Randomized Trial of DHA for Retinitis Pigmentosa Patients Receiving Vitamin A

Study Overview
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Brief Summary
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The purpose of this trial is to determine whether a nutritional supplement in addition to vitamin A will slow the course of retinitis pigmentosa.

Detailed Description
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Retinitis pigmentosa (RP) is a group of inherited retinal degenerations with a worldwide prevalence of approximately 1 in 4,000. Patients typically report night blindness and difficulty with midperipheral visual field in adolescence. As the condition progresses, they lose far peripheral visual field. Most patients have reductions in central vision by age 50 to 80 years. Based on electroretinograms (ERGs), the course of the disease can be slowed on average among adults on 15,000 IU/day of vitamin A palmitate. While conducting the trial on the effects of vitamin A on RP, it became apparent that another substance in the diet could be affecting the course of the disease. This prompted the present randomized, controlled trial. This study is a randomized, controlled, double-masked trial with a planned duration of 5 years. Patients with the common forms of RP are assigned to either a test or a control group. All receive 15,000 IU/day of vitamin A palmitate in addition to either 1200 mg/d of docosahexaenoic acid or control capsules. Participants will not know the contents of the supplement or the group to which they have been assigned until the end of the trial. The main outcome measurement is the total point score on the Humphrey Field Analyzer (HFA). In addition, computer-averaged 30-Hz cone ERG amplitudes and visual acuity are measured annually.

Official Title
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Clinical Trial of Docosahexaenoic Acid (DHA) in Patients With Retinitis Pigmentosa Receiving Vitamin A Treatment

Conditions
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Retinitis Pigmentosa

Intervention / Treatment
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* Dietary Supplement: Vitamin A
* Dietary Supplement: Docosahexaenoic acid
* Dietary Supplement: Control fatty acid


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ocular Criteria: Retinitis Pigmentosa, typical (non-syndromic) forms Best corrected visual acuity Greater than or equal to (GE )20/100 HFA 30-2 total point score GE 250 dB (decibels) 30 (Hertz) Hz ERG cone amplitude GE 0.68 microvolts Dietary Criteria: Dark fish intake Less than or equal to (LE) five servings per week Dietary omega-3 fatty acid intake LE 0.41 g/d Preformed Vitamin A intake in diet and supplements LE 10,000 IU/d Supplement intake LE 5000 IU/d of Vitamin A and LE 30 IU/d Vitamin E Consumption LE 3 alcoholic beverages per day Medical and other criteria: Body Mass Index Less than (LT )40 and weight GE 5th percentile for age, sex, and height Serum retinol level LE 100 mg/dl and serum retinyl ester levels LE 380 nm/L Serum cholesterol level LT 300 mg/dL and serum triglyceride levels LT 400 mg/dL Agree not to know study capsule content Exclusion criteria: Ocular criteria: No confounding ocular disease Dietary criteria: No intake of cod liver oil or omega-3 capsules Medical and other criteria: Not pregnant or planning to become pregnant No clinically significant abnormal result on Complete Blood Count or serum liver function profile No other disease which might affect absorption or metabolism of DHA or Vitamin A

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Docosahexaenoic acid + Vitamin A<br>Participants randomized to this arm received 1200 mg/d docosahexaenoic acid and 15000 IU/d Vitamin A as retinyl palmitate | Dietary Supplement: Vitamin A<br>* 15000 IU/d as retinyl palmitate<br>Dietary Supplement: Docosahexaenoic acid<br>* 1200 mg/d<br>|
| Placebo Comparator: Control fatty acid + Vitamin A<br>Patients randomized to this arm received 500 mg/d of fatty acid with no docosahexaenoic acid and 15000 IU/ Vitamin A as retinyl palmitate | Dietary Supplement: Vitamin A<br>* 15000 IU/d as retinyl palmitate<br>Dietary Supplement: Control fatty acid<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Humphrey Field Analyzer (HFA) total point score 30-2 program | Sum of points in Decibels of total points seen in 30-2 program. Higher scores = better vision/larger visual field | Annual percent change per year at each of 4 years of followup | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Humphrey Field Analyzer (HFA) total point score 30 -2 plus 30/60-2 programs combined | Sum of points in decibels of total points seen in 30-2 and 30/60-2 programs combined- Higher scores = better vision/ larger visual field | Annual percent change per year at each of four years of followup | 
| Change in 30Hz Electroretinogram ( ERG) amplitude | Value in microvolts of response to 30hz ERG. Higher values = greater visual function | Annual percent change per year at each of four years of followup | 
| Change in Early Treatment of Diabetic Retinopathy(EDTRS) Visual Acuity | Number of letters read per year. More letters read = better visual acuity | Change in number of letters read per year at each of four years of followup. |