Experimental Alzheimer's Drug Shows Promise in Delaying Symptoms

An experimental drug could potentially delay the onset of Alzheimer's symptoms in people genetically destined to develop the disease at a young age, researchers at Washington University School of Medicine reported this week.

The findings, published in The Lancet Neurology, hint that gantenerumab—an antibody that targets beta-amyloid protein plaques in the brain—might reduce the risk of cognitive decline by up to 50% in patients who received the treatment the longest.

"Everyone in this study was destined to develop Alzheimer’s disease and some of them haven’t yet," said senior author Randall J. Bateman, a professor of neurology at WashU Medicine, in a statement from the university. "We don’t yet know how long they will remain symptom-free—maybe a few years or maybe decades."

The research focused on people with DIAD, a rare genetic condition that virtually guarantees development of dementia between a person's 30s and 50s. The study followed 73 participants who received gantenerumab as part of the Dominantly Inherited Alzheimer Network Trials Unit (DIAN-TU) open-label extension study.

How gantenerumab works

For the subset of 22 asymptomatic patients who received gantenerumab the longest—averaging about eight years of treatment—the apparent reduction in risk was most pronounced. The study adds to a growing body of evidence supporting early intervention strategies in Alzheimer’s pathology and highlights the importance of preventative approaches in populations with dominantly inherited Alzheimer’s disease (DIAD), but researchers warned that such a small sample size means these results, while promising, require further confirmation.

The drug works by targeting beta amyloid, one of two proteins thought to drive Alzheimer's progression. In affected brains, misfolded versions of this protein accumulate into plaques that damage brain tissue. Gantenerumab helps break up these plaques and prevents new ones from forming.

“These exciting preliminary findings hint very clearly at the potential role of lowering beta amyloid in prevention of Alzheimer’s disease,” Maria C. Carrillo, chief science officer at the Alzheimer’s Association said in statements shared with Eurekalert.

Gantenerumab is not new. The drug previously failed in larger trials testing it in people already experiencing Alzheimer's symptoms, leading pharmaceutical company Roche to abandon its development in late 2022. But the new findings suggest timing might be crucial—perhaps the drug needs to be administered years before symptoms appear to be truly effective.

The study faced significant limitations. Many participants couldn't complete the full three-year extension period after Roche pulled support for the drug. The reduction in cognitive decline for the overall group wasn't statistically significant, possibly due to the small number of participants.

Also, nearly 30% of participants developed amyloid-related imaging abnormalities (ARIAs), markers of brain swelling or bleeding that are known side effects of anti-amyloid drugs. Two patients experienced severe cases that required stopping treatment, though they eventually recovered.

Overall, no life-threatening events or deaths occurred during the study.

Other studies show promise

The gantenerumab approach isn't the only novel Alzheimer's treatment making waves. As Decrypt previously reported, Chinese researchers recently published results from an experimental surgical procedure aimed at improving the brain's waste removal system.

Their study describes a "cervical shunting" operation that connects lymphatic vessels in the neck to veins, creating new pathways to flush out toxic proteins—helping reduce the effects of Alzheimer’s rather than preventing it.

One patient showed modest cognitive improvements after the procedure, with test scores improving across multiple measures. "My mother's memory is stabilizing and improving, and she is able to complete household chores every day," the patient's daughter told researchers four months after surgery.

Washington University is currently running additional prevention trials through its Dominantly Inherited Alzheimer Network-Trials Unit, testing both approved and newer experimental anti-amyloid drugs that might show even stronger benefits than gantenerumab. Many patients from the original extension study were switched to another drug called lecanemab—which has been found to reduce the brain degradation caused by Alzheimer’s—though data from this phase hasn't yet been analyzed.

While these findings mark potential progress, they represent early evidence rather than definitive proof that anti-amyloid drugs can prevent Alzheimer's when administered far enough in advance. The researchers emphasized that confirmation will require larger, longer-term studies specifically designed to test this preventive approach.

Edited by James Rubin