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

Choroideremia Clinical Trial

— DARC  

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

Clinical Trial Details — Status: Withdrawn

Administrative data

• NCT number: NCT05045703
• Other study ID #: Pro00108901
• Status: Withdrawn
• Phase: N/A
• Start date: May 2023
• Est. completion date: May 2024

Study information

• Verified date: June 2023
• Source: Duke University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

Recruitment information / eligibility

• Status: Withdrawn
• Enrollment: 0
• Est. completion date: May 2024
• Est. primary completion date: March 2024
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 15 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Choroideremia

Intervention

Dietary Supplement:
• Vitamin A palmitate
Vitamin A palmitate, 15,000 IU daily for 4 months

Locations

Country	Name	City	State
United States	Duke Eye Center	Durham	North Carolina

Sponsors (2)

Lead Sponsor	Collaborator
Duke University	Foundation Fighting Blindness

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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
Primary	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
Primary	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	Change in best corrected visual acuity	Best corrected visual acuity will be measured using the ETDRS chart	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	Change in low luminance visual acuity	Low luminance visual acuity will be measured using the ETDRS chart in low luminance conditions	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	Change in full-field light-adapted visual field sensitivity	Light-adapted full-field visual field sensitivity will be measured using the Octopus 172-point GATE full-field semi-automated kinetic perimetry (SKP)	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	Change in light-adapted macular visual field sensitivity	Light-adapted macular visual field sensitivity will be measured using the Centervue MAIA confocal macular microperimeter	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	Change in retinal pigmented epithelium (RPE) atrophy by optical coherence tomography	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)	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	Change in retinal pigmented epithelium (RPE) atrophy by color photography	Retinal pigmented epithelium (RPE) atrophy will be measured using the Optos wide-field color fundus photography (WF-CFP)	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	Change in retinal pigmented epithelium (RPE) atrophy by fundus autofluorescence	Retinal pigmented epithelium (RPE) atrophy will be measured using the Optos wide-field fundus auto-fluorescence (WF-FAF)	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	Change in retinal pigmented epithelium (RPE) atrophy by fundoscopy	Retinal pigmented epithelium (RPE) atrophy will be assessed by slit lamp biomicroscopy	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	Change in liver function	Liver function profile will be measured by laboratory using participant serum samples	Measurements at 0, 4, and 8 months
Secondary	Change in serum vitamin A levels	Serum vitamin A levels will be measured by laboratory using participant serum samples	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