UPDATED: Amylyx's ALS drug gets a three-month PDUFA delay, setting up the pivotal decision for September
ALS patients in the US are going to have to wait a little bit longer to find out whether they’ll have a new treatment option.
The FDA has extended the review period for Amylyx Pharmaceuticals’ experimental ALS drug AMX0035 by three months, the biotech announced Friday morning, setting up a decision date of Sept. 29. Regulators had previously said the approval or rejection would come by June 29.
According to Amylyx, the FDA had requested more time to review the company’s data, and the biotech said the extension is classified as a “major amendment.” Typically, such extensions involve the agency requesting new data from the company, though it’s not immediately clear if FDA asked for new efficacy or safety analyses.
In an email to Endpoints News, Amylyx co-CEO Justin Klee declined to comment beyond what the company shared in its press release. The company’s stock $AMLX rose on the news, jumping about 40% pre-market after rising more than 14% Thursday.
The biotech has been working to get AMX0035 across the finish line and win just the third ALS drug approval in the US. ALS patients and advocates have intensified pressure on the FDA to greenlight AMX0035, arguing that because their disease is universally fatal, they should have the option to try the drug.
But the FDA expressed serious reservations about its effectiveness at an advisory committee hearing in March, calling Amylyx’s Phase II data into question. Though the drug slowed disease progression by a statistically significant margin compared to placebo according to a functional rating scale, agency officials took issue with the way Amylyx conducted its study and the robustness of the data.
Ultimately, the FDA’s panel of advisors said in a 6-4 vote that the Phase II data did not “establish” a conclusion that the drug is effective.
Nevertheless, ALS patients have remained undeterred in their quest for more treatment options, with the pressure on FDA manifesting in a nearly two-hour public comment session during March’s adcomm. Many with ALS end up with experimental drugs as their only options, signing up for clinical trials in the hopes that something will work.
In a quick-take reaction to the news, SVB Securities analyst Marc Goodman noted it was “not surprising” that Amylyx isn’t specifying the nature of the FDA’s request for new data, “given the issues raised” at the adcomm. Goodman said that most of the investment community is expecting the drug to be rejected, but the PDUFA delay suggests the FDA is struggling to make a decision.
“Several KOLs have written individual editorials rebutting many of the controversies from the meeting in addition to the continued aggressive lobbying by the ALS groups, but it’s still unclear how much these efforts are having an impact,” Goodman wrote to investors.
The FDA has previously approved two ALS drugs — riluzole in the mid-1990s, which has a modest effect on extending survival times; and edaravone in 2017, after it showed limited improvement on clinical function.
Whatever the agency’s decision for Amylyx, the process has already echoed approvals for Sarepta’s Duchenne muscular dystrophy drug Exondys 51 and Biogen’s Alzheimer’s therapy Aduhelm. Both of those drugs faced similar, significant efficacy questions as Amylyx, as well as negative adcomm votes, but were greenlighted regardless.
This story has been updated to include Amylyx’s response to Endpoints’ request for comment, the stock market’s reaction and analysis from SVB Securities analyst Marc Goodman.