Riluzole in Huntington's Disease

Inclusion Criteria: * Clinical diagnosis of Huntington's disease and CAG repeat length of 36 or more * UHDRS Motor score of at least 5 points * UHDRS TFC score of at least 8 points, i.e. patients must be independently ambulatory and must not require nursing care * Females require a negative blood pregnancy test at inclusion Exclusion Criteria: * Any forms of chorea other than Huntington's disease * Patients on antichoreic treatment within one month prior to entry or foreseen to require such treatment within the first 3 months after randomization (antichoreic medication is prohibited during entire study) * Other unacceptable prior/concomitant medications * Uncontrolled major psychiatric disorders, in particular uncontrolled major depression (DSM IV definition) * Drug or alcohol dependence and/or abuse (DSM IV definition) within the past 6 months * Any other concomitant disease with a reasonable possibility to interfere with the study * Females who are breast-feeding, not sterilized, at least one year postmenopausal or don't use an adequate contraceptive method for at least one month prior to and during study participation * Participation in another clinical study with any investigational drug within 30 days prior to study screening * Prior exposure to riluzole * ALT and/or AST and/or Total Bilirubin levels greater than 1.5 times the upper limits of normal range, or hepatic disease other than Gilbert's disease * Creatinine serum concentrations above 200 µmol/l (resp. 2,3 mg/dl) or hematology parameters as follows: Hemoglobin smaller 11 g/dl for males resp. smaller 10 g/dl for females, or White Blood Cell smaller 3,5 x 10000000000/l