A new Cochrane review examined 17 studies involving 20,342 patients with mild cognitive impairment or mild dementia caused by Alzheimer's disease, according to multiple reports. The review found that anti-amyloid drugs, including lecanemab, donanemab, aducanumab, bapineuzumab, crenezumab, and solanezumab, have a trivial or absent impact on cognitive function and dementia severity after 18 months, researchers stated. The clinical effect of these new Alzheimer's drugs is practically meaningless or far below what is needed to be noticeable for patients and caregivers, the researchers added.
Anti-amyloid drugs heighten the risk of serious side effects, including brain swelling and bleeding, according to the research. Lecanemab and donanemab are currently licensed for use in the UK, according to major media reports. However, the treatments were rejected for use on the NHS because the National Institute for Health and Care Excellence ruled their benefits too small to warrant the cost, multiple reports indicate.
An 18-month course of these drugs would cost about £90,000 privately, according to major media. Trials of donanemab and lecanemab showed they could slow the pace of cognitive decline, marking the first time any drug had slowed brain destruction in Alzheimer's disease, according to major media reports. Charities have disputed the review's findings, arguing that experts have attempted to paint an entire class of drugs with the same brush by combining failed drug trials with more recent successful ones, according to major media reports.
Other experts say the review is fundamentally flawed because it unfairly groups older experimental drugs with newer ones proven to work, and differences in how each drug works are important, according to major media reports. Defining meaningful benefit for Alzheimer's patients remains challenging, as there is no consensus on specific clinical thresholds or metrics that determine a noticeable improvement in cognitive function or quality of life, according to experts. Quantifying the risks of brain swelling and bleeding versus the potential cognitive benefits is another unresolved issue, as the review did not provide a detailed comparative analysis, according to researchers.
Alternative research avenues beyond amyloid-targeting drugs are being explored, with promising approaches including targeting brain inflammation, tau protein accumulation, and lifestyle interventions, according to scientific studies. Policy implications are significant, as it remains uncertain whether regulatory bodies or health systems like the NHS will reconsider their decisions on funding these drugs based on this review or future evidence, according to analysts.