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Key findings
Key findings
- 34% reduction in plasma p-tau217 versus placebo at week 24 (p < 0.001)
- No drug-related serious adverse events across 312 dosed participants
- Cognitive composite (ADAS-Cog13) favored PTX-101 by 1.8 points, not yet significant
- Full 52-week data anticipated Q1 2027; Phase 3 design discussions with FDA planned
PharmatrophiX today announced that PTX-101, its lead p75NTR modulator, met both prespecified primary endpoints in a 24-week interim analysis of the BRIGHT-PATH Phase 2 study in early symptomatic Alzheimer’s disease.
Study design
A biomarker-first Phase 2 in early Alzheimer’s.
BRIGHT-PATH is a randomized, double-blind, placebo-controlled study of PTX-101 in 312 participants with early symptomatic Alzheimer’s disease and confirmed amyloid pathology. Participants were randomized 1:1:1 to PTX-101 40 mg once daily, PTX-101 80 mg once daily, or matching placebo, stratified by baseline MMSE and APOE-ε4 status.
The prespecified interim analysis was conducted after all participants completed the 24-week assessment. The co-primary endpoints were (1) incidence of treatment-related serious adverse events and (2) change from baseline in plasma p-tau217. Cognitive and volumetric MRI measures are secondary endpoints and will be evaluated at the 52-week primary analysis.
Biomarker data
p-tau217 separation emerged by week 12.
Plasma p-tau217 — an emerging blood biomarker tightly correlated with cortical tau burden — decreased in both PTX-101 arms relative to placebo beginning at the week 12 assessment. The effect was dose-responsive, with the 80 mg arm showing a 34% reduction from baseline versus the placebo arm’s 3% reduction (p < 0.001, ANCOVA).
