Mar 11, 2024 - Health

Setbacks reset views on highly touted Alzheimer's and ALS drugs

Illustration of an IV in the spotlight.

Illustration: Aïda Amer/Axios

A pair of setbacks to drugs for Alzheimer's disease and ALS on Friday served as another reminder that widely touted treatments for desperate patients aren't necessarily a sure thing.

Why it matters: Drugs are increasingly judged on the probability they'll work instead of real-world clinical results — often with energetic lobbying by patient advocacy groups.

  • That's putting more of a focus on how clinical trials are designed and the steps regulators have to take to validate a drug's effectiveness, even after it hits the market.

Driving the news: Amylyx Pharmaceuticals on Friday said Relyvrio, its drug for ALS, or Lou Gehrig's Disease, failed a post-approval trial of 664 patients by not showing a significant difference over a placebo.

  • The Food and Drug Administration approved Relyvrio in 2022 without the clinical trial evidence the agency typically requires over concerns from agency staff and amid an intense campaign by advocacy groups. Regulators concluded the level of uncertainty was acceptable.
  • The company said it will consult with patients and the FDA about next steps, which "may include voluntarily withdrawing" the $158,000-a-year treatment.

Also on Friday, Eli Lilly said the FDA said it would delay action on the company's experimental Alzheimer's drug donanemab while it convenes outside advisers to review its safety and efficacy.

  • A late-stage trial showed donanemab was effective in slowing the disease's progression, but there were lingering questions about whether its usefulness outweighs safety risks after some patients experienced brain swelling and bleeding.
  • The FDA's earlier controversial fast-track approval of the Alzheimer's drug Aduhelm, despite questions about its efficacy and safety, was seen as a black eye for the agency.

What we're watching: Even if Amylyx doesn't pull its ALS drug, analysts say doctors could stop prescribing it or significantly cut back their usage. That would be devastating for patients with a dreaded neurological condition that has few available treatments.

  • Analysts also questioned how long the company, which had $371 million in cash by the end of last year, can survive, per PharmaVoice.
  • On the Lilly Alzheimer's drug, even a delayed approval would improve prospects for a rival treatment, Eisai and Biogen's Leqembi, that was slightly less effective in slowing cognitive decline in early Alzheimer's patients.
  • The FDA's views on the way Lilly designed its trial could also give clues about how the agency will treat other Alzheimer's drugs that target proteins in the brain known as amyloid plaques that are believed to contribute to the development of Alzheimer's.
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