Biogen Presents Full Phase 2 CELIA Data for Diranersen (BIIB080) at AAIC 2026 on Tuesday July 14 During the Developing Topics in Phase 2 Clinical Trials Session (2:00-3:30 PM BST): The 76-Week Study Did Not Meet Its Primary Endpoint of Dose Response on the Clinical Dementia Rating-Sum of Boxes (CDR-SB), But Strong Tau Pathology Reductions Occurred Across All Three Doses (60 mg q24w, 115 mg q24w, 115 mg q12w) and Prespecified Cognitive Endpoints Showed Slowing of Clinical Decline Across All Doses (Particularly at the Lowest Dose), and Biogen Plans to Advance to Registrational Phase 3 Development
Biogen (NASDAQ: BIIB) presented full Phase 2 CELIA study data for diranersen (BIIB080), an investigational tau-targeting antisense oligonucleotide (ASO) delivered intrathecally, at AAIC 2026 in London on Tuesday July 14, 2026 during the Developing Topics in Phase 2 Clinical Trials Session (2:00-3:30 PM BST). The 76-week placebo-controlled study evaluated three doses (60 mg every 24 weeks, 115 mg every 24 weeks, and 115 mg every 12 weeks) and did not meet its primary endpoint of dose response on the Clinical Dementia Rating-Sum of Boxes (CDR-SB) at Week 76. Strong reductions in tau pathology occurred across all studied doses, generally consistent with the Phase 1b study. Prespecified analyses of cognitive endpoints demonstrated slowing of clinical decline across all doses, with the effect particularly pronounced at the lowest 60 mg q24w dose. Biogen framed the results as the first randomized Phase 2 evidence of a tau-directed therapy showing both biomarker impact and cognitive benefit, and plans to advance diranersen to registrational Phase 3 development.