Objective: To determine whether ethyl-eicosapentaenoic acid (ethyl-EPA), an omega-3 fatty acid, improves the motor features of Huntington disease.
Design: Six-month multicenter, randomized, double-blind, placebo-controlled trial followed by a 6-month open-label phase without disclosing initial treatment assignments.
Setting: Forty-one research sites in the United States and Canada.
Patients: Three hundred sixteen adults with Huntington disease, enriched for a population with shorter trinucleotide (cytosine-adenine-guanine) repeat length expansions.
Interventions: Random assignment to placebo or ethyl-EPA, 1 g twice a day, followed by open-label treatment with ethyl-EPA.
Main outcome measures: Six-month change in the Total Motor Score 4 component of the Unified Huntington's Disease Rating Scale analyzed for all research participants and those with shorter cytosine-adenine-guanine repeat length expansions (<45).
Results: At 6 months, the Total Motor Score 4 point change for patients receiving ethyl-EPA did not differ from that for those receiving placebo. No differences were found in measures of function, cognition, or global impression. Before public disclosure of the 6-month placebo-controlled results, 192 individuals completed the open-label phase. The Total Motor Score 4 change did not worsen for those who received active treatment for 12 continuous months compared with those who received active treatment for only 6 months (2.0-point worsening; P=.02).
Conclusion: Ethyl-EPA was not beneficial in patients with Huntington disease during 6 months of placebo-controlled evaluation. Clinical Trial Registry clinicaltrials.gov Identifier: NCT00146211.