Biogen's tau-targeting Alzheimer's drug shows cognitive slowing in mid-stage trial

Biogen reported results from its mid-stage "Celia" trial testing the experimental tau-targeting antibody BIIB080 in patients with early Alzheimer's disease. The study compared three dose levels of the drug against a placebo over an 18-month period.

Unlike approved amyloid‑targeting therapies such as Eli Lilly's Kisunla and the Biogen/Eisai combination Leqembi, BIIB080 aims to reduce the formation of the tau protein that also contributes to neurodegeneration. Researchers measured cognitive and functional decline using a standard scoring system.

All three dose groups showed statistically significant slowing of decline versus placebo, with the lowest dose achieving the greatest effect-a 26% reduction in the rate of decline. The findings suggest the drug can impact disease progression similarly to existing treatments.

However, the trial raised questions because higher doses did not produce larger benefits, leaving the optimal dosing strategy unclear.