Biogen reported mixed Phase 2 results for diranersen (BIIB080) on May 14, 2026 and is advancing the tau-targeting Alzheimer's drug to Phase 3 studies. The trial reduced tau levels in spinal fluid and brains of early-stage patients, correlating with slowed cognitive decline, but failed to achieve its primary efficacy goal of a dose response. The lowest dose showed the best results among three escalating regimens tested.
Phase 2 trial results
- ▪Adam Feuerstein is a senior writer and biotech columnist who reports on the crossroads of drug development, business, Wall Street, and biotechnology
- ▪Diranersen targets the protein tau, which is toxic to neurons and is believed to play a role in cognitive decline in Alzheimer's patients
- ▪Biogen investigated three escalating dosing regimens in the Phase 2 study of diranersen
- ▪Biogen reported mixed results on May 14, 2026 from a Phase 2 clinical trial investigating diranersen (BIIB080) for Alzheimer's disease
Tau protein reduction
- ▪Diranersen reduced levels of tau in the spinal fluid and brains of patients with early-stage Alzheimer's in the Phase 2 study
- ▪Tau reductions from diranersen correlated to a slowing of cognitive decline in the Phase 2 study
Dose response failure
- ▪The lowest dose of diranersen showed the best results in the Phase 2 study
- ▪The Phase 2 study of diranersen failed to achieve its primary efficacy goal, which was a dose response
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