NCT03205956

Measuring Parkinson's Disease Progression

Dopamine Buffering Capacity Measured by phMRI as a Novel Biomarker of Disease Progression in PD

• Status: Completed
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 31 (actual)
• Sponsor: Kevin J. Black, MD · Academic / Other
• Sex: All
• Age: 40 Years – 79 Years
• Healthy volunteers: Not accepted

Summary

The Measuring Parkinson's Disease Progression study aims to use MRI scans and a controlled dose of levodopa to find a biomarker (objective measurement) of Parkinson's disease (PD). Biomarkers would help determine the effectiveness of therapies in slowing or stopping PD progression, and accelerate the pace of research.

Detailed description

Early in the course of Parkinson's disease, a small dose of levodopa (L-DOPA) provides benefit for many hours. The body responds as if the levodopa in the plasma filled a reservoir and then slowly leaked out to produce benefit. With disease progression, even though the same amount of levodopa circulates in the blood, the benefit wears off much faster, as if the reservoir had become leakier. This wearing off of benefit can be characterized by a single number, the effect site rate constant Ke. On average, patients with more severe disease and longer disease duration have a larger ("leakier") Ke when the response to drug is measured using clinical features like tapping speed. Unfortunately, clinical measurements are influenced by confounding factors such as patient fatigue and comfort. A direct, objective brain measure of response to levodopa may improve the reliability of this measurement. Fortunately, we can assess the effect of levodopa on the brain directly, using an MRI machine to measure blood flow in different parts of the brain. For instance, the midbrain has a robust blood flow response to a single, clinically sensible dose of levodopa. This study's goal is to validate MRI measurement of Ke in the brain as an objective, quantitative measure of disease severity in PD. We will do this by comparing MRI-based Ke values from people with PD across a wide range of disease duration and severity. In a subgroup of participants, we will do this measurement twice, once before treatment and once after 6 weeks of treatment with carbidopa-levodopa (Sinemet® and other brand names).

Conditions

• Parkinson's Disease

Interventions

Type	Name	Description
DRUG	Levodopa	At least 1 hour after 200mg carbidopa p.o., each subject will receive an intravenous solution of levodopa in saline at a rate based on age and body mass according to the "final dose" described in Black et al 2003.The total dose for a 70-year-old, 70kg subject will be approximately 65mg. Subjects with untreated PD will then take 6 ± 1 weeks of clinically dosed oral carbidopa-levodopa tablets for clinical purposes and then repeat the carbidopa plus intravenous levodopa dose as above.

Timeline

• Start date: 2017-10-19
• Primary completion: 2019-10-18
• Completion: 2019-10-19
• First posted: 2017-07-02
• Last updated: 2022-10-14

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study