Cambridge researchers have cast doubt on whether new amyloid immunotherapy drugs will have the desired effect of significantly reducing the impact of Alzheimer's disease. Writing in the journal Alzheimer's & Dementia: The Journal of the Alzheimer's Association , the team from Cambridge Public Health argue that substantial challenges including the risk-benefit ratio, limited eligibility and high cost of roll-out will limit any benefits of these treatments. Alzheimer's disease is often quoted as causing 70% of the 55 million cases of dementia worldwide, though the definition of what constitutes the disease is hotly debated.
One characteristic of Alzheimer's is the build-up of clusters of misfolded proteins, one of these being a form of amyloid, leading to plaques in the brain. The cascade hypothesis, a dominant theory in the field, suggests that this triggers a series of processes which together lead to dementia symptoms. Advances in developing treatments to reduce symptoms and slow down the progression in the early stages of Alzheimer's has been slow.
However, there has been recent excitement surrounding amyloid immunotherapy agents, drugs that harness the immune system to remove amyloid pathology. Two completed phase III randomized controlled trials of amyloid immunotherapy reported statistically significant reductions in the rate of cognitive and functional decline compared to the placebo. But as the Cambridge team point out, the effect sizes were small – small enough that.