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FDA News Release

FDA Approves New Treatment Option for Patients with ALS

For Immediate Release:


The U.S. Food and Drug Administration today approved Relyvrio (sodium phenylbutyrate/taurursodiol) to treat patients with amyotrophic lateral sclerosis (ALS), commonly referred to as Lou Gehrig’s disease. 

“This approval provides another important treatment option for ALS, a life-threatening disease that currently has no cure,” said Billy Dunn, M.D., director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research. “The FDA remains committed to facilitating the development of additional ALS treatments.”

ALS is a rare disease that attacks and kills the nerve cells that control voluntary muscles. Voluntary muscles produce movements such as chewing, walking, breathing, and talking. ALS causes the nerves to lose the ability to activate specific muscles, which causes the muscles to become weak and leads to paralysis. ALS is a progressive disease that continues to get worse over time. Most cases will result in death from respiratory failure, usually within three to five years from when the symptoms first appear. Approximately 5,000 individuals in the United States are diagnosed with ALS annually, and approximately 20,000 Americans are currently living with the disease.

Relyvrio can be taken orally by combining one packet in 8 ounces of room temperature water. It can also be administered through a feeding tube. The recommended dosage for the first three weeks is one packet (3 grams sodium phenylbutyrate and 1-gram taurursodiol) daily. After three weeks, the dosage increases to one packet twice a day. The medication can be taken before a snack or meal.

The efficacy of Relyvrio for the treatment of ALS was demonstrated in a 24-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. In the trial, 137 adult patients with ALS were randomized to receive either Relyvrio or placebo. The patients treated with Relyvrio experienced a slower rate of decline on a clinical assessment of daily functioning compared to those receiving a placebo. Additionally, longer overall survival was observed in a post hoc, long-term analysis of patients who originally received Relyvrio versus those who originally received placebo.  

The most common adverse reactions experienced with Relyvrio were diarrhea, abdominal pain, nausea and upper respiratory tract infection. Relyvrio contains taurursodiol, a bile acid, which may cause worsening diarrhea in patients with disorders that interfere with bile acid circulation. These patients should consider consulting with a specialist before taking Relyvrio. The prescribing information includes additional information on risks associated with Relyvrio.

The FDA granted this application Priority Review designation. It also received orphan drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases. The FDA granted the approval of Relyvrio to Amylyx Pharmaceuticals Inc.

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The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.


April Grant

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