Effect of a methionine-enkephalin analog in Huntington's disease

The methionine-enkephalin analog FK 33-824 was administered intravenously to 12 patients with Huntington's disease in a crossover double-blind study. The abnormal involuntary movements (AIM) were not improved after administration of 0.5 mg of FK 33-824. A significant decrease in the AIM score was observed only 150 and 180 min after injection of high doses (2 mg); however, the difference between the active drug and the placebo was never statistically significant. These results are discussed in terms of experimental data suggesting a relationship between methionine-enkephalin and dopamine neurons in the brain and of methionine-enkephalin deficiency in the brain of patients with Huntington's disease.