FDA approves ALS drug from Amylyx, giving patients a much-needed treatment option

The Food and Drug Administration approved a new medicine for ALS from Amylyx Pharmaceuticals on Thursday, providing a desperately-needed new treatment option for a devastating disease.

The medicine, to be sold as Relyvrio, is not a cure for ALS but proved to moderately slow the progression of the neurological disease, which causes the destruction of neurons in the brain and spinal cord, resulting in weakened muscles, paralysis, and death.

The drug will be available in the U.S. within the next six weeks, Amylyx said. The company set a list price of about $158,000 per year for Relyvrio, which is slightly cheaper than the last medicine approved for ALS. That figure doesn’t reflect what patients can expect to pay, the company said, and Amylyx promised to set up a patient-assistance program that would limit copays for those with commercial insurance.

The approval is based on a small, 24-week study in which patients who received Amylyx’s drug performed about two points better on a 48-point scale of ALS symptoms than those who got placebo. The FDA initially took a dim view of Amylyx’s supporting evidence but later reversed course at a dramatic public hearing earlier this month, with the agency’s head of neurology promising to apply the “broadest regulatory flexibility” in light of the dire need for new ALS treatments.

Amylyx is conducting a larger, longer clinical trial to confirm Relyvrio’s benefits, with data expected in late 2023 or early 2024. In a rare commitment, the company has promised to remove the drug from the market if that study is not successful.

ALS patients and advocates vehemently supported Relyvrio’s approval, arguing that the FDA had not extended the same flexibility it applied to new medicines for Alzheimer’s disease and other neurological disorders. Canadian regulators approved Amylyx’s drug in June, escalating the pressure on the FDA.

The drug is a fixed-dose combination of two generic medicines, taurursodiol and sodium phenylbutyrate, sold as a powder to be mixed with water and taken orally or through a feeding tube. In a clinical trial, its most common side effects were diarrhea, abdominal pain, nausea, and upper respiratory tract infection.

Amylyx received about $2.4 million from the ALS Association to pay for the development of Relyvrio, money raised through 2014’s viral “Ice Bucket Challenge” fundraiser.

“It’s hard to put into words how significant this approval is for the thousands of Americans who are living with ALS and their families,” said Larry Falivena, a trustee of the ALS Association who was diagnosed with the disease in 2017, in a statement. “The ALS community has proven that our advocacy can impact decisions that are being made about our health.”

Amylyx’s share price rose about 10% in after-hours trading Thursday. The company, which went public in January on the promise of Relyvrio, has doubled in value since then.

About 20,000 people in the U.S. have ALS, or amyotrophic lateral sclerosis, with 5,000 new cases diagnosed each year. The cause of the disease is not fully understood, although genetic mutations and environmental factors are thought to play a role.

Of the medicines for ALS previously approved in the U.S., only riluzole, cleared in 1995, has been shown to help patients live longer, but only by a few months. A second drug called edaravone, approved in 2017, slows the progression of ALS.