ALS drug wins FDA OK despite questionable data

WASHINGTON — A much-debated drug for Lou Gehrig’s disease won U.S. approval Thursday, a longsought victory for patients that is likely to renew questions about the scientific rigor behind government reviews of experimental medicines.

The Food and Drug Administration approved the drug from Amylyx Pharmaceuticals based on results from one small, midstage study in which patients with the debilitating disease appeared to progress more slowly and survive several months longer. Typically, the FDA requires two large studies or one study with “very persuasive” survival results for approval.

“This approval provides another important treatment option for ALS, a lifethreatening disease that currently has no cure,” FDA’s neurology drug director Dr. Billy Dunn said in a statement.

The drug, Relyvrio, is the third U.S.-approved medicine for amyotrophic lateral sclerosis, or ALS, which destroys nerve cells needed for basic functions like walking, talking and swallowing.

The FDA’s review has become a flashpoint in broader debates about the regulatory agency, including how flexible it should be when reviewing drugs for deadly diseases and how much weight it should give to appeals from patients and other outside voices.

“I think it demonstrates the FDA’s ability to be facile and I think it demonstrates a lot of tenacity on the part of ALS patients and advocates,” said Dr. Catherine Lomen-Hoerth, an ALS specialist at the University of California San Francisco. “The company really tried to do everything possible to get this potentially promising drug out to patients.”

Amylyx’s drug is the latest in a string of neurological drugs that have won FDA approval despite questionable effectiveness data. The agency is still facing two government probes into its approval of the Alzheimer’s drug Aduhelm last year, which has not yet been shown to slow the disease.

In an online memo summarizing its decision, the FDA said “regulatory flexibility” was appropriate for approving Relyvrio, “given the serious and life-threatening nature of ALS and the substantial unmet need.”

The latest approval followed a remarkably turbulent path, including two negative reviews by the FDA’s internal scientists, who called the company’s results “borderline” and “not persuasive.” A panel of outside advisers backed that negative opinion in March, narrowly voting against the drug.

But the FDA has faced intense pressure from ALS patients, advocates and members of Congress. In recent weeks the agency received more than 1,300 written comments from the ALS community supporting the treatment.

That outpouring helped sway the same expert panel when the FDA reconvened them earlier this month to revisit Amylyx’s drug. The second time around, they backed the drug, 7-2. The vote was not binding, but it seemed to open the door for FDA approval.

Several panelists said they were reassured by an extraordinary exchange at the meeting in which an FDA official requested — and Amylyx affirmed — that the company would voluntarily pull its drug from the market if a large, ongoing study doesn’t confirm its benefit.

That 600-patient study is expected to report results in 2024.