Conditions: Retinitis Pigmentosa X-linked Genetic Diseases
Keywords: retina electroretinography clinical trial docosahexaenoic acid omega-3 fatty acid x-linked inheritance
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 78
Healthy volunteers: no

Brief summary:
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

Detailed description:
Location \& Contact Information:

Retina Foundation of the Southwest, 9600 N. Central Expressway, Suite 200, Dallas, TX 75231 Contact: Dr. D. Hoffman (dhoffman@retinafoundation.org) or Dr. D. Birch (dbirch@retinafoundation.org).

Arms:
arm 1: Oral Docosahexaenoic acid, dosage based on body weight arm 2: corn/soy oil placebo; oil not containing DHA...dosage based on body weight

Interventions: intervention 1: docosahexaenoic acid OR corn/soy oil placebo
Intervention descriptions: intervention 1: daily intake of DHA based on body weight or corn/soy oil placebo(oil not containing DHA; 4 year trial

Protocol document: