Amylyx Pharmaceuticals (Nasdaq:AML) has won FDA approval for Relyvrio (AMX0035; sodium phenylbutyrate and ursodoxicoltaurine), notching the first win for amyotrophic lateral sclerosis (ALS) in five years.
The drug received Health Canada approval in June. The drug is known as Albrioza in that country.
In a summary, FDA reviewers note that the limited clinical data available for the drug have resulted in “in a degree of residual uncertainty about the evidence of effectiveness” of the drug. The agency notes that the lack of clarity is acceptable given the significant disease burden of ALS.
“This approval provides another important treatment option for ALS, a life-threatening disease that currently has no cure,” said Dr. Billy Dunn, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, in a news release. “The FDA remains committed to facilitating the development of additional ALS treatments.”
AML shares were up 10.47%, hitting $33.35 in after-hours trading.
Its stock initially traded at $18.07 after its initial public offering on January 7, 2022.
Amylyx announced today that a 28-day supply of the drug would cost $12,500, equating to roughly $158,000 in the first year. The cost would rise to $163,000 annually in the following years.
Patient-advocacy groups such as the ALS Association have lobbied for the FDA approval of Relyvrio. The ALS Association donated $2.2 million to fund its development.
A Phase 2 study found that the combination of Relyvrio and the approved ALS drugs riluzole (Rilutek) or edaravone (Radicava) resulted in a 25% reduction in disease progression at six months.
The Phase 2 CENTAUR trial involved 137 participants with ALS. Meeting its primary endpoint, the study had a six-month randomized placebo-controlled phase and an open-label extension long-term follow-up phase.
While FDA reviewers generally require Phase 3 results, its decision to approve the drug with Phase 2 data is an example of “regulatory flexibility. “[T]he single study with positive results on a clinically meaningful primary outcome accompanied by confirmatory evidence of an observed survival benefit provides substantial evidence of effectiveness,” FDA reviewers noted in a summary. “The benefits of AMX0035 outweigh the risk, as the drug appears well tolerated without any significant safety signals of concern.”
A 48-week Phase 3 study is underway. Results from that study are expected in 2024.
In March, an FDA advisory committee expressed skepticism about the drug’s potential to help ALS patients. The committee narrowly concluded that the CENTAUR trial data did not establish that AMX0035 is effective in the treatment of ALS.
The FDA extended its initial deadline for deciding whether to approve the drug after a March meeting of an advisory committee.
“The company submitted additional analyses of data to the FDA from our clinical studies for AMX0035, including published analyses in the peer-reviewed medical journals Muscle & Nerve and the Journal of Neurology, Neurosurgery and Psychiatry, supporting the previously reported functional and overall survival benefit for AMX0035,” explained a Amylyx spokesperson. “We thought it was important to review the information in detail to ensure that the methodology was clear and that questions raised during the March advisory committee meeting and by the FDA were answered.”
The FDA determined that the submitted analyses constituted a major amendment to the NDA. The agency extended the PDUFA date to September 29, 2022, which is when the FDA is anticipated to make its decision on AMX0035 for the treatment of ALS in the U.S.
Filed Under: Neurological Disease