Amylyx Pharmaceuticals announced Thursday that it's (ALS) drug sodium phenylbutyrate and taurursodiol (Relyvrio), also known as AMX0035, from U.S. and Canadian markets.
The company said it is working with the FDA and Health Canada to voluntarily discontinue the marketing authorizations for the drug (sold as Albrioza in Canada) based on topline results from the trial, which did not meet its prespecified efficacy endpoints.
ALS patients currently using the therapy in the U.S. and Canada who wish to stay on treatment after consulting with their physician can be transitioned to a free drug program, the company said.
"While this is a difficult moment for the ALS community, we reached this path forward in partnership with the stakeholders who will be impacted and in line with our steadfast commitment to people living with ALS and other neurodegenerative diseases," stated Joshua Cohen and Justin Klee, Amylyx co-chief executive officers.
The decision was made after discussions with regulatory authorities and the ALS community, Cohen and Klee pointed out.
"We commend Amylyx for pulling Relyvrio off the market while still ensuring that people living with ALS can access the drug if they believe it is helping them," the ALS Association said in a statement.
"We believe the example of Relyvrio shows how the system can work," the ALS group noted. "Safe and potentially effective treatments can be made accessible rapidly until further research can confirm their efficacy. There are more than 40 more potential treatments in the pipeline and we are focused on trying to advance the safe and effective ones as quickly as possible."
The FDA's decision to approve AMX0035 in 2022 was based on the phase II CENTAUR trial. In CENTAUR, AMX0035 appeared to slow functional decline compared with placebo in people with rapidly advancing ALS, most of whom were already taking two FDA-approved ALS medications, riluzole (Rilutek) and edaravone (Radicava). Data from an open-label extension of CENTAUR suggested a survival benefit with AMX0035.
In a before an advisory committee meeting to discuss the drug, FDA reviewers said post hoc analyses did not appear to provide "independent confirmatory evidence" of the clinical effect of AMX0035 in ALS.
Klee told FDA advisors that if the phase III PHOENIX trial of AMX0035 read out negative, Amylyx would "do what is right for patients," which would include voluntarily removing the drug from the market.
In March, showed that while AMX0035 was safe and well tolerated, it did not meet the trial's primary or secondary endpoints. The topline results will be presented at the American Academy of Neurology annual meeting later this month.
The PHOENIX in ALS is ongoing. Amylyx said it intends to continue to collect available data on survival with AMX0035, at the encouragement of ALS specialists.
AMX0035 still is being investigated in ongoing trials of and , Amylyx said. The company also noted it plans to reduce its staff by about 70% as part of a restructuring effort.