FDA Approves Amylyx Pharmaceuticals Novel ALS Treatment

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FDA has approved Relyrio as a once-to-twice daily treatment for patients with ALS.

FDA announced approval of Amylyx Pharmaceutical’s Relyvrio (sodium phenylbutyrate/taurursodiol) to treat patients with amyotrophic lateral sclerosis (ALS) on Sept. 29, 2022. According to an agency press release, the decision to approve the drug was based on positive findings from a study evaluating the drug relative to placebo.

The 24-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study, comprised of 137 adult patients with ALS, randomized patients to receive either sodium phenylbutyrate/taurursodiol or placebo. The patients treated with sodium phenylbutyrate/taurursodiol experienced a slower rate of decline on a clinical assessment of daily functioning relative to those who received placebo. Additionally, a long-term analysis demonstrated longer overall survival in those who originally received sodium phenylbutyrate/taurursodiol.

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


Sodium phenylbutyrate/taurursodiol can be taken orally by combining one packet (3 ounces phenylbutyrate, 1 ounce taurusodiol) in 8 ounces of room temperature water, or via a feeding tube. For the first three weeks of treatment, it is recommended that patients take one dose each day; following this, it is recommended to take it twice daily.

According to the release, approximately 5,000 individuals in the United States are diagnosed with ALS each year; 20,000 are estimated to live with the disease, which usually results in death from respiratory failure three-to-five years after diagnosis, at any given time. The FDA granted this application both priority review and orphan drug designations.

Source: FDA