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Completed

NCT Number: NCT00100230

DHA and X-Linked Retinitis Pigmentosa

Purpose:

Retinitis pigmentosa (RP) is characterized by progressive loss of visual function due to specific genetic mutations. This trial is focused on patients with one of the most severe forms of the disease, X-linked inherited RP (XLRP). This disease is characterized by early onset (typically loss of night vision as a child) followed by loss of peripheral vision as a teenager and young adult. There is no male-to-male transmission of the disease in the family.

There is no cure for RP and treatment options are limited. Two clinical trials have not found a benefit from nutritional supplementation with the long-chain polyunsaturated fatty acid, docosahexaenoic acid (DHA), at low daily doses although there is evidence that it slows disease progression in certain instances. In this clinical trial, we propose that a high dose nutritional DHA supplement will slow the loss of visual function and preserve usable vision in patients with XLRP.

This study is a 4-year placebo-controlled randomized clinical trial meaning that patients have a 50-50 chance of receiving placebo or experimental treatment. A total of 66 patients will be enrolled; 33 will receive placebo and 33 will receive the treatment. Entry criteria include diagnosis of XLRP by an ophthalmologist, age 7 to 32 years, male, sufficient visual function such that disease progression can be followed for the entire duration of the trial, and a willingness to visit the testing site (Dallas, TX) once a year.

Annual visual function testing includes ETDRS visual acuity, full-field and multifocal electroretinography (ERG), static peripheral visual fields, and fundus photography. Cone ERG function is the primary outcome measure.

Funding Source - FDA, Foundation Fighting Blindness, DSM Nutritionals

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Key information

Conditions

Retinitis Pigmentosa Congenital, Hereditary, and Neonatal Diseases and Abnormalities Eye Diseases Eye Diseases, Hereditary Genetic Diseases, Inborn Genetic Diseases, X-Linked Retinal Degeneration Retinal Diseases Retinal Dystrophies X-linked Genetic Diseases

Age range

7 year–32 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 2

Primary location

Retina Foundation of the Southwest

Dallas, Texas, 75231, United States

About this study

Location & Contact Information:

Retina Foundation of the Southwest, 9600 N. Central Expressway, Suite 200, Dallas, TX 75231 Contact: Dr. D. Hoffman ([email protected]) or Dr. D. Birch ([email protected]).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of RP by a retinal specialist
  • Clinical diagnosis consistent with X-linked inheritance
  • Enrolling minors and young adults (early onset of X-linked disease; ages 7 to 32)
  • Measurable cone ERG responses --patients with less than 0.64 microvolt response to 31-Hz flicker will be excluded as they are more likely to become undetectable during the study
  • Both eyes must meet entry criteria as both will be tested (i.e., no cataracts requiring surgery or retinal detachments).
  • Media clarity sufficient for fundus photography
  • Able to return to study site at yearly intervals
  • Willing to supply blood samples at 6-month intervals
  • Judiciously take the placebo or DHA supplement for the 4-year study duration
  • Patient/parent/guardian understands and signs consent form.

Exclusion criteria

  • Excessive fish consumption (e.g., cold water fish such as salmon, tuna, sardines) and/or fish oil supplementation (or other oil containing DHA)
  • Baseline RBC-DHA levels showing evidence of supplementation (a typical level of RBC-DHA in normals is about 3.8%)
  • Chronic metabolic disease that may interfere with fatty acid metabolism or require anti-coagulant medication

No ethnic or racial groups will be excluded.

Treatment and study plan

docosahexaenoic acid OR corn/soy oil placebo

Drug

daily intake of DHA based on body weight or corn/soy oil placebo(oil not containing DHA; 4 year trial

Other names: DHA; omega-3 fatty acid, OR RANDOMIZED TO corn/soy oil placebo

Primary outcomes

  1. Rate of LOSS of 31 Hertz Cone Electroretinographic Function

    Time frame: 4 years

    Hypothesis #1: Elevation of red blood cell-docosahexaenoic acid levels will slow the progressive loss of 31 hertz cone electroretinographic response in this 4-year trial.

Secondary outcomes

  1. Rate of LOSS of Rod Electroretinographic Function

    Time frame: 4 years

    Hypothesis #1: Elevation of red blood cell-docosahexaenoic acid levels will slow the progressive loss of rod electroretinographic response in this 4-year trial.

Other outcomes

  1. Loss of Peripheral Visual Fields

    Time frame: 4 years

    Hypothesis: Elevation of red blood cell-docosahexaenoic acid levels will slow the progressive loss of peripheral visual fields in this 4-year trial.

Sponsors and collaborators

Lead sponsor

Retina Foundation of the Southwest

Other

Collaborators

  • Foundation Fighting Blindness
  • dsm-firmenich Switzerland AG

Registry information

Official study title

Investigation of Effectiveness and Safety of High Dose Docosahexaenoic Acid (DHA) in X-Linked Retinitis Pigmentosa

Important dates

Study start
2004
Primary completion
2012
Study completion
2014
First posted
Dec 28, 2004
Registry last updated
Mar 17, 2015

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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