Randomized Trial of DHA for Retinitis Pigmentosa Patients Receiving Vitamin A

Carol Weigel DiFranco221 enrolled

Overview

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

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

221

Conditions

Retinitis Pigmentosa

Interventions

Vitamin ADIETARY_SUPPLEMENT

15000 IU/d as retinyl palmitate

Docosahexaenoic acidDIETARY_SUPPLEMENT

1200 mg/d

Control fatty acidDIETARY_SUPPLEMENT

Eligibility

Sex: ALLMin age: 18 YearsMax age: 55 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary

Boston, Massachusetts, United States

Outcomes

Primary Outcomes

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

Time frame: Annual percent change per year at each of 4 years of followup

Secondary Outcomes

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

Time frame: 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

Time frame: 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

Time frame: Change in number of letters read per year at each of four years of followup.

Data from ClinicalTrials.gov

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