How does lecanemab work? When will it be rolled out? And is it dangerous? Everything you need to know about the breakthrough Alzheimer’s drug

It was hailed as a “memorable” breakthrough.

World-renowned experts have even boldly claimed that lecanemab’s breakthrough results represent the “beginning of the end” in halting the brutal progression of Alzheimer’s disease.

But what is the medicine? And how does it work?

Here MailOnline answers all your questions about lecanemab, including when it can be given to patients in the UK and US.

what does it do

Lecanemab is given once every two weeks as an infusion to patients with early stage Alzheimer’s disease.

It is designed to remove a build-up of amyloid proteins – toxic plaques in the brain that are thought to cause the cruel, memory-impairing disease.

Professor John Hardy (pictured), a world-leading dementia researcher and molecular biologist at University College London, said the drug was “the beginning of the end”.

The antibody treatment, which tells the immune system to remove amyloid from the brain, is made by Japanese and American pharmaceutical companies Eisai and Biogen.

What did tests show?

The phase III study of lecanemab evaluated the drug’s ability to reduce cognitive and functional decline in 1,795 early-stage Alzheimer’s patients.

Half of the participants received 10 mg/kg of the drug every two weeks, while the other received a placebo.

The researchers measured the memory, judgment, problem solving and judgment skills of all participants before they took part in the study and again 18 months later.

The results showed that those who took lecanemab had 27 percent less mental health deterioration than those who took the sham treatment.

Lecanemab recipients also experienced a slower build-up of amyloid in their brains, scans showed.

Lecanemab given as an infusion every two weeks to patients in the earliest stages of Alzheimer’s disease (stock)

The findings were presented at a medical conference in San Francisco and published in the prestigious New England Journal of Medicine.

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Is the drug dangerous?

Breakthrough drug was the ‘beginning of the end for dementia’ amid doubts over risk of brain haemorrhage, expert warns

Some experts say that with the risk of cerebral haemorrhage it may not be possible to safely introduce lecanemab into the NHS

In addition to promising results, the study also revealed some safety concerns.

Brain swelling was noted in 12.5 percent of the lecanemab group, compared to 1.7 percent in the placebo group.

Although they showed up on scans, many of these cases were asymptomatic, Eisai and Biogen pointed out.

The data also showed that 17 percent of the lecanemab group experienced microbleeds, or mini-cerebral hemorrhages, in the brain, compared with 8.7 percent of the placebo group.

Pharma chiefs insisted the numbers were within an expected range.

Two patients died while taking lecanemab during the study in events under investigation.

However, Eisai and Biogen noted that all available safety information shows that the therapy is not associated with an increased risk of death.

How close is the deployment?

The drugmakers are seeking approval for lecanemab from the US Food and Drug Administration, with a decision expected in early January.

The companies say they will also submit their findings to regulators in Japan and Europe by April 2023.

However, the watchdogs must then determine whether the drug is safe and effective before making a decision.

Experts predict that the drug will be available to British patients as early as 2023.

How does it differ from a similar drug Aduhelm?

Both Aduhelm and Lecanemab – both made by Eisai and Biogen – are antibodies designed to remove amyloid deposits.

However, Lecanemab targets amyloid that has not yet aggregated.

Aduhelm removes amyloid plaques that have built up in the brain.

The approval of Aduhelm was a rare bright spot for Alzheimer’s patients, but critics warned of the drug’s disappointing results and highlighted its risks.

Aren’t there already medications for Alzheimer’s?

There are currently no treatments for Alzheimer’s disease, and decades of efforts have repeatedly failed to produce a cure.

However, medication is dispensed to combat perceived symptoms.