Riluzole and ALS therapy.

Amyotrophic lateral sclerosis (ALS) is a severe neurological disorder clinically characterized by progressive muscle weakness, amyotrophy, fasciculations and signs of corticospinal tract deficits. The cause is unknown but several hypotheses are currently proposed. In familial forms of ALS, a mutation of the Cu-Zn superoxide dismutase gene was reported in some patients. Autoimmunity and neurofilament dysfunction were also observed. The last hypothesis is linked to excitotoxicity. This cellular phenomenon is associated with the overstimulation of glutamate post-synaptic receptors, leading to neuronal degeneration. Abnormal glutamate metabolism was also discovered in ALS patients. In these conditions, riluzole, a pharmacological agent that reduces glutamate release from nerve terminals, was administered to ALS patients. Riluzole is an anti-convulsant and a neuroprotective agent and specifically blocks sodium channels in their inactivated states. In a recent double blind placebo controlled study, riluzole was given to 77 patients (placebo 78 patients). After 1 year of treatment 58% of the placebo-treated patients were still alive compared to 74% of patients treated with riluzole. The prolonged survival was significant in the overall population and in the bulbar-onset group.