• Neurosciences

    Mayo Clinic expert talks benefits, risks of experimental Alzheimer’s drug

An experimental drug for Alzheimer's disease shows promise to slow the progression of the disease, according to clinical trial results reported by Eli Lilly and Company. Study participants with mild cognitive impairment or mild dementia stages of Alzheimer's disease who received donanemab showed a slowing of clinical decline by 35% compared to placebo and resulted in a 40% less decline in the ability to perform activities of daily living.  

"Donanemab is a drug that reduces one of the proteins that defines Alzheimer's disease in the brain, the amyloid protein," explains Dr. Ronald Petersen, a neurologist and director of the Mayo Clinic Alzheimer's Disease Research Center. "It reduces the amount of that protein over time, and this produces a slowing in the progression of the disease." The drug lowered amyloid levels in the brain to normal in 71% of the participants by 12 months.

Researchers have been working for years on developing Alzheimer's disease treatments that can stop or delay the progression of the disorder.

"There are two other drugs that have received accelerated approval from the Food and Drug Administration for the treatment of Alzheimer's disease," says Dr. Petersen. "This drug is in that class. So, if it is approved by the Food and Drug Administration, it will give our physicians other options to treat patients at an early stage of Alzheimer's disease."

Watch: Dr. Ronald Petersen talk about the pros and cons of experimental Alzheimer's drug

Journalists: Video is available in the downloads at the end of the post. Name super/CG: Ronald Petersen, M.D., Ph.D./Alzheimer's Disease Research Center/Mayo Clinic

Alzheimer's drug risks

As with any drug, Dr. Petersen says donanemab has potential side effects that can be serious.

"The risks are for what's called micro edema, or small swelling in the brain, micro hemorrhage, small bleeding in the brain. And rarely these can extend and actually cause large bleeding problems in the brain, which in some cases can be fatal," says Dr. Petersen.

Because of these risks, people who are on blood thinners or have certain genetic features likely would not be candidates for this drug, at least in the early stages, he says.

Other medications

Two other disease-modifying treatments, aducanumab and lecanemab, recently received accelerated FDA approval. Dr. Petersen says donanemab, if approved, would give doctors and patients more choices when it comes to treating the life-altering disease. All three medications are given by IV infusions.

About Alzheimer's disease

Alzheimer's disease is a brain disorder that affects memory, thinking and behavior. The disease causes the brain to shrink and brain cells to eventually die. The neurological disorder starts slowly and gradually worsens over time, causing significant impairment in memory and other cognitive functions.

According to the Centers for Disease and Prevention, 5.8 million Americans were living with Alzheimer's disease in 2020. Data show the number of people living with the disease doubles about every five years beyond age 65. Younger people may get Alzheimer’s disease, but it is less common.

There is currently no cure for Alzheimer's disease, and treatments have been aimed at managing symptoms and improving quality of life.

Further results for donanemab will be presented at the Alzheimer's Association International Conference in July.

Disclosures: Dr. Petersen has consulted previously with Eli Lilly, Eisai, Roche, Genentech and Nestle Health Science. He was not involved in the design or execution of clinical trials for donanemab, lecanemab or aducanumab.

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