US FDA faces criticism over Alzheimer’s drug approval

Biogen drug was authorised based on evidence that it can reduce brain plaques

In approving the first new Alzheimer's drug in nearly 20 years, the US Food and Drug Administration is taking its biggest risk yet with a strategy that allows new therapies onto the market without strong evidence that they work, regulatory and scientific experts say.

The Biogen Inc drug, Aduhelm, was authorised based on evidence that it can reduce brain plaques, a likely contributor to Alzheimer's, rather than proof that it slows progression of the lethal mind-wasting disease.

The FDA has granted socalled "accelerated approval" in more than 250 instances since 1992, mainly for rare diseases or small patient populations that have had no effective treatments available to them. In these cases, the agency requires that drugmakers conduct additional clinical trials to prove their therapy works, or face withdrawal from the market.

Aduhelm, however, is in a different league in terms of the number of potential patients and cost to the healthcare system.

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FDA approval ignored the recommendation of its outside advisors, who said Biogen did not provide enough evidence of clinical benefit. Three of the advisory panel's members have resigned in protest since the FDA decision was announced on Monday.

"This decision has shaken the foundations of the scientific process and methods," said Dr. Jason Karlawish, co-director of the Penn Memory Center in Philadelphia. Karlawish ran one of the trial sites for the Biogen drug.

He said the FDA made its decision "by fiat," and had not asked its advisors to consider whether the drug's ability to remove a type of brain plaques known as beta amyloid would improve outcomes for patients.

"It's a disturbing set of events, scientifically, clinically, politically," Karlawish said.

Biogen has said that some 1.5 million Americans with earlystage Alzheimer's will be eligible for the drug, priced at an average of $56,000 per year, with the federal Medicare insurance programme for seniors likely on the hook for most of the cost.

The FDA approval allows Biogen to sell its product over several years - with forecasts for potential annual sales reaching as high $10 billion to $50 billion - until the company completes a required follow-up study.

"No amount of unmet need can take the place of sufficient evidence," said

Johns Hopkins public health professor Dr. Caleb Alexander, a member of the FDA advisory panel.

The number of Americans living with Alzheimer's is expected to more than double to around 13 million by 2050, according to the Alzheimer's Association.

Biogen research chief Alfred Sandrock said the FDA had painstakingly analysed its clinical trial data over two years before reaching a conclusion.

"I believe they came to the right decision on behalf of the American public," Sandrock said in an interview.