Trial Outcomes & Findings for Dose Ranging Study of Carbidopa-levodopa (NCT NCT03023059)

Results Overview

This outcome is a measure of letters correctly identified using an Early Treatment Diabetic Retinopathy Study chart. The higher the number of letters identified, the better the participant's visual acuity.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

35 participants

Primary outcome timeframe

From the start of the study to the end (up to 120 days).

Results posted on

2025-09-12

Participant Flow

Participant milestones

Participant milestones
Measure	Escalating Dose of Carbidopa-levodopa The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Overall Study STARTED	35
Overall Study COMPLETED	30
Overall Study NOT COMPLETED	5

Reasons for withdrawal

Reasons for withdrawal
Measure	Escalating Dose of Carbidopa-levodopa The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Overall Study Withdrawal by Subject	5

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Escalating Dose of Carbidopa-levodopa n=30 Participants The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily at bedtime for one month, followed by one tablet dosed three times daily, in the morning, with supper and at bedtime for one month, followed by two tablets dosed three times daily, in the morning, with supper and bedtime for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Age, Categorical <=18 years	0 Participants n=30 Participants
Age, Categorical Between 18 and 65 years	2 Participants n=30 Participants
Age, Categorical >=65 years	28 Participants n=30 Participants
Age, Continuous	75.1 years n=30 Participants
Sex: Female, Male Female	16 Participants n=30 Participants
Sex: Female, Male Male	14 Participants n=30 Participants
Region of Enrollment United States	30 participants n=30 Participants
Patients naive to anti-VEGF injections at start of study	17 Participants n=30 Participants

PRIMARY outcome

Timeframe: From the start of the study to the end (up to 120 days).

Population: This population includes participants who completed NCT03022318 (naive to anti-VEGF injections at the time of enrollment) and patients who did not complete NCT03022318 but had been exposed to anti-VEGF injections before study initiation.

This outcome is a measure of letters correctly identified using an Early Treatment Diabetic Retinopathy Study chart. The higher the number of letters identified, the better the participant's visual acuity.

Outcome measures

Outcome measures
Measure	Escalating Dose of Carbidopa-levodopa n=30 Participants The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Change in Best Corrected Visual Acuity by Early Treatment Diabetic Retinopathy Study Chart Visual Scale Testing	4.5 Change in letters (BCVA) Standard Error 1.4

SECONDARY outcome

Timeframe: From the start of the study to the end (up to 120 days).

Population: This population includes participants who completed NCT03022318 (naive to anti-VEGF injections at the time of enrollment) and patients who did not complete NCT03022318 but had been exposed to anti-VEGF injections before study initiation.

Central retinal thickness (in microns) is measured by spectral domain-optical coherence tomography. An increase in retinal thickness is associated with disease progression. A negative value represents a decrease in retinal thickness and therefore a positive clinical outcome measure.

Outcome measures

Outcome measures
Measure	Escalating Dose of Carbidopa-levodopa n=30 Participants The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Change in Central Retinal (Macular) Thickness	-15.0 microns Standard Error 9.8

SECONDARY outcome

Timeframe: From the start of the study to the commonly used timeframe of 6 months (~192 days), given that fluid was assessed at 6 months from baseline as commonly evaluated in studies involving AMD.

Population: This population includes participants who completed NCT03022318 (naive to anti-VEGF injections at the time of enrollment) and patients who did not complete NCT03022318 but had been exposed to anti-VEGF injections before study initiation.

Retinal fluid changes on direct retinal examination on spectral domain - optical coherence tomography. Changes in retinal fluid were compared to baseline values. A negative percentage point represents a decrease in retinal fluid and therefore a positive clinical outcome.

Outcome measures

Outcome measures
Measure	Escalating Dose of Carbidopa-levodopa n=30 Participants The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Percent Change in Retinal Fluid From Baseline	11.2 percent change Standard Error 30.6

SECONDARY outcome

Timeframe: From the start of the study to the commonly used timeframe of 6 months (~192 days), given that fluid was assessed at 6 months, we opted to include the evaluation of adverse events within the six months.

Population: This population includes participants who completed NCT03022318 (naive to anti-VEGF injections at the time of enrollment) and patients who did not complete NCT03022318 but had been exposed to anti-VEGF injections before study initiation.

Vital signs, eye examinations and nondirected subjective adverse events (gastrointestinal distress, muscle spasms, headache, nightmares)

Outcome measures

Outcome measures
Measure	Escalating Dose of Carbidopa-levodopa n=30 Participants The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
Treatment Emergent Adverse Events	9 Participants

Adverse Events

Escalating Dose of Carbidopa-levodopa

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	Escalating Dose of Carbidopa-levodopa n=30 participants at risk The intervention is that patients will receive open label, commercially available Carbidopa-Levodopa 25 Mg-100 Mg oral tablet, once daily hs for one month, followed by one tablet dosed three times daily, in the morning, with supper and hs for one month, followed by two tablets dosed three times daily, in the morning, with supper and hs for one month (100-600 mg of levodopa daily). This is the equivalent of very low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). Carbidopa-Levodopa, 25 Mg-100 Mg Oral Tablet: See Arm description
General disorders Mild malaise/nausea	16.7% 5/30 • 6 months
Musculoskeletal and connective tissue disorders Mild-to-moderate back muscle spasms	3.3% 1/30 • 6 months
Gastrointestinal disorders Abdominal pain and gas	6.7% 2/30 • 6 months
Nervous system disorders Nightmares and mild headache	3.3% 1/30 • 6 months

Additional Information

Dr. Robert W. Snyder

Robert W Snyder, MD, PhD, PC

Phone: 5206616516

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place