(RTTNews) - Biogen Inc. (BIIB) presented new data from its Phase 2 CELIA study of Diranersen at the Alzheimer's Association International Conference (AAIC) 2026, highlighting meaningful clinical outcomes and strong biomarker responses in patients with early Alzheimer's disease.

Diranersen, an investigational antisense oligonucleotide therapy targeting tau, demonstrated efficacy across all studied doses at 18 months. The 60 mg dose showed the strongest response, slowing cognitive decline by 42% on ADAS-Cog13, 50% on MMSE, and 26% on CDR-SB compared to placebo.

Importantly, Diranersen became the first tau-directed therapy to show robust reductions in both cerebrospinal fluid total tau (50-65%) and brain tau pathology measured by PET imaging.

The therapy works by targeting MAPT mRNA to reduce production of all tau isoforms, lowering both intracellular and extracellular tau protein. These results expand upon earlier topline findings and provide Phase 2 proof of concept for Diranersen's novel mechanism.

Professor Cath Mummery of UCL Queen Square Institute of Neurology noted that the magnitude of tau reduction and cognitive benefit observed in CELIA is among the most compelling reported to date in Alzheimer's disease drug development. Biogen's Head of Development, Dr. Priya Singhal, emphasized that if confirmed in Phase 3, Diranersen could represent an important new therapeutic approach targeting one of the core pathologies of Alzheimer's disease.

Biogen plans to advance Diranersen into confirmatory Phase 3 development, underscoring its commitment to addressing the urgent need for new therapies in Alzheimer's disease.

BIIB has traded between $121.05 and $219.72 over the past year. The stock is currently trading at $194.06, down 7.16%.

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