Biogen to Advance Tau-Targeting Alzheimer’s Candidate after Mid-Stage Data

Biogen said Thursday it will move its investigational Alzheimer’s therapy diranersen into late-stage trials after mid-stage data showed reductions in tau protein in the brain and indications of slower cognitive deterioration among participants.

The company reported that shares rose roughly 6% in premarket trading following the announcement.

The randomized mid-stage study enrolled 416 people diagnosed with mild cognitive impairment who had not previously undergone anti-amyloid therapy. While diranersen did not meet the trial's pre-specified primary endpoint, Biogen reported reductions in tau levels across all three dose arms tested in the study.

Diranersen is designed to inhibit production of tau, a protein that accumulates in the brains of patients with Alzheimer’s disease and is associated with disrupted neuronal communication. According to the company, study participants also exhibited signs consistent with a slowing of cognitive decline, with the most pronounced clinical effect observed at the lowest dose administered.

Reflecting on the results, Priya Singhal, executive vice president and head of development at Biogen, said, "We believe we have seen an unprecedented and compelling confluence of efficacy and biomarkers results from a tau-directed agent in a randomized early Alzheimer’s disease study."

Singhal added that the dataset gives Biogen sufficient confidence to launch larger, late-stage trials that will be necessary to seek regulatory approval for the drug if those trials are successful.

Although the drug did not reach the trial's primary endpoint, the combination of biomarker reductions and clinical signals led the company to pursue further development. The mid-stage cohort excluded patients who had previously received anti-amyloid therapies, a detail Biogen has highlighted in presenting the results.

This decision initiates a new phase of testing for diranersen centered on larger populations and the confirmatory evidence regulators typically require for approval.

Market reaction: Biogen's stock moved higher in premarket trading after the company disclosed the mid-stage findings and its intent to proceed to late-stage study.