US approves breakthrough drug Leqembi to treat Alzheimer's

The US Food and Drug Administration [FDA] has approved a highly anticipated new drug designed to slow cognitive decline in patients in mild and early stages of Alzheimer's disease.

The FDA approval of the drug, Leqembi, also known as lecanemab, comes on Friday just days after the regulatory agency was harshly criticised in a congressional report for its green-lighting of another Alzheimer's drug, Aduhelm.

It was granted despite the fact that trial results showed the monoclonal antibody treatment carries risks of brain swelling and bleeding.

Both drugs were approved through an accelerated process that allows the FDA to fast-track approval of drugs for serious conditions where there is an unmet medical need.

Leqembi and Aduhelm, which were jointly developed by Japan's Eisai and Biogen of the United States, "represent an important advancement in the ongoing fight to effectively treat Alzheimer's disease," the FDA said in a statement.

"Alzheimer's disease immeasurably incapacitates the lives of those who suffer from it and has devastating effects on their loved ones," Billy Dunn of the FDA's Center for Drug Evaluation and Research said in a statement.

Leqembi, Dunn said, is "the latest therapy to target and affect the underlying disease process of Alzheimer's, instead of only treating the symptoms of the disease."

Approximately 6.5 million Americans suffer from Alzheimer's, which is characterised by memory loss and declining mental acuity.

READ MORE: Alzheimer's drug succeeds in 'slowing' cognitive decline

'Adverse effects'

Preliminary data from a trial of Leqembi was released in September and found it slowed cognitive decline in Alzheimer's patients by 27 percent.

The phase three trial involved nearly 1,800 people, divided between those given the drug and given a placebo, and ran over 18 months.

The complete trial data, published in the New England Journal of Medicine, raised concern about the incidence of "adverse effects" including brain bleeds and swelling.

The results showed that 17.3 percent of patients administered the drug experienced brain bleeds, compared with nine percent of those receiving a placebo.

And 12.6 percent of those taking the drug experienced brain swelling, compared with just 1.7 percent of those in the placebo group.

Deaths were reported at approximately the same rate in both arms of the trial of the drug.

In Alzheimer's disease, two key proteins, tau and amyloid beta, build up into tangles and plaques, known together as aggregates, which cause brain cells to die and lead to brain shrinkage.

Leqembi, which is administered intravenously once every two weeks, works by targeting amyloid.

In the trial, patients receiving Leqembi had a statistically significant reduction in brain amyloid plaque compared to the placebo arm, which had no reduction of amyloid beta plaque.

READ MORE: Can Alzheimer’s be cured?