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

NCT05045703 | Withdrawn

• 1 other identifier: Pro00108901
• Study Type: interventional
• Target: N/A
• Locations: 1 country
• Sites: 1

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.

Conditions

Choroideremia

Keywords

vitamin A; night vision

Outcome Measures

Primary Outcomes (3)

• Change in dark-adapted full-field visual field sensitivity

  Dark-adapted full-field visual field sensitivity will be measured using the Medmont dark-adapted chromatic perimeter.

  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

• Change in dark-adapted macular visual field sensitivity

  Dark-adapted macular visual field sensitivity will be measured using the Medmont dark-adapted chromatic perimeter.

  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

• Change in dark adaptometry

  Dark adaptometry will be measured using the MacuLogix AdaptDx dark adaptometer.

  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

Secondary Outcomes (10)

• Change in best corrected visual acuity

  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

• Change in low luminance visual acuity

  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

• Change in full-field light-adapted visual field sensitivity

  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

• Change in light-adapted macular visual field sensitivity

  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

• Change in retinal pigmented epithelium (RPE) atrophy by optical coherence tomography

  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

Study Arms (1)

Vitamin A palmitate

EXPERIMENTAL

Vitamin A palmitate, 15,000 IU daily for 4 months

Dietary Supplement: Vitamin A palmitate

Interventions

Vitamin A palmitate DIETARY_SUPPLEMENT

Vitamin A palmitate, 15,000 IU daily for 4 months

Vitamin A palmitate

Eligibility Criteria

• Age: 15 Years+
• Gender Eligibility Details: Choroideremia is an X-linked condition that affects males almost exclusively.
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• inability to participate in visual field testing reliably and reproducibly

Sponsors & Collaborators

• Duke University: lead
• Foundation Fighting Blindness: collaborator

Study Sites (1)

Duke Eye Center

Durham, North Carolina, 27710, United States

Location

MeSH Terms

Conditions

Choroideremia

Interventions

retinol palmitate

Condition Hierarchy (Ancestors)

Eye Diseases, Hereditary; Eye Diseases; Choroid Diseases; Uveal Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Genetic Diseases, X-Linked

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 7, 2021
• First Posted: September 16, 2021
• Study Start: May 1, 2023
• Primary Completion: March 1, 2024
• Study Completion: May 1, 2024
• Last Updated: June 29, 2023

Record last verified: 2023-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)