NCT07444892

Brief Summary

The purpose of this study is to determine optimum dosing strategies of levodopa and determine the physiologic mechanisms that provide the therapeutic response to restore abnormalities in the electrical conductivity of the retina in people with diabetes and no clinically visible retinopathy.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
230

participants targeted

Target at P75+ for phase_2

Timeline
Completed

Started Apr 2022

Typical duration for phase_2

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

April 18, 2022

Completed
3.6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

November 17, 2025

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

November 17, 2025

Completed
3 months until next milestone

First Submitted

Initial submission to the registry

February 25, 2026

Completed
6 days until next milestone

First Posted

Study publicly available on registry

March 3, 2026

Completed
Last Updated

March 3, 2026

Status Verified

February 1, 2026

Enrollment Period

3.6 years

First QC Date

February 25, 2026

Last Update Submit

February 25, 2026

Conditions

Diabetic Retinopathy

Keywords

ElectroretinographyOptical coherence tomography

Outcome Measures

Primary Outcomes (1)

  • ERG with dim flash stimuli

    Full-field electroretinography (ERG) will be performed to assess rod-mediated retinal function. A skin electrode placed below the eye records the response to flash stimuli. Participants will be dark-adapted for 10 minutes to sensitive retinal rod pathways. Flash stimuli will consist of dim (1.13 Td) or bright (85 Td) flashes to reveal early dysfunction in DR.

    Baseline, 3 and 6 months post-intervention

Secondary Outcomes (2)

  • Optical coherence tomography (OCT)

    Baseline, 3 and 6 months post-intervention

  • Optical coherence tomography (OCT-A)

    Baseline, 3 and 6 months post-intervention

Study Arms (4)

Placebo

ACTIVE COMPARATOR

Diabetic participants will be instructed to take the oral placebo daily with a meal for 6 months.

Drug: Placebo

Levodopa every other day

EXPERIMENTAL

Diabetic participants will be instructed to take the levodopa every other day with a meal for 6 months.

Drug: Levodopa

Levodopa once per day

EXPERIMENTAL

Diabetic participants will be instructed to take the oral levodopa daily with a meal for 6 months..

Drug: Levodopa

Levodopa twice per day

EXPERIMENTAL

Diabetic participants in the twice per day group will be instructed to take the drug 12 hours apart every day for 6 months.

Drug: Levodopa

Interventions

LevodopaDRUG

Patients will receive tablets of generic 25 mg carbidopa/100 mg levodopa as the drug treatment.

Levodopa every other dayLevodopa once per dayLevodopa twice per day
PlaceboDRUG

Patients will receive matching placebo tablets as the drug treatment.

Placebo

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Adults
  • diagnosed with diabetes mellitus

You may not qualify if:

  • taking dopamine effecting drugs
  • have a pituitary tumor
  • psychosis, Parkinson's disease
  • cognitive deficits
  • confounding ocular disease
  • Control Participants:
  • Non-diabetic participants with no visual problems to create control measurements.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Atlanta VA Medical Center

Decatur, Georgia, 30033, United States

Location

MeSH Terms

Conditions

Diabetic Retinopathy

Interventions

Levodopa

Condition Hierarchy (Ancestors)

Retinal DiseasesEye DiseasesDiabetic AngiopathiesVascular DiseasesCardiovascular DiseasesDiabetes ComplicationsDiabetes MellitusEndocrine System Diseases

Intervention Hierarchy (Ancestors)

DihydroxyphenylalanineCatecholaminesAminesOrganic ChemicalsCatecholsPhenolsBenzene DerivativesHydrocarbons, AromaticHydrocarbons, CyclicHydrocarbonsPhenylalanineAmino Acids, AromaticAmino Acids, CyclicAmino AcidsAmino Acids, Peptides, and ProteinsTyrosine

Study Officials

  • Andrew Hendrick, MD

    Emory University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
phase 2
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, INVESTIGATOR
Masking Details
Masking will be applied to diabetic participants.
Purpose
PREVENTION
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Associate Professor

Study Record Dates

First Submitted

February 25, 2026

First Posted

March 3, 2026

Study Start

April 18, 2022

Primary Completion

November 17, 2025

Study Completion

November 17, 2025

Last Updated

March 3, 2026

Record last verified: 2026-02

Data Sharing

IPD Sharing
Will not share

Locations

US(1)