1st October 2022
New drug slows progression of Alzheimer's
A breakthrough in treating Alzheimer's disease is reported by pharmaceutical companies Eisai and Biogen, using a new drug called lecanemab, designed to remove beta-amyloid proteins from the brain.
Two biotech companies, collaborating on a treatment for early-stage Alzheimer's, have reported positive results from a Phase 3 trial of lecanemab. The new and experimental drug is a humanised version of the mouse antibody mAb158. This had previously been shown to recognise protofibrils – which form the core of amyloid plaques – and to prevent their accumulation in animal models of the disease.
Beta-amyloid plaques are toxic, incorrectly folded proteins, which form in the spaces between nerve cells. Alzheimer's is a progressive disease, which means that over time, more parts of the brain are damaged. It begins with mild problems, such as memory loss, through increasing stages of cognitive decline and ultimately eliminating any possibility of independent living. Fewer than 3% of sufferers live more than 14 years. As of today, around 50 million people worldwide are living with Alzheimer's disease and this number is projected to reach 153 million by 2050.
Tokyo-based Eisai and Cambridge, Massachusetts-based Biogen tested lecanemab on 1,795 patients. Each of these volunteers received a 10 mg dose of the drug every two weeks and had their memory and mental agility tested regularly. The results of this 18-month study showed a clear reduction in beta-amyloid plaques. Compared to a placebo, the speed of cognitive decline slowed by an average of 27%.
Side effects, experienced by a minority of the patients, included headaches and nausea. Eisai and Biogen will present full details in November at the Clinical Trials on Alzheimer's Congress, held in San Francisco. They will also publish their findings in a peer-reviewed medical journal. Phase I of the clinical trials took place from 2010-2012, with Phase 2 from 2013-2021. The ongoing Phase 3 began in 2019 and is scheduled to end in 2024. Eisai plans to file for regulatory approval in Europe, Japan, and the U.S.
"Today's announcement gives patients and their families hope that lecanemab, if approved, can potentially slow the progression of Alzheimer's disease and provide a clinically meaningful impact on cognition and function," said Michel Vounatsos, Chief Executive Officer at Biogen. "Importantly, the study shows that removal of aggregated amyloid beta in the brain is associated with a slowing of disease in patients at the early stage of the disease. As pioneers in neuroscience, we believe defeating this disease will require multiple approaches and treatment options, and we look forward to continuing the discussion about the significance of these findings with the patient, scientific, and medical communities."
Rob Howard, Professor of Old-Age Psychiatry at University College London (UCL), told BBC News: "This is an unambiguously statistically positive result and represents something of an historic moment, when we see the first convincing modification of Alzheimer's disease."
John Hardy, Professor of Neuroscience, also at UCL, described the results as "truly encouraging". The results "look modest but real," he said. "This is clearly not a magic bullet, but it looks like a definite 'end of the beginning'."
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