On 9 September, an international team of researchers published a study in Alzheimer’s & Dementia investigating whether blood biomarkers could make screening for preclinical Alzheimer’s disease more efficient.
The researchers analysed recruitment to the AHEAD 3-45 trial, which is testing lecanemab in cognitively unimpaired people with amyloid pathology. At the beginning of the trial, more than 70% of people undergoing amyloid PET scans were found not to have sufficient amyloid levels to qualify. The team then developed a blood-based prediction approach using measures including the amyloid-beta 42/40 ratio, age and APOE status. The algorithm was subsequently updated to incorporate phosphorylated tau 217 (p-tau217), which improved its ability to identify people likely to have relevant amyloid accumulation. Those considered more likely to be eligible were then referred for confirmatory PET scanning.
As the approach was introduced and refined, the proportion of PET scans resulting in ineligibility fell from 71% to 31%, and eventually to 14%. The researchers also found that p-tau217 was particularly informative for identifying people with higher amyloid burden, while the amyloid-beta 42/40 ratio was more useful for identifying those with low amyloid levels. The approach showed good performance when tested in both AHEAD participants and an independent cohort.
The authors conclude that blood-based screening could reduce unnecessary PET scans and lessen the burden on both participants and research sites, while supporting efficient recruitment into trials targeting Alzheimer’s disease before symptoms develop.
