A new drug could “train” the immune system to slow down Alzheimer’s disease – and it's just been approved in the US.

Prof Sean Kennelly, Clinical Director of the Institute of Memory and Cognition at Tallaght University Hospital, said it is an “exciting era” for the disease. 

“For the last 30 or 40 years, we really just have had medicines that can manage symptoms,” he told The Anton Savage Show. 

“We've gone into this new era whereby we're able to make a much more accurate biological diagnosis by measuring the proteins that cause the condition.” 

Prof Kennelly explained that “disease-modifying therapies” could “alter the trajectory” of Alzheimer’s. 

Donanemab has just been approved by the Food and Drug Administration in the United States, the second to be approved in the US. 

While no drugs for Alzheimer’s have been approved by the European Medical Agency (EMA), Prof Kennelly said the evidence so far is “really positive”. 

Slowing down Alzheimer's

Donanemeb, also known as Kisunla, as well as drugs such as Leqembi “train the immune system” to target a protein called amyloid. 

Amyloid can develop within the brain up to 20 years before someone shows symptoms of Alzheimer’s - but new drugs could remove it before it even becomes a problem. 

“They train the immune system to remove that protein amyloid from the brain and therefore slow down that cognitive decline, slow down that risk of functional loss,” Prof Kennelly said. 

While it’s not a cure for Alzheimer’s, Prof Kennelly explained the drugs can clear the risky protein within a year, delaying the chance of developing the condition. 

Risk

Prof Kennelly explained these medicines would be most useful when given in the “very mild stages” of the condition – meaning it won’t work for everyone. 

Side effects of this drug could be “leaky blood vessels” as amyloid is removed – weakening the integrity of blood vessels. 

“For nearly 90% of [people taking the drug on trial], it's asymptomatic,” Prof Kennelly said. 

“But there's about 10% whereby people may get symptoms such as headache, feel nauseous or they'll need to come off the treatment for a period of time.” 

In a study of 1,800 people with early Alzheimer's, those who got Leqembi for 18 months experienced 27% less decline in memory and thinking. 

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