ALS Treatment Relyvrio to Be Removed From the Market

Amylyx has decided to voluntarily discontinue Relyvrio^® (sodium phenylbutyrate and taurursodiol) for the treatment of amyotrophic lateral sclerosis (ALS) based on results from the phase 3 PHOENIX trial.

Approved in September 2022, Relyvrio is an oral, fixed-dose coformulation of sodium phenylbutyrate and taurursodiol, also known as ursodoxicoltaurine. The approval was based on data from the phase 2 CENTAUR trial (ClinicalTrials.gov Identifier: NCT03127514), which showed Relyvrio significantly slowed the loss of physical function in patients with ALS compared with placebo.

However, topline results from the phase 3 PHOENIX trial (ClinicalTrials.gov Identifier: NCT05021536) showed the treatment was not associated with a statistically significant difference from baseline in the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale total score at week 48 compared with placebo (primary endpoint). Moreover, statistically significant differences were not observed across secondary endpoints. Additional data from the trial will be presented at the American Academy of Neurology annual meeting this month.

The Company has decided to provide Relyvrio through a free drug program for those who wish to stay on therapy. It will no longer be available to new patients. The open-label extension portion of the PHOENIX trial remains ongoing.

“The decision to remove [Relyvrio] from the market and provide therapy free of charge for those who wish to continue was informed by the PHOENIX trial results, engagement with regulatory authorities, and discussions with the ALS community,” said Joshua Cohen and Justin Klee, Co-CEOs of Amylyx.

The Company has started the process with the Food and Drug Administration to discontinue marketing authorization for Relyvrio.