson’s disease: a randomised, double-blind, active-controlled, phase 3 trial. The Lancet Neurology. 2022;21:1099-1109. doi: 10.1016/S1474-4422(22)00400-8
3. Aldred J, Freire-Alvarez E, Amelin AV, Antonini A, Bergmans B, Bergquist F, Bouchard M, Budur K, Carroll C, Chaudhuri KR, 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. Neurology and Therapy. 2023;12:1937-1958. doi: 10.1007/s40120-023-00533-1
4. Georgiades MJ, Tsui D, Chen X, Bray S, Qiu J, Waller S, Williams L, Dal S, Ong TL, Martin A et al. Continuous subcutaneous foslevodopa/foscarbidopa infusion therapy leads to a sustained reduction in dyskinesias in Parkinson’s disease [abstract]. Mov Disord. 2025;40(S1)

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MDS Abstracts - https://www.mdsabstracts.org/abstract/foslevodopa-foscarbidopa-continuous-subcutaneous-infusion-leads-to-long-term-reduction-in-dyskinesia-in-parkinsons-disease-results-from-5-year-follow-up/