17 July 2023
Another experimental Alzheimer's drug has been shown to slow patients' worsening conditions, researchers reported Monday.
The American drug company Eli Lilly said it is seeking U.S. Food and Drug Administration (FDA) approval for the drug donanemab. If approved, it would be the second Alzheimer's treatment for delaying the disease. Alzheimer's affects the brain and causes memory loss and dementia.
The FDA approved Leqembi, from Japanese drugmaker Eisai, earlier this month.
"Finally there's some hope, right, that we can talk about," Lilly's Dr. John Sims told reporters Monday at the Alzheimer's Association International Conference in Amsterdam, the Netherlands.
The drug does not cure the disease. Instead, it slows its progression by about four to seven months. But Sims noted that "it doesn't mean you can't have very meaningful treatments for patients."
Eli Lilly published the full results of its study of 1,700 patients in the Journal of the American Medical Association. It also presented its results at the Alzheimer's conference.
Both donanemab and Leqembi are laboratory-made antibodies. The treatments are injected into the patients. The drugs target a protein buildup, called beta amyloid, in the brain of Alzheimer's patients.
Both drugs come with serious safety concerns. Patients can experience brain swelling or bleeding. In the Lilly study, such side effects were linked to three deaths.
Dr. Liana Apostolova was the study investigator. She is also a professor in Alzheimer's Disease research at Indiana University School of Medicine. She said, "These side effects should not be taken lightly." But she added that, in most cases, the effects were well controlled by monitoring with magnetic resonance imaging (MRI) or by stopping using the drug.
The Eli Lilly study
Lilly's study included people ages 60 to 85 who were in the early stages of Alzheimer's. Half of the study subjects received a monthly injection of donanemab for up to 18 months. The other half received an inactive substance, called a placebo.
Patients were also switched to inactive substances if enough amyloid cleared out. The study found that it happened to half of the patients within a year.
Amyloid alone does not cause Alzheimer's. So researchers also studied the levels of tau, another protein that causes the disease in the brain. Patients with higher levels of tau are considered to be in the more advanced stages of Alzheimer's.
The results: both groups declined during the 18-month study but the drug appears to work better for patients in earlier stages of the disease. Those with low to medium tau levels saw a 35- percent slower decline. For high tau patients, donanemab slowed the disease progression by about 17 percent.
Anne White is the president of neuroscience at Lilly. She said, "At the end of the trial, the average patient had been without drugs for seven months and yet they continued to benefit."
Scientists say that, while these drugs may mark a new era in Alzheimer's treatment, huge questions remain about which patients should try them. Questions also remain about how much benefit patients will really experience.
The main safety concern is brain swelling or bleeding. These conditions often cause no symptoms but sometimes can be serious, even deadly.
Another concern is that more than 90 percent of the study's patients were white. That means there is little data on how effective the treatment could be for other populations, said Alzheimer's specialist Jennifer Manly of Columbia University.
Lilly expects the FDA to decide by the end of this year whether to approve donanemab. The company is also seeking approval from other health agencies worldwide.
I'm Jill Robbins.
Hai Do adapted this story for Learning English based on reporting by The Associated Press and Reuters.
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Words in This Story
dementia - n. a mental illness that causes someone to be unable to think clearly
stage - n. a particular point or period in the development of something
decline - v. to become worse in condition
benefit - v. to be helped