A new amyloid antibody drug has the potential to slow down cognitive decline in Alzheimer’s patients in the early stages of the disease. This is the result of a study now published in the “New England Journal of Medicine”, in which the Central Institute of Mental Health (CIMH) in Mannheim is also involved. The antibody Lecanemab attaches to the protein amyloid-beta in the brain, which is deposited there in the form of so-called plaques. In the treated patients, the process of deposition could be slowed down. The plaques are considered to be a significant characteristic of Alzheimer’s and are one of the causes of the disease. Their exact origin has not yet been fully clarified. 

New era in Alzheimer’s therapy

“Finally, we have a convincingly positive study that no one can question on methodological grounds. This could be the beginning of a new era in Alzheimer’s therapy,” says Prof. Dr. Lutz Frölich, head of the Department of Gerontopsychiatry at the CIMH and co-author of the study. 

The drug Lecanemab is being developed by the companies Biogen and Eisai. For the phase III study, 1,795 people in the early stages of Alzheimer’s disease were included worldwide, eight of them in Mannheim at the CIMH. In this stage of the disease, forgetfulness is at the centre of the symptoms, and those affected are still competent in everyday life. This treatment only makes sense at this stage. Half of the participants received the drug Lecanemab as an intravenous infusion every fortnight for 18 months, the other half received a placebo. 

Disease is slowed down

At the end of the study, it was shown that the course of the disease could be slowed down by 27 percent in the people treated with Lecanemab compared to the control group. The scientists involved consider this to be an important success. The treatment also led to an improvement in the quality of life for the patients and a decrease in the burden for the caregivers. Nevertheless, Frölich qualifies: “Even this drug will not cure the disease, and its long-term effectiveness has yet to be proven.” 

Nor was the treatment without side effects, most commonly infusion reactions (in 26.4 per cent of patients on Lecanemab, in 7.4 per cent on placebo). A specific side effect of Lecanemab and other amyloid antibodies are abnormalities in the imaging – so-called “amyloid-related imaging abnormalities” (ARIA). These show up as small haemorrhages in the brain (ARIA-H) in 17.3 per cent of patients taking Lecanemab and in 9 per cent taking placebo, or as localised brain swelling (ARIA-E) detected in 12.6 per cent and 1.7 per cent of patients. These side effects remain without noticeable symptoms in about three-quarters of patients. 

Further research is necessary, especially the safety of the treatment must be further investigated in longer studies, says Frölich. The drug is expected to receive approval in Europe in 2023.

Alzheimer’s is the most common form of dementia. In this disease, nerve cells and nerve cell contacts gradually perish. Over many years, the disease leads to the need for care and death through forgetfulness, speech and orientation disorders and other extensive cognitive losses. 

Publication: C.H. van Dyck, C.J. Swanson, P. Aisen, R.J. Bateman, C. Chen, M. Gee, M. Kanekiyo, D. Li, L. Reyderman, S. Cohen, L. Froelich, S. Katayama, M. Sabbagh, B. Vellas, D. Watson, S. Dhadda, M. Irizarry, L.D. Kramer, and T. Iwatsubo: Lecanemab in Early Alzheimer’s Disease. N Engl J Med. 2022 Nov 29. doi: 10.1056/NEJMoa2212948.