Early on-set cases: New Alzheimer's drug shows promise in slowing disease

Rahul Sidhu

Alzheimer's disease is usually associated with old age. However, around 5%-10% of all Alzheimer's cases occur in people under the age of 65. Early-onset Alzheimer's disease progresses more rapidly and often strikes people in the prime of their lives. Treatment options remain limited.

However, new data from a recent clinical trial suggests that a previously discontinued experimental drug, called gantenerumab, could help. The study found that gantenerumab reduced the buildup of amyloid plaques – one of the hallmarks of Alzheimer's disease – in the brain. This may help slow cognitive decline in people with early-onset Alzheimer's.

Early-onset Alzheimer's is often linked to genetic mutations in three specific genes. These mutations cause the brain to produce excessive amounts of amyloid beta, a protein that clumps together to form plaques. These plaques disrupt brain function, leading to memory loss.

Early-onset Alzheimer's advances quickly, and the rapid decline is devastating. That's why researchers are racing to find treatments that can slow the disease.

The recent clinical trial was a randomised, placebo-controlled study to evaluate gantenerumab's effects on people with early-onset Alzheimer's. Researchers monitored changes in the participants' cognitive abilities and also used brain imaging and blood biomarkers (the presence of specific proteins in the blood which are linked to Alzheimer's), to track the disease's progress throughout the study.

The trial included 73 participants with rare inherited genetic mutations known to cause early-onset Alzheimer's. These participants were either asymptomatic or had mild Alzheimer's symptoms at the start of the study.

The results were intriguing. In a subgroup of 22 participants who hadn't had any cognitive issues at the start of the study, taking the treatment for an average of eight years reduced the risk of developing symptoms from a nearly 100% likelihood to 50%. Brain scans also showed a notable decrease in amyloid buildup.

Gantenerumab is a monoclonal antibody – a lab-engineered protein designed to attach to amyloid beta in the brain. By binding to these plaques, it signals the immune system to clear them away. This may potentially slow Alzheimer's progression.

The drug works by engaging microglial cells. These are the brain's primary immune defenders. Microglia constantly monitor the brain for damage and remove harmful substances, including amyloid beta. However, in people with Alzheimer's disease, microglia often fail to clear plaques efficiently. Gantenerumab enhances this natural defence mechanism by tagging amyloid plaques, making them easier for the microglia to recognise and break down.

Amyloid beta is thought to play a central role in Alzheimer's by triggering inflammation, interfering with cell communication and ultimately killing neurons. By removing these plaques, gantenerumab may help to protect brain function. However, it doesn't reverse existing damage – which is why early intervention is critical.

Alzheimer's research is advancing faster than ever before. Whether a success or a setback, each new study adds to our understanding of the disease and brings us closer to more effective treatments. For now, the gantenerumab trial offers a hopeful sign that scientists are making progress in slowing the course of this devastating condition.