Recognizing Pyroglutamate-Modified Amyloid Plaque
Donanemab binds a modified amyloid epitope specific to established plaque.
- N3pG-Aβ: Target epitope (placeholder — pyroglutamate form)
- IgG1: Antibody class (placeholder — humanized mAb)
- IV infusion: Route (placeholder — monthly dosing)
- High: Plaque specificity (placeholder — mature plaque only)
Antibody-plaque recognition mechanism
Placeholder: donanemab targets pyroglutamate-modified amyloid on plaque surfaces.
Amyloid Plaque Removal Over the Trial Course
Plaque burden falls month over month as antibody exposure accumulates.
- 4 weeks: Dosing interval (placeholder — IV infusion)
- 18 months: Trial duration (placeholder — TRAILBLAZER-style)
- Progressive: Burden decline (placeholder — dose-dependent)
- MRI checks: ARIA monitoring (placeholder — safety surveillance)
Plaque clearance trajectory
Placeholder: microglia-mediated clearance reduces plaque volume over successive visits.
PET-Based Clearance Confirmation
Amyloid PET scans quantify Centiloid burden to confirm clearance.
- Amyloid PET: Imaging modality (placeholder — florbetapir tracer)
- <24.1 CL: Clearance threshold (placeholder — illustrative cutoff)
- Periodic: Scan cadence (placeholder — every few months)
- Centiloid: Readout unit (placeholder — standardized scale)
Interpreting the PET clearance signal
Placeholder: Centiloid values below threshold indicate amyloid-negative status.
Treatment Discontinuation Once Cleared
Dosing is stopped for participants who reach confirmed clearance.
- Threshold-based: Discontinuation rule (placeholder — stop on clearance)
- If burden returns: Re-treatment (placeholder — monitored)
- Limit exposure: Rationale (placeholder — reduce ARIA risk)
- Novel: Design feature (placeholder — vs. fixed dosing)
Fixed-duration dosing design
Placeholder: clearance-triggered discontinuation distinguishes this trial design.
Trial Cognitive Outcome Measurement
Cognitive and functional scales measure whether clearance slows decline.
- iADRS: Primary endpoint (placeholder — integrated scale)
- CDR-SB: Secondary endpoint (placeholder — functional decline)
- vs. placebo: Comparison (placeholder — slowed decline)
- Early AD: Population (placeholder — biomarker-confirmed)
Linking clearance to clinical benefit
Placeholder: cognitive trend compared between cleared and ongoing-decline groups.
Placeholder highlight: amyloid clearance associates with modestly slowed cognitive decline.