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# Amylyx Mulls Withdrawing ALS Drug
- URL: https://www.fdaweb.com/amylyx-mulls-withdrawing-als-drug/
- Published: 2024-03-08T12:00:00.000Z
- Updated: 2026-09-14T14:24:53.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5156515

Faced with disappointing data from the Phase 3 PHOENIX clinical trial of Amylyx Pharmaceuticals’ amyotrophic lateral sclerosis (ALS) drug Relyvrio (sodium phenylbutyrate and taurursodiol), the company says it is considering voluntarily withdrawing the drug. “Amylyx will continue to engage with regulatory authorities and the broader ALS community, including ALS specialists and other multidisciplinary experts, people living with ALS, and advocates, to discuss the results from PHOENIX within the next eight weeks and make informed decisions,” the company says.

Before gaining approval for the drug in 2022, the company pledged during an advisory committee meeting that if the confirmatory study failed to show a benefit, then the company would remove the drug from the market ([see earlier story](https://fdaweb.com/login.php?sa=v&aid=D5152858&cate=&stid=%241%24v.0.MB4.%24pyTtkwQCHQJbDYue0OV4b%2F&ref=fdaweb.com)). While it discusses its next steps with regulators and ALS stakeholders, Amylyx says it has voluntarily decided to pause promotion of the medication.

Regarding the PHOENIX study, Amylyx says it did not meet its primary endpoint of reaching statistical significance (p=0.667) as measured by change from baseline in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) total score at Week 48, and there was no statistical significance seen in secondary endpoints. “We are surprised and deeply disappointed by the PHOENIX results following the positive data from the CENTAUR trial,” it says.