Continuous subcutaneous foslevodopa/foscarbidopa improves off time in Parkinson's disease; severe adverse events higher in prior DBS group

INTRODUCTION: As Parkinson's disease (PD) advances, limitations of oral medication include pill burden, increasing "Off" time, and "On" time with bothersome dyskinesia. Deep brain stimulation (DBS) can improve motor complications, but disease progression may warrant further intervention later. An approved nonsurgical option, continuous subcutaneous infusion of foslevodopa/foscarbidopa (LDp/CDp), has been shown to improve motor fluctuations, though the impact of prior DBS on its efficacy and safety is unknown. METHODS: Post hoc analysis of a 52-week open-label phase 3 trial (NCT03781167) evaluated baseline characteristics, safety, and efficacy in patients treated with LDp/CDp with or without prior DBS. Fisher's exact test, t test, Wilcoxon rank-sum test, and analysis of covariance were performed. RESULTS: Twenty-four (9.8%) of 244 patients received prior DBS. Both groups had similar baseline characteristics, although prior patients treated with DBS had significantly more time since diagnosis and more "speech" and "gait" impairment (Movement Disorders Society-Unified Parkinson's Disease Rating Scale [MDS-UPDRS] Parts II/III single items). Both groups showed significant within-group improvements in "Off" time and "On" time without dyskinesia, and the between-group difference for these improvements was not significant, indicating LDp/CDp had efficacy regardless of DBS exposure. The no DBS group had significant improvement in sleep and quality of life, while the prior DBS group had nonsignificant trends in the same direction. The no DBS group had significant improvement in MDS-UPDRS Part II score but worsening in Part III score, as expected with advancing disease; change from baseline in the prior DBS group was not significant. The safety data were similar in both groups, with the only significant difference being a higher percentage of prior patients treated with DBS experiencing severe treatment-emergent adverse events than no DBS (45.8% vs 23.6%). CONCLUSION: While limited by small prior DBS patient numbers, this post hoc study suggests generally similar overall baseline, safety, and efficacy profiles in LDp/CDp-treated prior DBS and no DBS. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03781167.