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Updates on New Alzheimer’s Disease Drugs

Health Letter, April 2024

By Robert Steinbrook, M.D.
Director, Public Citizen's Health Research Group

Biogen has announced that it will give up ownership of the controversial Alzheimer’s disease drug aducanumab (ADUHELM) and withdraw it from the U.S. market. As the Food and Drug Administration (FDA) should never have approved aducanumab, the announcement was welcome news. In 2021, Public Citizen’s Health Research Group called the FDA’s decision to grant aducanumab accelerated approval “indefensible,” characterizing the action as “one of the most irresponsible and egregious decisions in the history of the agency.” Fortunately, very few patients were prescribed aducanumab; the commercial failure of the drug hastened its demise.

Attention will now focus on lecanemab (LEQEMBI). In July 2023, the FDA granted lecanemab full approval (aducanumab never received full approval) despite the evidence that the drug’s clinical benefits did not outweigh its substantial health risks. Administered as an intravenous infusion, lecanemab, which costs about $26,500 a year, is a monoclonal antibody that targets beta-amyloid plaque in the brains of patients with Alzheimer’s disease. The drug was approved for patients with mild cognitive impairment and in the mild dementia stages of the disease (the groups of patients that were studied in clinical trials). The prescribing information includes a boxed warning for brain swelling and bleeding risks. Public Citizen’s Health Research Group has classified lecanemab as a Do Not Use drug; it neither cures nor reverses Alzheimer’s disease.

In the seven months after FDA approval, only about 2,000 patients were taking lecanemab, although about twice that number of patients have enrolled in registries, a necessary step for Medicare beneficiaries to be eligible to receive the drug. It is too soon to say what the eventual uptake of lecanemab will be.

Meanwhile, there have been several concerning developments regarding these drugs. First, the FDA continues to use amyloid lowering, a surrogate endpoint, for approving anti-amyloid drugs for Alzheimer’s disease instead of demanding “rock-solid clinical data” establishing benefit, as it should.

Second, the efficacy and safety of lecanemab are being studied in people who have no memory problems but do have abnormal levels of amyloid proteins. Although the motivation to prevent disabling memory impairments from Alzheimer’s disease before they develop is understandable, the approach is more likely to lead to the overdiagnosis of Alzheimer’s, anxiety or depression and subject people to potentially dangerous treatments for a disease they may never develop. A recent article in the Los Angeles Times detailed the disturbing plan not only to diagnose Alzheimer’s disease in people without memory problems but also to redefine what it means to have Alzheimer’s disease. As one geriatrician explained, “You no longer need to have cognitive impairment to have this disease. You just need the positive blood test.” If we have learned anything from the aducanumab debacle, it is that decisions about diagnosing and treating Alzheimer’s disease should be based on strong evidence that people will benefit and not be harmed, not wishful thinking or the quest for medical industry profits.