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FDA approves controversial new drug designed to slow the progress of ALS

The drug, made by Amylyx Pharmaceuticals, joins a handful of approved medications for the fatal neurodegenerative disease.
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The Food and Drug Administration on Thursday approved a controversial new drug designed to slow the progress of Lou Gehrig's disease, a victory for patients and advocates despite limited evidence that the drug is effective.

The drug, from Amylyx Pharmaceuticals of Massachusetts, joins only a handful of drugs approved by the agency for the fatal neurodegenerative disease and its symptoms. 

The disease, also called amyotrophic lateral sclerosis, or ALS, affects nerve cells needed for activities like walking, speaking and eating. There is no known cure, and most people live only two to five years after diagnosis, according to The ALS Association.

The FDA's decision was based on a single phase 2 clinical trial of 137 ALS patients that found people who took Amylyx’s drug, which will be sold under the name Relyvrio, lived about 10 months longer than those who didn’t. The drug also appeared to delay hospitalizations. 

The medicine, which comes in a powder, is a combination of two existing products: sodium phenylbutyrate, which is prescribed to treat a metabolic disorder, and taurursodiol, an over-the-counter supplement used to help prevent liver disease.

Amylyx said Friday that Relyvrio will cost about $12,500 for a 28-day supply, or $158,000 a year before insurance. That's below the price of an older ALS drug, edaravone, which costs around $170,000 a year. But Relyvrio's price is still above the Institute for Clinical and Economic Review's recommended price of between $9,100 to $30,700 per year.

The approval is likely to spawn some disagreement among neurologists who treat ALS.

Generally, the FDA requires at least two well-controlled clinical trials to demonstrate that a drug is effective or a single trial that is "highly statistically persuasive," said Holly Fernandez Lynch, an assistant professor of medical ethics at the University of Pennsylvania. Amylyx's trial, she said, didn't meet the agency's standards.

Concerns about the trial results were raised in March, when the drug was first brought before an FDA advisory committee. In briefing documents released ahead of the meeting, agency scientists questioned the Amylyx trial's persuasiveness. The committee voted narrowly against recommending approval.

The FDA, however, took the unusual step of calling for a second advisory committee just six months later, after Amylyx submitted an additional analysis of its trial data. During that meeting, the advisory committee reversed course, voting to recommend the drug.

The favorable vote came despite yet another poor review from FDA scientists, as well as concerns from several members of the advisory committee about whether the clinical trial data provided by Amylyx showed clear evidence that the drug slows the progression of the disease.

The agency’s consideration of the drug has been compared to that of Biogen’s Alzheimer’s drug, Aduhelm. That drug received full approval from the FDA last year, even though the advisory committee voted overwhelmingly against its recommendation, citing a lack of evidence that it was effective.

Amylyx's drug approval suggests that the FDA is willing to show the utmost flexibility for life-threatening diseases for which there is an "unmet treatment need," Lynch said.

However, the decision could pose further challenges for the agency, she added, because it may not give the company much incentive to prove that the drug works.

"It also puts the onus on payers to decide whether the evidence is sufficient to support coverage, so in that sense, it may simply kick the can," she said.

Advocates say that while questions remain about the drug's effectiveness, patients should be allowed to at least try it.

"We need new treatments as quickly as possible if we are going to turn ALS into a livable disease and eventually cure it," Larry Falivena, a member of The ALS Association, an advocacy group, said in an email.

Amylyx is running a larger phase 3 clinical trial, which it expects to complete in late 2023 or early 2024. 

During the September advisory committee meeting, company representatives agreed to pull the drug from the market if those trial results showed it was not effective. The drug has already received conditional approval in Canada. 

CORRECTION (Sept. 29, 2022, 9:34 p.m. ET): An earlier version of this article misstated how the Amylyx drug is taken. It is taken orally as a powder, not as a pill.

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