Trial Outcomes & Findings for Does N-Acetylcysteine Decrease Spontaneous Oxidation of Central Neural Dopamine in Parkinson's Disease? (NCT NCT03104725)

NCT ID: NCT03104725

Last Updated: 2021-11-04

Results Overview

Patients with Parkinson's Disease (PD) who took N-acetylcysteine (NAC), and healthy volunteers who did not take NAC, each had two separate lumbar punctures (LP 1 and LP 2) to obtain spinal fluid. The spinal fluid samples were used to measure the amount of a brain chemical called 5-S-cysteinyl-dopamine (Cys-DA). The primary outcome measure is the mean change in CSF Cys-DA levels between pre and post-NAC treatment, which is calculated as the difference of CSF Cys-DA levels at pre-treatment (LP 1) and post-treatment (LP 2) divided by CSF Cys-DA at pre-treatment (LP 1). A greater percent decrease in Cys-DA levels in the brain would suggest that NAC may contribute to a reduction in the oxidation of brain dopamine, while a smaller percent decrease would suggest that NAC had no effect on the oxidation of brain dopamine.

Recruitment status

TERMINATED

Study phase

PHASE1

Target enrollment

6 participants

Primary outcome timeframe

All participants underwent a baseline LP. For PD participants, the second LP occurred approximately 2 hours after the participant had taken NAC the last NAC dose. For HV participants the second LP takes place approximately 48 hours after the first LP.

Results posted on

2021-11-04

Participant Flow

Participants with Parkinson's disease were recruited from the NINDS Parkinsons Clinic and the Patient Recruitment and Public Liaison Office (PRPL). Healthy participants were recruited from the PRPL.

All participants were screened for eligibility. Eligible participants with PD underwent a baseline LP (LP 1), followed by administration of NAC, followed by post-treatment LP (LP 2). Healthy Volunteer participants underwent a baseline LP (LP 1) and follow-up LP (LP 2) 48 hours after the baseline LP.

Participant milestones

Participant milestones
Measure
Healthy Volunteers (HVs)
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
Overall Study
STARTED
2
4
Overall Study
COMPLETED
2
4
Overall Study
NOT COMPLETED
0
0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Does N-Acetylcysteine Decrease Spontaneous Oxidation of Central Neural Dopamine in Parkinson's Disease?

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Healthy Volunteers
n=2 Participants
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
n=4 Participants
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
Total
n=6 Participants
Total of all reporting groups
Age, Categorical
<=18 years
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Age, Categorical
Between 18 and 65 years
2 Participants
n=93 Participants
2 Participants
n=4 Participants
4 Participants
n=27 Participants
Age, Categorical
>=65 years
0 Participants
n=93 Participants
2 Participants
n=4 Participants
2 Participants
n=27 Participants
Age, Continuous
47.5 Years
STANDARD_DEVIATION 11.7 • n=93 Participants
65.6 Years
STANDARD_DEVIATION 9.7 • n=4 Participants
59.5 Years
STANDARD_DEVIATION 11.9 • n=27 Participants
Sex: Female, Male
Female
1 Participants
n=93 Participants
2 Participants
n=4 Participants
3 Participants
n=27 Participants
Sex: Female, Male
Male
1 Participants
n=93 Participants
2 Participants
n=4 Participants
3 Participants
n=27 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
2 Participants
n=93 Participants
3 Participants
n=4 Participants
5 Participants
n=27 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=93 Participants
1 Participants
n=4 Participants
1 Participants
n=27 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Race (NIH/OMB)
Asian
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Race (NIH/OMB)
Black or African American
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Race (NIH/OMB)
White
2 Participants
n=93 Participants
3 Participants
n=4 Participants
5 Participants
n=27 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=93 Participants
0 Participants
n=4 Participants
0 Participants
n=27 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=93 Participants
1 Participants
n=4 Participants
1 Participants
n=27 Participants

PRIMARY outcome

Timeframe: All participants underwent a baseline LP. For PD participants, the second LP occurred approximately 2 hours after the participant had taken NAC the last NAC dose. For HV participants the second LP takes place approximately 48 hours after the first LP.

Patients with Parkinson's Disease (PD) who took N-acetylcysteine (NAC), and healthy volunteers who did not take NAC, each had two separate lumbar punctures (LP 1 and LP 2) to obtain spinal fluid. The spinal fluid samples were used to measure the amount of a brain chemical called 5-S-cysteinyl-dopamine (Cys-DA). The primary outcome measure is the mean change in CSF Cys-DA levels between pre and post-NAC treatment, which is calculated as the difference of CSF Cys-DA levels at pre-treatment (LP 1) and post-treatment (LP 2) divided by CSF Cys-DA at pre-treatment (LP 1). A greater percent decrease in Cys-DA levels in the brain would suggest that NAC may contribute to a reduction in the oxidation of brain dopamine, while a smaller percent decrease would suggest that NAC had no effect on the oxidation of brain dopamine.

Outcome measures

Outcome measures
Measure
Healthy Volunteers (HVs)
n=2 Participants
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
n=4 Participants
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
The Mean Percent Change in Cerebrospinal Fluid (CSF) Concentration of 5-S-cysteinyl-dopamine (Cys-DA) Pre and Post-N-acetylcysteine (NAC) Treatment
45.7 percent change
Standard Error 28.1
20.1 percent change
Standard Error 14.2

SECONDARY outcome

Timeframe: All participants underwent a baseline LP. For PD participants, the second LP occurred approximately 2 hours after the participant had taken NAC the last NAC dose. For HV participants the second LP takes place approximately 48 hours after the first LP.

Patients with Parkinson's Disease (PD) who took N-acetylcysteine (NAC), and healthy volunteers who did not take NAC, each had two separate lumbar punctures (LPs) to obtain spinal fluid. The spinal fluid samples were used to measure the ratio of the brain chemical called 5-S-cysteinyl-dopamine (Cys-DA) to the brain chemical called 3,4-Dihydroxyphenylacetic acid (Cys-DOPAC). Dopamine has 2 possible metabolic fates or processes of degradation. One fate is the breakdown of Dopamine by an enzyme to form DOPAC. The other fate is spontaneous oxidation to form Cys-DA. The ratio of Cys-DA to DOPAC may reflect these relative fates. If NAC reduced spontaneous oxidation to Cys-DA, then the ratio Cys-DA/DOPAC ratio would decrease between LP 1 and LP 2.

Outcome measures

Outcome measures
Measure
Healthy Volunteers (HVs)
n=2 Participants
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
n=4 Participants
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
Mean Ratio of Cys-DA/DOPAC Pre and Post-treatment Lumbar Puncture With and Without N-acetylcysteine (NAC)
Cys-DA/DOPAC LP1
0.12 ratio
Standard Error 0.05
0.16 ratio
Standard Error 0.10
Mean Ratio of Cys-DA/DOPAC Pre and Post-treatment Lumbar Puncture With and Without N-acetylcysteine (NAC)
Cys-DA/DOPAC LP2
0.05 ratio
Standard Error 0.01
0.13 ratio
Standard Error 0.08

SECONDARY outcome

Timeframe: All participants underwent a baseline LP. For PD participants, the second LP occurred approximately 2 hours after the participant had taken NAC the last NAC dose. For HV participants the second LP takes place approximately 48 hours after the first LP.

Patients with Parkinson's Disease (PD) who took N-acetylcysteine (NAC), and healthy volunteers who did not take NAC, each had two separate lumbar punctures (LPs) to obtain spinal fluid. The spinal fluid samples were used to measure the ratio of the brain chemical called 5-S-cysteinyl-dopamine (Cys-DA) to the brain chemical called 3,4-Dihydroxyphenylacetic acid (Cys-DOPAC). Dopamine has 2 metabolic fates. One is the breakdown of dopamine by an enzyme to form DOPAC. The other is spontaneous oxidation to form Cys-DA. The ratio of Cys-DA/DOPAC may reflect these relative fates. If NAC reduced spontaneous oxidation to Cys-DA, then the ratio Cys-DA/DOPAC would decrease between LP 1 and LP 2, which would be reflected as a percent decrease.

Outcome measures

Outcome measures
Measure
Healthy Volunteers (HVs)
n=2 Participants
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
n=4 Participants
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
Mean Percent Change in Cys-DA/DOPAC Between Pre and Post-treatment Lumbar Puncture With and Without N-acetylcysteine (NAC)
50.1 percent change
Standard Error 16.2
27.2 percent change
Standard Error 5.0

Adverse Events

Healthy Volunteers (HVs)

Serious events: 0 serious events
Other events: 2 other events
Deaths: 0 deaths

Parkinson's Disease (PD) Patients

Serious events: 0 serious events
Other events: 1 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Healthy Volunteers (HVs)
n=2 participants at risk
HV participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed within 48 hours of LP 1. No NAC treatment is administered.
Parkinson's Disease (PD) Patients
n=4 participants at risk
PD participants undergo a baseline lumbar puncture (LP 1) as an inpatient at the NIH Clinical Center to obtain cerebrospinal fluid (CSF) for assays of Cys-DA, 3,4- dihydroxyphenylacetic acid (DOPAC), and related biochemicals. The second LP (LP 2) is completed after the patient has taken at least 5 doses of N-Acetylcysteine (NAC) (2 grams orally twice per day).
General disorders
Puncture site pain
100.0%
2/2 • Number of events 2 • Duration of participation in study and up to 8 days following the second LP
0.00%
0/4 • Duration of participation in study and up to 8 days following the second LP
Musculoskeletal and connective tissue disorders
Myalgia
50.0%
1/2 • Number of events 1 • Duration of participation in study and up to 8 days following the second LP
0.00%
0/4 • Duration of participation in study and up to 8 days following the second LP
Nervous system disorders
Headache
0.00%
0/2 • Duration of participation in study and up to 8 days following the second LP
25.0%
1/4 • Number of events 1 • Duration of participation in study and up to 8 days following the second LP
Nervous system disorders
Paresthesia
50.0%
1/2 • Number of events 1 • Duration of participation in study and up to 8 days following the second LP
0.00%
0/4 • Duration of participation in study and up to 8 days following the second LP

Additional Information

Dr. David Goldstein

National Institutes of Health/NINDS

Phone: 301-496-2103

Results disclosure agreements

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