Rilutek (riluzole) was the first drug approved by the U.S. Food and Drug Administration (FDA), in December 1995, to treat amyotrophic lateral sclerosis (ALS). Rilutek is an oral formulation that acts to slow the progression of ALS symptoms and prolong survival. It was originally developed by French company Rhone-Poulenc Rorer and is now marketed by Sanofi.

How Rilutek works

In many cases of ALS, it is believed that excess levels of the neurotransmitter glutamate damages nerve cells. Neurotransmitters are molecules that nerve cells use to communicate: the cells release the substance, which is then picked up by receptors situated on the surface of a neighboring cell, successfully transmitting the message. Normally, the neurotransmitter is quickly removed from the region surrounding the cell so that the signal is brief. This process is critical to normal neural function, as remaining neurotransmitters continue to send messages to neighboring cells, and such prolonged activity is toxic.

The exact mechanism for Rilutek in treating ALS is unknown. However, it is believed the drug blocks the release of glutamate from nerve cells. This may reduce the rate of glutamate-induced deterioration in nerve cells, slowing initial progression of symptoms.

Rilutek in clinical trials

The FDA’s approval of Rilutek was based on two key clinical studies in humans.

The first trial was a randomized, double-blind clinical study that followed 155 ALS patients in France and Belgium for 13 to 18 months. The patients were randomly assigned either 50 mg of Rilutek twice daily or a placebo. The trial showed that it had a significant effect on the rate of survival. The time until tracheostomy — a medical procedure to create an opening in the neck to allow breathing — or death was about 90 days longer in the Rilutek-treated group than in the placebo-treated group.

The second trial tested the effect of its dosage. A total of 959 ALS patients from Europe and North America were randomly assigned either 50, 100, or 200 mg a day of Rilutek or placebo for 12 months (North America) or 18 months (Europe). There was no difference observed between the placebo and 50 mg a day of Rilutek. Doctors saw an early increase in survival rates of patients treated with either 100 or 200 mg a day of Rilutek compared to placebo. The median survival time was about 60 days longer in the Rilutek-treated group than in those receiving placebo.

Researchers observed no change in survival when they increased the dosage to 200 mg per day, though they did see an increase in the rate of adverse effects. From the clinical trials, the most common adverse effects associated with Rilutek were nausea and asthenia (weakness).

These trials showed that Rilutek can increase early survival by two to three months, but it does not improve muscle strength and neurological function, and has no effect in later stages of ALS.

The recommended dosage is 50 mg twice daily on an empty stomach.

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