AAIC 2026 highlighted the transformative role of biomarkers in [Alzheimer's disease](/diseases/alzheimers-disease) (AD) clinical trials, from patient selection to outcome measures and regulatory approval. Biomarker-guided approaches are now essential for efficient trial design and successful therapeutic development.
Biomarker-Based Patient Selection
Amyloid-Positive Enrichment
Selecting patients based on biomarker confirmation[@cummings2024]:
Anti-amyloid trials: Requiring amyloid PET positivity or CSF biomarker evidence
Impact on trial efficiency: Reduced sample sizes and shorter trial durations
Diversity considerations: Ensuring biomarker criteria don't exclude diverse populations
Tau PET Stratification
Utilizing [tau](/proteins/tau) pathology for patient stratification:
Baseline tau burden: Predicting treatment response
Regional tau targeting: Matching patients to specific mechanisms
Tau spread patterns: Identifying therapeutic targets
Blood Biomarker Screening
Revolutionizing trial recruitment:
Pre-screening with [p-Tau217](/biomarkers/p-tau-217)/p-Tau181: Identifying amyloid-positive individuals
Reducing screening failure rates: Up to 70% reduction in screen failures
Cost implications: Significant cost savings in recruitment
Surrogate Endpoints
Amyloid Clearance
Measuring biological effects of anti-amyloid therapies[@mintun2021]:
...
Biomarker-Guided Clinical Trials at AAIC 2026
AAIC 2026 highlighted the transformative role of biomarkers in [Alzheimer's disease](/diseases/alzheimers-disease) (AD) clinical trials, from patient selection to outcome measures and regulatory approval. Biomarker-guided approaches are now essential for efficient trial design and successful therapeutic development.
Biomarker-Based Patient Selection
Amyloid-Positive Enrichment
Selecting patients based on biomarker confirmation[@cummings2024]:
Anti-amyloid trials: Requiring amyloid PET positivity or CSF biomarker evidence
Impact on trial efficiency: Reduced sample sizes and shorter trial durations
Diversity considerations: Ensuring biomarker criteria don't exclude diverse populations
Tau PET Stratification
Utilizing [tau](/proteins/tau) pathology for patient stratification:
Baseline tau burden: Predicting treatment response
Regional tau targeting: Matching patients to specific mechanisms
Tau spread patterns: Identifying therapeutic targets
Blood Biomarker Screening
Revolutionizing trial recruitment:
Pre-screening with [p-Tau217](/biomarkers/p-tau-217)/p-Tau181: Identifying amyloid-positive individuals
Reducing screening failure rates: Up to 70% reduction in screen failures
Cost implications: Significant cost savings in recruitment
Surrogate Endpoints
Amyloid Clearance
Measuring biological effects of anti-amyloid therapies[@mintun2021]:
PET amyloid reduction: Centiloid change as endpoint
CSF biomarker changes: [Aβ42](/proteins/amyloid-beta)/40 ratio normalization
Time course: Relationship between amyloid removal and clinical outcomes
Tau Modification
Emerging tau-focused endpoints:
Tau PET change: Regional tau burden modification
Fluid tau biomarkers: p-Tau changes as surrogate
Neurodegeneration markers: NfL as downstream marker
Neurodegeneration Biomarkers
General markers of disease modification:
Brain atrophy rates: MRI volumetric changes
[Neurofilament light](/biomarkers/neurofilament-light-chain-nfl) chain: NfL as marker of neuronal injury