Lecanemab, developed by pharmaceutical company Eisai, is a targeted antibody treatment that binds to amyloid, a protein which builds up in the brains of people living with Alzheimer’s disease.
It is designed to help clear the build-up and slow down cognitive decline in people with the condition and is given to patients via an intravenous drip fortnightly.
The decision from the Medicines and Healthcare products Regulatory Agency (MHRA) is set to be announced shortly, but it is understood to have approved the treatment.
It will also need the green light from health service spending watchdog the National Institute for Health and Care Excellence (Nice) before it is rolled out on the NHS in England.
Lecanemab is already licensed in the US, where it costs about £20,000 per patient per year, although it was rejected by the European Medicines Agency (EMA) in late July.
The EMA said the benefits of lecanemab did not counterbalance the risk of people suffering serious side-effects such as bleeding and swelling in the brain.
It also said the effects of the drug on delaying cognitive decline were small.
A similar drug called donanemab, which is developed by Eli Lilly, is also being assessed for approval in the UK by medicine regulators.
NHS England estimates between 50,000 and 280,000 patients might be eligible for the new treatments.
Prior to being given the drugs, they will need to have a baseline MRI scan and then either a Pet-CT scan or lumbar puncture to confirm Alzheimer’s.