Completed

Randomized Trial of DHA for Retinitis Pigmentosa Patients Receiving Vitamin A

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What is being tested

Vitamin A

+ Docosahexaenoic acid
+ Control fatty acid
Dietary Supplement
Who is being recruted

Retinitis Pigmentosa

From 18 to 55 Years

See all eligibility criteria

How is the trial designed

Treatment Study

Placebo-Controlled
Phase 3
Interventional
Study Start: May 1996

See protocol details

Summary

Principal SponsorCarol Weigel DiFranco
Last updated: March 8, 2023
Sourced from a government-validated database.Claim as a partner
Study start date: May 1, 1996Actual date on which the first participant was enrolled.

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.

Official TitleClinical Trial of Docosahexaenoic Acid (DHA) in Patients With Retinitis Pigmentosa Receiving Vitamin A Treatment 
Principal SponsorCarol Weigel DiFranco
Last updated: March 8, 2023
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details
221 patients to be enrolledTotal number of participants that the clinical trial aims to recruit.
Treatment Study
These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.

How participants are assigned to different groups/arms
In this clinical study, participants are placed into groups randomly, like flipping a coin. This ensures that the study is fair and unbiased, making the results more reliable. By assigning participants by chance, researchers can better compare treatments without external influences.

Other Ways to Assign Participants
Non-randomized allocation: Participants are assigned based on specific factors, such as their medical condition or a doctor's decision.
None (Single-arm trial): If the study has only one group, all participants receive the same treatment, and no allocation is needed.

How treatments are given to participants
Participants are divided into different groups, each receiving a specific treatment at the same time. This helps researchers compare how well different treatments work against each other.

Other Ways to Assign Treatments
Single-group assignment: Everyone gets the same treatment.
Cross-over assignment: Participants switch between treatments during the study.
Factorial assignment: Participants receive different combinations of treatments.
Sequential assignment: Participants receive treatments one after another in a specific order, possibly based on individual responses.
Other assignment: Treatment assignment does not follow a standard or predefined design.

How the effectiveness of the treatment is controlled
In a placebo-controlled study, some participants receive the experimental treatment, while others receive an inert substance (placebo) to compare outcomes. This method helps to isolate the effect of the treatment from the psychological effects of receiving any treatment at all.

Other Options
Non-placebo-controlled: No placebo is used. All participants receive the actual treatment or alternative interventions (often the Standard of Care), and comparisons are made between these treatments.

How the interventions assigned to participants is kept confidential
Participants, researchers, outcome assessors, and care providers do not know which treatment is being given. This is the most complete way to prevent bias and keep the study as neutral as possible.

Other Ways to Mask Information
Open-label: Everyone knows which treatment is being given.
Single-blind: Participants do not know which treatment they are receiving, but researchers do.
Double-blind: Neither participants nor researchers know which treatment is given.
Triple-blind: Participants, researchers, and outcome assessors do not know which treatment is given.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria
Any sexBiological sex of participants that are eligible to enroll.
From 18 to 55 YearsRange of ages for which participants are eligible to join.
Healthy volunteers allowedIf individuals who are healthy and do not have the condition being studied can participate.
Conditions
Pathology
Retinitis Pigmentosa
Criteria

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

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives
2 intervention groups 

are designated in this study

50% chance 

of being blinded to the placebo group

Treatment Groups
Group I
Experimental
Participants randomized to this arm received 1200 mg/d docosahexaenoic acid and 15000 IU/d Vitamin A as retinyl palmitate
Group II
Placebo
Patients randomized to this arm received 500 mg/d of fatty acid with no docosahexaenoic acid and 15000 IU/ Vitamin A as retinyl palmitate
Study Objectives
Primary Objectives

Sum of points in Decibels of total points seen in 30-2 program. Higher scores = better vision/larger visual field
Secondary Objectives

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

Value in microvolts of response to 30hz ERG. Higher values = greater visual function

Number of letters read per year. More letters read = better visual acuity

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.
This study has 1 location
Suspended
Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear InfirmaryBoston, United StatesSee the location
CompletedOne Study Center