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# Amylyx Pulls ALS Drug From the Market
- URL: https://www.fdaweb.com/amylyx-pulls-als-drug-from-the-market/
- Published: 2024-04-04T12:00:00.000Z
- Updated: 2026-09-14T14:27:25.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5156711

After reporting disappointing data last month 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 voluntarily removing the drug from U.S. and Canadian markets. At the time the data came out, Amylyx said it planned to engage with regulatory authorities and the broader ALS community, but it appears the regulators gave the company no path for maintaining the drug’s approval. “Patients currently on therapy in the U.S. and Canada who, in consultation with their physician, wish to stay on treatment can be transitioned to a free drug program,” 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 it 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)).

Regarding the PHOENIX confirmatory 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 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,” the company says.

Amylyx says it will continue to evaluate and share learnings from PHOENIX to aid future ALS research. “At this time, Amylyx intends to continue to collect available data on survival at the encouragement of ALS specialists,” it says.