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Trial Outcomes & Findings for High and Low Dose Carbidopa Treatment of Parkinson's Disease (NCT NCT01399905)

NCT ID: NCT01399905

Last Updated: 2020-01-09

Results Overview

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.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

14 participants

Primary outcome timeframe

Performed every 30 minutes from 8 AM to 2 PM

Results posted on

2020-01-09

Participant Flow

Subjects were recruited from the Movement Disorders Clinic at Oregon Health and Science University in Portland, Oregon.

Of the 17 subjects screened, 14 subjects met enrollment criteria and were randomized into one of the two treatment arms.

Participant milestones

Participant milestones
Measure
Low Carbidopa Followed by High Carbidopa
75 mg of carbidopa per day for four weeks followed by 450 mg of carbidopa per day for four weeks
High Carbidopa Followed by Low Carbidopa
450 mg of carbidopa per day for four weeks followed by 75 mg of carbidopa per day for four weeks
Overall Study
STARTED
7
7
Overall Study
COMPLETED
6
6
Overall Study
NOT COMPLETED
1
1

Reasons for withdrawal

Reasons for withdrawal
Measure
Low Carbidopa Followed by High Carbidopa
75 mg of carbidopa per day for four weeks followed by 450 mg of carbidopa per day for four weeks
High Carbidopa Followed by Low Carbidopa
450 mg of carbidopa per day for four weeks followed by 75 mg of carbidopa per day for four weeks
Overall Study
Withdrawal by Subject
1
1

Baseline Characteristics

High and Low Dose Carbidopa Treatment of Parkinson's Disease

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Low Carbidopa Followed by High Carbidopa
n=7 Participants
75 mg of carbidopa per day for four weeks followed by 450 mg of carbidopa per day for four weeks
High Carbidopa Followed by Low Carbidopa
n=7 Participants
450 mg of carbidopa per day for four weeks followed by 75 mg of carbidopa per day for four weeks
Total
n=14 Participants
Total of all reporting groups
Age, Categorical
<=18 years
0 Participants
n=5 Participants
0 Participants
n=7 Participants
0 Participants
n=5 Participants
Age, Categorical
Between 18 and 65 years
6 Participants
n=5 Participants
5 Participants
n=7 Participants
11 Participants
n=5 Participants
Age, Categorical
>=65 years
1 Participants
n=5 Participants
2 Participants
n=7 Participants
3 Participants
n=5 Participants
Age, Continuous
61 years
STANDARD_DEVIATION 6 • n=5 Participants
65 years
STANDARD_DEVIATION 5 • n=7 Participants
63 years
STANDARD_DEVIATION 6 • n=5 Participants
Sex: Female, Male
Female
4 Participants
n=5 Participants
1 Participants
n=7 Participants
5 Participants
n=5 Participants
Sex: Female, Male
Male
3 Participants
n=5 Participants
6 Participants
n=7 Participants
9 Participants
n=5 Participants

PRIMARY outcome

Timeframe: Performed every 30 minutes from 8 AM to 2 PM

Population: All 12 participants who completed the study were included in the data analysis. Each arm contains data from all 12 participants because this is a cross-over study. All participants participated in both the high-dose and low-dose carbidopa arms.

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.

Outcome measures

Outcome measures
Measure
Low-dose Carbidopa (75 mg/Day) Day 1
n=12 Participants
Day 1 of levodopa infusions following 4 weeks of low-dose carbidopa (75 mg/day). Carbidopa 25 mg administered at 8 AM, 10 AM and 12 PM for day 1 infusion.
Low-dose Carbidopa (75 mg/Day) Day 2
n=12 Participants
Day 2 of levodopa infusions following 4 weeks of low-dose carbidopa (75 mg/day). Carbidopa 25 mg administered at 8 AM, 10 AM, and 12 PM for day 2 infusion.
High-dose Carbidopa (450 mg/Day) Day 1
n=12 Participants
Day 1 of levodopa infusions following 4 weeks of high-dose carbidopa (450 mg/day). Carbidopa 25 mg administered at 8 AM 10 AM and 12 PM for day 1 infusion.
High-dose Carbidopa (450 mg/Day) Day 2
n=12 Participants
Day 2 of levodopa infusions following 4 weeks of high-dose carbidopa (450 mg/day). Carbidopa 150 mg administered at 8 AM, 10 AM and 12 PM for day 2 levodopa infusion.
Area Under the Curve (AUC) of Tapping Speed
141 (taps/min)*(hours)
Standard Deviation 103
141 (taps/min)*(hours)
Standard Deviation 131
145 (taps/min)*(hours)
Standard Deviation 123
201 (taps/min)*(hours)
Standard Deviation 214

SECONDARY outcome

Timeframe: Measured every 30 minutes from 9 AM until 2 PM

Population: The levodopa plasma samples of one subject were accidently thawed so samples from 11 participants were used in this data analysis.

Baseline value is levodopa concentration at 9 AM. AUC is calculated as levodopa concentrations minus 9 AM value at 30 minute intervals until 2 PM.

Outcome measures

Outcome measures
Measure
Low-dose Carbidopa (75 mg/Day) Day 1
n=11 Participants
Day 1 of levodopa infusions following 4 weeks of low-dose carbidopa (75 mg/day). Carbidopa 25 mg administered at 8 AM, 10 AM and 12 PM for day 1 infusion.
Low-dose Carbidopa (75 mg/Day) Day 2
n=11 Participants
Day 2 of levodopa infusions following 4 weeks of low-dose carbidopa (75 mg/day). Carbidopa 25 mg administered at 8 AM, 10 AM, and 12 PM for day 2 infusion.
High-dose Carbidopa (450 mg/Day) Day 1
n=11 Participants
Day 1 of levodopa infusions following 4 weeks of high-dose carbidopa (450 mg/day). Carbidopa 25 mg administered at 8 AM 10 AM and 12 PM for day 1 infusion.
High-dose Carbidopa (450 mg/Day) Day 2
n=11 Participants
Day 2 of levodopa infusions following 4 weeks of high-dose carbidopa (450 mg/day). Carbidopa 150 mg administered at 8 AM, 10 AM and 12 PM for day 2 levodopa infusion.
AUC of Levodopa Plasma Concentrations Above Baseline
5.38 (µg/ml)*(hours)
Standard Deviation 1.38
5.91 (µg/ml)*(hours)
Standard Deviation 1.64
5.23 (µg/ml)*(hours)
Standard Deviation 1.23
6.13 (µg/ml)*(hours)
Standard Deviation 1.45

Adverse Events

Low-dose Carbidopa (75 mg/Day)

Serious events: 0 serious events
Other events: 11 other events
Deaths: 0 deaths

High-dose Carbidopa (450 mg/Day)

Serious events: 0 serious events
Other events: 9 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Low-dose Carbidopa (75 mg/Day)
n=12 participants at risk
Due to the cross-over study design all 12 participants who completed the study are included in both the high-dose and low-dose treatment arms.
High-dose Carbidopa (450 mg/Day)
n=13 participants at risk
Due to the cross-over study design all 12 participants who completed the study are included in both the high-dose and low-dose treatment arms. In addition, the subject who initiated treatment but did not complete the study is included in this arm for the purpose of reporting adverse events.
Musculoskeletal and connective tissue disorders
Back pain
16.7%
2/12 • Number of events 2
0.00%
0/13
General disorders
Body aches
0.00%
0/12
7.7%
1/13 • Number of events 1
Ear and labyrinth disorders
Difficulty swallowing study drug
16.7%
2/12 • Number of events 2
0.00%
0/13
Respiratory, thoracic and mediastinal disorders
Dyspnea
0.00%
0/12
7.7%
1/13 • Number of events 1
General disorders
Falls
8.3%
1/12 • Number of events 1
0.00%
0/13
Gastrointestinal disorders
GERD
25.0%
3/12 • Number of events 3
0.00%
0/12
Nervous system disorders
Headache
0.00%
0/12
7.7%
1/13 • Number of events 1
Nervous system disorders
Increased dyskinesia
8.3%
1/12 • Number of events 1
38.5%
5/13 • Number of events 5
Psychiatric disorders
Mania/anxiety
0.00%
0/12
7.7%
1/13 • Number of events 1
Nervous system disorders
More off time/tremor
83.3%
10/12 • Number of events 10
38.5%
5/13 • Number of events 5
Cardiac disorders
Orthostasis
8.3%
1/12 • Number of events 1
0.00%
0/13
Nervous system disorders
Sciatica
16.7%
2/12 • Number of events 2
0.00%
0/13
Respiratory, thoracic and mediastinal disorders
Upper Respiratory Infection
8.3%
1/12 • Number of events 1
0.00%
0/13
Ear and labyrinth disorders
Voice fading
8.3%
1/12 • Number of events 1
0.00%
0/13

Additional Information

John G. Nutt, MD

Oregon Health and Science University

Phone: 503-494-9054

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place