Medical Information Only. Always consult your healthcare provider before enrolling in any clinical trial.
Investigating the Effect of Vitamin A Supplementation on Retinitis Pigmentosa
NCT00065455 · View on ClinicalTrials.gov ↗
Study Summary
Retinitis pigmentosa (RP) is a collective term for a group of inherited retinal dystrophies that are a major cause of irreversible blindness. RP of some type occurs in approximately 1 out of 3500 persons in the United States(1). Gene mutations are responsible for the majority of RP. To date, mutations have been identified in 30 different genes linked to RP(2). The visual prognosis of RP is poor, since the gradual but relentless visual field loss leads eventually to some degree of blindness(3). Although no effective treatment for RP has been identified, participants supplemented with a daily oral dose of 15,000 IU vitamin A palmitate have shown, on average, a slower rate of deterioration of retinal function when the intervention is continued over several years(4). The purpose of this research is to determine whether administration of high oral doses of vitamin A can acutely improve cone photoreceptor function in RP participants as measured by electroretinography (ERG). In this interventional, non-randomized, prospective, pilot study, 5 participants will receive a daily oral dose of 50,000 IU of vitamin A palmitate for 4 weeks, followed by a maintenance dose of 15,000 IU daily for the subsequent 2 weeks. The primary efficacy outcome is a relative percentage change in ERG response amplitude subsequent to vitamin A supplementation. A secondary efficacy outcome is a relative percentage change in implicit time from pre- to post- vitamin A supplementation, with improvement specified as a shorter response implicit time. Other secondary outcomes will be improvements in visual field (Humphery, 10-2; sum of thresholds). Safety outcomes include visual fields, ETDRS visual acuity, intraocular pressure, serum vitamin A level and liver function tests.
Conditions Studied
Interventions
- DRUG Vitamin A
Study Locations (1)
Maryland
- National Institutes of Health Clinical Center, 9000 Rockville Pike — Bethesda
Trial Details
| Field | Value |
|---|---|
| Enrollment Target | 11 participants |
| Start Date | 2003-07-17 |
| Est. Completion | 2009-05-06 |
| Phase | Phase 1 |
Interested in This Trial?
Always speak with your doctor before enrolling in a clinical trial.
Full Details on ClinicalTrials.gov ↗What the Registry Record Tells You About NCT00065455
The ClinicalTrials.gov registry entry for NCT00065455 describes a study currently listed as completed. It is categorized as Phase 1, which is the standard way researchers label where a study sits along the investigational pathway from early safety work through later efficacy and post-marketing evaluation. The registered enrollment target is 11 participants, a figure that helps gauge the scale of data the investigators plan to collect. The listed sponsor is National Eye Institute (NEI), which has 214 total studies on file at ClinicalTrials.gov, and sponsors are the parties responsible for study design, oversight, and regulatory filings.
The record links to 1 condition, with Retinitis Pigmentosa appearing as the primary indexed condition, and to 1 intervention — of which Vitamin A is the first listed. Interventions can include drugs, devices, procedures, behavioral programs, or observational arms, and each is tracked as a separate registry field so that downstream queries can filter accurately. When a trial lists multiple interventions, it usually reflects a multi-arm design or a comparison protocol rather than a single treatment being tested in isolation. The brief summary published in the registry is the clearest source of protocol intent and should be read before drawing conclusions from any sidebar tags.
Geographic footprint matters for practical reasons: NCT00065455 reports 1 study location spanning 1 distinct geographic area — top geographies include Maryland. A larger site network tends to correlate with broader recruitment capacity, but it does not imply anything about study quality, and site-level enrollment status can diverge from the overall registry status shown above. Every data point on this page comes from the public ClinicalTrials.gov dataset and is reproduced here for reference only; it is not a medical recommendation, an endorsement of the sponsor, or an invitation to enroll. Verify current status, eligibility criteria, and contact details directly at ClinicalTrials.gov, and discuss any participation decision with your own healthcare provider.
Frequently Asked Questions
What is clinical trial NCT00065455 about?
NCT00065455 is a clinical study titled "Investigating the Effect of Vitamin A Supplementation on Retinitis Pigmentosa". Retinitis pigmentosa (RP) is a collective term for a group of inherited retinal dystrophies that are a major cause of irreversible blindness. RP of some type occurs in approximately 1 out of 3500 persons in the United States(1). Gene mutations are responsible for the majority of RP. To date, mutatio...
What is the current status of trial NCT00065455?
This trial is currently completed. It is a Phase 1 study. The enrollment target is 11 participants. The study started on 2003-07-17. Estimated completion is 2009-05-06.
What conditions does trial NCT00065455 study?
This clinical trial studies the following conditions: Retinitis Pigmentosa. These conditions were identified from the trial registry and reflect the primary focus areas of the research.
What interventions are being tested in trial NCT00065455?
The interventions under investigation include: Vitamin A (DRUG). Each intervention is being evaluated for safety and efficacy as part of this clinical study.
Who is sponsoring clinical trial NCT00065455?
This trial is sponsored by National Eye Institute (NEI), which has 214 total clinical trials registered on ClinicalTrials.gov. The sponsor is responsible for the study's design, funding, and regulatory compliance.
Where is trial NCT00065455 being conducted?
This trial has 1 study location across Maryland. Contact the study sites directly through ClinicalTrials.gov for enrollment availability.
Learn More About Clinical Trials
How Clinical Trials Work
Understand phases 1-4, trial design, randomization, and the informed consent process.
Patient Rights in Clinical Trials
Your rights as a participant: consent, withdrawal, privacy, and who to contact.
Finding the Right Clinical Trial
A practical guide to searching trials, understanding eligibility, and evaluating options.
All Guides
Browse our complete library of clinical trial educational resources.
Read our methodology — how this data is sourced, computed, and verified.