Controlled Maxillofacial Administration of Levodopa in a Patient With Parkinson's Disease: A First-in-Human 24-Hour Follow-Up Study.

BACKGROUND

In advanced Parkinson's disease (PD), the clinical response to oral levodopa diminishes over time, leading to dyskinesia and unpredictable "off" periods. In PD patients with dementia, those with a Ryle's tube in situ, or those who decline existing levodopa delivery routes such as intraduodenal, subcutaneous, or oral inhalation, alternative approaches are required. This study evaluates a novel maxillofacial route and platform as a clinically viable alternative to conventional levodopa delivery methods.

OBJECTIVE

This study evaluates the feasibility and safety of low-dose levodopa administered using a maxillofacial platform in a PD patient and assesses systemic exposure and its relationship to clinically meaningful motor outcomes over a 24-hour period following dosing at regular intervals.

METHODS

A PD patient received four cycles of 5 mg levodopa (one-twentieth of the patient's usual oral dose) through a maxillofacial route at regular 3.5-hour intervals. Levodopa was administered using a maxillofacial platform designed to enable controlled, repeated dosing through this route. The patient was monitored over a 24-hour period. Motor outcomes were assessed using the Movement Disorders Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Part III: Motor Examination (ME). Clinically meaningful improvement was evaluated using Minimal Clinically Important Difference (MCID) thresholds. Plasma levodopa concentrations were quantified using high-performance liquid chromatography (HPLC). Local and systemic adverse events were monitored throughout the study period.

RESULTS

MCID-level improvement was observed in 16 (94%) post-dose MDS-UPDRS assessments. Robust improvement was observed in 13 (76%) post-dose assessments. The median improvement from baseline was nine points, the interquartile range (IQR) was eight points (5-13), and the observed range was fourteen points (2-16). Clinically meaningful benefit was detected within 30-60 minutes, peaked at 1-2 hours, and persisted for approximately 3 hours per dose. Robust motor responses occurred across a wide range of systemic exposures, demonstrating a temporal and quantitative dissociation between plasma levodopa area under the concentration-time curve (AUC) and clinical effect. No local or systemic adverse events were observed.

CONCLUSION

Low-dose levodopa administered at regular intervals through the maxillofacial platform yielded reproducible and clinically meaningful improvement. The platform was safe, effective, and well tolerated over the 24-hour study period.