After reporting the failure of a confirmatory trial of its amyotrophic lateral sclerosis (ALS) drug Relyvrio (AMX0035), Amylyx Pharmaceuticals is uncertain whether it will pull the treatment from the market in the U.S. and in Canada, where it is known as Albrioza.
“We’ll spend the next eight weeks engaging with regulatory authorities and the ALS community to share the top-line data,” co-CEO Justin Klee said on a Friday conference call. “We’ll follow the science and do what’s right for the community which may include voluntarily removing the product from the market.”
The 11-year-old Cambridge, Massachusetts-based company has decided to pause promotion of Relyvrio. Patient support services will remain in place, it said.
Two weeks ago, Amylyx reported sales of Relyvrio at $380 million in its first full year on the market, following its approval in September 2022. While sales initially scaled up quickly, the trajectory had slowed, going from $103 million in the third quarter to $108 million in the fourth quarter.
Other than to report that the PHOENIX trial did not meet its primary endpoint, failing to reach statistical significance as measured by change from baseline in the revised ALS functional rating scale (ALSFRS-R), or any of its secondary objectives, Amylyx did not reveal figures from the 48-week trial that enrolled 664 ALS patients.
The company said it will present the data at an upcoming medical conference, and results will be published in a medical journal later this year.
With the devastating news, Amylyx’s shares plummeted 83% by midmorning.
“The news comes as a massive disappointment—not only for us (where AMLX has been a top pick) and investors—but also to ALS patients and the overall ALS community,” analysts from Mizuho Securities wrote in a note to clients.
The company said it will continue to study AMX0035 as a treatment for two other neurodegenerative diseases—Wolfram syndrome and progressive supranuclear palsy. Amylyx also hopes to enter the clinic in the second half of this year with AMX0114, a treatment for ALS patients designed to lower their levels of calpain-2 to strengthen their nerve fibers.
After much consternation and two advisory committee meetings—one voting down AMX0035 6-4 and the other giving it a thumbs-up vote of 7-2 after new analysis of trial data—the FDA signed off on Relyvrio 19 months ago.
The decision was based on results of the phase 2 CENTAUR trial, which showed that AMX0035 slowed progression and functional decline and extended survival. Experts who recommended rejection urged the FDA to wait until results of the phase 3 PHOENIX trial were available.
On Friday, Klee would not speculate on the difference between the trial results.
“I think it’s early,” Klee said. “It’s particularly important to take time to meet with the ALS experts. I think it speaks to the heterogeneity of ALS and also the difficulty in ALS and neurodegenerative diseases more in general. It’s so imperative that when we all, fighting these diseases, have setbacks like this, we learn from them so we can continue to advance because I do very strongly believe that we can have meaningful advances for people with neurodegenerative diseases."
The ALS Association was heavily invested in the success of the drug as well. Through its Ice Bucket Challenge in 2014, the organization donated $2.2 million to assist in its development. It also collected more than 50,000 signatures and submitted them to the FDA in 2020, urging the regulator for approval.
"While today's news is disappointing, there are more than 50 potential treatments in the clinical stage of development, including more than a dozen in phase 3 trials," the ALS Association said in a statement. "We are more committed than ever to ensuring that safe and effective treatments are approved and available to people living with ALS as quickly as possible."