- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT03451500
Carbidopa-Levodopa in Dry AMD With Geographic Atrophy
Carbidopa-Levodopa in Dry Age Related Macular Degeneration With Geographic Atrophy
From 3 large patient databases, patients diagnosed with AMD who have never taken levodopa(L-DOPA) containing medications have a mean age of diagnosis at 71 years.
Patients who have been treated with L-DOPA containing medications have a mean age of diagnosis of AMD at 79 years. L-DOPA binds to GPR143 in the retinal pigment epithelium, and releases PEDF, which protects the retina and downregulates VEGF, which is the cause of neovascularization.
The Investigators will evaluate the safety and tolerability of carbidopa-levodopa in patients with Neovascular AMD, and measure the effects on visual acuity and retinal abnormalities due to "wet" (neovascular) AMD. The Investigators will evaluate the safety and tolerability of carbidopa-levodopa in patients with Dry AMD and Geographic Atrophy, and measure the effects on visual acuity, area of geographic atrophy and other retinal abnormalities due to "dry" AMD.
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
Age-related macular degeneration (AMD) is the most common cause of blindness, in individuals over the age of 50, in the developed world. AMD becomes more common as people age, and is more common in lightly pigmented individuals. AMD appears more common in patients with Parkinson's Disease, than in those without. The AREDS nutritional supplements are effective in slowing the progress of intermediate AMD(5).
Most AMD is "dry AMD", which progresses relatively slowly and may impair vision, but usually does not lead to legal blindness. There are two forms of AMD, "wet AMD" and geographic atrophy (GA), that can cause more profound vision loss. In aggregate they occur in about 25% patients with AMD. Wet AMD is due to new growth of abnormal blood vessels under the retina. The new blood vessels are believed to be due to an excessive release of vascular endothelial growth factor (VEGF) by the retinal pigment epithelium(RPE) cells. Wet AMD is now effectively treated with intraocular injections of VEGF inhibitors. Geographic Atrophy, the other form of advanced AMD, represents focal death of the RPE cells and overlying neurosensory retina. There is no current treatment for GA. It is suspected that GA is due in part to a localized inflammatory response, damage to RPE cells and loss of RPE cell function. It may also be speculated that stimulation of RPE cells to release a potent neurotrophic factor, pigment epithelium derived factor (PEDF) may slow progression of GA. In 2008, Dr. Brian McKay identified a receptor, G protein coupled receptor
#143(GPR143), on the surface of RPE cells and discovered that L-DOPA was the natural ligand or stimulator of GPR143. Dr McKay showed that treatment of RPE cells with exogenous L-DOPA resulted in the release of additional PEDF. In subsequent work Dr McKay's group also showed that L-DOPA stimulation of PEDF in RPE cells was also associated with a decrease in VEGF. Thus, Dr McKay hypothesized that exogenous LDOPA may prevent the onset of AMD or progression to wet AMD.
In 2015, Dr McKay and his associates published a paper that showed that patients, who had been treated with L-DOPA, had a delay in the onset of AMD by 8 years, compared to patients who had not been treated with L-DOPA. In addition, those who had AMD and went on to develop wet AMD, did so 5 years later than those with no history of L-DOPA treatment. L-DOPA is an intermediate in the pigmentation pathway. Dr McKay and his associates suggested that the reason darkly pigmented races do not get AMD nearly as frequently as lighter pigmented races, is that they produce more pigment, and thus more L-DOPA to stimulate GPR143 on RPE cells. According to this hypothesis, the stimulated RPE cells release PEDF and decrease VEGF, which together are responsible for the protective effect.
Pharmacology of L-DOPA and carbidopa:
L-DOPA is formed by 3-hydroxylation of tyrosine by tyrosine-3-monooxygenase (tyrosinase).(18) The primary metabolic pathway of L-DOPA is decarboxylation by amino acid decarboxylase to dopamine, which is responsible for most, but not all, of its pharmacologic effects and toxicity. When carbidopa is administered with LDOPA, systemic levels of L-DOPA double and central nervous system (CNS) L-DOPA increases from about 1% of the administered dose to about 4%. Levodopa freely passes from the systemic circulation into the retina and brain, but dopamine and carbidopa do not. Adverse events are markedly decreased when carbidopa is administered with L-DOPA, because systemic levels of the toxic metabolite of L-DOPA, dopamine, are markedly reduced. In most patients, 25 mg of carbidopa is sufficient to control side effects of 100 mg of L-DOPA, primarily nausea, by 90%. L-DOPA is the natural ligand for GPR143 in the RPE cells. The Investigators' intent is to increase the L-DOPA available to RPE surface receptors (GPR 143) while minimizing peripheral toxicity. This concept is unique, because all other uses of L-DOPA rely on CNS conversion of L-DOPA to dopamine, in order to produce the desired effect.
Since there are no established animal models for AMD, and L-DOPA has a good safety profile in healthy volunteers and patients with Parkinson's disease, the Investigators propose a prospective experiment to determine the safety and tolerability of L-DOPA, in a population of patients with AMD. The participants will be made aware of potential side effects of L-DOPA, which are listed in the Informed Consent, during the consent process. Adverse events will be elicited by questioning the participants at each visit.
The participants will also be advised to call the site, if they have any medical problem between visits.
The Investigators will also use this study to examine whether L-DOPA has a positive effect on visual acuity and pathologic retinal changes of "dry" AMD with geographic atrophy.
The parameters to be evaluated are best corrected ETDRS visual acuity, area of geographic atrophy by Fundus AutoFluorescence (FAF), macular thickness by spectral domain optical coherence tomography (SD OCT), new blood (hemorrhage) by direct retinal examination, and subjective decrease in vision.
Treatments:
Study participants will receive randomly assigned, single blind, commercially available carbidopa-levodopa 25-100 mg, two tablets once daily hs, or two tablets dosed TID (three times daily), in the morning, with supper and hs for one month, or placebo two tablets dosed three times daily, in the morning, with supper and hs (200-600 mg of levodopa daily). This is the equivalent of low to moderate doses of carbidopa-levodopa in patients with Parkinson's disease (daily dose of levodopa 200-800 mg). If a study participant experiences non-serious, but bothersome adverse effects while taking the study medication, the dose may be reduced to 1 tablet hs, or 1 tablet TID.
Number of subjects: 154 randomized.
Duration: 12 months of treatment, with visits at Baseline, 1 week, 1 month, 3 months, 6 months, 9 months and 12 months.
Primary Endpoint: A statistically significant difference in progression of area of geographic atrophy with carbidopa-levodopa treatment compared to treatment with placebo.
Measurements and Activities:
- Informed Consent at Baseline;
- Ophthalmic history and comprehensive eye examination; including visual acuity, with best optical correction, using an EDTRS chart, in both eyes prior to randomization, ophthalmoscopic examination, a subjective vision questionnaire and SD OCT with FAF;
- Repeat assessment of visual acuity using an EDTRS chart, subjective vision questionnaire, ophthalmoscopic examination, and SD OCT at 1, 3, 6 9, and 12 month visits;
- Demographics at Baseline;
- Medical History, Vital Signs and Physical Examination at Baseline;
- ECG, CBC, Chem 20 and HbA1C at Baseline;
- Dispense study medication at visits 2, 3, 4, 5, 6 and 7;
- Pill count at visits 3, 4, 5, 6 and 7;
- Non-directed assessment of adverse events at each visit, including classification as to severity, seriousness and body system.
- Concomitant medications at each visit.
Statistics: Statistics will be generated for, at a minimum, , area of geographic atrophty, ETDRS visual acuity, central retinal thickness and presence of hemorrhage. Within patient trajectories for these outcomes will be plotted, incorporating information on dose and duration. Analysis of Variance may be conducted to relate logarithm of dose and duration of treatment to the outcomes listed above.
Study Type
Enrollment (Actual)
Phase
- Phase 2
Contacts and Locations
Study Locations
-
-
Arizona
-
Tucson, Arizona, United States, 85712
- Robert W Snyder, MD, PhD, PC
-
-
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- A diagnosis of dry AMD with geographic atrophy in one or both eyes. In patients with geographic atrophy in both eyes, the eye with the larger area of geographic atrophy will be designated eye A and the eye with the smaller area of geographic atrophy will be designated eye B.
- Normal or dry AMD of any grade in the second eye;
- Age 50-85 years;
- Willingness to maintain AREDS vitamin supplements throughout the study, or remain off these supplements for the duration of the study, if not taking them prior to the study;
- Signed Informed Consent.
Exclusion criteria:
- Any previous or current use of L-DOPA containing medication or dopamine agonist medication, or any planned use of any of these agents, except for study medication, during the study;
- Concurrent use of monoamine oxidase (MAO) inhibitors;
- Any eye condition, disease, or history of trauma in either eye, which can impair vision, except cataract or cataract surgery;
- BCVA worse than 20/100 in the eye with better BCVA;
- Current, or history of, neovascular AMD in either eye;
- Neurologic conditions which can impair vision;
- Parkinson's Disease;
- Significant orthostatic hypotension, defined as a drop in systolic blood pressure, immediately upon changing from the supine to standing position, of >19 mmHg, or a symptomatic drop in systolic blood pressure, immediately upon changing from the supine to standing position;
- Significant ECG abnormalities, as judged by the Investigator;
- Estimated glomerular filtration rate (eGFR) <20 ml/min;
- Liver enzymes >3 X the upper limit of normal;
- HbA1C >9.0;
- Any other significant lab abnormalities, as judged by the Investigator.
- Women of childbearing potential;
- Known retinal hemorrhage;
- Subjects who are not fluent in English.
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Triple
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Experimental: Carbidopa-levodopa 2 tablets daily
carbidopa-levodopa 25-100 mg 2 tablets daily hs
|
See previous
|
Experimental: carbidopa-levodopa 6 tablets daily
carbidopa-levodopa 25-100 mg, 2 tablets, 3 times daily, with breakfast, with supper and hs
|
See previous
|
Placebo Comparator: Placebo
Placebo, 2 tablets, 3 times daily, with breakfast, with supper and hs
|
See previous
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Area of Geographic Atrophy
Time Frame: Change over 12 months
|
area of retinal geographic atrophy measured by fundus autofluorescence
|
Change over 12 months
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Best Corrected Visual Acuity by ETDRS
Time Frame: Change over 12 months
|
Best Corrected Visual Acuity by ETDRS
|
Change over 12 months
|
Central retinal thickness
Time Frame: Change over 12 months
|
Central Retinal Thickness, measured by SD-OCT
|
Change over 12 months
|
Development of neovascular macular degeneration
Time Frame: New diagnosis during 12 months of treatment
|
New diagnosis of neovascular macular degeneration
|
New diagnosis during 12 months of treatment
|
Collaborators and Investigators
Investigators
- Study Director: Timothy C Fagan, MD, Robert Snyder, MD, PhD, PC
- Principal Investigator: Robert W Snyder, MD, PhD, Robert Snyder, MD, PhD, PC
Study record dates
Study Major Dates
Study Start (Actual)
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Estimated)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
- Eye Diseases
- Retinal Degeneration
- Retinal Diseases
- Pathological Conditions, Anatomical
- Macular Degeneration
- Geographic Atrophy
- Atrophy
- Physiological Effects of Drugs
- Neurotransmitter Agents
- Molecular Mechanisms of Pharmacological Action
- Enzyme Inhibitors
- Immunologic Factors
- Dopamine Agonists
- Dopamine Agents
- Adjuvants, Immunologic
- Antiparkinson Agents
- Anti-Dyskinesia Agents
- Aromatic Amino Acid Decarboxylase Inhibitors
- Levodopa
- Carbidopa
- Carbidopa, levodopa drug combination
Other Study ID Numbers
- 0004
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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