For decades, the treatment of dementia has seemed frustratingly dormant. Two classes of drugs that were introduced three decades ago can improve symptoms: Cholinesterase inhibitors boost acetylcholine, a chemical the brain needs for alertness, memory and judgment; and memantine regulates glutamate, a chemical messenger needed for learning and memory. But neither offers a way to limit the disease’s progress. Aducanumab, launched two years ago, can reduce buildup of amyloid plaques in the brains in Alzheimer’s patients, but it has not been proved to slow cognitive decline.
Now, thanks to years of research progress, we’re on the brink of major advances in treatment and prevention.
“The new drugs are big, exciting breakthroughs,” says Gill Livingston, a professor of psychiatry of older people at University College London. However, she adds, it’s still early.
In January of this year, the U.S. Food and Drug Administration approved the first drug that slows the progress of Alzheimer’s rather than just treating the symptoms. In clinical trials, people with Alzheimer’s who took the drug lecanemab (Leqembi) for 18 months showed their rate of memory and cognition decline was 27% less than in those who took a placebo. But it’s not clear what that decline translates to in the real world. And there are downsides to the new drug, which is given by IV. It’s expensive, and it can have serious side effects, including bleeding in the brain.
A second drug, donanemab, not yet approved by the FDA, has also shown promise in clinical trials. It slows the rate of cognitive decline from Alzheimer’s by about one-third. But, like lecanemab, it can have similar serious side effects.
“So we’re not quite there,” says Dr. Livingston. “But it’s fantastic that we’re beginning to be there.”