TAC Health Card | Alzheimer’s disease target validation
T layer — Mechanistic evidence
Status: STRONG
BACE1 mediates the rate-limiting cleavage of APP into amyloid-β peptides.
Amyloid accumulation is a central component of the dominant mechanistic hypothesis of Alzheimer’s disease pathogenesis.
Pharmacologic inhibition reliably reduces amyloid production in both preclinical systems and human biomarker studies.
Φ layer — Genetic evidence
Status: WEAK / INDIRECT
Unlike APP and PSEN1, BACE1 lacks strong Mendelian causal mutations linked to Alzheimer’s disease.
Protective APP variants support the amyloid pathway but do not directly validate sustained inhibition of BACE1 as a therapeutic strategy.
Genetic evidence supports the pathway, not the target.
Σ layer — Clinical evidence
Status: NEGATIVE
Multiple late-stage inhibitors failed:
verubecestat
lanabecestat
atabecestat
elenbecestat
Trials showed lack of cognitive improvement and possible worsening outcomes despite biomarker effects.
Alignment topology
TΦΣ
Pattern: mechanistic-only support topology
Decision interpretation
BACE1 represents a canonical example where mechanistic plausibility does not translate into clinical efficacy.
The absence of strong human genetic validation likely contributed to repeated late-stage trial failure.
Cross-layer evidence alignment indicates high translational risk prior to Phase III evaluation.