The first drug found to slow dementia onset has had trial results confirmed in what scientists say could “herald a new era” for people with Alzheimer’s.
The drug, lecanemab, is an antibody therapy that removes clumps of a protein called beta-amyloid which builds up in the brain. It is unclear how much the clumps drive Alzheimer’s, but in patients with inherited forms of the disease, they appear to pave the way for a cascade of brain changes that steadily destroy brain cells.
Lecanemab’s developers, Biogen in the US and Eisai in Japan, announced top-line results from the clinical trial in nearly 1,800 patients in September, but researchers in the field have anxiously awaited the full data published this week in the New England Journal of Medicine.
With Lecanemab, the way Alzheimer’s is treated is about to change. Essentially, it is an antibody like the ones that the human body makes to combat viruses.
This showed the drug reduced the decline in patients’ overall mental skills by 27% over 18 months – a modest but significant result. The new drug is giving hope to new ways of treating the condition.
Alzheimer’s accounts for nearly two-thirds of the 55 million people living with dementia worldwide. It is the leading cause of death in the UK: patients typically die within seven years of a diagnosis.
Amid widespread excitement at the results, researchers highlighted a host of issues that could hamper the drug’s adoption.
Lecanemab is expensive – between £10,000 and £30,000 per patient a year – and has such a modest effect, at least over 18 months, that it is unclear whether patients would notice any benefit. There is still a long way to go before we could see lecanemab available, and we await clarity on how and when the approval process will take place and whether regulators believe it is cost-effective. We mustn’t forget that lecanemab can only be given to people with early Alzheimer’s disease who have amyloid in their brains. This means people with other types of dementia, or in the later stages of Alzheimer’s disease, cannot benefit from this drug.
Also, the news of a second patient death linked to the drug has dampened expectations and potentially created a more complicated path for the drug to hit the market. The FDA will likely consider those deaths, as well as data from the trial showing that people taking anti-coagulant drugs may have a slightly higher risk of bleeding events, before determining whether lecanemab is safe to prescribe as it stands, or if an additional warning on the label about hemorrhage risk is warranted.
But based on the positive results, the door is now open to investigating how these anti-amyloid therapies can best be used to slow cognitive decline. Scientists are calling it the beginning of the beginning for the treatment of Alzheimer’s.