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The Dark-Adapted Retinal Function Response in Choroideremia (DARC) Study (DARC)

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ClinicalTrials.gov Identifier: NCT05045703
Recruitment Status : Not yet recruiting
First Posted : September 16, 2021
Last Update Posted : September 13, 2022
Sponsor:
Collaborator:
Foundation Fighting Blindness
Information provided by (Responsible Party):
Duke University

Brief Summary:
Choroideremia (CHM) is an inherited retinal disorder that causes progressive vision loss, ultimately leading to complete blindness. The first symptom is generally night blindness, although, to date, little is known about the extent, type, pattern, and progression of dark-adapted visual function measures in CHM patients. We hypothesize that one of the key events causing night blindness in CHM is deficiency in the chromophore of the rod visual pigment, rhodopsin. We propose that this deficiency is at least in part due to inadequate delivery of vitamin A (all-trans-retinol) to the photoreceptors (PRs) from the ailing retinal pigment epithelium (RPE), characteristic of CHM. We hypothesize that increased availability of vitamin A would potentiate its entry into the RPE-mediated visual cycle, ultimately enabling delivery to the PRs. This would in turn allow rods to perform better by partially overcoming the RPE damage and the impaired chromophore recycling that we postulate exists in CHM. The goals of this proposal are: (1) to test the hypothesis that oral vitamin A supplementation can improve night time and peripheral vision in CHM patients, and (2) to provide detailed characterization of dark-adapted visual function outcome measures to guide interventional CHM trials.

Condition or disease Intervention/treatment Phase
Choroideremia Dietary Supplement: Vitamin A palmitate Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 10 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Characterization of Night Vision Impairment in Choroideremia and Short-Term Vitamin A Supplementation: The Dark-Adapted Retinal Function Response in Choroideremia (DARC) Study
Estimated Study Start Date : October 2022
Estimated Primary Completion Date : March 2023
Estimated Study Completion Date : May 2023


Arm Intervention/treatment
Experimental: Vitamin A palmitate
Vitamin A palmitate, 15,000 IU daily for 4 months
Dietary Supplement: Vitamin A palmitate
Vitamin A palmitate, 15,000 IU daily for 4 months




Primary Outcome Measures :
  1. Change in dark-adapted full-field visual field sensitivity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Dark-adapted full-field visual field sensitivity will be measured using the Medmont dark-adapted chromatic perimeter.

  2. Change in dark-adapted macular visual field sensitivity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Dark-adapted macular visual field sensitivity will be measured using the Medmont dark-adapted chromatic perimeter.

  3. Change in dark adaptometry [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Dark adaptometry will be measured using the MacuLogix AdaptDx dark adaptometer.


Secondary Outcome Measures :
  1. Change in best corrected visual acuity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Best corrected visual acuity will be measured using the ETDRS chart

  2. Change in low luminance visual acuity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Low luminance visual acuity will be measured using the ETDRS chart in low luminance conditions

  3. Change in full-field light-adapted visual field sensitivity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Light-adapted full-field visual field sensitivity will be measured using the Octopus 172-point GATE full-field semi-automated kinetic perimetry (SKP)

  4. Change in light-adapted macular visual field sensitivity [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Light-adapted macular visual field sensitivity will be measured using the Centervue MAIA confocal macular microperimeter

  5. Change in retinal pigmented epithelium (RPE) atrophy by optical coherence tomography [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Retinal pigmented epithelium (RPE) atrophy will be measured using the Spectralis macular spectral domain optical coherence tomography (SD-OCT) with and without enhanced depth imaging (EDI)

  6. Change in retinal pigmented epithelium (RPE) atrophy by color photography [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Retinal pigmented epithelium (RPE) atrophy will be measured using the Optos wide-field color fundus photography (WF-CFP)

  7. Change in retinal pigmented epithelium (RPE) atrophy by fundus autofluorescence [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Retinal pigmented epithelium (RPE) atrophy will be measured using the Optos wide-field fundus auto-fluorescence (WF-FAF)

  8. Change in retinal pigmented epithelium (RPE) atrophy by fundoscopy [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Retinal pigmented epithelium (RPE) atrophy will be assessed by slit lamp biomicroscopy

  9. Change in liver function [ Time Frame: Measurements at 0, 4, and 8 months ]
    Liver function profile will be measured by laboratory using participant serum samples

  10. Change in serum vitamin A levels [ Time Frame: Measurements at 0, 4, and 8 months. The 0 months measurement will serve as the baseline. The 4 month measurement will assess change due to vitamin A supplementation. The 8 month measurement will assess reversal of this change following washout period ]
    Serum vitamin A levels will be measured by laboratory using participant serum samples



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Ages Eligible for Study:   15 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   Male
Gender Based Eligibility:   Yes
Gender Eligibility Description:   Choroideremia is an X-linked condition that affects males almost exclusively.
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • males at least 15 years of age with molecularly-confirmed diagnosis of choroideremia

Exclusion Criteria:

  • inability to participate in visual field testing reliably and reproducibly

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05045703


Contacts
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Contact: Alessandro Iannaccone, MD, MS 919.684.1857 alessandro.iannaccone@duke.edu
Contact: Oleg Alekseev, MD, PhD 919.684.1857 oleg.alekseev@duke.edu

Locations
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United States, North Carolina
Duke Eye Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
Duke University
Foundation Fighting Blindness
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Responsible Party: Duke University
ClinicalTrials.gov Identifier: NCT05045703    
Other Study ID Numbers: Pro00108901
First Posted: September 16, 2021    Key Record Dates
Last Update Posted: September 13, 2022
Last Verified: September 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Duke University:
vitamin A
night vision
Additional relevant MeSH terms:
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Choroideremia
Eye Diseases, Hereditary
Eye Diseases
Choroid Diseases
Uveal Diseases
Genetic Diseases, Inborn
Genetic Diseases, X-Linked
Vitamin A
Retinol palmitate
Vitamins
Micronutrients
Physiological Effects of Drugs
Antioxidants
Molecular Mechanisms of Pharmacological Action
Protective Agents
Anticarcinogenic Agents
Antineoplastic Agents