We will one day be able to slow, halt and even eradicate Alzheimer's

Alzheimer’s is, quite rightly, among the most dreaded conditions of old age. It robs people of memories, puts immense strain on their carers and exerts a huge financial burden on both individuals and society. Tens of millions of people already have a diagnosis and, if projections are correct, that will more than double by 2050.

Until recently, there seemed no hope of averting this catastrophe, but rapid medical progress has raised the realistic prospect that Alzheimer’s can be treated – and eventually eradicated (see, How a new kind of vaccine could lead to the eradication of Alzheimer’s).

One of the first of a new class of drugs is already making waves, but not always for the right reasons. Last week, the UK’s Medicines and Healthcare Products Regulatory Agency approved a medicine called lecanemab. But NICE, a body that advises whether new treatments are cost-effective, has issued a preliminary decision that this won’t be funded by the taxpayer in England. Decisions have yet to be made for the rest of the UK.

This is obviously a bitter pill for people with Alzheimer’s and their loved ones to swallow. But in the grand scheme of things, it is good news. Lecanemab isn’t a particularly effective drug – its benefits are modest, it can have severe side effects and it is expensive – but it shows we now understand the causes of Alzheimer’s and can treat them. That is strengthened by the fact that the drug has also been approved in the US and Japan, though the European Medicines Agency has rejected it.

The path is therefore largely cleared for the next wave of drugs that go after the causes of Alzheimer’s, which could be ready by around 2030. These are vaccines – not in the traditional sense of providing immunity against infectious diseases, but they work in fundamentally the same way, prompting an immune response, in this case against the misfolded proteins that cause Alzheimer’s symptoms. The first will be therapeutic vaccines to slow or halt the progression of the condition, but the next generation will be prophylactic, designed to prevent it from ever developing. Eventually, the only fading memory will be of Alzheimer’s itself.