Experimental Drug Shows Promise in Preventing Alzheimer’s, Researchers Say

An experimental drug is offering new hope in the fight against Alzheimer’s, showing potential to prevent the disease in individuals at high risk, according to researchers from Washington University School of Medicine in St. Louis.

The study focused on 73 individuals in their 30s, 40s, and 50s who carry rare genetic mutations that nearly guarantee the development of Alzheimer’s. These mutations cause an overproduction of amyloid, a protein that accumulates in the brain, disrupting cognitive functions and marking the onset of the disease.

Participants either had no cognitive decline or only mild symptoms. They were chosen based on their family history of Alzheimer’s and their proximity to the expected age of symptom onset—either 15 years before or 10 years after.

For 22 participants who were treated with the drug gantenerumab over an eight-year period, the risk of developing Alzheimer’s symptoms was halved—from 100% down to 50%. However, no significant effects were observed in those treated for just two to three years, according to Dr. Randall J. Bateman, senior author of the study.

The findings, published in The Lancet Neurology, mark a significant milestone in Alzheimer’s research. Gantenerumab, a monoclonal antibody developed by Roche and its U.S. affiliate Genentech, was designed to target and remove amyloid plaques in the brain. Despite these promising results, Roche halted the drug’s development in 2023 after it failed to meet primary endpoints in slowing cognitive decline during broader clinical trials.

"Everyone in this study was destined to develop Alzheimer’s disease, and some of them haven’t yet," Dr. Bateman said. "We cannot predict how long they will remain symptom-free—it could be years or even decades. However, delaying the onset of symptoms provides individuals more years of healthy life."

While gantenerumab is no longer being developed, alternative anti-amyloid drugs, such as remternetug by Eli Lilly, are being evaluated for their preventive potential. Researchers are optimistic that late-onset Alzheimer’s trials could yield similarly encouraging results for the general population.

Dr. Howard Fillit, co-founder and chief science officer of the Alzheimer’s Drug Discovery Foundation, emphasized the importance of this breakthrough, calling it "a new era of Alzheimer’s research." He noted that early treatment to clear amyloid plaques before symptoms emerge could be a game-changer, much like preventive measures for other chronic diseases.

However, experts caution that more research is necessary. The study’s limitations include its small sample size, reliance on external controls, and initial lower doses of the drug. Additionally, 30% of participants experienced amyloid-related imaging abnormalities (ARIA), a side effect that can cause brain swelling or small spots of blood on the brain. Although most cases were mild, two participants discontinued treatment due to severe ARIA.

Dr. Chris Vercammen, a specialist in geriatrics, called the findings "encouraging" but stressed the need for larger, randomized trials involving diverse populations to validate the results and explore the drug’s impact on late-stage Alzheimer’s.

Despite the hurdles, researchers are hopeful. Dr. Bateman highlighted the importance of continuing trials and engaging families with genetic mutations in these studies. "One day soon, we may be delaying the onset of Alzheimer’s disease for millions," he said.

The study was funded by the Alzheimer’s Association, GHR Foundation, and the National Institutes of Health. While gantenerumab may no longer be in the spotlight, its legacy might pave the way for groundbreaking preventive treatments in the years to come.