The findings of a research study that discovered a treatment for early stage Alzheimer’s disease have been hailed as “momentous” by Alzheimer’s Research UK. 

The new treatment, lecanemab, is the first drug to slow cognitive decline in people with early signs of the condition.

The CLARITY-AD study enrolled 1,795 patients with early-stage Alzheimer’s globally, including Join Dementia Research volunteers who took part in the UK clinical trials.

About the drug

Lecanemab, developed by pharmaceutical companies Eisai and Biogen, is an antibody that is designed to remove toxic beta-amyloid deposits. These are proteins that build up in the brains of people with Alzheimer’s disease.

Participants on the phase 3 clinical trial received infusions of lecanemab or a placebo (dummy drug) every two weeks to compare the two. They also regularly had their memory and mental agility tested over an 18 month period.

Whilst the drug is not a cure, results from the trial showed that brain function decline was slowed by 27% over the course of the 18 months of treatment.

The results were presented at the Clinical Trials on Alzheimer’s Disease conference in San Francisco and published in the New England Journal of Medicine. 

Study results

The drug appears to reduce toxic plaques in the brain, thereby reducing the rate of decline in people’s memory and thinking.

The study adds further evidence to the theory that the buildup of amyloid proteins in the brain is the primary cause of Alzheimer’s disease. Prior to this ground-breaking study, dozens of other drug trials in this area had failed, leading to questions about whether amyloid was really causing the disease.

A reduced decline of 27% is a modest change in clinical outcome but it is the first time any drug has been clearly shown to alter the disease’s trajectory.

Side effects included brain swelling and headaches, which is in line with the expectations of the pharmaceutical companies.

Eisai and Biogen are now applying for regulatory approval for the drug to be given in the US, Europe and Japan.

What does it mean?

Professor John O’Brien, NIHR Clinical Research Network National Speciality Lead for Dementia said: “We are pleased to see the results of this study, which is the first trial to show significant benefits in people with early stage Alzheimer’s disease from lowering amyloid levels in the brain – and are excited about the future potential of this new generation of treatments.

“Whilst it is not a cure for people with Alzheimer’s disease, it can help slow the decline in brain function in people in the early stages of the condition. It is important we continue research as we need more effective drugs and ones that are easier to administer, but this also greatly adds to our knowledge of the types of drugs that can be used to treat Alzheimer’s disease.” 

A big thank you to all the Join Dementia Research volunteers who took part in this study and helped to test this new potential treatment.