Alzheimer’s disease: positive results for a drug that reduces cognitive decline

“Lekanemab”. There may be good news behind this name. On Wednesday, scientists welcomed the detailed results of a new drug clinical study confirming its effectiveness in slowing cognitive decline in patients with neurodegenerative Alzheimer’s disease, but also noted its sometimes serious side effects.

The full results of this extended clinical study (Phase III) of nearly 1,800 people followed for 18 months confirmed a 27% reduction in cognitive decline in patients treated with lecanemab, a drug developed by the Japanese pharmaceutical group Eisai and an American company Biogen. This “statistically significant” proportion across the two groups was announced back in late September.

Serious Side Effects

But the full study, published this Wednesday in the New England Journal of Medicine, also indicates the incidence of lekanemab side effects, sometimes serious and markedly more frequent than in the placebo group.

Thus, 17.3% of patients treated with lecanemab suffered from cerebral hemorrhages, compared with 9% in the placebo group. And 12.6% of people who received this experimental drug suffered from cerebral edema, compared with 1.7% in the placebo group. However, the overall mortality rate is almost the same in the two groups of patients in the study (0.7% in people treated with lecanemab, 0.8% in patients treated with placebo).

“This is the first drug that provides a real opportunity to treat people with Alzheimer’s disease,” said Bart de Strooper, director of the UK’s Dementia Research Institute. “While the clinical benefits appear to be somewhat limited, they can be expected to become more apparent if the drug is administered over a longer period of time,” the professor said.

40 million patients

In Alzheimer’s disease, two key proteins – tau and another called beta-amyloid – gradually accumulate abnormally in the brain, causing brain cell death and brain shrinkage.

This causes, among other things, memory loss and a growing inability to perform daily tasks. This disease is a major public health problem affecting more than 40 million people worldwide. Lecanemab acts on beta-amyloid protein deposits, but only in the early stages of Alzheimer’s disease, which may limit its use as the disease is often diagnosed late.