LEVOROTATORY FORM OF 5-HYDROXYTRYPTOPHAN IN FRIEDREICHS ATAXIA - RESULTS OF A DOUBLE-BLIND DRUG-PLACEBO COOPERATIVE STUDY

Objective: To study the effect of the levorotatory form of 5-hydroxytryptophan on the cerebellar symptoms of Friedreich's ataxia. Design: Cooperative double-blind study of the levorotatory form of 5-hydroxytryptophan vs placebo. Setting: Twelve centers in research hospitals. Patients: Twenty-six patients were included; 19 completed the study (mean+/-SD age of patients, 25.9+/-8.1 years). Of these 19 patients, eight were treated with placebo and 11 were treated with the drug. Main Outcome Measures: A semiquantitative scale for kinetic and static (''postural'') cerebellar functions and quantitative measurements of time in standard tests that evaluated stance, speech, writing, and drawing. Results: In the active treatment group, a significant decrease of the kinetic score was observed (P=.03), indicating an improvement in coordination. Conclusions: These results demonstrated that the levorotatory form of 5-hydroxytryptophan is able to modify significantly the cerebellar symptoms in patients with Friedreich's ataxia. However, the effect is only partial and not clinically major.