DHA and X-Linked Retinitis Pigmentosa

Retinitis Pigmentosa Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00100230
• Other study ID #: 2543
• Secondary ID: FD-R-0025435R01F
• Status: Completed
• Phase: Phase 2
• First received: December 27, 2004
• Last updated: March 4, 2015
• Start date: September 2004
• Est. completion date: August 2014

Study information

• Verified date: March 2015
• Source: Retina Foundation of the Southwest
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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

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).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 78
• Est. completion date: August 2014
• Est. primary completion date: May 2012
• Accepts healthy volunteers: No
• Gender: Male
• Age group: 7 Years to 32 Years

Eligibility

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.

Related Conditions & MeSH terms

• Genetic Diseases, Inborn
• Genetic Diseases, X-Linked
• Retinitis
• Retinitis Pigmentosa
• X-linked Genetic Diseases

Intervention

Drug:
• docosahexaenoic acid OR corn/soy oil placebo
daily intake of DHA based on body weight or corn/soy oil placebo(oil not containing DHA; 4 year trial

Locations

Country	Name	City	State
United States	Retina Foundation of the Southwest	Dallas	Texas

Sponsors (3)

Lead Sponsor	Collaborator
Retina Foundation of the Southwest	DSM Nutritional Products, Inc., Foundation Fighting Blindness

Country where clinical trial is conducted

United States, 

References & Publications (2)

Hoffman DR, Hughbanks-Wheaton DK, Pearson NS, Fish GE, Spencer R, Takacs A, Klein M, Locke KG, Birch DG. Four-year placebo-controlled trial of docosahexaenoic acid in X-linked retinitis pigmentosa (DHAX trial): a randomized clinical trial. JAMA Ophthalmol — View Citation

Hughbanks-Wheaton DK, Birch DG, Fish GE, Spencer R, Pearson NS, Takacs A, Hoffman DR. Safety assessment of docosahexaenoic acid in X-linked retinitis pigmentosa: the 4-year DHAX trial. Invest Ophthalmol Vis Sci. 2014 Jul 11;55(8):4958-66. doi: 10.1167/iov — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Loss of Peripheral Visual Fields	Hypothesis: Elevation of red blood cell-docosahexaenoic acid levels will slow the progressive loss of peripheral visual fields in this 4-year trial.	4 years
Primary	Rate of LOSS of 31 Hertz Cone Electroretinographic Function	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.	4 years
Secondary	Rate of LOSS of Rod Electroretinographic Function	Hypothesis #1: Elevation of red blood cell-docosahexaenoic acid levels will slow the progressive loss of rod electroretinographic response in this 4-year trial.	4 years

External Links

•   website for Retina Foundation of the Southwest