Transition from subcutaneous levodopa/carbidopa (ND0612) to Foslevodopa/Foscarbidopa in advanced Parkinson's disease

Background: Continuous subcutaneous levodopa infusion is an established option for advanced Parkinson's disease (PD). Subcutaneous levodopa/carbidopa infusion (ND0612) and foslevodopa/foscarbidopa (ABBV-951) are available infusion systems; however, no clinical guidance exists regarding conversion between these treatments. Methods: We report two patients with advanced PD receiving ND0612 in combination with oral levodopa who underwent complete transition to ABBV-951. Initial foslevodopa/foscarbidopa dosing was estimated according to levodopa equivalent daily dose and subsequently titrated under close neurological supervision. Motor fluctuations, non-motor symptoms, quality of life, and infusion-site tolerability were evaluated at baseline and at 3-month follow-up using standardized clinical assessments. Results: Both transitions were completed within one day without acute adverse events. At three months, both patients showed a marked reduction in daily off time, improvement in dyskinesias and freezing of gait, and stabilization of sleep and behavioral symptoms. ABBV-951 demonstrated improved local tolerability, with no infusion-site complications observed during follow-up. Conclusions: Conversion from ND0612 to ABBV-951 appears feasible, and safe in advanced PD. These preliminary observations may provide practical insight in the absence of published data addressing this specific therapeutic transition.