Drug Development

Area of Science:

• Neurology
• Biomarkers
• Clinical Trials

Background:

• Alzheimer's disease (AD) has a preclinical phase with biomarker accumulation before cognitive impairment.
• Recruiting for preclinical AD (preAD) trials is difficult due to a lack of triage tools.
• Individuals with subjective cognitive decline (SCD) reporting symptoms but no objective impairment may be a key recruitment pool.

Purpose of the Study:

• To estimate the number of amyloid-positive (Aβ+) individuals aged 50+ with SCD in nine European countries.
• To assess the potential pool of preAD individuals with SCD who seek healthcare professional (HCP) consultation.
• To determine the estimated number of preAD individuals eligible for clinical trials.

Main Methods:

• Applied age-stratified SCD prevalence to UN population data for nine European countries.
• Utilized age-stratified Aβ+ probability estimates from the Amyloid Biomarker Study.
• Incorporated European help-seeking data for SCD symptoms and preAD trial screen-failure criteria.

Main Results:

• Approximately 8.4 million individuals aged 50+ with SCD were estimated to be potentially preAD across nine European countries.
• An estimated 1.5 million preAD individuals with SCD likely consulted an HCP.
• Around 460,000 individuals were estimated to be eligible for preAD clinical trials.

Conclusions:

• Only 5.5% of the estimated 8 million preAD individuals with SCD in Europe are likely identifiable and eligible for trials.
• Future research should include tau pathology and APOE ε4 status in estimates.
• Developing better biomarkers and diagnostic tools is crucial for increasing preAD trial participant identification.