Biogen and Eisai announced that data from approximately 7,000 plasma samples from more than 1,800 patients in phase III clinical trials of aducanumab showed a statistically significant correlation between reduced plasma p-tau protein levels and less cognitive decline or functional decline in Alzheimer's disease. Reduced plasma concentrations of p-tau181 protein were also correlated with reduced concentrations of β-amyloid deposits. The predefined analysis of the plasma samples was performed by an independent laboratory and came from two pivotal phase III aducanumab trials, EMERGE and ENGAGE.
The analysis presented here highlights that aducanumab significantly reduced tau protein-associated pathology, a hallmark of Alzheimer's disease, as measured by plasma phosphorylated p-tau181 protein levels compared to placebo. This effect was greater with higher drug doses and longer duration of aducanumab use. Greater reductions in plasma p-tau181 protein levels showed a statistically significant correlation with less cognitive decline and decreased daily functioning in patients taking aducanumab. In addition, the analysis showed a statistically significant correlation between the change in plasma p-tau181 protein levels and the reduction in β-amyloid deposits, indicating an effect of aducanumab on two key factors relevant to the development of Alzheimer's disease.
"We now have robust and consistent data that aducanumab affects the two underlying causes of Alzheimer's disease, as well as substantial evidence of a treatment effect on the correlation between changes in plasma p-tau181 protein levels and slowing disease progression," - said Dr Alfred Sandrock Jr., head of research and development at Biogen.
Results from both phase III studies confirm that aducanumab significantly reduces plasma p-tau181 protein concentrations in a dose- and time-dependent manner compared to placebo. In the EMERGE study, in the high-dose group, p-tau concentrations decreased by 13% from baseline (p<0.001), while concentrations in the placebo group increased by 8%; in the ENGAGE study, in the high-dose group, p-tau concentrations decreased by 16% from baseline (p<0.001), while concentrations in the placebo group increased by 9%.
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