At the end of September preliminary results of a phase 3 trial into the drug lecanemab were published, showing a slowing of pace in cognitive decline of individuals living with Alzheimer's.

The drug lecanemab is intended to remove the deposits of the protein amyloid, that build up in the brains of individual with Alzheimer's.

This drug trial involved 1,795 volunteer participants, each in the early stages of Alzheimer's disease. Participants in the intervention group were injected with lecanemab every two weeks. Participants in the control group were given a placebo. The preliminary results show that the pace of cognitive decline in the intervention group was reduced by 27% over the course of the 18-month trial.

Phase 3 drug trial: Aim to test the safety and efficacy of a drug in a large group of people, often in multiple locations. This is usually assessed by monitoring results in an intervention group versus a control group.

Intervention group: The group in a clinical research study that receives the drug, vaccine, or other intervention being tested.

Control group: The group in a clinical research study that do not receive the experimental treatment.

Placebo: A placebo is anything that seems to be a "real" medical treatment -- but isn't. Placebos are given to the control group in a drug trial. If the trial is blind, the participants do not know they are receiving a placebo. If the trial is double blind, neither the participants nor the researchers know they are being given a placebo.