A phase I/IIb study presented at the International Congress demonstrated the safety and efficacy of continuous circadian intracerebroventricular (i.c.v.) administration of anaerobically preserved dopamine (A-dopamine) in reducing severe L-DOPA-related complications (LDRC) in Parkinson's disease (PD) patients. The innovative approach addresses the challenge of dopamine oxidation by preserving dopamine anaerobically without preservatives, offering a potential breakthrough in symptomatic PD treatment.
The study included four patients, with plans to include eight more, and involved a phase I safety assessment followed by a phase IIb efficacy study. The phase IIb study employed a crossover design, comparing i.c.v. A-dopamine against optimized oral medical treatment over two one-month periods in patients experiencing severe LDRC. A-dopamine, at concentrations of 50 mg/ml or 100 mg/ml, was delivered via a pump implanted in the abdomen and connected to the frontal horn of the right ventricle. Telemetry adjustments allowed for continuous, personalized delivery, with transcutaneous refills every 7 to 21 days. Patients were monitored using diaries and actimetry at home.
Significant Reduction in L-DOPA Complications
Results from the initial four patients showed no serious adverse events related to the A-dopamine treatment. The primary adverse events reported were nausea and drowsiness, typically associated with rapid titration. Notably, there were no recurrences of addictive behavior or hallucinations. Doses of approximately 100 mg/24h enabled a 40% reduction in oral L-DOPA dosage, accompanied by an 80% reduction in dyskinesias and a 75% reduction in severe "off" periods compared to oral treatment alone. Higher doses, around 200 mg/24h, led to a 70% reduction in oral L-DOPA, with near-elimination of dyskinesias and severe "off" periods, though short "off" periods persisted.
Patient Response and Future Directions
All patients expressed a desire to continue the treatment long-term under compassionate use, with one patient already receiving transcutaneous home refills for 18 months as of March 2022. These early findings suggest that continuous circadian i.c.v. administration of A-dopamine is safe and highly effective in mitigating LDRC, particularly dyskinesia, with a favorable therapeutic index. Further studies with a larger cohort are needed to confirm these results and optimize treatment protocols. The research team plans to enroll additional patients to further validate these findings.
