Biogen’s diranersen shows benefits in early Alzheimer’s Disease

Biogen (BIIB) announced “compelling” topline results from the Phase 2 CELIA study evaluating diranersen, an investigational antisense oligonucleotide therapy targeting tau, in individuals with early Alzheimer’s disease. The CELIA results provide the first evidence from a randomized Phase 2 study of a tau-directed therapy demonstrating both robust biomarker impact and cognitive benefit in early Alzheimer’s disease. Pre-specified analyses of cognitive endpoints demonstrated slowing of clinical decline across all studied doses, particularly in participants receiving the lowest dose of diranersen, 60 mg administered every 24 weeks. Diranersen also demonstrated robust reductions in both cerebrospinal fluid tau and tau pathology, as measured by positron emission tomography, across all studied doses, with reductions maintained throughout the dosing period. CELIA did not meet its primary endpoint assessing dose response for change from baseline at Week 76. The safety and tolerability profile of diranersen across all studied doses was generally consistent with the Phase 1b study and the known profile of diranersen to date. In Alzheimer’s disease abnormal tau can accumulate and form intracellular tangles that contribute to neurodegeneration and cognitive decline. Diranersen is designed to reduce both extracellular and intracellular tau. In 2025, the FDA granted Fast Track designation to diranersen for the treatment of Alzheimer’s disease. In December 2019, Biogen exercised a license option with Ionis (IONS) and obtained a worldwide, exclusive, royalty-bearing license to develop and commercialize diranersen. Diranersen was discovered by Ionis.