Clinical trial NCT05045703: The Dark-Adapted Retinal Function Response in Choroideremia (DARC) Study
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
Study type: INTERVENTIONAL
Overall status: WITHDRAWN
Phase: NA
Conditions: Choroideremia
Keywords: vitamin A
night vision
Lead sponsor: Duke University
Sponsor class: OTHER
Collaborators: name: Foundation Fighting Blindness
First posted: 2021-09-16
Enrollment: 0
Sex: MALE
Minimum age (years): 15
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

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.


Eligibility 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

Primary outcomes:
measure: Change in dark-adapted full-field visual field sensitivity
timeFrame: 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
measure: Change in dark-adapted macular visual field sensitivity
timeFrame: 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
measure: Change in dark adaptometry
timeFrame: 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:
measure: Change in best corrected visual acuity
timeFrame: 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
measure: Change in low luminance visual acuity
timeFrame: 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
measure: Change in full-field light-adapted visual field sensitivity
timeFrame: 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
measure: Change in light-adapted macular visual field sensitivity
timeFrame: 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
measure: Change in retinal pigmented epithelium (RPE) atrophy by optical coherence tomography
timeFrame: 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
measure: Change in retinal pigmented epithelium (RPE) atrophy by color photography
timeFrame: 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
measure: Change in retinal pigmented epithelium (RPE) atrophy by fundus autofluorescence
timeFrame: 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
measure: Change in retinal pigmented epithelium (RPE) atrophy by fundoscopy
timeFrame: 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
measure: Change in liver function
timeFrame: Measurements at 0, 4, and 8 months
measure: Change in serum vitamin A levels
timeFrame: 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
Other outcomes:
Locations:
city: Durham
country: United States
facility: Duke Eye Center
state: North Carolina
Study officials:
References: