High and Low Dose Carbidopa Treatment of Parkinson's Disease

NCT01399905 | Completed Phase 2 Results

• 1 other identifier: IRB00004133
• Study Type: interventional
• Target: 14
• Locations: 1 country
• Sites: 1

Brief Summary

Hypothesis: We hypothesize that carbidopa in daily doses of 450mg will enter the central nervous system and partially inhibit AAAD, thereby reducing the decarboxylation of exogenous levodopa to dopamine, and thereby blunt the therapeutic effects of levodopa in PD subjects. The purpose of this study is to see how low dose vs. high dose of the study drug, carbidopa effect movement in subjects with Parkinson's disease. The low dose of the study drug is 75 mg and the high dose is 450mg. Subjects will be recruited from the investigators clinic when they are seen for treatment for Parkinson's disease. Subjects will also be recruited through flyers hung at OHSU and at the VA. Subjects will take part in 2 screening visits one week apart to determine eligibility. Subjects will be randomly chosen to start either high or low dose carbidopa and take it for 4 weeks. Subjects will be called 2, 4, and 6 or 7 days after this visit to ask how they are doing after starting this dose of study drug. We will leave them a message if we cannot reach them. If there are any problems, we will schedule them to come to the clinic within the next 2 days. Subjects will have an outpatient visit 2 weeks after screening and a hospital admission 2 weeks after that. At the hospital, subjects will stay for 3 days. They will have blood drawn and their Parkinson's disease assessed by a finger tapping exercise, timing their walking, and looking at their uncontrolled movements. The subject will then receive the opposite dose of carbidopa for 4 weeks. Subjects will be called 2, 4, and 6 or 7 days after this visit to ask how they are doing after starting this dose of study drug. We will leave them a message if we cannot reach them. If there are any problems, we will schedule them to come to the clinic within the next 2 days. The outpatient visit and hospital admission will repeat again. At the end of the second hospital admission, treatment on the study is over and subjects will go back to their original Parkinson's disease medications. The study will end with a follow up phone call or clinic visit 2 - 4 weeks after the final hospital admission. Subjects will fill out a daily diary that asks about their movement throughout the day for 3 days before they come to the Oregon Clinical and Translational Research Institute. Carbidopa is used for the treatment of Parkinson's disease with levodopa. This protocol is using a high dose of 450mg of carbidopa. This study is also using IV levodopa, which is a different route than is normally given. Finger tapping rates will be compared between high and low dose study drug use to see if one group has slower rates than the other.

Conditions

Parkinson's Disease

Keywords

Parkinson's disease; Levodopa; Carbidopa; Blood brain barrier

Outcome Measures

Primary Outcomes (1)

• Area Under the Curve (AUC) of Tapping Speed

  Tapping speed is an index of bradykinesia and is used as a response to levodopa infusion. Reported as increase over average of three measurements between 8 AM and 9 AM (baseline tapping speed) as (taps/min)\*(hours) for tapping scores from beginning of levodopa infusion to 3 hours after conclusion of levodopa infusion.

  Performed every 30 minutes from 8 AM to 2 PM

Secondary Outcomes (1)

• AUC of Levodopa Plasma Concentrations Above Baseline

  Measured every 30 minutes from 9 AM until 2 PM

Study Arms (2)

High carbidopa followed by low carbidopa

EXPERIMENTAL

450 mg of carbidopa per day for four weeks followed by 75 mg of carbidopa per day for four weeks

Drug: carbidopa

Low carbidopa followed by high carbidopa

EXPERIMENTAL

75 mg of carbidopa per day for four weeks followed by 450 mg of carbidopa per day

Drug: carbidopa

Interventions

carbidopa DRUG

75 mg of carbidopa per day versus 450 mg of carbidopa per day

High carbidopa followed by low carbidopa; Low carbidopa followed by high carbidopa

Eligibility Criteria

• Age: 35 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Idiopathic Parkinson's disease
• Treatment with carbidopa/levodopa
• Motor fluctuations

You may not qualify if:

• Dementia
• Hallucinations
• Age greater than 85

Sponsors & Collaborators

• Oregon Health and Science University: lead

Study Sites (1)

Oregon Health & Science University

Portland, Oregon, 97239, United States

Location

MeSH Terms

Conditions

Parkinson Disease

Interventions

Carbidopa

Condition Hierarchy (Ancestors)

Parkinsonian Disorders; Basal Ganglia Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Movement Disorders; Synucleinopathies; Neurodegenerative Diseases

Intervention Hierarchy (Ancestors)

Methyldopa; Dihydroxyphenylalanine; Catecholamines; Amines; Organic Chemicals; Hydrazines; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Limitations and Caveats

Small study with limited quantity of patients

Results Point of Contact

• Title: John G. Nutt, MD
• Organization: Oregon Health and Science University

nuttj@ohsu.edu

503-494-9054

Study Officials

• John G Nutt, MD

  Oregon Health and Science University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Director, Parkinson Center of Oregon

Study Record Dates

• First Submitted: July 21, 2011
• First Posted: July 22, 2011
• Study Start: March 1, 2009
• Primary Completion: April 1, 2011
• Study Completion: May 1, 2011
• Last Updated: January 9, 2020
• Results First Posted: January 9, 2020

Record last verified: 2019-12

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)