Overview
- On Tuesday, researchers presented Phase 2 CELIA results showing diranersen reduced brain and spinal fluid tau by about 50 to 65 percent across three intrathecal dosing regimens.
- The 18‑month trial enrolled 416 people with early Alzheimer's and tested 60 mg every 24 weeks, 115 mg every 24 weeks, and 115 mg every 12 weeks delivered by lumbar puncture.
- Clinical benefit was clearest at the lowest 60 mg dose, which slowed decline about 26 percent on the CDR‑SB and showed gains on multiple other cognitive tests, but the study failed its pre‑specified dose‑response primary endpoint.
- Side effects were mostly tied to the lumbar puncture or were short lived and reversible, investigators reported no cases of ARIA that are seen with some anti‑amyloid drugs.
- Biogen will start a single pivotal Phase 3 in 2027 with expected readouts in 2030–2031, and the results have renewed investment and trial activity across other tau‑targeting programs because they offer the first clear proof‑of‑principle that lowering tau can alter disease course.