Is my patient eligible for enrollment in the Trailblazer ALZ2 Alzheimer’s disease trial?

Trailblazer-ALZ 2 Eligibility Assessment

Your patient is eligible for TRAILBLAZER-ALZ 2 enrollment only if they have early symptomatic Alzheimer's disease (mild cognitive impairment or mild dementia) with confirmed amyloid AND tau pathology on PET imaging, are 60-85 years old, and meet strict exclusion criteria that eliminate approximately 75-85% of otherwise eligible patients. 1

Core Eligibility Requirements

The TRAILBLAZER-ALZ 2 trial enrolled participants with the following mandatory criteria 1:

• Age: 60-85 years
• Disease stage: Early symptomatic AD (mild cognitive impairment OR mild dementia)
• Biomarker confirmation:
  • Elevated amyloid on PET imaging
  • Low/medium OR high tau pathology on PET imaging
• Cognitive status: MMSE scores consistent with mild impairment (typically 20-28 range based on trial design)
• Study partner: Must have a qualified study partner who can report on daily cognition and function

Common Exclusion Criteria That Disqualify Most Patients

Real-world data demonstrates that 76-85% of community-dwelling individuals with MCI or early AD are ineligible for trials like TRAILBLAZER-ALZ 2 2. The most frequent disqualifying factors include:

Cardiovascular Exclusions (~35% of patients)

• Active cardiovascular disease
• Recent stroke or TIA
• Uncontrolled hypertension

Medication Exclusions (~31% of patients)

• Anticoagulant use (warfarin, DOACs) - this is a critical exclusion due to ARIA-H (hemorrhage) risk
• Antiplatelet agents beyond aspirin monotherapy in some protocols
• Psychotropic medications (20% of patients)
• Immunological medications

Brain MRI Exclusions (~33% of patients)

• Cerebral small vessel disease (most common imaging exclusion)
• More than 4 cerebral microhemorrhages
• Superficial siderosis
• Prior large territorial infarcts
• Significant white matter disease beyond what's expected

Clinical/Psychiatric Exclusions

• Active depression or anxiety requiring treatment (16% of patients)
• Other neurological conditions affecting cognition
• Lack of adequate social support (16% of patients)

Biomarker Exclusions (~40% of patients)

• Amyloid-negative status - approximately 40% of clinically suspected AD patients are amyloid-negative 2
• Insufficient tau pathology

Critical Pitfalls to Avoid

1. Don't assume clinical diagnosis equals biomarker positivity: Up to 40% of patients with clinical AD syndrome are amyloid-negative and therefore ineligible 2

2. Screen for anticoagulation early: This is a hard stop due to ARIA-related bleeding risk - 24% of donanemab-treated participants developed ARIA-edema/effusion, with 52 symptomatic cases 1

3. MRI screening is essential: One-third of patients are excluded based on brain imaging alone, predominantly due to cerebral small vessel disease that increases hemorrhage risk 2

4. APOE ε4 homozygotes may be excluded: Some protocols (particularly European appropriate use recommendations) exclude APOE ε4/ε4 carriers due to higher ARIA risk 3

Practical Eligibility Algorithm

Step 1: Verify age 60-85 years and early symptomatic disease (MCI or mild dementia, not moderate-severe)

Step 2: Confirm availability of qualified study partner

Step 3: Screen for hard exclusions:

• Anticoagulant use
• Active cardiovascular disease
• Psychotropic/immunological medications

Step 4: Obtain brain MRI to exclude:

• Significant microhemorrhages (>4)
• Superficial siderosis
• Large infarcts
• Severe white matter disease

Step 5: Confirm biomarker status:

• Amyloid PET positive
• Tau PET positive (low/medium or high)

Step 6: Assess MMSE/cognitive testing within trial range

Real-World Applicability

Only 8-15% of community-dwelling individuals with MCI or early AD meet full eligibility criteria for trials like TRAILBLAZER-ALZ 2 2. This severely limits generalizability - the trial excluded 6,504 of 8,240 screened participants, with inadequate amyloid or tau pathology being the predominant reason 4.

The trial demonstrated efficacy (3.25-point difference on iADRS at 76 weeks in low/medium tau population), but three deaths in the donanemab group were considered treatment-related, and symptomatic ARIA occurred in 52 participants 1. This underscores why exclusion criteria are stringent and must be rigorously applied.