Long-Term Subcutaneous Foslevodopa/Foscarbidopa Infusion Restores Oral Intake and Ambulation in Advanced Parkinson’s Disease After Deep Brain Stimulation: A Case Report

Several clinical trials have shown that a 24-hour continuous subcutaneous infusion of the foslevodopa/foscarbidopa (LD/CD) hydrate combination reduces "off" time and extends "on" time without causing marked dyskinesia in patients with advanced Parkinson's disease (aPD; Hoehn & Yahr stage V).However, whether this treatment is effective in patients with severe chronic disease progression remains unclear.Moreover, to our knowledge, no studies have addressed the subsequent functional outcomes or described detailed clinical courses specifically in patients who received such formulations of LD/CD after deep brain stimulation (DBS).A 74-year-old woman with aPD (Hoehn & Yahr V) and prior bilateral subthalamic nucleus DBS presented with severe motor fluctuations, akinesia, gait disturbance, and progressive dysphagia requiring percutaneous endoscopic gastrostomy (PEG).Previous pharmacotherapy and DBS adjustments had not improved the severe symptoms.The patient was bedridden and required tube feeding.She was transitioned to home care and subsequently experienced severe "off" periods with lifethreatening non-motor symptoms, including systolic hypertension (180-200 mmHg) and severe hypoxia (SpO2 < 40%) from breath-holding spells.Although intermittent subcutaneous apomorphine resolved the acute "off" episodes, concerns over risks of sudden death prompted the initiation of continuous subcutaneous levodopa/carbidopa prodrug (LDp/CDp) infusion to stabilize the levodopa levels.Before the treatment change, the patient received 450mg of oral levodopa, 32mg of transdermal ropinirole (200 mg per day of levodopa equivalent dose [LED]), 100mg of safinamide (150 mg per day of LED), and 25mg of opicapone (225mg per day of LED), yielding a total daily LED of 1,025 mg/day.To minimize outpatient burden, LDp/CDp was initiated at a dose of 0.15 mL/hr (26 mg/hr and 624mg/day of LED) upon admission without a preliminary levodopa challenge test.Daily oral levodopa dose was reduced from 450 to 350 mg, while safinamide was continued at 100 mg/day.The LDp/CDp rate was adjusted to 0.17 mL/hr (708 mg of daily LED) following the development of transient auditory hallucinations, and total daily LED finally increased from 1,025 to 1,208 mg/day.The non-motor fluctuations and symptoms immediately resolved, including severe respiratory dysfunction.Motor symptoms, orthostatic regulation, and gait also improved, enabling walker-assisted gait during rehabilitation sessions.Remarkably, the oral intake resumed despite long-term PEG dependence.As of the two-year follow-up, ongoing LDp/CDp therapy at a consistent dosage has successfully maintained the patient's improved quality of life.LDp/CDp may be useful for improving the quality of life in select patients with aPD, showing its potential as a therapy for secondary DBS failure.