Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study

P. Trouillas, G. Serratrice, D. Laplane, A. Rascol, P. Augustin, G. Barroche, M. Clanet, C. F. Degos, C. Desnuelle, R. Dumas and al. et
Ataxia Research Center, Hopital Neurologique, Lyons, France.

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.